Search

Background AtrioVentricular (AV) and InterVentricular (VV) delay optimization can improve ventricular function in Cardiac Resynchronization Therapy (CRT) and is usually performed by means of echocardiography. St Jude Medical has developed an automated algorhythm which calculates the optimal AV and VV delays (QuickOpt™) based on Intracardiac ElectroGrams, (IEGM), within 2 min. So far, the efficacy of the algorhythm has been tested acutely with standard lead position at right ventricular (RV) apex. Aim of this project is to evaluate the algorhythm performance in the mid- and long-term with RV lead located in mid-septum. Methods AV and VV delays optimization data were collected in 13 centers using both echocardiographic and QuickOpt™ guidance in CRTD implanted patients provided with this algorhythm. Measurements of the aortic Velocity Time Integral (aVTI) were performed with both methods in a random order at pre-discharge, 6-month and 12-month follow-up. Results Fifty-three patients were studied (46 males; age 68 ± 10y; EF 28 ± 7%). Maximum aVTI obtained by echocardiography at different AV delays, were compared with aVTI acquired at AV delays suggested by QuickOpt. The AV Pearson correlations were 0.96 at pre-discharge, 0.95 and 0,98 at 6- and 12- month follow-up respectively. After programming optimal AV, the same approach was used to compare echocardiographic aVTI with aVTI corresponding to the VV values provided by QuickOpt. The VV Pearson Correlation were 0,92 at pre-discharge, 0,88 and 0.90 at 6-month and 12- month follow-up respectively. Conclusions IEGM-based optimization provides comparable results with echocardiographic method (maximum aVTI) used as reference with mid-septum RV lead location.

Identifying the left ventricular (LV) site associated with the maximum spontaneous interventricular conduction time (right ventricle (RV)-to-LV interval) has proved to be an effective strategy for optimal LV pacing site selection in cardiac resynchronization therapy (CRT). The aim of our study was to determine whether quadripolar LV lead technology allows RV-to-LV interval maximization.We enrolled 108 patients undergoing implantation of a CRT system using an LV quadripolar lead and 114 patients who received a bipolar lead. On implantation, the RV-to-LV interval was measured for the dipole of the bipolar leads and for each electrode of the LV lead (tip, ring 2, ring 3, ring 4).In the quadripolar group, the mean RV-to-LV interval ranged from 90 ± 33 ms (tip) to 94 ± 32 ms (R4) (p 0.05 for all comparisons). In 55 (51%) patients, the RV-to-LV interval was 80 ms at all electrodes, while in 27 (25%) patients, no electrodes were associated with an RV-to-LV interval 80 ms. At least one LV pacing electrode was associated with an RV-to-LV interval 80 ms in 62 (70%) patients with a short (36 mm) inter-electrode distance, and in 19 (95%, p = 0.022) of those with a long distance (50.5 mm). In the bipolar group, the mean RV-to-LV interval was 72 ± 37 ms (p 0.001 versus quadripolar). The RV-to-LV interval was 80 ms in 44 (39%) patients (p 0.001 versus quadripolar leads with both short and long inter-electrode distance).Quadripolar leads allow RV-to-LV interval maximization. An optimal RV-to-LV interval seems achievable in the majority of patients, especially if the leads present a long inter-electrode distance.

Objectives We investigated whether the reverse remodeling after cardiac resynchronization therapy (CRT) might reduce the occurrence of ventricular arrhythmias (VAs). Background It is currently debated whether CRT has an effect on the burden of VAs. Methods The study included 398 patients treated with a CRT defibrillator and with a follow-up of at least 12 months. Spontaneous VAs detected by the device were reviewed and validated. Results A significant reduction in VA episodes and shock therapies was evident during the follow-up with greater decrease after 1 month. After 6 months of CRT, 227 patients (57%) showed a reduction in end-systolic volume of ≥10% and were defined as “responders.” The baseline characteristics were similar between the responders and the nonresponders. Nonetheless, the proportion of patients with recurrence of VA after 1 month of CRT was significantly lower in responders (32% vs. 43%, p = 0.024). Among baseline variables no parameters emerged as predictors of tachyarrhythmia recurrence. However, receiver-operating curve analysis recognized a reduction of left ventricular end-systolic volume at 6 months of 13% as the best cutoff to identify the reduction of VAs (with a sensitivity of 58% and a specificity of 54%). Conclusions In patients treated with CRT defibrillators, a reduction in ventricular arrhythmic events occurs during the initial 12 months after implant and is correlated with the degree of ventricular remodeling induced by the therapy. Patients demonstrating reverse remodeling at midterm follow-up show a reduction in arrhythmias soon after the implant, pronounced improvements at long-term, and a better survival.

Aims To assess the effects of cardiac resynchronization therapy (CRT) in ≥80-year-old patients vs. patients

Background: Studies reporting the long-term survival of patients treated with cardiac resynchronization therapy (CRT) outside the realm of randomized controlled trials are still lacking. The aim of this study was to quantify the survival of patients treated with CRT in clinical practice and to investigate the long-term effects of CRT on clinical status and echocardiographic parameters. Methods: The study population consisted of 317 consecutive patients with implanted CRT devices from eight Italian University/Teaching Hospitals. The patients were enrolled in a national observational registry and had a minimum follow-up of 2 years. A visit was performed in surviving patients and mortality data were obtained by hospital file review or direct telephone contact. Results: During the study period, 83 (26%) patients died. The rate of all-cause mortality was significantly higher in ischemic than nonischemic patients (14% vs 8%, P = 0.002). Multivariate analysis showed that ischemic etiology (HR 1.72, CI 1.06‐2.79; P = 0.028) and New York Heart Association (NYHA) class IV (HR 2.87, CI 1.24‐6.64; P = 0.014) were the strongest predictors of all-cause mortality. The effects of CRT persisted at long-term follow-up (for at least 2 years) in terms of NYHA class improvement, increase of left ventricular ejection fraction, decrease of QRS duration (all P = 0.0001), and reduction of left ventricular end-diastolic and end-systolic diameters (P = 0.024 and P = 0.011, respectively). Conclusions: During long-term (3 years) follow-up after CRT, total mortality rate was 10%/year. The outcome of ischemic patients was worse mainly due to a higher rate of death from progressive heart failure. Ischemic etiology along with NYHA class IV was identified as predictors of death. Benefits of CRT in terms of clinical function and echocardiographic parameters persisted at the time of long-term follow-up. (PACE 2006; 29:S2‐S10)

Objective Cryoenergy is a new valuable treatment option to perform ablation close to the atrioventricular (AV) node in the cure of supraventricular tachycardias because of its favourable properties, such as the possibility of creating reversible lesions. The aim of this study was to report our experience on the effectiveness and safety of catheter cryoablation performed in "critical areas" to treat a large cohort of patients with supraventricular arrhythmias. Methods One hundred and thirty-one patients suffering from supraventricular tachycardias underwent catheter cryoablation using a 7F catheter. Eighty-seven patients presented with AV nodal re-entrant tachycardia (AVNRT), 39 had accessory pathways (APs) either manifest or concealed (15 midseptal, 24 parahissian), three had ectopic right atrial tachycardia (AT), and two patients had a permanent junctional reciprocating tachycardia (PJRT). When the optimal parameters were recorded, ice mapping at -30 degrees C was performed for 80 s to validate the ablation site. If the expected result occurred, cryoablation was carried out by lowering the temperature to -75 degrees C for 4 min. Results In two patients cryoablation was not performed because of technical reasons. Cryoablation was acutely successful in 84 out of 85 patients with AVNRT, in 37 of 39 with APs and in all patients with AT and PJRT. No complications occurred in any patient. Transient AV conduction impairment occurred in seven patients with midseptal APs and in two patients with AVNRT. In particular, in these patients no late permanent AV block was observed at follow-up. At a mean follow-up of 27 +/- 12.9 months, clinical success rate was 87%. Conclusions Cryoablation is a safe and effective technique with a high success rate in the long term. It may be particularly useful when performing ablation close to the AV node or His bundle owing to the possibility of validating the ablation site with ice mapping, which creates only a reversible lesion, mainly in the midseptal APs.

OBJECTIVES We aimed to evaluate: 1) the behavior of electrical activity simultaneously in different atrial regions during atrial fibrillation (AF); 2) the difference of atrial activation between paroxysmal and chronic AF; 3) the atrial refractoriness dispersion; and 4) the correlation between the effective refractory periods (ERPs) and the FF intervals. BACKGROUND Little data exist on the electrophysiologic characteristics of the different atrial regions in patients with AF. A more detailed knowledge of the electrical activity during AF may provide further insights to improve treatment of AF. METHODS Right and left atria were extensively mapped in 30 patients with idiopathic AF (18 paroxysmal and 12 chronic). In different atrial locations, we analyzed 1) the FF interval duration; and 2) the grade of organization and, in case of organized electrical activity, the direction of atrial activation. Furthermore, in patients with paroxysmal AF, we determined the atrial ERP, evaluated the ERP dispersion and assessed the presence of a correlation between the ERPs and the FF intervals. RESULTS In patients with chronic AF, we observed a shortening of the FF intervals and a greater prevalence of disorganized activity in all the atrial sites examined. In patients with paroxysmal AF, a significant dispersion of refractoriness was observed. The right lateral wall showed longer FF intervals and more organized atrial activity and, unexpectedly, the shortest mean ERPs. In contrast, the septal area showed shorter FF intervals, greater disorganization and the longest mean ERPs. CONCLUSIONS Electrical activity during AF showed a significant spatial inhomogeneity, which was more evident in patients with paroxysmal AF. The mean FF intervals did not correlate with the mean ERPs.

Background A novel method to estimate cardiac volumes based on impedance measurements using the leads of a resynchronization device has been developed. This study investigated the method in patients with ischemic cardiomyopathy and documented wall motion abnormalities. Method and Results Fifteen postinfarction patients (age 68 ± 8 years, ejection fraction 27 ± 5%) with symptomatic heart failure and ≥1 akinetic or dyskinetic segment were included. During the implantation of a cardiac resynchronization therapy (CRT) device, acute impedance curves were recorded along with stroke volume determined by the arterial pulse contour method. In an overdrive protocol, the impedance parameter “stroke impedance” decreased in significant correlation with stroke volume in all patients. The median correlation coefficient between stroke volume and stroke impedance was 0.83 (interquartile range 0.70–0.89). Furthermore, the atrioventricular delay was optimized based on impedance and reference stroke volume. After optimization by the impedance method, it differed by 18 ± 15 ms from the figure after optimization by the invasive reference. Compared with a standard atrioventricular delay of 120 ms, stroke volume was improved by 8.6 ± 9.8% with the use of invasive optimization and by 6.4 ± 10.8% with the use of impedance-based optimization. Conclusions In CRT patients with chronic infarction and wall motion abnormalities, impedance is a valid parameter to estimate stroke volume and to guide optimization of CRT timing.

Aims For successful cardiac resynchronization therapy (CRT), an optimization of left ventricular (LV) lead position and stimulation timing is required. The feasibility of optimizing LV lead position, atrioventricular delay (AVd), and interventricular delay (VVd) in CRT using intracardiac impedance measurement was evaluated. Methods and results Heart failure patients ( n = 14, NYHA 13×III, 1×II, ejection fraction: 26 ± 6%, QRS: 165 ± 30 ms) were stimulated by AAI and biventricular (DDD-BiV) pacing in turn. Left ventricular lead site, AVd, and VVd were varied. An external pacemaker measured impedance, and a micromanometer catheter measured LV and aortic pressure. Left ventricular d P /d t max, pulse pressure (PP), stroke volume (SV), end-systolic impedance (ESZ), and stroke impedance (SZ) were determined. Optimization results achieved by maximum increase in PP, SV, SZ, or ESZ were compared with the reference method (d P /d t max increase). Left ventricular lead site variation resulted in a mean optimal d P /d t max benefit of 18.2%. Lead site selection by SZ/PP/SV showed benefits of 17.4/17.9/17.2%, respectively. Atrioventricular delay optimization increased the optimal benefit to 22.1%, the methods ESZ/PP/SV achieved 20.1/20.8/19.4%. Interventricular delay optimization resulted in a benefit of 19.1/19.4/19.9% (SZ/PP/SV) with an optimum of 21.8%. The achieved benefit did not differ significantly between impedance, SV, and PP methods. A significant correlation between AVd values selected by d P /d t max and by the other methods was observed ( r = 0.75/0.67/0.60 for ESZ/PP/SV). Conclusion The feasibility of optimizing LV lead site, AVd, and VVd by intracardiac impedance has been demonstrated for CRT patients with a similar performance as using SV and PP. Application of intracardiac impedance for automatic implant-based CRT optimization appears to be within reach.

Aims Monitoring of haemodynamic parameters or surrogate parameters of the left ventricle is especially important for patients under cardiac resynchronization therapy (CRT). Intracardiac impedance reflects left ventricular (LV) volume changes well in animal models. Since it is unknown whether this also holds in humans with heart failure (HF), we examined the correlation of LV intracardiac impedance with haemodynamic parameters in CRT patients for different positions of the LV lead. Methods and results In 14 HF patients with non-ischaemic cardiomyopathy (four female, age 70 ± 6 years, NYHA 2.9 ± 0.3, EF 26 ± 6%), one or two suitable implantation sites for the LV lead were selected. Following atrial, right ventricular, and LV catheter positioning, a micro-manometer catheter was placed in the ascending aorta. Surface ECG, impedance, and aortic pressure were recorded during graded overdrive bi-ventricular pacing in DDD mode. The correlation between impedance and stroke volume (SV) or pulse pressure (PP) changes was compared for different LV lead positions. In total, 20 overdrive pacing tests were performed at six different LV lead positions. Strong correlations were found between stroke impedance (SZ) and SV ( R = 0.82 ± 0.16) as well as between SZ and PP ( R = 0.81 ± 0.16) without significant influence of LV lead position. Conclusion In HF patients, a strong correlation between changes in intracardiac impedance and LV SV was found. Typical LV lead implant positions have been tested and all appear to be suitable for this method of LV volume monitoring.

A 48-year-old man who had previously undergone a Bentall procedure came to our Emergency Department after 4 days of retrosternal discomfort and mild dyspnea. Electrocardiography showed sinus rhythm and normal ventricular repolarisation, and there was no increase in myocardial enzyme levels. A chest X-ray showed an enlarged mediastinum, and CT revealed the …

While much is known concerning the hemodynamic effects of biventricular (BV) pacing, little has been reported concerning the efficacy of BV sensing and pacing in the detection and treatment of ventricular tachyarrhythmias. Two hundred nineteen heart failure (HF) patients with VT or VF and a QRS > or = 120 ms during sinus rhythm received an ICD capable of BV pacing and sensing. Detection times of induced VF and success rates for terminating induced VT were measured. The ICD system used a left ventricular epicardial lead implanted via thoracotomy (52 patients) or a specially designed percutaneous, over-the-wire lead inserted in the coronary venous system. VF detection times and VT termination rates by antitachycardia pacing (ATP) were compared with those measured in a population of recipients of ICD using a RV lead alone. Median induced VF detection times were comparable (2.0-s BV vs 1.8-s RV). Termination of induced VT on the first attempt was comparable with BV pacing (87.4%) versus RV pacing (89.6%). The time to detect induced VF was not different with ICDs using BV sensing versus conventional ICDs using RV sensing alone. Similarly, the rates of successful termination of induced VT by ATP with BV or RV pacing were comparable.

Introduction: It is currently debated whether cardiac resynchronization therapy (CRT) has an effect on the burden of ventricular arrhythmias (VA). We investigated whether the reverse remodeling after CRT may reduce the occurrence of VA. Methods : The study included 398 patients enrolled in the InSync ICD Italian Registry, treated with CRT-D and with a follow-up of at least 12 months. Spontaneous VA detected by the device were reviewed and validated. Results: After 6 months of follow-up no VA episodes occurred in 319 patients (group 1), while VA episodes persisted in the remaining 79 (group 2). At baseline, clinical and echocardiographic characteristics of the two groups were comparable: NYHA class (2.9±0.6 vs. 3.0±0.7), QRS width (166±31ms vs. 163±34ms), ejection fraction (26±7% vs. 26±6%), LVEDV (251±98ml vs. 226±45ml), LVESV (182±84ml vs. 158±38ml) (All p=NS). At 6 month visit, ventricular remodeling was apparent only in group 2 pts: LVEDV (200±83ml, p=0.042 vs. Baseline), LVESV (133±65ml, p=0.002 vs. Baseline). No changes were evident in group 2 pts: LVEDV (216±69ml, p=0.769 vs. Baseline), LVESV (160±59ml, p=0.521 vs. Baseline). The long-term survival from all-cause death resulted higher in group 1 pts (Log-rank test: p=0.032). (Figure ) Conclusions: In patients treated with CRT, a reduction of ventricular arrhythmic events occurs during the initial 12 months following implant and is correlated with the degree of ventricular remodeling induced by the therapy. Patients demonstrating the remission of arrhythmic episodes will have better survival and more pronounced long term improvements.

Clustering of Ventricular Tachyarrhythmias in HF Patients. Background: Temporal patterns of ventricular tachyarrhythmia (VT/VF) have been studied only in patients who have received implantable cardioverter defibrillators (ICD) for secondary prevention of sudden death, and mainly in ischemic patients. The aim of this study was to evaluate VT/VF recurrence patterns in heart failure (HF) patients with biventricular ICD and to stratify results according to HF etiology and ICD indication. Methods and Results: We studied 421 patients (91% male, 66 ± 9 years). HF etiology was ischemic in 292 patients and nonischemic in 129. ICD indication was for primary prevention in 227 patients and secondary prevention in 194. Baseline left ventricular ejection fraction (LVEF) was 26 ± 7%, QRS duration 168 ± 32 msec, and NYHA class 2.9 ± 0.6. In a follow-up of 19 ± 11 months, 1,838 VT/VF in 110 patients were appropriately detected. In 59 patients who had >4 episodes, we tried to determine whether VT/VF occurred randomly or rather tended to cluster by fitting the frequency distribution of tachycardia interdetection intervals with exponential functions: VT/VF clusters were observed in 46 patients (78% of the subgroup of patients with >4 episodes and 11% of the overall population). On multivariate logistic analysis, VT/VF clusters were significantly (P < 0.01) associated with ICD indication for secondary prevention (odds ratio [OR] = 3.12; confidence interval [CI] = 1.56-6.92), nonischemic HF etiology (OR = 4.34; CI = 2.02-9.32), monomorphic VT (OR = 4.96; CI = 2.28-10.8), and LVEF < 25% (OR = 3.34; CI = 1.54-7.23). Cardiovascular hospitalizations and deaths occurred more frequently in cluster (21/46 [46%]) than in noncluster patients (63/375 (17%), P < 0.0001). Conclusions: In HF patients with biventricular ICDs, VT/VF clusters may be regarded as the epiphenomenon of HF deterioration or as a marker of suboptimal response to cardiac resynchronization therapy.

ADVANCE CRT-D Study Design. Background: The purpose of this investigation is to compare the efficacy of antitachycardia pacing (ATP) delivered via the right ventricular (RV) lead versus ATP delivered simultaneously via the right and left ventricular leads (biventricular [BiV]) in the termination of ventricular tachyarrhythmia (VT) in patients receiving cardiac resynchronization therapy (CRT) with ICD capabilities. Methods and Results: The ADVANCE CRT is a prospective, multicenter, randomized, parallel trial evaluating RV versus BiV ATP in the termination of VT in CRT patients. The study will test the hypothesis that BiV ATP is superior to RV ATP in the termination of VT and fast VT. All patients with class I and IIa indications for an ICD implantation and CRT are included. The sample size has been estimated to 400 participants followed for 12 months to show a 10% benefit of BiV versus RV ATP. The efficacy of BiV ATP to terminate all VT presents the primary endpoint. The investigation is expected to be completed in 2007. Conclusions: The ADVANCE CRT trial is the first large randomized clinical investigation evaluating the efficacy of BiV ATP in patients under CRT and ICD therapy.

Aims To verify if sites of conduction gaps on the isthmus correlate with anatomical peculiarities using the intracardiac echo (ICE) and a new 3D device to reconstruct the isthmus in patients undergoing cavotricuspid isthmus ablation. Methods and results Twenty patients underwent isthmus ablation using an 8 mm tip ablation catheter. Two-dimensional and 3D ICE reconstruction of the isthmus was made before, during and after ablation. At the end of the lesion line isthmus block was validated by electrophysiological criteria. In case of its absence we closed the remaining conduction gaps verifying the position of the sites with ICE. Fourteen patients required a median of 8 RF pulses to obtain complete isthmus block (Group A). In the remaining 6 patients isthmus block was obtained with a median of 25 RF pulses due to conduction gaps ‘resistant’ to ablation (Group B). Conduction gap positions assessed by ICE were located in the central portion of the isthmus below the coronary sinus os in 71% of cases in Group A and along a prominent Eustachian ridge in Group B patients, respectively. 3D reconstruction showed a smooth isthmus in Group A with a ‘peak and valleys’ isthmus in Group B. In these latter patients isthmus block was obtained only after the complete ablation of the prominent Eustachian ridge. Conclusion The isthmus presents anatomical variants particularly due to Eustachian ridge peculiarities which may represent a site of conduction gaps “resistant” to ablation.

Radiofrequency catheter ablation is nowadays a widely used technique for the treatment of arrhythmias; however, due to the possible complications such as atrioventricular block when radiofrequency is delivered in the septal area, this type of energy is not optimal. In contrast, cryoenergy has several positive features; first of all, it allows for the creation of reversible lesions and hence to test the effects of the ablation while the lesion is still forming thus reducing the number of ineffective and useless lesions. In addition, it also allows for the evaluation of the acute effects on the structures adjacent to the ablation site. The aim of the present study was to analyze the effectiveness and safety of catheter cryoablation in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT).Thirty-two patients presenting with AVNRT underwent catheter cryoablation using a 7F catheter. When the optimal parameters were recorded, "ice mapping" at -30 degrees C was performed for 80 s to validate the ablation site by means of a reversible lesion. If the expected result was achieved, the cryoablation was carried out lowering the temperature to -75 degrees C for 4 min thus creating a permanent lesion.Slow pathway ablation guided by a slow pathway potential was successfully performed in 31 out of the 32 patients with a mean of 2.6 +/- 1.0 cryoapplications. No complications occurred in any patients. Transient AH prolongation was observed in 2 patients in a midseptal site during the ice mapping phase of AVNRT ablation.Cryoablation is a safe and effective technique for AVNRT ablation. It may be useful particularly when the ablation must be performed close to the atrioventricular node or His bundle, due to the possibility of validating the site of ablation by means of ice mapping that creates only a reversible lesion.

Transcatheter ablation of atrial fibrillation has been recently developed and is part now of the armamentarium in the treatment of atrial fibrillation. The ablation of atrial fibrillation started out from the experience of the surgical maze procedure, which showed very encouraging results but at a high price because it required open chest surgery. In the following years the attempt has been made to produce similar results using transcatheter ablation. Different approaches have been used: linear lesions mimicking the surgical maze operation, linear lesions in the right or left atrium using different schemes, or a sequential approach ablating first in the right and then in the left atrium.

This study investigated whether a minimal approach to typical atrial flutter ablation using an 8 mm tip catheter with a 150 W generator with only the documentation of clockwise block by means of local criteria predicts a good long-term outcome.Seventy patients underwent typical atrial flutter ablation. A multipolar catheter was inserted into the coronary sinus (CS) and an 8 mm tip ablation catheter was used to ablate and map the isthmus. The ablation line was performed in the posteroseptal region. The clockwise block was confirmed by recording a corridor of double potentials along the line and by counterclockwise activation of the portion of the isthmus just beyond the lesion line as demonstrated by measuring the conduction times during CS pacing.In case of block, the mean distance between the two split atrial electrograms was 129 +/- 31 ms. Acute isthmus block was achieved in all 70 patients. The median of the radiofrequency pulses was 10 (range 1-36). No immediate or late complications were noted. The long-term follow-up (19.5 +/- 4 months) revealed recurrence of typical atrial flutter in 2 cases (2.8%).Our results demonstrate that the acute success rate following typical atrial flutter isthmus ablation using an 8 mm tip catheter with a 150 W generator is high. No complications occurred. Moreover, the documentation of just the clockwise isthmus block using a minimal approach according to local electrogram criteria is a good predictor of the long-term success.

The Ventak CHF/CONTAK CD Biventricular Pacing Study is a prospective randomized trial to examine the safety and efficacy of biventricular (BV) pacing in patients with standard indications for an ICD, symptomatic heart failure, a LVEFor = 0.35, and a QRSor = 120 ms. Patients underwent implantation of a BV pacing and sensing system with backup defibrillation capability, which includes a steroid-eluting coronary venous lead that is advanced into the coronary venous vasculature by over-the-wire techniques. LV pacing threshold, BV impedance, and BV R wave amplitude were measured in 58 consecutive patients. Using a percutaneous over-the-wire insertion technique, steroid-eluting coronary venous leads were associated with satisfactory mean LV pacing threshold, BV impedance, and BV R wave amplitude acutely up to 4 months after implantation. Pacing threshold stabilized 2 weeks after lead implantation and sensing threshold remained stable from the time of implant.

Biventricular (BV) pacing is under clinical investigation for the treatment of heart failure. Its impact on mortality is unknown. Patients with heart failure and ventricular tachyarrhythmias received an implantable cardioverter defibrillator with BV pacing capability. Patients were randomized 1:1 to BV pacing or no pacing, then crossed over to the alternate mode after 3 months. All-cause mortality was measured in each arm up to the point of crossover. Fifteen of 222 patients died between implant and crossover. Five patients died while programmed to BV pacing and 19 died while programmed to no pacing. Survival in the BV pacing arm was 93 +/- 4% versus 86 +/- 6% in the no pacing arm (P = 0.18). In a patient population with symptomatic heart failure and ventricular arrhythmias, BV pacing does not appear to be associated with excess mortality. Larger and longer studies will be needed to determine if BV pacing confers a survival benefit.

Biventricular pacing has been proposed to resynchronize ventricular contraction in patients with congestive heart failure (CHF) and interventricular conduction delay. However, the sudden death rate is still high despite the improvement in cardiac performance. Devices combining biventricular pacing with implantable cardioverter defibrillator (ICD) backup are now under clinical investigation to demonstrate whether they can decrease sudden death. From the first implant of an ICD with biventricular transvenous pacing on August 1998 to April 2000, 96 patients underwent such implants: 67 (70%) received pacemakers alone and 29 (30%), who had class I ICD indications, received combined pacemaker/ICD systems. During a mean follow-up of 283 +/- 170 days, 13 (14%) patients died: 5 of 29 (17%) in the ICD group and 8 of 67 (12%) in the pacemaker group. A total of 15 patients (52%) had ICD shocks and 6 patients (21%) had 113 episodes of ventricular tachyarrhythmias, of which 96 (85%) were converted to sinus rhythm with antitachypacing. The echocardiograms showed a narrowing of the delay between the onset of right and left ventricular outflow from 40 +/- 37 msec to 17 +/- 16 msec (p = 0.03) and a reduction of the mitral regurgitation area from 7 +/- 3.8 cm2 to 5 +/- 4 cm2 (p = 0.04) at 3 months. Functional class improved from 2.8 +/- 0.7 to 1.6 +/- 0.5 (p0.001) 3 months after implant. Thus, ischemic patients with reduced left ventricular ejection fraction and ventricular tachyarrhythmias seem good candidates for biventricular pacing with ICD backup. The sudden death risk for those with idiopathic dilated cardiomyopathy, however, is difficult to stratify, and the choice of ICD backup has to be considered on the basis of patient safety, as well as of costs.

Little is known on the chronic effects of left ventricular pacing (LV) in heart failure.Seventy-four patients with LBBB, QRS130 milliseconds, New York Heart Association class (Bradley DJ, Bradley EA, Braughman KL, et al. Cardiac resynchronization and death from progressive heart failure: a meta-analysis of randomized controlled trials. JAMA 2003;289:730-40.) II, LV ejection fraction (LVEF)35%, and a class I cardioverter/defibrillator indication were implanted with CRT-D devices and were randomized to either LV or biventricular (BiV) pacing. Response (defined as increases of5 points increase of LVEF and/oror = 10% 6-minute walking test [6MWT]) between LV and BiV pacing were compared in an attempt to define the number of patients needed to claim noninferiority of LV pacing. In addition, absolute change in LVEF at 12 months in heart failure patients treated with LV pacing was evaluated. The safety of LV pacing was assessed comparing the total number of ventricular arrhythmia episodes, of hospitalizations, and of deaths between the two pacing modes.The percentage of responders was comparable for both groups (LV = 75%, BiV = 70%, P = .788); based on the 95% CI of the difference between the groups, 1100 patients would be needed to claim noninferiority of LV pacing (with a 5% CI lower limit). LV pacing induced siginificant LVEF increase (5.2%, P = .002). These results remained unchanged after performing adjustment analyses. There were no differences in the numbers of ventricular arrhythmias, hospitalizations, and death events between the 2 pacing modes.At 12 months, percentage of responders to LV pacing was similar to BIV pacing. Furthermore, LV pacing achieved a significant increase of ejection fraction. LV pacing is both safe and feasible.

The effectiveness of short- (15 days) and long- (12 months) term propafenone treatment was assessed in 53 patients presenting with more than 30 premature ventricular complexes per hour as detected by 24-hour ambulatory Holter monitoring. Thirty-nine patients had no apparent concomitant heart disease while 14 had chronic coronary artery disease. The effects of propafenone were analysed by ambulatory Holter monitoring after 15 days and at 3, 6 and 12 months. The initial dose was 150 mg four times daily and was increased up to 300 mg four times daily when necessary. Favourable short-term effects were obtained in 39 patients (73.6%). After 12 months, 17 patients (32.1%) were still on propafenone treatment with good results. Treatment was discontinued on account of low compliance in 28.3%. This was because treatment was ineffective even at high doses in 15.2%, because of severe side effects in 13.2%, because of proarrhythmic effects in 5.6% and for other causes in 5.6%.

Myopotential inhibition was produced by a combination of different provocative maneuvers in 423 (77%) out of 550 consecutive unipolar pacemaker patients. The most useful maneuvers were the hand-to-shoulder press (90% positivity) and the hand-to-hand press (60% positivity). Three groups of 20 patients were then submitted to 24 hours of Holter monitoring. Group A during the provocative maneuvers had shown myopotential inhibition and symptoms of cerebral ischemia. In group B symptomless myopotential inhibition had been induced. Group C had no myopotential inhibition nor symptoms during the tests. Abnormal pacemaker pauses related to myopotential inhibition were recorded during Holter monitoring in 90% of group A and in 80% of group B patients, but only group A patients showed symptoms. Thus in patients who are able to practice provocative isometric maneuvers and who can be selected according to their response, Holter monitoring seems to offer few advantages in discovering myopotential inhibition and related symptoms.

The aim of this study was to evaluate ventricular arrhythmias occurring in recipients of the InSync ICD for the primary and secondary prevention of sudden death. The InSync ICD was implanted in 142 patients (128 men; mean age 65 +/- 10 years) with heart failure (mean NYHA functional Class 3.0 +/- 0.7) and wide QRS (mean 159 +/- 33 ms). The underlying etiology was ischemic in 55%, idiopathic in 33%, and valvular or hypertensive cardiomyopathy in 12% of patients. The numbers of arrhythmic episodes/100 patient-months was computed with their 95% CI, assuming a Poisson distribution. Implants were performed in 48 (34%) patients who did not have an ACC/AHA guidelines Class I indication for ICD therapy. A total of 104 patients were compliant for follow-up visits. During a 9-month median (range 0.1-24) follow-up of 104 compliant patients, 19 experienced a total of 94 ventricular arrhythmias, all successfully interrupted or self-terminated, with a median number of two separate episodes, corresponding to a rate of 10 episodes/100 person-month (95% CI 8-12). A rate of 12 episodes/100 person-months (95% CI 10-15) was measured in the subgroup of patients with ACC/AHA class I indications, versus two episodes/100 person-months (95% CI 1-5) in the remainder of the population. Among 12 deaths, 9 were due to heart failure, 1 to a non-cardiovascular cause, and 2 to unknown causes. The implantation of ICD in heart failure patients has been prominently extended to primary prevention. Patients without standard ICD indications experienced life-threatening arrhythmic events. The impact of ICD combined with cardiac resynchronization therapy on arrhythmic profile, mortality, and costs in this subgroup of patients need to be more precisely studied, with a particular focus on the various types of underlying heart disease.