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Background Mortality and morbidity are higher among patients with atrial fibrillation and heart failure than among those with heart failure alone. Catheter ablation for atrial fibrillation has been proposed as a means of improving outcomes among patients with heart failure who are otherwise receiving appropriate treatment. Methods We randomly assigned patients with symptomatic paroxysmal or persistent atrial fibrillation who did not have a response to antiarrhythmic drugs, had unacceptable side effects, or were unwilling to take these drugs to undergo either catheter ablation (179 patients) or medical therapy (rate or rhythm control) (184 patients) for atrial fibrillation in addition to guidelines-based therapy for heart failure. All the patients had New York Heart Association class II, III, or IV heart failure, a left ventricular ejection fraction of 35% or less, and an implanted defibrillator. The primary end point was a composite of death from any cause or hospitalization for worsening heart f...

Aims: The FREEZE-cohort study (NCT 01360008) is a prospective observational, multicenter and multinational study to evaluate safety and effectiveness of cryoballoon ablation for pulmonary vein isolation as compared to radiofrequency ablation in patients with paroxysmal or persistent atrial fibrillation (lasting < one year) under the conditions of clinical routine. Methods and Results: The study started in 2011 and anticipates inclusion up to 2000 patients in each of the two treatment groups. A total of 37 centers from 8 countries worldwide, all experienced in at least one of the two ablation techniques, participate in the study. The primary outcome parameter of the study is defined as atrial fibrillation recurrence rate during twelve months of follow-up. Secondary outcome parameters include primary success rates, complication rates in general, specific complications with respect to phrenic nerve palsy and pulmonary vein stenosis, radiation exposure, clinical course including death and repeat ablation. Finally specific procedural aspects will be evaluated in a descriptive manner. Preliminary data of the first 1882 patients show that in clinical practice cryoablation is preferentially performed in patients with paroxysmal atrial fibrillation, whereas application of radiofrequency ablation is equally distributed between patients with persistent and paroxysmal atrial fibrillation. Conclusion: Based on multi-center and multi-national data the FREEZE-cohort study will provide important information on long-term efficacy, clinical effectiveness, complication rates and procedural differences between atrial fibrillation patients treated with either cryoablation or radiofrequency ablation.

To analyze whether left ventricular dyssynchrony (LVD) at baseline is predictive for long-term outcome in heart failure (CHF) patients with left ventricular (LV) dysfunction and conduction disturbances treated with cardiac resynchronization therapy (CRT).In 535 consecutive individuals with CHF scheduled for implantation of a CRT device, LVD was assessed by tissue Doppler imaging (TDI), defined as an electromechanical delay (EMD) difference of ≥40 ms in 2 opposed left ventricular wall regions (septal vs. lateral, anterior vs. inferior). All-cause mortality, heart transplantation, or assist device implantation was defined as combined primary end point. Secondary end points were measures of reverse LV remodeling and of symptomatic improvement.Mean follow-up was 68 ± 36 [range: 4-150] months. LVD at baseline was present in 308 patients (61%). Of these, 24% reached the combined primary endpoint in contrast to 58% of patients without LVD (p0.001). Furthermore, patients with LVD showed pronounced improvement of all secondary end point parameters. In our cohort LVD was an independent predictor for outcome (hazard ratio [95% CI]: 0.30 [0.21-0.42], p0.001).LVD at baseline as assessed by TDI is associated with a more pronounced clinical improvement and is a predictor for transplant-free long-term survival in CRT recipients.

Cheyne-Stokes Respiration and Arrhythmias ObjectiveThis study aimed to investigate whether adequate treatment of Cheyne-Stokes respiration (CSR) reduces the risk of arrhythmic events in patients with chronic heart failure (CHF). MethodsA cohort of 403 registry patients with CHF (LVEF45%, NYHA-class2) and implanted cardioverter-defibrillator devices (ICD) was studied. They underwent overnight polygraphy, with 221 having mild or no CSR (apnea-hypopnea index [AHI] 15/h). Latter ones were offered therapy with adaptive servoventilation (ASV), which 96 patients accepted and 86 rejected. During follow-up (21 15 months) defibrillator therapies were recorded in addition to clinical and physiologic measures of heart failure severity. ResultsEvent-free survival from (a) appropriate cardioverter-defibrillator therapies and (b) appropriately monitored ventricular arrhythmias was shorter in the untreated CSR group compared to the treated CSR and the no CSR group. Stepwise Cox proportional hazard regression analysis showed untreated CSR (a: hazard ratio [HR] 1.99, 95% confidence interval [CI] 1.46-2.72, P < 0.001; b: HR 2.19, 95%CI 1.42-3.37, P < 0.001), but not treated CSR (a: HR 1.06, 95%CI 0.74-1.50; P = 0.77; b: HR 1.21, 95%CI 0.75-1.93, P = 0.43) was an independent risk factor. The treated CSR group showed improvements in cardiac function and respiratory stability compared to the untreated CSR group. ConclusionThis study demonstrates a decrease of appropriate defibrillator therapies by ASV treated CSR in patients with CHF and ICD. A reduced exposure to hyperventilation, hypoxia, and improvement in indices of CHF severity and neurohumoral disarrangements are potential causative mechanisms.

Until now, there is no consensus regarding the definition of a clinical response to cardiac resynchronization therapy (CRT) in patients with chronic heart failure (CHF) and systolic left ventricular (LV) dysfunction. The aim of this study was to evaluate if echocardiography is predictive for an objective improvement in exercise capacity during long-term follow-up of CRT.Each patient underwent echocardiography and spiroergometry both at baseline and at last follow-up. Left ventricular dyssynchrony (LVD) before CRT was defined by tissue Doppler imaging (TDI) as intra-LV delay ≥40 msec (septal-lateral or anterior-posterior). Clinical response to CRT was defined as increase of peakVO2 or as increase of maximal workload10% as compared to baseline.Mean follow-up was 69 ± 37 months. From the 238 consecutive patients included in the study, 141 (59%) were classified as clinical responders and 97 (41%) as nonresponders. Baseline data of responders and nonresponders were comparable. However, clinical responders showed more often LVD (64%) than nonresponders (42%, P = 0.004). On multivariate regression analysis, nonischemic origin of CHF (β-coefficient in the final model 0.1, P = 0.04) and LVD at baseline (β-coefficient in the final model 0.2, P 0.001) were independently associated with clinical response during long-term follow-up. Patients with LVD at baseline had significant more often an improvement of left ventricular ejection fraction10% (P = 0.02) and a reduction of left ventricular end-diastolic diameter (LVEDD)10% (P 0.01) than patients without LVD at baseline.LVD at baseline as assessed by a straightforward echocardiographic approach predicts the long-term clinical response to CRT and is associated with a more pronounced reverse LV remodeling.

Background The purpose of our study was to correlate the incidence of adequate implantable cardioverter-defibrillator (ICD) interventions in hypertrophic cardiomyopathy (HCM) patients with risk markers (RMs) for sudden cardiac death (SCD) plus myocardial fibrosis as detected by late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) imaging. Methods In all, 87 patients with HCM underwent LGE-CMR imaging prior to ICD implantation, performed for secondary (n = 2; 2%) or primary SCD prophylaxis (n = 85; 98%). Fibrosis was graded with a 17-segment left ventricular model (0 = absent, 1=point-shaped, 2=limited to 1 left ventricular segment, 3=involving ≥ 2 segments). During follow-up, ICD memories were read out by a physician blinded to the individual patient data. Results The number of RMs per patient was 1.9 ± 0.8. Myocardial fibrosis was present in 78 patients (90%); 26 (30%) had a fibrosis score of 3. During follow-up (3.5 ± 2.6 [range, 0.2-11.4 years]), 15 patients had 50 appropriate ICD interventions. Episodes of atrial fibrillation were found in 28 patients. Fibrosis severity correlated with occurrence of ventricular tachycardia (Cramer's V, or φc = 0.4, P 0.001) and atrial fibrillation (φc = 0.6, P 0.001). On multivariate regression analysis, an independent association between myocardial fibrosis (s = 0.6, P 0.01) and sustained ventricular tachycardia was found. Conclusions In HCM patients treated with ICD implantation because of a high SCD risk by traditional RM assessment, a high rate of arrhythmic events was observed during long-term follow-up. In a cohort of patients with clinical markers for high risk of SCD, severity of myocardial fibrosis as detected by an easy LGE-CMR scoring system was associated with future arrhythmic events and appropriate ICD therapies.

Predictors of AF Recurrence After Cryoballoon PVI. Introduction: In patients with atrial fibrillation (AF) undergoing pulmonary vein isolation, cryoballoon technique (cryoPVI) has been adopted in many centers. This study aimed to evaluate predictors of AF recurrence including impact of sleep-disordered breathing (SDB). Methods and Results: In 82 patients consecutively assigned to cryoPVI cardiorespiratory screening for SDB, assessment of medical history, ECG, echocardiography, standard laboratory measurement, and blood gas analysis were performed prior to intervention. After a 3-month blanking period, a 7-day Holter ECG was performed at 3, 6 and then every 6 months to determine AF recurrence. Seventy-five patients (69 paroxysmal AF, 6 persistent AF, 22 female, age 60 ± 9 years) completed at least 6-month follow-up. Median follow-up of 12 months (interquartile range 6–18 months) confirmed maintenance of sinus rhythm in 69.4% of these patients. Stepwise forward regression model revealed moderate to severe SDB (cut-off apnea-hypopnea-index (AHI) ≥ 15 per hour; Hazard Ratio (HR) 2.95, P = 0.04), early recurrence of AF (HR 8.74, P < 0.001), persistent AF (HR 7.16, P < 0.001), preprocedural class III-antiarrhythmic drug treatment (HR 3.63, P = 0.02), but not SDB per se (AHI ≥ 5 per hour) as independent predictors for AF recurrence. Conclusion: Moderate to severe SDB is a treatable condition that independently predicts AF recurrence in patients undergoing cryoPVI. Screening for SDB and adequate treatment may improve long-term success of cryoPVI. (J Cardiovasc Electrophysiol, Vol. 23, pp. 18-25, January 2012)

We report on the efficacy and follow-up data of pulmonary vein Isolation using the 23 / 28 mm Arctic Front Cryoballoon (Cryocath Canada), which isolates parts of the venous antrum and venous ostium in patients with atrial fibrillation. The technique is safe and highly effective in treating paroxysmal atrial fibrillation. Acutely we could isolate 100 % of the targeted veins comparable to radiofrequency energy. During a mean follow-up period of 8,5 ± 6 months 57 % of the patients had no recurrence of atrial fibrillation at all. 15 % showed a recurrence only during the first three months. Right phrenic nerve damage is the most common complication, but it recovers within months. Avoidance of phrenic nerve palsy is possible with refined use of different balloon diameters and pacing maneuvers.

Background: All current cardiac resynchronization therapy (CRT) devices allow the programming of the atrioventricular (AV/PV) delays and the sequential stimulation of the ventricles via the inter ventricular (VV) delay. Aim: This post hoc analysis of the RHYTHM II study was conducted to compare the reverse remodeling associated with VV delay optimization in patients randomly assigned to simultaneous (SIM) biventricular stimulation versus patients assigned to optimized VV delay programming (OPT) (1:3 randomization scheme). Methods: The analysis included 14 patients assigned to the SIM group and 34 patients to the OPT group who completed the 6-month follow-up period with paired echocardiographic recordings. Results: In both study groups, changes consistent with left ventricular (LV) remodeling were observed between baseline and 6 months, with significant improvements in LV function and decrease in LV dimensions. In the OPT group, there was also a decrease in left atrial diameter and mitral valve closure to opening time. At 6 months, the overall proportion of echocardiographic responders (≥10% decrease in LV end-systolic volume or ≥5% absolute increase in LV ejection fraction) was similar in both groups. The optimal AV/VV delays, evaluated by maximization of LV outflow tract velocity time integral, changed over time. Conclusions: Ventriculo-ventricular delay optimization was associated with better immediate hemodynamic function than simultaneous biventricular stimulation, though did not promote additional reverse remodeling at 6 months and did not increase the proportion of echocardiographic responders to CRT. Optimization of both the AV and VV intervals was patient-specific and optimal values changed over time.

Objectives The purpose of this study was to investigate the efficacy safety of the novel cryoballoon device (Arctic Front, Cryocath, Quebec, Canada). Background Antral pulmonary vein (PV) ablation with radiofrequency energy is widely used as a strategy for catheter ablation of paroxysmal atrial fibrillation (PAF). A novel double lumen cryoballoon catheter was designed for circumferential pulmonary vein isolation (PVI) with the cryoablation technique. Methods We consecutively enrolled 346 patients with symptomatic, drug refractory paroxysmal (n = 293) or persistent (n = 53) atrial fibrillation (AF). In all patients, PVI of all targeted PVs was the therapeutic aim. The primary end points of this nonrandomized study were: 1) acute isolation rate of targeted PV; and 2) first electrocardiogram-documented recurrence of AF. The secondary end point was occurrence of PV stenosis or atrio-esophageal fistula. Results The 1,360 of 1,403 PVs (97%) were targeted with balloons or balloons in combination with the use of Freezor Max (Cryocath). We found that ablation with the cryoballoon resulted in maintenance of sinus rhythm in 74% of patients with PAF and 42% of patients with persistent AF. No PV narrowing occurred. The most frequent complication was right phrenic nerve palsy observed during cryoballoon ablation at the right superior PV. Conclusions Pulmonary vein isolation with a new cryoballoon technique is feasible. Sinus rhythm can be maintained in the majority of patients with PAF by circumferential PVI using a cryoballoon ablation system. Cryoablation was less effective in patients with persistent AF than in patients with PAF.

Aims This study investigates the influence of cardiac resynchronisation therapy (CRT) on sleep disordered breathing (SDB) in patients with severe heart failure (HF). Methods and results Seventy-seven patients with HF (19 females; 62.6±10 years) eligible for CRT were screened for presence, type, and severity of SDB before and after CRT initiation (5.3±3 months) using cardiorespiratory polygraphy. NYHA class, frequency of nycturia, cardiopulmonary exercise, 6-minute walking test results, and echocardiography parameters were obtained at baseline and follow-up. Central sleep apnoea (CSA) was documented in 36 (47%), obstructive sleep apnoea (OSA) in 26 (34%), and no SDB in 15 (19%) patients. CRT improved clinical and haemodynamic parameters. SDB parameters improved in CSA patients only (apnoea hypopnoea index: 31.2±15.5 to 17.3±13.7/h, p

Failure to enter the coronary sinus (CS) with a guiding catheter and entering its tributaries remains challenging in left ventricle (LV) pacing lead implants for cardiac resynchronization therapy (CRT). A dual telescoping catheter system (8F outer/6F inner) is designed to provide the ability to adjust the catheter curve size, shape and/or reach to the patients' anatomy avoiding the need for catheter change.Five different designs for CS cannulation were randomly tested in 64 patients scheduled for CRT device implant.In 33 consecutive patients three adaptable telescoping guiding catheter systems were tested per patient, the adaptable catheters had higher overall cannulation success rates (68, 63 and 62%) compared to the fixed shape catheter (46%) and an greater cannulation success rate when the CS location was not known (70, 53 and 72% vs 33% for the fixed shape). In a second group of 31 CRT patients the two telescoping catheters had similar high levels of success (71-80%), with or without using the inner catheter.The telescopic system is adaptable to a wide range of anatomical variations in patients and can result in a higher CS cannulation success rate due to its adjustability in the RA in search for the CS ostium. On top of this the inner catheter allows for sub-selecting the CS tributaries.

Sirs: A 68-year-old man with mitral valve replacement but former mitral regurgitation II (left atrial size 39 mm) and coronary artery sclerosis suffered syncope due to a sustained ventricular tachycardia. Before this event, the patient had neither palpitations nor was arrhythmia documented by Holter ECGs. A single chamber cardioverter/defibrillator (SJM, Atlas VR) was implanted. Routine abdominal ultrasound did not reveal pathologic findings at that

Background The clinical value of interventricular (V-V) delay optimization in patients with chronic congestive heart failure (CHF) undergoing implantation of a device for cardiac resynchronization therapy (CRT) has not been clearly demonstrated. Methods RHYTHM II was a single-blind randomized trial including 121 recipients of a device for CRT with cardioverter/defibrillator capabilities (CRT-D) randomly assigned in a 1:3 ratio to simultaneous (n = 30) versus optimized (OPT) (n = 91) biventricular pacing. V-V delay was optimized by echocardiography. The study end points were (1) freedom from CRT-D system–related complications and (2) changes between preimplant and 6 months of follow-up in ( a ) New York Heart Association CHF functional class, ( b ) distance covered during a 6-minute hall walk, and ( c ) quality of life (QOL). Results In the OPT group, the V-V delay ranged from 0 to 80 milliseconds, with 28.4% of patients stimulated at an OPT V-V delay of 0 milliseconds. The overall 6-month survival free of adverse events requiring invasive interventions was 81.8%. In the whole cohort, 6 months of CRT-D was associated with a significant decrease in New York Heart Association class, increase in the distance covered during the 6-minute hall walk, and improvement in QOL (each P Conclusions Cardioverter-defibrillator capabilities was associated with a significant alleviation of CHF symptoms, increase in functional capacity, and improvement in QOL. The optimization of the V-V delay conferred no additional benefit compared with simultaneous biventricular stimulation.

Since the development of the first epicardial left ventricular pacemaker leads, the design of transvenous coronary leads has progressed tremendously. Due to the safe access to the target region independent of previous surgical interventions and a low morbidity, the transvenous placement has become the method of choice. Catheterization of the coronary sinus is required to place the coronary venous lead. The most difficult anatomical situation is the pipe-shaped coronary sinus. A systolic compression of the proximal coronary sinus may be associated with a risk of dissection particularly in elderly patients. Access to the coronary sinus is best made by two combinationsystemswithasteerableelectrophysiology catheter oratelescoping inner catheter. Furthermore, special guiding catheters for the access from the right subclavian vein particularly to upgrade right-sided pacemakers and ICD systems have been developed. Complex, i.e. sharp-angled and corkscrew veins may only serve as target veins, if sharp-angled angiography catheters and over the wire technique are used. The pseudobipolar stimulation against the ring of the right ventricular lead has been developed for the safe function of a CRT defibrillator. This design is associated with an anodal stimulation of the right ventricle, which might result in clinical nonresponders especially in patients with optimal left ventricular pacing mode (30%). For this reason, coronary sinus leads should basically be designed as bipolar leads.

Introduction Patients with advanced heart failure received cardiac resynchronisation therapy at our centre, if the following selection criteria were fulfilled: NYH/ class ≥3, left bundle branch block with QRS width ≥150 ms, left ventricular ejection fraction 60 mm, VO 2 peak

Inter- and intraventricular conduction defects may result in unfavourable haemodynamic consequences which may significantly deteriorate preexisting heart failure. Cardiac resynchronization therapy (CRT) has been shown to improve the outcome in patients with severely symptomatic systolic heart failure and wide QRS complex. Still unanswered questions are: (a) optimal patient selection and prediction of response, (b) optimal definition of "asynchrony" (QRS duration, echo parameters), (c) optimal tailoring of CRT (AV-delay, VV-delay, pacing site), (d) extended indications. This review will discuss "extended" indications for CRT not yet proven effective but worth being studied in controlled trials in the near future.

Pressure–volume measurements by conductance catheter enable assessment of systolic and diastolic left ventricular function and quantification of mechanical dyssynchrony in a continuous and on-line fashion. The present review gives an overview of the (potential) applications of this methodology in relation to cardiac resynchronization therapy.

Aims Several studies on the acute effect of cardiac resynchronization in patients with advanced heart failure (HF) and left bundle branch block (LBBB) have shown that left and biventricular stimulation increase pulse pressure and contractility, while patients with a QRS complex \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \({\) \end{document}150 ms underwent right, left and biventricular stimulation at different AV delays. Acute response was defined as 10% pulse pressure increase. 165 of 188 patients (88%) in sinus rhythm (47 women, mean age 62.5±10 years, ejection fraction 23±8%, NYHA class 3.1±0.3) were regarded acute responders. 10% of 103 patients with dilated cardiomyopathy and 16.5% of 79 patients with coronary artery disease were considered non-responders. 29 patients (81%) with two posterolateral veins were acute responders with 10 of them (33%) being responders in only one vein. 54 patients had an atrio-left ventricular pulse pressure increase of 10.7±10.6%, 9.8±6.4% in 48 patients with atrio-biventricular stimulation. At one-year follow-up, heart failure had significantly improved from NYHA class 3.1±0.4 to 2.1±0.7 (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(P{

In patients with systolic heart failure the assessment of peak oxygen consumption during cardiopulmonary exercise (CPX) testing provides an objective measure of functional capacity and important prognostic information. Several studies in pacemaker therapy and in cardiac resynchronization therapy (CRT) have used peak oxygen uptake as an endpoint. This article reviews the impact of CPX testing on patient selection for CRT.

Based on the recent experience of 464 patients with left ventricular pacing, we report on specific characteristics of various leads and lead types for left ventricular stimulation. In addition to describing the technique and indications for epicardial lead usage, commercially available coronary vein leads are introduced and discussed. Since there is no universally applicable coronary vein lead, the individually optimal lead choice and the sequelae of an erroneous lead selection are described in typical clinical examples.

The implantable defibrillator (ICD) is an established therapy in the prevention of sudden cardiac death by defibrillation of ventricular fibrillation. Another specific feature of the ICDs is antitachycardia pacing (ATP) of ventricular tachycardia. Several studies report success rates of ATP in 83 to 98% of cases. In clinical practice the success of terminating ventricular tachycardia is estimated only by automatic device analysis. Therefore the objective of this study was to confirm the efficacy of ATP based on the evaluation of stored electrograms. From the German Ventritex MD-register stored electrograms of 613 monomorphic ventricular tachycardias in 44 patients were analyzed retrospectively. The cycle length of the ventricular tachycardias was between 265 and 560 ms. The success rate of ATP-induced termination of the episodes reached 89.3%; another 2.3% of the ventricular tachycardias were accelerated by antitachycardia pacing into ventricular fibrillation. Left ventricular function did not influence the success rate, but the success rate was lower for fast ventricular tachycardias >200/min (63.9%). For ventricular tachycardias 90% was recorded for 80% of them. The very high success rate of the first ATP attempt in ICD therapy can be achieved with uniform programming, and is confirmed for ventricular tachycardias analyzed on the basis of stored electrograms.

Supraventricular tachyarrhythmias are a major cause of inappropriate defibrillator shocks. Sleep-disordered breathing (SDB) is a known risk factor for atrial fibrillation (AF). We hypothesized that Cheyne–Stokes respiration (CSA) and obstructive sleep apnea (OSA) have an impact on inappropriate defibrillator discharges in patients witch chronic heart failure (CHF) and cardiac resynchronization therapy with defibrillator (CRT-D). In this study, 172 patients with CHF (LVEF ≤ 45 %, NYHA-class ≥ 2) and CRT-D underwent overnight polygraphy; 54 had no SDB (apnea–hypopnea index

GRONEFELD, G.C., et al.: Morphology Discrimination: A Beat-to-Beat Algorithm for the Discrimination of Ventricular From Supraventricular Tachycardia by Implantable Cardioverter Defibrillators. Inappropriate therapy of SVTs by ICDs remains a major clinical problem despite enhanced detection criteria like “sudden onset” and “rate stability” in third-generation devices. Electrogram morphology discrimination offers an additional approach to improve discrimination of supraventricular tachycardia (SVT) from ventricular tachycardia (VT). In a prospective, multicenter study, patients received an ICD with a beat-to-beat algorithm for morphological analysis of the intracardiac electrogram (Morphology Discrimination, MD). A nominal programming for standard enhancement criteria and morphology discrimination was required at implant. Electrogram storage of tachycardia episodes irrespective of delivery of therapy was used to assess sensitivity and specificity of the morphology algorithm alone and in combination with established detection criteria. During a 12 6 6-month follow-up, 886 episodes of device stored electrograms from 82 of 256 patients were evaluated. At nominal settings, the MD algorithm correctly identified 423 of 551 episodes as VT resulting in sensitivity of 77%. The classification of SVT was met in 239 of 335 episodes resulting in specificity of 71%. In combination with sudden onset, sensitivity increased to 99.5% at the expense of specificity (48%). In conclusion, SVT-VT discrimination based on morphological analysis alone results in limited sensitivity and specificity. Programming the monitor mode allows individual assessment of the performance of this detection enhancement feature during clinical followup without compromising device safety. Only in patients with documented efficacy of morphology discrimination should this feature be subsequently activated.

Background —Previous studies of pacing therapy for dilated congestive heart failure (CHF) have not established the relative importance of pacing site, AV delay, and patient heterogeneity on outcome. These variables were compared by a novel technique that evaluated immediate changes in hemodynamic function during brief periods of atrial-synchronous ventricular pacing. Methods and Results —Twenty-seven CHF patients with severe left ventricular (LV) systolic dysfunction and LV conduction disorder were implanted with endocardial pacing leads in the right atrium and right ventricle (RV) and an epicardial lead on the LV and instrumented with micromanometer catheters in the LV, aorta, and RV. Patients in normal sinus rhythm were stimulated in the RV, LV, or both ventricles simultaneously (BV) at preselected AV delays in a repeating 5-paced/15-nonpaced beat sequence. Maximum LV pressure derivative (LV+dP/dt) and aortic pulse pressure (PP) changed immediately at pacing onset, increasing at a patient-specific optimal AV delay in 20 patients with wide surface QRS (180±22 ms) and decreasing at short AV delays in 5 patients with narrower QRS (128±12 ms) ( P P P Conclusions —In this population, CHF patients with sufficiently wide surface QRS benefit from atrial-synchronous ventricular pacing, LV stimulation is required for maximum acute benefit, and the maximum benefit at any site occurs with a patient-specific AV delay.

In conjunction with pharmacologic therapy, pacing has been proposed as a potential treatment to decrease symptoms in patients with moderate-to-severe congestive heart failure (CHF). Uncontrolled studies of pacing therapy for CHF dealing with different pacing sites, modes of pacing, and atrioventricular delays have reported mixed outcomes. The Pacing Therapies in Congestive Heart Failure (PATH-CHF) study is a single-blind, randomized, crossover, controlled trial designed to evaluate the effects of pacing on acute hemodynamic function and to assess chronic clinical benefit in patients with moderate-to-severe CHF. The effect of pacing on oxygen consumption at peak exercise and at anaerobic threshold during cardiopulmonary exercise tests, and on 6-minute walk distance, have been selected as primary endpoints of the study. Secondary endpoints of the trial were changes in New York Heart Association (NYHA) functional class, quality-of-life as assessed by the Minnesota Living with Heart Failure questionnaire, and hospitalization frequency. Finally, changes in ejection fraction, cardiac output, and filling pattern were assessed by echocardiography. The trial was planned to include 53 patients from 7 centers in Europe over a period of 3 years. The study was divided into 2 parts: acute testing and chronic follow-up. The acute study, performed during the pacemaker implantation, involved extensive testing using a custom-designed computer (FLEXSTIM) and a unique burst pacing protocol (FLEXSTIM protocol) to determine the best ventricular pacing sites and the most appropriate atrioventricular delays. The chronic phase consisted of a crossover study designed to test in each patient the best univentricular pacing site and biventricular pacing as assessed by the acute hemodynamic study. The study started with the first implant in 1995 and has, to date, included 42 patients. The study is expected to be completed by the end of 1998. The results of a first interim analysis showed trends toward improvement in all primary and secondary endpoints during the pacing periods compared with no pacing.

Our goal was to evaluate acute effects of left atrial lesion formation and volume overload on hemodynamics during pulmonary vein antrum isolation (PVAI) as it might be a potential cause of acute pulmonary edema. In consecutive patients presenting for PVAI, open irrigation ablation was performed (50 W, 48°C, 15 s lesion duration, saline flow rate 30 mL/min). Blood samples were drawn from the left atrium and the pulmonary artery immediately before and 30 min after PVAI. The cardiac output (CO) and stroke volume (SV) were calculated by the method of Fick. We included 61 (27 female, 61 ± 11 years) patients suffering from paroxysmal (px; 33) or persistent (per; 28) atrial fibrillation (AF) in this study. A total of 2,917 ± 242 mL of volume was infused (2,651 ± 223 mL pxAF vs. 3,184 ± 255 mL perAF, (p

SUMMARY Background: Obstructive sleep apnea (OSA) is more common in patients with atrial fibrillation (AFib). Recently, an additional association between central sleep apnea/CheyneStokes respiration (CSA/CSR) and AFib has been described. The aim of this study was to investigate the prevalence and type of sleep-disordered breathing in patients with AFib and normal systolic left ventricular function. Methods: 150 patients (110 men and 40 women, aged 66.1 ± 1.7 years) underwent cardiorespiratory polygraphy, capillary blood gas analysis, measurement of NT-proBNP, and echocardiography to determine the diameter of the left atrium (LAD) and the peak systolic pulmonary artery pressure (PAP). Results: Sleep-disordered breathing was documented in 74% of all patients with AFib (43% had OSA and 31% had CSA/CSR). Patients with CSA/CSR had a higher PAP, a higher apnea-hypopnea index, a greater LAD, and a lower capillary blood pCO2 than patients with OSA. Conclusions: Patients with AFib were found to have not only a high prevalence of obstructive sleep apnea, as has been described previously, but also a high prevalence of CSA/CSR. It remains unknown whether CSA/CSR is more common in AFib because of diastolic dysfunction or whether phenomena associated with CSA/CSR predispose to AFib. Further research on this question is needed.

Background Cardiac transplantation remains the gold standard for treating end-stage heart failure. However, because of donor shortage and posttransplant complications alternative options are needed. Methods We investigated the impact of cardiac resynchronization therapy on clinical outcome in 545 patients with left bundle-branch block and interventricular asynchrony, who fulfilled the cardiac criteria for cardiac transplantation listing. Primary end point was heart failure death. Secondary end points were New York Heart Association class, functional (cardiopulmonary exercise tolerance, 6-minute hall walk distance), and morphologic (left ventricular end-diastolic diameter) factors. Results The average follow-up period was 39.6 months (standard deviation, 26.1 months). In total, 1,784 years of observation were accrued. The percentage of nonresponders (no functional and morphologic improvement during follow-up) was 21.2%. One-year and 3-year freedom from heart failure death was 92.3% and 77.3%, respectively. Functional variables improved, but the left ventricular end-diastolic diameter decreased during the first 6 months of cardiac resynchronization therapy only in patients who survived during follow-up. Under cardiac resynchronization therapy, 42.5% (n = 34) of the cardiac transplantation candidates with atrial fibrillation at baseline returned to sinus rhythm. Conclusions Our data suggest that cardiac resynchronization therapy is a reliable long-term therapeutic option for the treatment of end-stage heart failure and intraventricular asynchrony.

Objective: In patients with dilated cardiomyopathy (DCM), left bundle branch block (LBBB) is a common finding. The characteristic feature is an asynchronous septal wall motion and most frequently a delay of the lateral and/or posterior wall segments. With the onset of cardiac resynchronization therapy, there is a focus on the specific pathophysiology of a LBBB. However, quantitative data on regional myocardial oxygen consumption (MVO2) and blood flow (MBF) are missing. Methods: We studied 31 patients with severe DCM and LBBB (ejection fraction 22.1±7.1%) and 14 patients with mild to moderate DCM without LBBB (ejection fraction 46.7±7.9%). Global and regional MVO2 as well as MBF were determined from a dynamic 11C-acetate positron emission tomography (PET) study. Results: Global MVO2 and MBF were lower in the DCM group with LBBB than in the control group (P

NIEHAUS, M., et al.: Adjustment of Maximum Automatic Sensitivity (Automatic Gain Control) Reduces Inappropriate Therapies in Patients with Implantable Cardioverter Defibrillators. Patients with ICDs might experience oversensing associated with inappropriate shock therapy when paced at low bradycardia rates or if they have a low intrinsic rhythm. The amplifier gain of automatic gain control is maximal at long RR intervals and might lead to oversensing of myopotentials. The hypothesis was that an individual adjustment of the sensitivity floor could reduce inappropriate ICD therapies. Fourteen patients implanted with the VENTAK MINI I/II and III in whom oversensing and/or inappropriate shocks had been documented were included in this evaluation based on stored episodes. Sensitivity was modified in all ICDs by means of noninvasive software downloading that allowed reprogramming of the maximum sensitivity from 0.14 mV in two steps to 0.27 mV (“Normal,”“Less,”“Least”). Provocation testing (deep inspiration, sit-ups, and abdominal pressing) was conducted at “Nominal” settings (0.14 mV) while the intracardiac electrogram with annotated event marker was running continuously and was repeated at 0.22 mV (Less) and 0.27 mV (Least). All patients evaluated had documented spontaneous episodes due to oversensing before the sensitivity floor was reprogrammed. During provocation testing at Nominal settings, oversensing could be documented in 9 of (64.3%) 14 patients. Provocation testing was repeated after the sensitivity selection was reprogrammed and oversensing could not be provoked in any of the 14 implanted devices. Sensitivity was reprogrammed in all 14 patients to a higher value (5 patients Less, 9 patients Least). After sensitivity adjustment, VF was induced in all patients to verify appropriate arrhythmia detection and termination. Sensitivity reprogramming in patients with documented oversensing eliminates the incidence of inappropriate shock therapy without compromising the ability to detect VF appropriately.

Ventricular resynchronization therapy (VRT) by left or biventricular stimulation is gaining increasing acceptance as a new therapy in addition to drugs in patients with advanced heart failure and intraventricular conduction disturbances. Several studies have demonstrated acute hemodynamic benefit of VRT in these patients, although there are only limited long-term data in small patient cohorts. Many open questions remain: whether to pace both ventricles or the left ventricle alone, the optimal left ventricular pacing site, the criteria used to identify the optimal candidate for VRT (e.g., QRS width), and the importance of an integrated defibrillator function in a VRT device. The Pacing Therapy in Congestive Heart Failure (PATH-CHF) II study is a prospective, randomized, cross-over study currently investigating the potential benefit of VRT in a population with advanced heart failure, with or without an accepted indication for an implantable defibrillator. It focuses on the effects of optimized univentricular pacing in these patients, and both acute hemodynamic and chronic functional effects are assessed. Acute hemodynamic testing mainly investigates the impact of different left ventricular pacing sites, alone or combined with right ventricular sites, on hemodynamic performance. Primary endpoint of the study is an improvement in functional capacity as assessed by cardiopulmonary exercise testing and 6-minute walk distance; secondary endpoints include improvement in quality of life (assessed by Minnesota quality of life score, New York Heart Association (NYHA) functional class, and hospitalization frequency), and improvements in prognostic and hemodynamic parameters. The trial aims to enroll 64 patients with full datum sets (separately in 2 groups with a QRS ofor = 150 or150 msec, respectively) in 9 European centers. The enrollment began September 1998, and is expected to conclude in summer 2000 to reach the number of necessary datum sets.

Rationale: This study investigates the influence of cardiac resynchronization therapy (CRT) on sleep disordered breathing (SDB) in patients with severe chronic heart failure (CHF). Methods and Results: A total of 100 consecutive patients with CHF eligible for CRT (NYHA class III, LBBB, QRS width 150 ms, EF 35%, LVEDD 60 mm) were screened for SDB using cardiorespiratory polygraphy (Embletta®) before device implantation. Mean age 64.8 9.8 years, CAD n 42, DCM n 54, valvular heart disease n 4, mean EF 25.7 6.8%, mean VO2peak 13.4 4.8 ml/kg/min, mean QRS width 185 18 ms. Central sleep apnea (CSA) was documented in 39 patients (39%) and obstructive sleep apnea (OSA) in 34 patients (34%). Only 27 patients (27%) had normal results during cardiorespiratory polygraphy. Twenty-two patients with CSA (central apnea index 15/hr) and 8 patients with OSA were reinvestigated 12 24 weeks after biventricular pacemaker implantation for apnea-hypopnea-index (AHI), NYHA classification, and peak oxygen uptake. Eleven patients demonstrated a significant improvement of CSA by CRT: AHI 32.0 vs 10.8, p 0.0001, EF (23.1 vs 27.8%, p 0.026), NYHA (2.9 vs 2.1 p 0.0002), and oxygen uptake (13.7 vs 17.4, p 0.01). In contrast, CSA remained unchanged in the other 11 patients (AHI 33.9/hr vs 30.7/hr, ns). All nonresponders were also nonresponders with respect to CRT (neither improvement of NYHA, EF nor of oxygen uptake after 3 months of CRT). OSA was not influenced by CRT (AHI 14.0 versus 12.0, p ns), despite good clinical response to CRT (NYHA 3.1 versus 2.3; VO2peak 13.7 versus 17.6 ml/kg/min, p 0.02). Conclusion: In appr. 50 % of patients with CRT, a short term improvement of heart failure symptoms and parameters correlates with a marked improvement in central sleep apnea. In patients who do not show a clinical improvement during the first 3 months of CRT, CSA does also not improve, which supports CSA being a marker for the severity of CHF. In contrast OSA is not influenced by CRT. Because of its pathophysiologic and prognostic significance and the availability of modern treatment options, cardiorespiratory screening should be routinely implemented in the evaluation of CRT patients.

The letter from Dr Knaapen and co-workers raised an interesting and critical point about our conclusion that further studies have to clarify whether long-term cardiac resynchronization therapy (CRT) is able to improve myocardial perfusion and metabolism at a global level, suggesting a regression of cardiomyopathy. This conclusion was based on the observation that global resting MBF and MVO2, which were reduced in our cardiomyopathy patients, …

ObjectivesWe assessed the clinical efficacy of single-site left ventricular (LV) pacing and determined the impact of baseline conduction delay severity on the magnitude of benefit.BackgroundMultisite biventricular pacing can improve heart failure (HF) symptoms in patients with an intraventricular conduction delay by resynchronizing abnormal ventricular contractions and improving LV systolic function.MethodsEighty-six patients with at least New York Heart Association functional class II HF, chronic LV systolic dysfunction, normal sinus rhythm, and a QRS interval over 120 ms were implanted for atrial-synchronized LV pacing. The single-blinded, randomized, controlled, crossover study stratified patients 1:1 by the baseline QRS interval into long (QRS >150 ms) and short (QRS 120 to 150 ms) groups, which were compared during a three-month period of active (univentricular) pacing and a three-month period of inactive (ventricular inhibited) pacing. The primary end point was peak oxygen consumption (Vo2) followed by anaerobic threshold, distance walked in 6 min, and quality-of-life questionnaire score.ResultsTwelve patients were withdrawn before randomization and 17 could not complete both study periods. The short QRS group did not improve in any end point with active pacing. For the long QRS group, peak Vo2increased 2.46 ml/min/kg (p < 0.001), the anaerobic threshold increased 1.55 ml/min/kg (p < 0.001), the distance walked in 6 min increased 47 m (p = 0.024), and the quality-of-life score improved 8.1 points (p = 0.004).ConclusionsLeft ventricular pacing significantly improves exercise tolerance and quality of life in patients with chronic HF, LV systolic dysfunction, and a QRS interval over 150 ms.