Search

Background Cardiac implanted electronic devices (CIEDs) can detect short durations of previously unrecognised atrial fibrillation (AF). The prognostic significance of device-detected subclinical AF, in the context of contemporary heart failure (HF) therapy, is unclear. Methods Amongst patients enrolled in the Remote Monitoring in HF with implanted devices (REM-HF) trial, three categories were defined based on total AF duration in the first year of follow-up: no AF, subclinical AF (≥6 min to ≤24 h), and AF >24 h. All-cause mortality, stroke, and cardiovascular hospitalisation were assessed. Results 1561 patients (94.6%) had rhythm data: 71 (4.6%) had subclinical AF (median of 4 episodes, total duration 3.1 h) and 279 (17.9%) had AF >24 h. During 2.8 ± 0.8 years' follow-up, 39 (2.5%) patients had a stroke. Stroke rate was highest amongst patients with subclinical AF (2.0 per 100-person years) versus no AF or AF >24 h (0.8 and 1.0 per 100-person years, respectively). In the overall cohort, AF >24 h was not an independent predictor of stroke. However, amongst patients with no history of AF (n = 932), new-onset subclinical AF conferred a three-fold higher stroke risk (adjusted HR 3.35, 95%CI 1.15–9.77, p = 0.027). AF >24 h was associated with more frequent emergency cardiovascular hospitalisation (adjusted HR 1.46, 95%CI 1.19–1.79, p Conclusions In patients with HF and a CIED, subclinical AF was infrequent but, as a new finding, was associated with an increased risk of stroke. Anticoagulation remains an important consideration in this population, particularly when the clinical profile indicates a high stroke risk.

Among different cardiac arrhythmias, Ventricular Arrhythmias (VA) are fatal and life-threatening. Therefore, the detection and classification of VA is crucial task for cardiologists. However, in some cases, the ECG morphologies of two kinds of VA - Ventricular Tachycardia (VT) and Ventricular Fibrillation (VF) are similar and difficult to distinguish by human eyes. In this study, we present a low computational complexity arrhythmia classifier with high accuracy based on Phase Space Reconstruction (PSR). It is used to classify normal electrocardiogram (ECG), atrial fibrillation (AF), VT, VF and VT followed by VF. The Creighton University Ventricular Tachyarrhythmia Database (CUDB), Physikalisch-Technische Bundesanstalt Diagnostic Database (PTBDB), MIT-BIH Atrial Fibrillation Database (MIT-BIH AFDB) from PhysioNet databank and University Hospital Southampton database (UHSDB) are used for evaluation and comparison of the proposed algorithm. Two PSR diagrams were plotted based on a window length of 5 s ECG with two different time delays and the PSR-based features were extracted from them using the box-counting technique. This process was applied on 122 records with more than 5500 windows of ECG signals. The results show an average sensitivity of 98.73%, specificity of 99.71% and accuracy of 99.56%. The average computational time of our proposed method for one 5 s window processing is 1.9 s and therefore has the potential in real-time arrhythmia classification applications.

Introduction Techniques exist which allow surface ECGs to be reconstructed from reduced lead sets. We aimed to reconstruct an 8-lead ECG from two independent S-ICD sensing electrodes vectors as proof of this principle. Methods Participants with ICDs ( N =61) underwent 3minute ECGs using a TMSi Porti7 multi-channel signal recorder (TMS international, The Netherlands) with electrodes in the standard S-ICD and 12-lead positions. Participants were randomised to either a training ( N =31) or validation ( N =30) group. The transformation used was a linear combination of the 2 independent S-ICD vectors to each of the 8 independent leads of the 12-lead ECG, with coefficients selected that minimized the root mean square error (RMSE) between recorded and derived ECGs when applied to the training group. The transformation was then applied to the validation group and agreement between the recorded and derived lead pairs was measured by Pearson correlation coefficient ( r ) and normalised RMSE (NRMSE). Results In total, 27 patients with complete data sets were included in the validation set consisting of 57,888 data points from 216 full lead sets. The distribution of the r and NRMSE were skewed. Mean r =0.770 (SE 0.024), median r =0.925. NRMSE mean=0.233 (SE 0.015) median=0.171. Conclusions We have demonstrated that the reconstruction of an 8-lead ECG from two S-ICD vectors is possible. If perfected, the ability to generate accurate multi-lead surface ECG data from an S-ICD would potentially allow recording and review of clinical arrhythmias at follow-up.

Objectives This study was conceived to determine the safety and efficacy of the subcutaneous implantable cardioverter-defibrillator (S-ICD) in patients with congenital heart disease (CHD). Background The S-ICD is a treatment option for patients with CHD in which a transvenous device is contraindicated due to anatomic considerations. However, efficacy in this group has not been determined. Methods A pooled analysis of 865 patients in the EFFORTLESS (Evaluation of Factors Affecting the Clinical Outcome and Cost-Effectiveness) registry (an international observational database) and a U.S. Investigational Device Exemption study were reviewed. Results Nineteen CHD patients versus 846 non-CHD patients with a median follow-up of 567 days and 639 days, respectively, were included. There were no deaths and no appropriate shocks for ventricular tachycardia/ventricular fibrillation in the CHD cohort, versus 26 deaths (3.1%, p = 0.42) and 111 appropriate shocks in 59 patients (7.1%) in the non-CHD cohort (p = 0.23). There were similar complication rates for the CHD versus non-CHD groups (10.5 vs. 9.6% [p = 0.89]), with inappropriate shocks for T-wave oversensing as the only complication in the CHD group (n = 2). The rate of inappropriate shocks was similar for both groups (10.5% vs. 10.9% [p = 0.96]). Successful defibrillation testing at 80J was comparable for the CHD versus non-CHD groups (100% vs. 98.5%). Conclusions The overall analysis of the CHD cohort from the pooled data of the Investigational Device Exemption study and the EFFORTLESS registry shows that the S-ICD is a safe option in CHD patients deemed to be at high risk for sudden cardiac death who do not have pacing indications. Further research to accurately define sudden cardiac death risk in the diverse anatomic substrates of CHD patients is warranted.

BackgroundThe sensitivity and specificity of the subcutaneous implantable cardioverter defibrillator (S-ICD) pre-implant screening tool required clinical evaluation.MethodsBipolar vectors were derived from electrodes positioned at locations similar to those employed for S-ICD sensing and pre-implant screening electrodes, and recordings collected through 80-electrode PRIME®-ECGs, in six different postures, from 40 subjects (10 healthy controls, and 30 patients with complex congenital heart disease (CCHD); 10 with Tetralogy of Fallot (TOF), 10 with single ventricle physiology (SVP), and 10 with transposition of great arteries (TGA)). The resulting vectors were analysed using the S-ICD pre-implant screening tool (Boston Scientific) and processed through the sensing algorithm of S-ICD (Boston Scientific). The data were then evaluated using 2 × 2 contingency tables. Fisher exact and McNemar tests were used for a comparison of the different categories of CCHD, and p < 0.05 vs. controls considered to be statistically significant.Results57% of patients were male, mean age of 36.3 years. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the S-ICD screening tool were 95%, 79%, 59% and 98%, respectively, for controls, and 84%, 79%, 76% and 86%, respectively, in patients with CCHD (p = 0.0001).ConclusionThe S-ICD screening tool was comparatively more sensitive in normal controls but less specific in both CCHD patients and controls; a possible explanation for the reported high incidence of inappropriate S-ICD shocks. Thus, we propose a pre-implant screening device using the S-ICD sensing algorithm to minimise false exclusion and selection, and hence minimise potentially inappropriate shocks.

Ventricular arrhythmias comprise a group of disorders which manifest clinically in a variety of ways from ventricular premature beats (VPB) and no sustained ventricular tachycardia (in healthy subjects) to sudden cardiac death due to ventricular tachyarrhythmia in patients with and/or without structural heart disease. Ventricular fibrillation (VF) and ventricular tachycardia (VT) are the most common electrical mechanisms for cardiac arrest. Accurate and automatic recognition of these arrhythmias from electrocardiography (ECG) is a crucial task for medical professionals. The purpose of this research is to develop a new index for the differential diagnosis of normal sinus rhythm (SR) and ventricular arrhythmias, based on phase space reconstruction (PSR)., 7 pages, 2 figures

Objectives 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. Background 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. Methods 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. Results 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. Conclusions 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.

ObjectivesThis study was aimed at evaluating global characteristics of electrical restitution in the human ventricle using noncontact mapping.BackgroundSteep action potential restitution (slope >1) and conduction velocity (CV) restitution have been linked with propensity to ventricular fibrillation, but clinical measurement of global electrical restitution had not been feasible.MethodsActivation-recovery interval (ARI) and CV restitution curves were simultaneously constructed from 16 regional segments of the left and right ventricles in 8 patients (6 male, 2 female, age 42 ± 17 years) following successful ablation of idiopathic ventricular tachycardia in the absence of structural disease guided by the Ensite 3000 system (Endocardial Solutions Inc., St. Paul, Minnesota). The ARIs were determined from reconstructed unipolar electrograms as validated with monophasic action potential recordings. The ARI restitution slopes were determined using the overlapping least-squares linear segments.ResultsGlobal electrical restitution curves were heterogeneous in shape and distribution. ARI restitution slope was >1 at 25% of 128 sites. The overall mean slope was 0.79 and was greater in the left than the right ventricle (0.93 ± 0.49 vs. 0.65 ± 0.26, p < 0.001). Dispersion of ARI restitution slopes increased with decreasing diastolic intervals. The CV restitution operated over a narrower range of diastolic intervals compared with ARI restitution, reaching a plateau (10 ± 6 ms vs. 38 ± 13 ms, p < 0.001) after refractoriness. The magnitude of CV restitution was also greater (steeper) than ARI restitution (25 ± 10% vs. 18 ± 9%, p < 0.001).ConclusionsNoncontact mapping can be used to examine global electrical restitution in the human ventricle. The ARI restitution is heterogeneous, with a slope >1 at 25% of all sites. The heterogeneity of ARI and CV restitution may be important in determining myocardial electrical stability.

ObjectivesSymptoms from low cardiac output or refractory atrial arrhythmias are complicating atriopulmonary (classical) Fontan connections. We present our experience of converting such patients to total cavopulmonary connections with and without arrhythmia surgery.MethodsBetween 1997 and 2002, 15 patients (mean age, 19.7 ± 7.0 years) underwent conversion operations 12.7 ± 3.5 years after atriopulmonary Fontan operations. Preoperative New York Heart Association functional class was I in 2 patients, II in 2 patients, III in 6 patients, and IV in 5 patients. Four patients underwent intracardiac lateral tunnel conversion alone, and 11 received extracardiac total cavopulmonary connection, right atrial reduction, and cryoablation.ResultsNo mortality occurred. One patient had conduit obstruction in the immediate postoperative period requiring replacement, and another required a redo operation for endocarditis. Average hospitalization was 17.9 ± 9.38 days; chest drains were removed on median day 4 (range, 1-29; mean, 7.4 ± 7.58 days). At follow-up (mean, 42.6 ± 22.1 months), late atrial arrhythmias had recurred in 3 of 4 patients with intracardiac total cavopulmonary connections (without ablation) and 1 of 11 patients with extracardiac total cavopulmonary connections with ablation. All patients are in New York Heart Association class I or II. Exercise ability (Bruce protocol) improved 69% from a mean of 6.18 ± 4.01 minutes to 10.45 ± 2.11 minutes (P < .05). Need for antiarrhythmic agents decreased postoperatively (patients receiving ≤1 antiarrhythmic: 9 preoperatively vs 15 at long-term follow-up, P < .05). No patient has required transplantation. Protein-losing enteropathy, which was present in 1 patient, improved transiently with conversion. There was 1 late death from gastrointestinal hemorrhage.ConclusionsFontan conversion can be achieved with low mortality and improvement in New York Heart Association class and exercise ability. Concomitant arrhythmia surgery reduces the incidence of late arrhythmias.

Patients with combined hyperlipidemia and low high-density lipoprotein (HDL) cholesterol levels may benefit from combination therapy with a statin and niacin; therefore, we assessed the efficacy and safety of rosuvastatin and extended-release (ER) niacin alone and in combination in 270 patients with this atherogenic dyslipidemia. Men and women > or =18 years with fasting total cholesterol levels > or =200 mg/dl, triglycerides 200 to 800 mg/dl, apolipoprotein B > or cf=110 mg/dl, and HDL cholesterol

Background & Aims: The megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disease of childhood that presents early with intestinal hypoperistalsis, hydronephrosis, and hydroureters. Transgenic mice that lack the a3 subunit containing nicotinic acetylcholine (nAChR) have a phenotype similar to that of MMIHS. Methods: We examined the expression of this subunit in control and MMIHS tissue derived from patients using in situ hybridization (ISH) and immunocytochemistry (ICC). Results: In controls, both techniques showed a wide distribution of a3 nAChRs present in ganglion cells, muscle, and epithelium. By contrast, most MMIHS tissue gave negative staining with ISH and variable results with ICC. Conclusions: These observations are consistent with a lack of a3 nAChRs contributing to the pathogenesis of MMIHS.

This multicenter trial evaluated the safety and efficacy of escalating doses of Niaspan (niacin extended-release tablets) and placebo (administered once-a-day at bedtime) in patients with primary hyperlipidemia on the percent change from baseline in levels of low-density lipoprotein (LDL) cholesterol and apolipoprotein B. Extended-release niacin was initiated at a dose of 375 mg/day, raised to 500 mg/day, and further increased in 500-mg increments at 4-week intervals to a maximum of 3,000 mg/day. A total of 131 patients (n = 87, extended-release niacin; n = 44, placebo) were treated for 25 weeks with study medication after a 6-week diet lead-in/drug washout phase and 2-week baseline LDL cholesterol stability phase. Significant decreases from baseline in levels of LDL cholesterol and apolipoprotein B became apparent with the 500-mg/day dose and were consistent at all subsequent doses (por =0. 05), reaching 21% and 20%, respectively, at the 3,000-mg/day dose. Significant increases from baseline in levels of high-density lipoprotein cholesterol became apparent with the 500-mg/day dose and were consistent at all subsequent doses (por = 0.05), reaching 30% at the 3,000-mg dose. Significant decreases from baseline in triglycerides and lipoprotein(a) occurred at the 1,000-mg dose and were apparent at all subsequent doses (por =0.05), reaching 44% and 26%, respectively, at the 3,000-mg dose. The most common adverse events were flushing and gastrointestinal disturbance. Transaminase increases were relatively small, and the proportion of patients who developed liver function abnormalities on extended-release niacin was not significantly different from placebo. Thus, extended-release niacin was generally well tolerated and demonstrated a dose-related ability to alter favorably most elements of the lipid profile.

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.

Using appropriate dietary modification, many studies have shown a beneficial impact of serum cholesterol lowering on the risk of coronary heart disease (CHD). In addition, an association between certain types of food, specifically the consumption of nuts, has been associated with reduced cardiovascular risks. Two small studies carried out in volunteers in a controlled environment provided suggestive evidence for a cholesterol lowering effect attributable to walnut ingestion. The purpose of this study was to determine whether the consumption of walnuts by hypercholesterolemic, free living men and women had a favorable effect on their serum lipid levels [total cholesterol (TC), HDL cholesterol (HDL-C), LDL cholesterol (LDL-C), triglycerides (TG)] when consumed as part of a NCEP Step I diet. A total of 67 subjects with total cholesterol levels >200 mg/dl enrolled in an open-label, randomized, crossover design trial. Subjects received diet instruction by a registered dietitian on the NCEP Step I diet and maintained 3-day diet records between visits. Subjects completed a 6-week dietary lead-in period during which lipid response to this diet was established. Subjects were then randomly assigned to one of two treatment groups for a 6 week period: continuation of Step I diet (reference diet group) or to a diet group wherein subjects consumed 2.25 ounces/day of walnuts as part of the NCEP Step I diet (the Walnut diet). After 6 weeks, all patients were switched to the alternate diet for an additional 6-week period. Results of the study showed that TC, LDL-C, and TG levels remained stable when subjects were randomized to the reference diet. However, while consuming the Walnut diet, subjects demonstrated a reduction in TC by 3%, LDL-C by 4% and TG by 12%. These changes in lipid levels demonstrated a beneficial trend of the Walnut diet (p= 0.10, NS) and no adverse changes in serum lipoprotein regulation. The results suggest that consumption of walnuts favorably affect serum lipid levels, and can be used as a flavorflil snack while adhering to the NCEP Step I diet.

The treatment of ameloblastoma is briefly presented. A case, which may represent the largest ameloblastoma successfully removed, has been presented. An unusually good cosmetic result was obtained without prosthesis or bone graft. Certain advances in the management of such cases are suggested.