Search

The Scientific Initiatives Committee (SIC) of the European Heart Rhythm Association is a new venture, which is charged with developing and supporting links between European centres practising in the field of cardiac rhythm management. The committee members are drawn from across Europe (link to homepage). There are many challenges to cross-border research activity, not least of which are language barriers, funding limitations, and conflicting regulatory environments. However, cardiac rhythm management specialists/cardiac electrophysiologists in the European nations share many …

There is significant motion of the heart with each cardiac cycle. We examine the feasibility of harvesting surplus energy (HE) using a catheter-mounted device (CMD) that could be incorporated into a pacemaker/ICD lead and assist powering. The CMD consisted of a pacemaker electrode incorporating a coaxially mounted device with 2 pressure responsive bladders that utilise cardiac pressure (RV/RA) to drive a linear generator. CMD was placed at the RVA of an anesthetized pig (Landrace, 45kg) via the internal jugular vein. Arterial and RV pressure were recorded. The energy generated by the device was continuously monitored using a portable data acquisition system during steady state and then during induced tachycardia (isoproterenol), bradycardia (adenosine) and hypotension (pentobarbital). Placement of the device was uncomplicated. The figure illustrates the effect of 4 mcg isoproterenol on HE from device. In steady state (80 bpm, BP 100/60) the energy generated by each cardiac cycle was 4.3μJ (variance ± 0.8μJ). Incremental changes in heart rate produced a corresponding increase in HE e.g. 104 to 128 bpm produced 140% increase in HE (10.0μJ). Relative bradycardia/hypotension following adenosine/pentobarbitol administration produced a proportionate decrease in HE. Post mortem examination demonstrated no significant endocardial trauma. This study has demonstrated the feasibility of energy harvesting of cardiac motion. The device produced 17% of the energy required to power a conventional pacemaker. With further material modification it is envisaged that HE will be efficient enough to allow for complete and indefinite powering of pacemakers.

This document represents expert consensus concerning the Monitoring of Cardiovascular Implantable Electronic Devices (CIEDs). The views expressed are of the international writing group consisting of seven cardiac electrophysiologists representing the Heart Rhythm Society (HRS), six from the European Heart Rhythm Association (EHRA) as well as one heart failure specialist representing the Heart Failure Society of America and another from the Heart Failure Association of the European Society of Cardiology. Members from our writing group also represented the American College of Cardiology (Kenneth A. Ellenbogen, MD), the European Society of Cardiology (Silvia G. Priori, MD, PhD), and the American Heart Association (David L. Hayes, MD). The topic covered by this document includes the monitoring of CIEDs with a description of the technology, indications for use, personnel involved in monitoring and the frequency and types of monitoring events. Also covered are issues in regard to data management, regulatory environments, reimbursement and ethical considerations in respect to device inactivation. This statement summarizes the opinion of the writing group members based on their own experience in treating patients, as well as a review of the literature, and is directed to all health care professionals, health care institutions, CIED manufacturers and governmental, reimbursement and regulatory bodies who are involved in the care of patients with CIEDs. When using or considering the guidance given in this document, it is important to remember that the ultimate judgment regarding care of a particular patient must be made by the health care provider and patient in light of all the circumstances presented by that patient. INTRODUCTION 708 DEFINITIONS 708 SECTION 1: Description of CIED Technology 709 SECTION 2: Indications, Paradigms, Frequency and Content of CIED Follow-up 710 SECTION 3: Data Management Considerations 713 SECTION 4: Responsibilities and Roles of Personnel 715 SECTION 5: Ethical Considerations 718 SECTION 6: Reimbursement Considerations 721 CONCLUSIONS 722 APPENDICES 722 REFERENCES 724 Cardiovascular implantable electronic …

Aims Paced electrogram fractionation analysis (PEFA) has been assessed for the prediction of sudden cardiac death (SCD) in a large-scale, prospective study of patients with hypertrophic cardiomyopathy (HCM). Methods and results We determined the positive predictive value (PPV) of PEFA in relation to other risk factors for SCD and outcomes in 179 patients with HCM and no prior history of cardiac arrest. Patients were followed over a mean 4.3 years (range: 1.1–6.3 years). Thirteen patients had SCD-equivalent events: four of these patients died suddenly, three were resuscitated from ventricular fibrillation (VF), and six had implantable cardioverter-defibrillator (ICD) discharges in response to VF. PEFA identified nine of these patients and another 14 non-VF patients yielding a censored PPV of between 0.19 and 0.59 that was greater than the PPV that was the formal stopping point of the trial (0.18). Eighty per cent of patients were followed for 4 years or more. The PPV for the identification of SCD in this group was 0.38 (0.17–0.59). The use of two or more conventional markers to predict SCD identified five patients with SCD-equivalent events in the 4-year follow-up group and 42 other patients without events yielding a PPV of 0.106 (confidence limits 0.02–0.15). Conclusion PEFA identifies HCM patients at risk of SCD with greater accuracy than non-invasive techniques and may have an important role in determining indications for ICD prescription.

Before the introduction of computed tomographic (CT) scanning, aortography was the investigation of choice for acute aortic dissection. Between 1978 and 1982, 24 patients were referred to the Brompton Hospital with suspected acute thoracic aortic dissection; all had aortography with diagnosis confirmed at surgery (n = 12) or necropsy (n = 2) or supported by clinical outcome (n = 8). One patient in whom aortography was negative had type B dissection at necropsy and another patient was lost to follow up. CT scanning became available in this unit in 1983 and between 1983 and 1987 was used as the only imaging investigation in 32 patients with suspected acute dissection of the thoracic aorta while in a further 22 patients aortography was used alone. Results were confirmed at surgery (n = 18), necropsy (n = 3), or supported by clinical outcome (n = 31). Two patients were lost to follow up. In an additional 16 patients both aortography and CT scanning were performed with concordant findings in 10. In six in whom the results were discordant, aortography was normal in three in whom subsequent CT scanning showed type B dissection and CT scanning was normal in three patients in whom aortography showed type A dissection. Both CT scanning and aortography are reliable techniques for assessment of suspected acute dissection of the thoracic aorta. Both techniques misdiagnose occasionally and the frequency of misdiagnosis will be minimised by performing both investigations in patients where the level of clinical suspicion is high and the initial investigation negative. CT scanning tends to miss type A dissection and in view of the success of surgery in this condition this failing has the more serious clinical consequences.

Percutaneous transluminal coronary angioplasty may be complicated by the occurrence of major coronary artery dissection, which may precipitate critical myocardial ischemia, necessitating urgent surgical intervention. We report two cases of massive dissection following angioplasty, in which novel methods were used to stabilize arterial integrity. In the first, laser balloon angioplasty was used to repair the dissection; in the other, a coronary stent was inserted. In both cases, coronary artery patency was achieved with reperfusion of the distal coronary bed, thus avoiding the need for acute surgical intervention. Both patients are free of limiting symptoms at follow-up.

We have reviewed the 25 patients who, between 1973 and 1988, presented to the Brompton Hospital in adulthood with persistence of the arterial duct (ductus arteriosus). As pulmonary arteriolar resistance is the main determinant of management and prognosis in this condition, the patients were divided into groups with either normal or mild elevation of resistance (less than 10 units/m2: 19 patients) or with severe elevation (greater than 10 units/m2: 6 patients). Patients with normal pressures or mild elevation tended to be older (mean age 45 years). Many (70%) were asymptomatic, but dyspnoea with signs of left heart failure was the commonest presenting complaint. Surgical closure of the duct was performed in 16 with good result in all. Survival for the entire group, however, was long. There was a symptomatic indication for surgery (due to hyperdynamic circulation) in 5. In those with severely elevated pulmonary arteriolar resistance, the mean age of presentation was 31 years and the survival short. The commonest presenting symptom was dyspnoea. Surgical closure of the duct was attempted in two patients but with a poor outcome in both. All patients with an elevated resistance had developed this complication by the third decade of life. Significant elevation was not a feature of older patients, suggesting that, in this age group, the risk of elevation is slight. Surgery, nonetheless, may be indicated for relief of symptoms due to a large systemic to pulmonary shunt.

Three patients with ischemic heart disease in whom ventricular arrhythmia was thought to be the consequence of acute myocardial ischemia underwent percutaneous transluminal coronary angioplasty. This approach was not consistently successful. The mechanisms of ventricular tachyarrhythmia in ischemic heart disease and the rationale for the treatment of ventricular arrhythmia by revascularization remain unclear. The role of percutaneous transluminal coronary angioplasty needs to be defined in this context.

Hidradenitis suppurativa is a debilitating condition characterized by progressive tissue infection and destruction in the apocrine gland-bearing areas. Advanced cases often require aggressive surgical intervention. This report documents The University of Alabama at Birmingham experience with advanced hidradenitis suppurativa of the vulva and perianus, with particular emphasis on delayed split-thickness skin grafting after radical resection. (J GYNECOL SURG 6:129, 1990)

A surface electrocardiogram (SECG) for pacing threshold measurements during routine implantable cardioverter-defibrillator (ICD) follow-up can be cumbersome. This study evaluated the use of an intrathoracic far-field electrogram (EGM) derived between the Can and superior vena cava (SVC) electrode -- the Leadless electrocardiogram (LLECG), in dual chamber ICDs in performing pacing threshold tests.The LLECG was evaluated prospectively during atrial and ventricular pacing threshold testing as a substudy of the Comparison of Empiric to Physician-Tailored Programming of Implantable Cardioverter-Defibrillators trial (EMPIRIC) in which dual chamber ICDs were implanted in 888 patients. Threshold tests were conducted at 1 volt by decrementing the pulse width. Follow-up at three months compared pacing thresholds measured using LLECG with those using Lead I of the surface ECG (SECG). The timesaving afforded by LLECG was assessed by a questionnaire.The median threshold difference between LLECG and SECG measurements for both atrial (0.00 ms, P = 0.90) and ventricular (0.00 ms, P = 0.34) threshold tests were not significant. Ninety percent of atrial and ventricular threshold differences were bounded by +/- 0.10 ms and -0.10 to +0.04 ms, respectively. We found that 99% of atrial and ventricular thresholds tests at six and 12 months attempted using LLECG were successfully completed. The questionnaire indicated that 65% of healthcare professionals found LLECG to afford at least some timesaving during device follow-ups.Routine follow-up can be performed reliably and expeditiously in dual chamber Medtronic (Minneapolis, MN, USA) ICDs using LLECG alone, resulting in overall timesaving.

The determination of dynamic changes in ventricular repolarization may provide insight into arrhythmogenic mechanisms as a consequence of pacing site. This study investigated acute pacing site effects on global characteristics of electrical restitution using high resolution, non-contact mapping (NCM).Activation-recovery intervals (ARIs) were determined from reconstructed left ventricular electrograms by the NCM system and were analysed during pacing from the right atrial appendage (RAA, intrinsic), right ventricular apex (RVA), and right ventricular septum (RVS) with extrasystoles delivered at intermediate and short coupling intervals in anesthetized swine (n = 5). Electrical restitution curves were determined by the S1-S2 pacing protocol. Activation-recovery interval restitution slopes were determined by the overlapping linear segments regression method. Global distribution of repolarization was defined as the coefficient of variation of the ARIs during restitution. The maximum ARI slopes yielded by RVA pacing were significantly greater than RAA pacing (0.44 vs. 0.32; P0.05) and RVS pacing (0.44 vs. 0.37; P = 0.05). There was no significant difference between RAA and RVS pacing (0.32 vs. 0.37). The global distribution of ARIs during restitution from RVA pacing was significantly greater than RAA pacing (12.0 vs. 8.1%; P0.05).Right ventricular apex pacing is associated with impaired global repolarization patterns compared to RAA and RVS. These observations support the hypothesis that RVA pacing may be associated with increased risk of ventricular arrhythmias compared to RVS pacing.

AIMS: Progressive systemic right ventricular (sRV) dysfunction, atrial and ventricular arrhythmias and sudden cardiac death are well-recognized late sequelae of atrial redirection surgery in which the right ventricle is left connected to the systemic circulation. Although cardiac resynchronization therapy (CRT) poses an attractive therapeutic option, little is known about indications, patient selection, and technical aspects of best lead placement. METHODS AND RESULTS: We undertook CRT in a 27-year-old female patient post-Mustard correction for d-transposition (d-TGA) with New York Heart Association (NYHA) grade III disability with QRS duration measuring 130 ms. There was also echocardiographic (TTE) evidence of severe sRV dysfunction. Non-contact mapping (NCM) was used to define sites of late activation within the sRV and the acute intra-arterial blood pressure (BP) response was assessed during implantation of a 4 french (F) lead onto the endocardial surface of the sRV. At 4 weeks post-implant sRV lateral wall motion had improved and the ejection fraction (EF) rose from 23 to 33%. The patient has been successfully anticoagulated and improved to NYHA II status after 6 months. CONCLUSION: The use of NCM proved safe and effective and provided a qualitative assessment of electrical viability of the sRV complimenting the measurement of mechanical function provided by TTE. The favourable clinical response in the above case justifies a prospective evaluation of this strategy.

Results of well-controlled prospective clinical trials showed the efficacy of lipid-lowering therapies in the reduction of cardiovascular (CV) events in western populations, but they were not reported with a Chinese population. This multicenter study was conducted to determine the effects of Xuezhikang (XZK), a partially purified extract of red yeast rice, on lipoprotein and CV end points in Chinese patients who experienced a previous myocardial infarction. Nearly 5,000 of these patients with average low-density lipoprotein cholesterol levels at baseline were randomly assigned either to placebo or to XZK daily for an average of 4.5 years. The primary end point was a major coronary event that included nonfatal myocardial infarction and death from coronary heart disease. Frequencies of the primary end point were 10.4% in the placebo group and 5.7% in the XZK-treated group, with absolute and relative decreases of 4.7% and 45%, respectively. Treatment with XZK also significantly decreased CV and total mortality by 30% and 33%, the need for coronary revascularization by 1/3, and lowered total and low-density lipoprotein cholesterol and triglycerides, but raised high-density lipoprotein cholesterol levels. In conclusion, long-term therapy with XZK significantly decreased the recurrence of coronary events and the occurrence of new CV events and deaths, improved lipoprotein regulation, and was safe and well tolerated.

Aim To review techniques of implantable cardioverter-defibrillators (ICD) in patients after Mustard surgery for arterial transposition. Methods and results Retrospective analysis of all Mustard patients receiving ICDs at our institution. Five patients (median age 24 years, range 19–35, 3 male) with systemic right ventricular dysfunction (sRV) dysfunction and New York Heart Association (NYHA) II and III, received ICDs. Implantation was performed transvenously in three patients, epicardial patches and subcutaneous arrays at surgery in two patients. Two patients required lead extraction and baffle stent angioplasty before ICD implantation. Defibrillation vectors incorporating the anterior sRV mass [i.e., sub-pulmonary left ventricle (pLV) to generator can, and between epicardial defibrillator patches], consistently achieved a minimum 10 joule(J) safety margin during defibrillation threshold (DFT) testing. Subcutaneous arrays and endocardial vectors that included a superior vena cava (SVC) electrode were less effective. One patient developed pulmonary oedema post-procedure. At a median 20 months, all patients were alive and in NYHA class II. Follow-up over 24 months documented multiple non-sustained ventricular tachycardia (VT) in the group and one patient had recurrent VT with aborted device therapy. Conclusion Defibrillator implantation in Mustard patients is challenging. Sub-optimal defibrillation should be anticipated and can be overcome using vectors which integrate the RV mass and high-energy devices. A staged procedure involving pre-implant interventions or separate DFT tests, where indicated, may be better tolerated by patients.

Background Niacin, the lipid-regulating agent with the longest therapeutic experience, has been demonstrated to both raise high-density lipoprotein cholesterol (HDL-C) levels and to diminish the risk of atherosclerosis and its vascular complications. Objective The present study was carried out to explore niacin's effect on scavenger receptor class B type I (SR-BI)–mediated cholesterol efflux, a component of reverse cholesterol transport, using an in vitro model system. Methods Thirty frozen samples from a large randomized, multicenter trial comparing crystalline niacin, extended-release niacin (Niaspan), and placebo were analyzed for SR-BI efflux. Results Both the extended-release and crystalline niacin demonstrated significant increases in HDL-C (approximately 50%) over baseline values compared to the placebo group (14%). This was associated with a significant increase in SR-BI efflux of 2.7% and 3.4% for extended-release niacin and niacin, respectively, compared to placebo (0.4%). Although, there was no relationship between HDL-C and SR-BI efflux at baseline or at the end of treatment, there was a linear relation between the changes in HDL-C and SR-BI efflux ( r = 0.58, P Conclusion This study suggests that niacin has a beneficial effect on SR-BI efflux that is related to the change in level of HDL-C.

We congratulate Barra et al. on a thoughtful review of implantable cardioverter-defibrillators (ICDs) in the elderly.1 The article is timely given the increasing pressures of caring for an ageing population. It deals well with the issue of survival in elderly ICD recipients and the discussion on cost effectiveness is in line with what we had long suspected. We agree with many of the points raised in this review and would like to make two points: First, the comparison of an octogenarian ICD population with another (e.g. pacemaker) octogenarian ICD population is not valid as it is comparing two distinct entities, one …

Background— The ability to determine spatial and dynamic changes in ventricular repolarization may help to understand arrhythmogenic mechanisms in humans. We hypothesized that noncontact mapping could be used to investigate global activation-repolarization coupling in the human ventricle during steady state and premature extrastimulation. Methods and Results— Activation-recovery intervals (ARIs) determined from reconstructed unipolar electrograms by the Ensite system were analyzed during sinus rhythm, constant pacing, spontaneous ventricular ectopic beats, and premature stimulation at intermediate and short coupling intervals in the left or right ventricle of 13 patients (6 female; mean age, 48 years) without structural myocardial disease. ARIs were measured from 32 sites in each ventricle with the use of a method validated with monophasic action potential recordings and unipolar contact electrograms. Global T-wave distribution was displayed on a 3-dimensional geometry of the ventricle, with polarities opposite to the direction of activation during steady state and premature stimulation. There was a significant inverse correlation between activation times and ARIs during sinus rhythm, ventricular ectopy, and premature stimulation ( r =0.72, slope=−0.76, P P =0.05), but the global pattern of repolarization was preserved. In comparison to our method, the Wyatt method of ARI measurement failed to demonstrate significant coupling between activation and repolarization ( r =0.34, slope=0.19). Conclusions— Global, dynamic repolarization mapping of the human ventricle is feasible. An inverse coupling of activation and repolarization during steady state and premature stimulation may preserve electric stability in the normal ventricle.

The purpose of this randomized study was to determine whether a strategically chosen standardized set of programmable settings is at least as effective as physician-tailored choices, as measured by the shock-related morbidity of implantable cardioverter-defibrillator (ICD) therapy.Programming of ventricular tachyarrhythmia (ventricular tachycardia [VT] or ventricular fibrillation [VF]) detection and therapy for ICDs is complex, requires many choices by highly trained physicians, and directly influences the frequency of shocks and patient morbidity.A total of 900 ICD patients were randomly assigned to standardized (EMPIRIC, n = 445) or physician-tailored (TAILORED, n = 455) VT/VF programming and followed for 1 year.The primary end point was met: the adjusted percentages of both VT/VF (22.3% vs. 28.7%) and supraventricular tachycardia or other non-VT/VF event episodes (11.9% vs. 26.1%) that resulted in a shock were non-inferior and lower in the EMPIRIC arm compared to the TAILORED arm. The time to first all-cause shock was non-inferior in the EMPIRIC arm (hazard ratio = 0.95, 90% confidence interval 0.74 to 1.23, non-inferiority p = 0.0016). The EMPIRIC trial had a significant reduction of patients with 5 or more shocks for all-cause (3.8% vs. 7.0%, p = 0.039) and true VT/VF (0.9% vs. 3.3%, p = 0.018). There were no significant differences in total mortality, syncope, emergency room visits, or unscheduled outpatient visits. Unscheduled hospitalizations occurred significantly less often (p = 0.001) in the EMPIRIC arm.Standardized empiric ICD programming for VT/VF settings is at least as effective as patient-specific, physician-tailored programming, as measured by many clinical outcomes. Simplified and pre-specified ICD programming is possible without an increase in shock-related morbidity.

The evidence base for implantable cardioverter-defibrillator (ICD) therapy requires expansion of guidance/indications to allow UK physicians to treat a broader range of patients. The ICD clinical consultees to the National Institute for Health and Clinical Excellence (NICE) review current guidance/guidelines, explain the evidence base, and suggest a UK ICD implantation strategy.

Ventricular tachycardia (VT) is rarely recognized in patients with congenitally corrected transposition of the great arteries (CCTGA). We describe a 48-year-old woman with CCTGA, systemic atrioventricular valve replacement for Ebsteinoid malformation of the valve, ventricular dysfunction and ventricular tachycardia related to the previous surgical scar. The patient had successful non-contact mapping and radiofrequency ablation of the offending tachycardia substrate.

Combination therapy with a statin and niacin may provide optimal therapy for patients with combined hyperlipidemia and low levels of high-density lipoprotein (HDL) cholesterol. The authors assessed the efficacy and safety of rosuvastatin monotherapy, extended-release (ER) niacin monotherapy, or rosuvastatin and ER niacin combined therapy in patients with atherogenic dyslipidemia. In a 24-week, open-label, multicenter trial, men and women aged > or =18 years with fasting levels of total cholesterol > or =200 mg/dL, HDL cholesterol > or =45 mg/dL, triglycerides 200-800 mg/dL, and apolipoprotein B > or =110 mg/dL were randomly assigned to one of four treatment groups: rosuvastatin 10-40 mg, ER niacin 0.5-2 g, rosuvastatin 40 mg plus ER niacin 0.5-1 g, or rosuvastatin 10 mg plus ER niacin 0.5-2 g. Daily doses of rosuvastatin 40 mg monotherapy reduced low-density lipoprotein (LDL) cholesterol and non-HDL cholesterol levels significantly more than did either ER niacin 2 g monotherapy or rosuvastatin 10 mg combined with ER niacin 2 g. Addition of ER niacin 1 g to rosuvastatin 40 mg did not further reduce total or non-HDL cholesterol. Triglyceride reductions were similar among the four treatment groups. ER niacin mono- and combined therapy produced significantly greater rises in HDL cholesterol and apolipoprotein A-1 than did rosuvastatin monotherapy. Rosuvastatin monotherapy was better tolerated than ER niacin taken either alone or with rosuvastatin. In this study, rosuvastatin very effectively improved the three major lipoprotein-lipid abnormalities of combined hyperlipidemia.

The delivery of implantable cardioverter defibrillator (ICD) therapy is sophisticated and requires the programming of over 100 settings. Physicians tailor these settings with the intention of optimizing ICD therapeutic efficacy, but the usefulness of this approach has not been studied and is unknown. Empiric programming of settings such as anti-tachycardia pacing (ATP) has been demonstrated to be effective, but an empiric approach to programming all VT/VF detection and therapy settings has not been studied. A single standardized empiric programming regimen was developed based on key strategies with the intention of restricting shock delivery to circumstances when it is the only effective and appropriate therapy. The EMPIRIC trial is a worldwide, multi-center, prospective, one-to-one randomized comparison of empiric to physician tailored programming for VT/VF detection and therapy in a broad group of about 900 dual chamber ICD patients. The trial will provide a better understanding of how particular programming strategies impact the quantity of shocks delivered and facilitate optimization of complex ICD programming.

Aims: To evaluate the use of tissue microarray (TMA) technology as a validation tool for HER2 testing by both immunocytochemistry (ICC) and fluorescence in situ hybridisation (FISH) in the diagnostic setting. Methods: TMA constructs from 57 cases of breast cancer were evaluated for HER2 (by ICC and FISH) by two centres. The results were compared. Results: There was a high level of concordance for both ICC and FISH. In five “discrepant” cases only three would have had a potential impact on patient management. Conclusions: Validation of HER2 analysis in the clinical setting by ICC and FISH is essential. The use of TMAs provides for an economy of scale and would be practical in the setting of interlaboratory and intralaboratory validation. It is suggested that routine HER2 ICC and FISH should continue to be performed in laboratories on whole sections. Following this, TMAs would be constructed for all cases of breast cancer. ICC and FISH would be performed on these to validate the results. The TMAs would be available for circulation to other centres for validation purposes. The standardisation of testing between centres, the potential difficulty of minimum case numbers, and the workload issues surrounding validation would all be facilitated by this approach.

Numerous studies have shown that levels of high-density lipoprotein (HDL) cholesterol are inversely related to coronary artery disease risk. The HDL subfractions, however, seem to differ in their capacity to confer protection, with the large HDL2 subfraction appearing to be more important than the small HDL3 subfraction. Lipid-modifying drugs differ in their HDL-raising efficacy, and they also differ in how they affect HDL subfractions. Clinical trials show that raising total HDL cholesterol improves clinical and angiographic outcomes. It remains to be determined, however, whether a shift in distribution of HDL particles provides greater benefit than just an increase in total HDL.

Coronary heart disease (CHD) is a significant cause of morbidity and mortality in older patients. Therefore, its treatment and prevention is vital to improving the length and quality of life for the geriatric population at large. Clinical trial data have demonstrated that patients age 65 and older derive the same benefit from blood cholesterol reduction as younger adults. As a result, the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) recommends appropriate therapeutic lifestyle changes and drug therapy for older individuals with established CHD or for those at high risk for CHD. Drug therapy in this population, while safe, requires careful monitoring and dose adjustment due to potentially altered drug metabolism and concomitant medications. These factors lead to use of lower starting doses of lipid-lowering medications in older patients. Prudent individualized evaluation and customized therapy provide optimal cardiovascular outcomes.

The efficacy of extended-release niacin (niacin ER) on lipoprotein subclasses was evaluated in patients with primary hypercholesterolemia using a proton nuclear magnetic resonance method. Paired plasma samples collected at baseline and after 12 weeks' treatment with niacin ER 1,000 (n = 21) or 2,000 (n = 20) mg/day or placebo (n = 19) were available for 60 eligible patients from a previous multicenter, randomized, controlled trial. Niacin ER increased high-density lipoprotein (HDL) cholesterol and decreased low-density lipoprotein (LDL) cholesterol and very low-density lipoprotein triglycerides in a dose-dependent manner relative to placebo. Niacin ER increased large HDL particles (H5 and H4, corresponding to the HDL(2ab) fraction) without having a net effect on small HDL particles (H3, H2, and H1, corresponding to the HDL(3abc) fraction). It also decreased smaller, denser LDL particles (L1 and L2) and increased the larger, more buoyant L3 subclass. The inhibitory effect of niacin ER on very low-density lipoprotein was evident on the larger particles (V6, V5, V4, and V3 subclasses) rather than the smaller ones (V2 and V1). The results show that niacin ER produces a beneficial effect on lipoprotein subclasses, specifically decreasing the more atherogenic small, dense LDL particles and enhancing the cardioprotective large HDL particles.

The potential clinical value of implantable devices, for both diagnostic and therapeutic uses in cardiology practice, has increased greatly with technical innovation. This coupled with an increased recipient population size (as the population ages) and increased referral rates (as that population and its healthcarers are educated), has increased the demand for such devices and the associated economic burden is impacting on healthcare resources. Although there is a commonality of approach to clinical practice in Europe, aided by the publication of European guidelines, the implementation of these is hindered by the need to overcome national obstacles, particularly for new indications for established therapies and for innovative therapies. Cost efficacy assessments and evidence-based medicine are blurred and used as rationing tools. National inequalities and disparate healthcare systems will become divisive in a European theatre that is otherwise seeing greater political and economic integration. There needs to be a mature and honest debate on how to bring the benefits of implantable device medical technology to the patient population which will benefit.

Current guidelines recommend the use of cardiac resynchronisation therapy (CRT) where ejection fraction (LVEF) is under 35%, QRS duration is over 130 ms and the patients symptoms put them in New York Heart Association (NYHA) class III or IV after appropriate medical therapy [1]. These criteria follow scientific scrutiny of CRT by biventricular pacing for moderate to severe congestive heart failure (CHF) with interventricular conduction delay [2–6]. Implantable cardioverter defibrillators (ICD) are established as the treatment of choice for primary [7–9] and secondary [10–12] prevention of life threatening ventricular arrhythmias, particularly in ischaemic heart disease. Application of internationally recognised guidelines [1] for their usage would lead to implantation rates of over 100 per million per year and extension to include the most recent evidence [9] over 200 per million per year [13]. The majority of ICD and all CRT recipients have left ventricular impairment [1]. There is, therefore, a significant overlap in indications for the two devices. ICDs capable of delivering CRT (CRT-ICD) have been commercially available for several years. CHF and conduction delay are progressive conditions, it is inevitable that a number of individuals implanted with ICD will develop CRT indications during the lifetime of their device. Identification of those most likely to progress would allow the implantation of CRT-ICD in those patients in whom only ICD were indicated at the time of insertion.

Previous mapping studies of sinus rhythm suggest faster rates arise from more cranial sites within the lateral right atrium. In the intact, beating heart, mapping has been limited to epicardial plaques or single endocardial catheters. The present study was designed to examine shifts in the site of the earliest endocardial depolarization during sinus rhythm and sinus tachycardia using high density activation mapping. Noncontact mapping of the right atrium during sinus rhythm was performed on ten anesthetized swine. Recordings were made during sinus rhythm, phenylephrine infusion, and isoproterenol infusion. The hearts were then excised and the histological sinus node identified. The mean minimum and maximum cycle lengths recorded were 355 +/- 43 and 717 +/- 108 ms. A median of three (range two to five) sites of earliest endocardial depolarization were documented in each animal. With increasing heart rate the site of earliest endocardial depolarization remained stationary until a sudden shift in a cranial or caudal direction, often to sites beyond the histological sinoatrial node. The endocardial shift was unpredictable with considerable variation between animals; however, faster rates arose from more cranial sites (r = 0.46, P = 0.023). There was no difference in the mean cycle length of sinus rhythm originating from specific positions on the terminal crest (r = 0.44, P = 0.17). Cranial sites displayed a more diffuse pattern of early depolarization than caudal sites. In the porcine heart the relationship between heart rate and site of earliest endocardial depolarization shows considerable variation between individual animals. These findings may have implications for clinical mapping and ablation procedures.

Background: Implantable loop recorders (ILR) are a valuable tool in the investigation of syncope and compare favourably with non-invasive and intracardiac electrophysiological assessment of bradycardia. They are known to detect tachyarrhythmias but have not been shown to add to the diagnostic yield of electrophysiological testing in symptomatic patients. Methods: We prospectively studied the first 41 patients (aged 48±19 years) in whom ILR were used at our institution after negative electrophysiological studies (EPS). All patients were symptomatic with palpitations (11), syncope (22) or both (8). Nine patients had known structural heart disease (two ischaemic, four cardiomyopathy, two valvular and one congenital). Patients were assessed according to demographic factors, symptoms and investigations. Loop recordings were analysed and assessed according to conventional criteria. Results: Among 41 patients in whom electrophysiological studies had failed to demonstrate arrhythmias, six were found to have clinically significant tachyarrhythmias (four ventricular and two supraventricular). Conclusion: ILR diagnose prognostically significant tachyarrhythmias in symptomatic patients with negative electrophysiological studies.

Double Potentials in Cavotricuspid Isthmus Block. Introduction: A novel mapping/ablation catheter using a coaxially ablation electrode (E) that is moveable between distal and proximal ring electrodes along its shaft was used to create a linear lesion over the cavotricuspid isthmus (CTI) and bidirectional block in 32 patients (21 men; age 38–79 years) undergoing ablation for counterclockwise atrial flutter. Methods and Results: Two bipolar electrograms (E1 and E2) were recorded: between E and the distal ring electrode and between E and the proximal ring electrode. Interpole distance varied for both as the E traversed the slide shaft. Given the catheter's concept, these bipoles are orientated exactly along the line of lesion creation. Prior to ablation, unitary bipolar electrograms were recorded along the catheter slide shaft position. As the CTI lesion was created (E moved along the catheter slide shaft in 2-mm steps with radiofrequency energy delivered to achieve 65°C for 60 sec at each), double potentials (DP) were observed. Interpotential distance became maximal with completion of the linear lesion and bidirectional block. DPs were noted in all these procedures. With pacing from the low septal right atrium at bidirectional block creation, interpotential timing was140.9 ± 15 msecand from the low right atrial free wall was145.13 ± 18 msec.In sinus rhythm, DP interpotential timing was less(35.13 ± 9 msec)as activation fronts arrived from both septal and anterior atrial aspects. Conclusion: Bipolar recordings from the coaxially moveable electrode catheter provide unique electrogram data. DPs recorded during and after linear lesion creation can define conduction block across that lesion without the need for additional mapping catheters or complex mapping technology.

Late enhancement cardiac magnetic resonance images (MRI) has the ability to precisely delineate myocardial scars. We present a semi-automated method for detecting scars in cardiac MRI. This model has the potential to improve routine clinical practice since quantification is not currently offered due to time constraints. A first segmentation step was developed for extracting the target regions for potential scar and determining pre-candidate objects. Pattern recognition methods are then applied to the segmented images in order to detect the position of the myocardial scar. The database of late gadolinium enhancement (LE) cardiac MR images consists of 111 blocks of images acquired from 63 patients at the University Hospital Southampton NHS Foundation Trust (UK). At least one scar was present for each patient, and all the scars were manually annotated by an expert. A group of images (around one third of the entire set) was used for training the system which was subsequently tested on all the remaining images. Four different classifiers were trained (Support Vector Machine (SVM), k-nearest neighbor (KNN), Bayesian and feed-forward neural network) and their performance was evaluated by using Free response Receiver Operating Characteristic (FROC) analysis. Feature selection was implemented for analyzing the importance of the various features. The segmentation method proposed allowed the region affected by the scar to be extracted correctly in 96% of the blocks of images. The SVM was shown to be the best classifier for our task, and our system reached an overall sensitivity of 80% with less than 7 false positives per patient. The method we present provides an effective tool for detection of scars on cardiac MRI. This may be of value in clinical practice by permitting routine reporting of scar quantification.

Introduction: Previous mapping studies of right atrial (RA) activation during sinus rhythm have been limited by the use of epicardial electrode plaques in open chest subjects or microelectrodes in the excised heart. This study describes global RA endocardial activation patterns using high-density mapping and compares the results with underlying endocardial architecture. Methods and Results: Noncontact mapping of the RA was performed in 21 anesthetized swine. Isopotential and isochronal maps were superimposed upon three-dimensional reconstructions of RA geometry. Hearts were excised and endocardial dissection performed. Two patterns of RA activation were recorded. The site of earliest endocardial activation occurred either laterally at a position consistent with the terminal crest or superiorly at the junction between the superior caval vein and RA appendage. The subsequent spread of depolarization followed the longitudinal orientation of muscle fibers. Areas of conduction delay and block were seen at the junction between the terminal crest and posterior wall, the cavotricuspid isthmus, and around the margins of the triangle of Koch. Endocardial dissection at these sites demonstrated complex fiber orientation. A lateral site of earliest activation demonstrated a more prominent display of conduction delay or block. Conclusion: The spread of the sinus impulse follows endocardial myofiber orientation and is dictated by the site of earliest activation. Even during sinus rhythm, anisotropic conduction results in areas of conduction block or delay. These findings have implications in the development of reentrant arrhythmias and may influence surgical or electrophysiologic procedures.

Serum components, such as lipoproteins, coagulation factors (factor VII, tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), fibrinogen), and homocysteine have been associated with cardiovascular disease. Dietary intervention with a low-fat, low-cholesterol diet has favorably influenced cardiovascular disease and certain food, specifically the consumption of nuts, has been associated with reduced cardiovascular risks. The effects of walnuts, as part of a low-fat, low-cholesterol diet, on serum cardiovascular risk factors were determined. Sixty-seven (67) outpatients with borderline high total cholesterol following a low-fat, low-cholesterol diet for six weeks before being randomly assigned to continue the diet or have 64 grams/day of walnuts in conjunction with the diet. After six weeks, the patients’ diets were switched. Therefore, all patients consumed 64 grams/day of walnuts for six weeks during part of the trial as part of a low-fat, low cholesterol diet. Serum lipids demonstrated a significant reduction in triacyglycerols and favorable trend with decreases in total cholesterol, low-density lipoprotein (LDL) cholesterol, and a slight increase in high-density lipoprotein (HDL) cholesterol. No statistical effects on homocysteine or the coagulation factors were observed. However, there was a slight favorable trend for tPA and PAI-1. This study demonstrated that walnuts, when consumed as part of a low fat, low-cholesterol diet, have a beneficial effect on serum cardiovascular risk factors. However, these changes may not explain all of the beneficial effects that walnut consumption has on cardiovascular disease.

Ventricular arrhythmia management can present a difficult clinical challenge. A proportion of the presenting population will be at high risk of sudden cardiac death (SCD). Little or no protection against SCD is afforded by simple prescription of drug treatment.1,2 Antiarrhythmic drugs may be proarrhythmic and prescribed without secure understanding of drug effect. Though many ventricular arrhythmias are dangerous, the spectrum of risk ranges from the immediately life threatening to very benign (for example, from ventricular fibrillation through to true right ventricular outflow tract tachycardia). Generating the range of ventricular arrhythmias are diverse disease processes and understanding of the relation between witnessed arrhythmia and underlying disease process is often incomplete. There is debate over whether right ventricular outflow tract tachycardia overlaps with right ventricular cardiomyopathy—the one being a “benign” arrhythmia whose disease process is not understood, the other being a disease process whose principal manifestation is “malignant” arrhythmia.3,4 A parallel management challenge to ventricular arrhythmia control is the prevention of SCD in patients with no previous symptomatic ventricular arrhythmia but who are at high risk. SCD may have non-arrhythmia causes, but evidence strongly suggests that many or even most patients suffering or rescued from SCD have ventricular arrhythmia as the index event.5 Depending on the clinical scenario, the approach to the management of the phenomenon of SCD includes risk stratification, family screening, genetic analysis, and prophylactic therapeutic strategies in addition to the management of an SCD survivor (fig 1). Figure 1 An example of delivery of implantable cardioverter-defibrillator (ICD) shock therapy. The device senses ventricular electrograms. This sensed electrical activity satisfies the criteria of the device’s detection algorithm and a 34 J shock is delivered (thick arrow). This returns the patient to (initially) a ventricular paced rhythm with normal sinus rhythm following shortly. The electrophysiology specialist has the …

To ensure the accuracy and reproducibility of immunohistochemical assays for determining HER2/neu status of patients with breast cancer, a reliable standard for monitoring assay sensitivity is necessary. We optimally fixed and paraffin processed human ovarian and breast carcinoma cell lines SKOV-3, MDAMB-453, BT-20, and MCF-7 in quantities sufficient to meet the needs of a laboratory for the foreseeable future. The material was tested, alongside HercepTest kit cell lines (DAKO, Carpinteria, CA), by 7 breast cancer centers in the United Kingdom and France with different immunohistochemical assays and markers. The cell lines also were analyzed by fluorescence in situ hybridization (FISH) by 2 centers using HER-2/ neu kits. FISH produced 100% agreement between the 2 centers: SKOV-3 and MDA-MB-453 showed HER-2/neu amplification and BT-20 and MCF-7 did not. Immunohistochemical analysis and a common evaluation method produced 100% agreement that SKOV-3 and MCF-7 showed 3+ and zero HER-2/neu overexpression, respectively. For MDA-MB-453, there was 71% (5/7) concordance of 2+ immunohistochemical staining and 86% (6/7) concordance of zero or 1+ staining for BT-20. The cell lines provide a valuable standard for gauging HER-2/neu assay sensitivity irrespective of the antibody, antigen retrieval system, detection system, or method of evaluation used. Clinical trials have shown the potential benefits of Herceptin (trastuzumab) therapy for patients with invasive breast carcinomas that overexpress the HER-2/neu protein. 1-3 The HER-2/neu gene codes for a membrane surface protein related to epidermal growth factor receptor. Each of the surface receptors in this family has a closely associated intracellular tyrosine kinase that is activated when the receptors bind to their respective ligands, in turn activating other intracellular signals that ultimately are transmitted to the cell nucleus, resulting in the transcription of genes involved in controlling cellular replication and differentiation. 4 Trastuzumab therapy, consisting of a humanized monoclonal antibody, targets the HER-2/neu antigen and inhibits the growth of HER-2/neu–overexpressing tumor cells. To identify the 20% to 30% of women with breast cancer that will benefit most from trastuzumab therapy, a reliable and reproducible assay is required to detect HER-2/neu overexpression. 5-7 Two main test types have evolved: those directed at detecting amplification of the HER-2/neu gene by fluorescence in situ hybridization (FISH) and those directed at detecting overexpression of the HER-2/neu protein by immunohistochemical analysis. 4,8-11 Both test types have the advantage of allowing evaluation of gene amplification (FISH) or protein overexpression (immunohistochemical analysis) in relation to tumor morphologic features, unlike molecular techniques that require homogenization of the tumor. 9,12

INTRODUCTION: Transcatheter Left Atrial Electrical Disconnection. An effective, catheter-based treatment for persistent atrial fibrillation (AF) remains elusive. This study assessed the feasibility of transcatheter left atrial (LA) electrical disconnection and its effect on AF inducibility. METHOD AND RESULTS: Thirteen anesthetized swine underwent noncontact mapping of the right atrium (RA) during coronary sinus (CS) pacing. Sites of earliest RA activation were identified using isopotential maps. An ablation catheter was navigated to these sites and a cluster of radiofrequency (RF) lesions applied until earliest activation shifted to a new site. The procedure was repeated until the atria were electrically disconnected. AF induction was attempted before and after ablation. Earliest RA activation was the CS os during proximal CS pacing and Bachmann's bundle during distal CS pacing. These two sites were successfully ablated in all 13 animals. Earliest activation then shifted to the fossa ovalis. RF energy was applied at a median of 2.5 sites (range 1 to 5) around the fossa, then at sites in the triangle of Koch, septum, cavotricuspid isthmus, and posterior wall. Atrial electrical disconnection was achieved in 10 of 13 animals (5 LA electrical disconnection, 3 RA electrical disconnection, 2 biatrial electrical disconnection with complete heart block). After atrial electrical disconnection, the LA became electrically silent. Before ablation, AF was inducible in every animal. After atrial electrical disconnection, AF was inducible in 3 of 10 animals. CONCLUSION: Atrial electrical disconnection is feasible using noncontact mapping and RF ablation. Successful electrical disconnection of the atria reduces AF inducibility. This approach is worthy of further evaluation as a management strategy for persistent AF, combined with device therapies.

Introduction Ambulatory cardiac monitoring devices and the novel subcutaneous ICD (SICD) sensing algorithms are based on the surface electrocardiograms (ECGs) parameters for detection and discrimination of arrhythmias. However the impact of posture, cardiac morphologies (normal and congenital heart diseases), and electrode placement on these parameters are not known. Aim To determine the impact of posture (standing, sitting, supine, left lateral, right lateral) and bipolar electrode location (LI, LII, LIII), cardiac morphologies (normal, TOF, TGA, SVP) and gender on R-wave amplitude, T-wave amplitude, R/T ratio, QRS, QTc, Tpeak-end duration. Method 720 bipolar vectors were collected in a set of three lead (LI, LII, LIII) transcutaneous ECGs at gain 10, at a speed 25mm/sec from three location of SICD sensing arrays in 6 postures from 40 patients including 10 normal controls, 10TOF, 10 SVP, 10 TGA. The ECGs were digitally measured and analysed using repeated-measures ANOVA and Post hoc Helmert contrast pair wise analysis with Bonferroni adjustment. A p value of less than 0.05 was considered significant. Results The mean R-wave amplitude was significantly smaller in LI than LIII (p = 0.025), and right lateral posture in comparison to left lateral posture (p = 0.02). The T-wave amplitude in individuals with TOF was significantly greater than individuals with normal cardiac morphology (p = 0.013) and SVP (p = 0.005). The mean QRS duration in individuals with normal cardiac morphology was significantly smaller than individuals with TOF (p = 0.0001) and SVP (p = 0.006). Also the mean QRS duration in female was significantly smaller than male (p = 0.03). There were no statistically significant differences in the mean R/T ratio, QTc interval, Tpeak-end duration between subgroups, six postures and three lead (p > 0.05). Conclusion Postures, electrodes location and cardiac morphologies have impact on the surface ECG morphological components which may have to be considered while designing sensing algorithm of monitoring devices and specifically SICD.

A 63-year-old male with dilated cardiomyopathy underwent implantation of a "heart failure" defibrillator capable of biventricular pacing. He received an inappropriate shock 5 hours after the procedure. Stored electrograms revealed that during each sinus beat the ventricular channel recorded up to three separate events. These resulted from far-field atrial sensing by the coronary venous lead, appropriate right ventricular sensing, then delayed left ventricular sensing (the result of left bundle branch block). As a consequence of far-field left atrial sensing the two subsequent ventricular electrograms fell within the VF zone. Following an atrial premature beat, VF detection criteria were satisfied and shock therapy delivered. Although coronary venous lead repositioning eliminated far-field atrial sensing, double counting of the widely split right and left ventricular electrograms still occurred during sinus rhythm. Shortening the programmed AV delay resulted in constant biventricular pacing with a single electrogram.

Pediatric patients undergoing electrophysiology procedures are a heterogeneous group, ranging from small children with structurally normal hearts and WPW syndrome, to young adults with congenital heart disease who have undergone extensive palliative surgery and have multiple complex arrhythmias. For over a decade radiofrequency ablation has been an effective therapy for “simpler” arrhythmias such as atrioventricular reentry tachycardias, which account for 60–82% of pediatric ablation procedures.1–3 Conventional mapping and ablation techniques abolish accessory pathways with long term success rates of 83–98%.2–7 Radiofrequency ablation of focal atrial tachycardias (a minority of patients) is less successful, with higher recurrence rates.1–3 Pediatric patients with idiopathic ventricular tachycardia have also been successfully ablated.8

Haemodialysis (HD) patients are at increased risk of vascular access complications with device therapy. We report a case of transvenous defibrillator lead extraction from the ipsilateral side as an HD fistula. The procedure was successfully performed using a hybrid approach, with extraction of the lead with a powered sheath, and surgical cut-down and closure of the subclavian vein defect.

Background —Atrial tachyarrhythmias are a complication of Fontan surgery. Conventional electrophysiological mapping and ablation techniques are limited by the complex anatomic and surgical substrate and a high arrhythmia recurrence rate. This study investigates the use of noncontact mapping to identify arrhythmia circuits and guide ablation in Fontan patients. Methods and Results —Eleven arrhythmias were recorded in 6 patients. Noncontact mapping improved recognition of the anatomic and surgical substrate and identified exit sites from zones of slow conduction in all clinical arrhythmias. Radiofrequency linear lesions were targeted across these critical zones in 5 patients. One patient underwent surgical cryotherapy. Although immediate success was achieved in 3 of 5 patients with radiofrequency ablation, 2 patients had a recurrence after a mean of 6.4 months of follow-up. The patient who underwent cryoablation remains free of arrhythmias. Conclusions —Noncontact mapping can identify arrhythmia circuits in the Fontan atrium and guide placement of ablation lesions. Arrhythmia recurrence is high, possibly because of inadequate lesion creation rather than inaccurate mapping and lesion targeting.

This study compares the effect of plant stanol ester spread with a placebo spread on cholesterol in patients taking statin therapy, but who still had elevated low-density lipoprotein (LDL) cholesterol. This was a randomized, double-blind, placebo-controlled clinical trial, with 67 women and 100 men with LDL cholesterol/=130 mg/dl and triglycerides/=350 mg/dl who had been taking a stable dose of a statin drug for at least 90 days before the start of the study. For 8 weeks, participants consumed 3 servings/day of the plant stanol ester spread that provided 5.1 g/day of plant stanol ester or a placebo. The addition of plant stanol ester spread significantly reduced total cholesterol and LDL cholesterol at 2, 4, and 8 weeks when compared with placebo spread. Plant stanol ester spread reduced total cholesterol at 8 weeks by 12% compared with a placebo reduction of 5% (-7% difference; p0.0001). Plant stanol ester spread reduced LDL cholesterol at 8 weeks by 17% compared with a 7% reduction in the placebo group (-10% difference, p0.0001). The absolute reduction in LDL cholesterol at 8 weeks was 24 and 10 mg/dl in the stanol ester and placebo groups, respectively. The plant stanol ester spread group also had greater reductions in both serum total cholesterol and LDL cholesterol than the placebo group at 2 and 4 weeks (p0.001 for all comparisons). Both spreads were well tolerated by study participants, and no significant adverse events were noted. Consumption of spread that provided 5.1 g/day of plant stanol esters effectively reduced elevated total and LDL cholesterol levels in participants on a stable regimen of a statin.

Although it is generally assumed that defibrillation becomes more difficult when the duration of VF is prolonged, after a failed defibrillation attempt, there is little information on the defibrillation efficacy of multiple shocks delivered at the same energy. The purpose of this study was to systematically examine the efficacy of a second shock delivered at the same or reversed polarity after a failed first shock. Defibrillation was attempted after 10 seconds of VF in 12 pigs (30-56 kg) using biphasic waveforms and a nonthoracotomy lead system. Shock energy was held constant for the first and second shocks at 50%-90% of the DFT. The second shock was delivered 10 seconds after a failed first shock. First and second shock polarity (first phase) was randomized to (+, +), (+, -), (-, -), (-, +). The incidence of successful defibrillation (for all polarities) was 12.3% for first and 49.1% for second shocks (P < 0.0001). Anodal first shocks had a 17.2% incidence of success as opposed to a 7.4% incidence of success with cathodal first shocks (P = 0.001). Anodal second shocks had a 55.5% incidence of success compared to a 42.7% incidence of success with cathodal second shocks (P = 0.008). There was no significant benefit from polarity reversal after a failed first shock (P = 0.29). In conclusion, less energy is required for successful defibrillation by a second shock after a failed first. The optimal configuration for first and second shocks is with the RV as anode. Polarity reversal of a second shock after a failed first does not affect the probability of second shock success.

Coaxially Moveable Ablation Catheter. Introduction: Use of a novel ablation catheter for the creation of linear transmural endocardial lesions, which uses a coaxially moving ablation electrode mounted on the terminal portion of a catheter shaft and able to move axially for a distance of up to 4 cm. is reported. Methods and Results: The coaxially moving ablation electrode is moved by a sliding mechanism in the catheter handle. The distal portion of the catheter shaft is steerable. Bipolar or unipolar electrograms can be recorded from electrodes on the catheter tip and the coaxially moving ablation. Radiofrequency (RF) current is delivered to the coaxially moving ablation electrode with thermocouple temperature control. This ablation catheter was evaluated in five (30 to 65 kg) anesthetized pigs and introduced via the venous/arterial systems into the right and left atrium (1 lesion) (using the retrograde aortic approach). The catheter was maneuvered to bring the slide range into apposition with atrial endocardium. The coaxially moving ablation electrode was deployed to the terminal portion of the catheter's slide range and then withdrawn in 2-mm steps. RF current was delivered to the coaxially moving ablation electrode at each point (maximum temperature 70° C), Postmortem examination of eight endocardial linear lesions (2.2 to 4.1 cm length) was made 1 to 3 hours after creation. Histopathologic examination confirmed transmural myocyte necrosis along the length of the lesion, that included the trabeculated right atrium. Conclusion: We conclude that a catheter using a moveable electrode creates continuous linear transmural lesions and could find clinical application in the therapy of a variety of reentry tachycardia mechanisms.