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Cardiac resynchronization therapy (CRT) using biventricular pacing has limited efficacy in patients with heart failure (HF) and right bundle branch block (RBBB). Left bundle branch area pacing (LBBAP) is a novel physiologic pacing option. OBJECTIVE The aim of the study was to assess the feasibility and outcomes of LBBAP in HF patients with RBBB and reduced left ventricular systolic function, and indication for CRT or ventricular pacing. METHODS LBBAP was attempted in patients with left ventricular ejection fraction (LVEF) = 5% increase in ejection fraction) to LBBAP were assessed. RESULTS LBBAP was attempted in 121 patients and successful in 107 (88%). Patient characteristics included age 74 +/- 12 years, female 25%, ischemic cardiomyopathy 49%, and ejection fraction 35% +/- 9%. QRS axis at baseline was normal in 24%, left axis 63%, right axis 13%. LBBAP threshold and R-wave amplitudes were 0.8 +/- 0.3 V@ 0.5 ms and 10 +/- 9 mV at implant and remained stable during mean follow-up of 13 +/- 8 months. LBBAP resulted in narrowing of QRS duration (156 +/- 20 ms to 150 +/- 24 ms (P = .01) with R-wave peak times in V-6 of 85 +/- 16 ms. LVEF improved from 35% +/- 9% to 43% +/- 12% (P,.01). Clinical and echocardiographic response was observed in 60% and 61% of patients, respectively. Female sex and reduction in QRS duration with LBBAP were predictive of echocardiographic response and super-response. CONCLUSION LBBAP is a feasible alternative to deliver CRT or physiologic ventricular pacing in patients with RBBB, HF, and LV dysfunction.

INTRODUCTION: MARVEL 2 assessed the efficacy of mechanical atrial sensing by a ventricular leadless pacemaker, enabling a VDD pacing mode. The behavior of the enhanced MARVEL 2 algorithm during variable atrio-ventricular conduction (AVC) and/or arrhythmias has not been characterized and is the focus of this study. METHODS: Of the 75 patients enrolled in the MARVEL 2 study, 73 had a rhythm assessment and were included in the analysis. The enhanced MARVEL 2 algorithm included a mode-switching algorithm that automatically switches between VDD and ventricular only antibradycardia pacing (VVI)-40 depending upon AVC status. RESULTS: Forty-two patients (58%) had persistent third degree AV block (AVB), 18 (25%) had 1:1 AVC, 5 (7%) had variable AVC status, and 8 (11%) had atrial arrhythmias. Among the 42 patients with persistent third degree AVB, the median ventricular pacing (VP) percentage was 99.9% compared to 0.2% among those with 1:1 AVC. As AVC status changed, the algorithm switched to VDD when the ventricular rate dropped less than 40 bpm. During atrial fibrillation (AF) with ventricular response greater than 40 bpm, VVI-40 mode was maintained. No pauses longer than 1500 ms were observed. Frequent ventricular premature beats reduced the percentage of AV synchrony. During AF, the atrial signal was of low amplitude and there was infrequent sensing. CONCLUSION: The mode switching algorithm reduced VP in patients with 1:1 AVC and appropriately switched to VDD during AV block. No pacing safety issues were observed during arrhythmias. ispartof: JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY vol:32 issue:7 pages:1947-1957 ispartof: location:United States status: published

Left ventricular hypertrophy (LVH) caused by cardiac variant Fabry disease (FD) is typically late-onset and may mimic LVH caused by abnormal loading conditions. We aimed to determine the prevalence of FD in a non-selective patient population of everyday practice presenting with LVH, including those with hypertension and valve disease. We measured plasma alpha-galactosidase A activity using dried blood spot tests in 499 (age = 66 ± 13 years, 336 men) Hong Kong Chinese patients with LVH defined as maximal LV septal/posterior wall thickness ≥13 mm on echocardiography. Patients with low enzyme activity underwent mutation analysis of the GLA gene. Eight (age = 53−74 years, all men) unrelated patients (1.6%) had low plasma alpha-galactosidase A activity (0.57 ± 0.27 μmol/L wb/hr) and all were confirmed to have the GLA IVS4 + 919G &gt, A mutation. FD patients presented with heart failure (n = 5), heart block (n = 2), ventricular tachycardia (n = 1), chest pain (n = 3), and/or murmur (n = 1). Uncontrolled hypertension (n = 4) and/or severe mitral/aortic valve pathology (n = 2) were frequent. Ethnic subgroups included Teochew (n = 5), Canton (n = 2), and Wenzhou (n = 1). Endomyocardial biopsy (n = 6) revealed hypertrophic myocytes with vacuolization and dense lamellar bodies. Late-onset IVS4 + 919G &gt, A FD is prevalent among Chinese LVH patients, and should be considered as a cause of LVH in adult patients even when hypertension and/or valve pathology are present.

Background: Cardiac resynchronization therapy (CRT) using biventricular pacing (BVP) has limited efficacy in patients with heart failure (HF) and right bundle branch block (RBBB). Left bundle branch area pacing (LBBAP) has been reported as an alternative option for BVP-CRT. The aim of the study was to assess the feasibility and outcomes of LBBAP in patients with RBBB and indication for CRT in an international, multicenter, collaborative study. Methods: LBBAP was attempted in patients with LVEF

BACKGROUND: The MARVEL (Micra Atrial TRacking Using a Ventricular AccELerometer) 2 study assessed the efficacy of atrioventricular (AV) synchronous pacing with a Micra leadless pacemaker. Average atrioventricular synchrony (AVS) was 89.2%. Previously, low amplitude of the Micra-sensed atrial signal (A4) was observed to be a factor of low AVS. OBJECTIVE: The purpose of this study was to identify predictors of A4 amplitude and high AVS. METHODS: We analyzed 64 patients enrolled in MARVEL 2 who had visible P waves on electrocardiogram for assessing A4 amplitude and 40 patients with third-degree AV block for assessing AVS at rest. High AVS was defined as >90% correct atrial-triggered ventricular pacing. The association between clinical factors and echocardiographic parameters with A4 amplitude was investigated using a multivariable model with lasso variable selection. Variables associated with A4 amplitude together with premature ventricular contraction burden, sinus rate, and sinus rate variability (standard deviation of successive differences of P-P intervals [SDSD]) were assessed for association with AVS. RESULTS: In univariate analysis, low A4 amplitude was inversely related to atrial function assessed by E/A ratio and e'/a' ratio, and was directly related to atrial contraction excursion (ACE) and atrial strain (Ɛa) on echocardiography (all P ≤.05). The multivariable lasso regression model found coronary artery bypass graft history, E/A ratio, ACE, and Ɛa were associated with low A4 amplitude. E/A ratio and SDSD were multivariable predictors of high AVS, with >90% probability if E/A

Fabry Disease (FD) is a systemic disorder that can result in cardiovascular, renal, and neurovascular disease leading to reduced life expectancy. FD should be considered in the differential of all patients with unexplained left ventricular hypertrophy (LVH). We therefore performed a prospective screening study in Edmonton and Hong Kong using Dried Blood Spot (DBS) testing on patients with undiagnosed LVH. Participants found to have unexplained LVH on echocardiography were invited to participate and subsequently subjected to DBS testing. DBS testing was used to measure α-galactosidase (α-GAL) enzyme activity and for mutation analysis of the α-galactosidase (GLA) gene, both of which are required to make a diagnosis of FD. DBS testing was performed as a screening tool on patients (n = 266) in Edmonton and Hong Kong, allowing for detection of five patients with FD (2% prevalence of FD) and one patient with hydroxychloroquine-induced phenocopy. Left ventricular mass index (LVMI) by GLA genotype showed a higher LVMI in patients with IVS4 + 919G > A mutations compared to those without the mutation. Two patients were initiated on ERT and hydroxychloroquine was discontinued in the patient with a phenocopy of FD. Overall, we detected FD in 2% of our screening cohort using DBS testing as an effective and easy to administer screening tool in patients with unexplained LVH. Utilizing DBS testing to screen for FD in patients with otherwise undiagnosed LVH is clinically important due to the availability of effective therapies and the value of cascade screening in extended families.

Funding Acknowledgements Medtronic, Inc. Background/Introduction Accelerometer (ACC)-based AV synchronous pacing by tracking atrial activity is feasible using a leadless ventricular pacemaker. Patients may experience variable AV conduction (AVC) and/or atrial arrhythmias during the lifetime of their device. ACC-based AV synchronous pacing should facilitate AVC and pace appropriately in those two common rhythms. Purpose To characterize the behavior of ACC-based AV synchronous pacing algorithms during paroxysmal AV block (AVB) and atrial arrhythmias. Methods The MARVEL2 (Micra Atrial tRacking using a Ventricular accELerometer) was a 5-hour acute study to assess the efficacy of atrial tracking with a temporarily downloaded algorithm into a Micra leadless pacemaker. Patients with a history of AVB were eligible for inclusion. The MARVEL2 algorithm included a mode-switching algorithm that switched between VDD and VVI-40 depending upon AVC status. The AVC algorithm requires 2 ventricular paces (VP) at 40 bpm out of 4 pacing cycles to switch to VDD. Results Overall, 75 patients (age 77.5 ± 11.8 years, 40% female, median time from Micra implant 9.7 months) from 12 centers worldwide were enrolled. During study procedures, 40 patients (53%) had normal sinus rhythm with complete AVB, 18 (24%) had 1:1 AVC, 5 (7%) had varying AVC status, 8 (11%) had atrial arrhythmias, and 2 other rhythms. Two patients with complete AVB had the AVC mode switch feature disabled due to an idioventricular rate >40 bpm. Among the 40 subjects with a predominant 3rd degree AVB and normal sinus function the median %VP was 99.9% compared to 0.2% among those with 1:1 AVC (Figure). In the patients with 1:1 AVC, there were 64 opportunities to AVC mode switch with 48 switching to VDI-40. In the other 16 cases (2 patients) the mode remained VDD due to sinus bradycardia varying between 40-45 bpm. High %VP was observed in 2 patients with 1:1 AVC and sinus bradycardia 300 ms (N = 2). Among patients with varying AVC, the algorithm appropriately switched to VDD when the ventricular rate was paced at 40 bpm. During infrequent AVB or AF with ventricular response >40 bpm, VVI-40 mode was maintained. In patients with AF, the ACC signal was of low amplitude and there was infrequent sensing, resulting in VP at the lower rate (50 bpm). In the one patient with atrial flutter, the ACC was intermittently detected, resulting in VP at 67 bpm (IQR 66-67 bpm). Conclusion(s) The mode switching algorithm in the MARVEL2 reduced %VP in patients with 1:1 AVC and appropriately switched to VDD during complete AVB. If greater AV synchrony or rate support is required, disabling the AVC algorithm may be appropriate for low grade AVB or idioventricular rhythms. In the presence of atrial arrhythmias, the algorithm paced near the lower rate. Abstract Figure. Distribution of VP% by heart rhythm

Background Utilization of cardiac Magnetic Resonance Imaging (cMRI) as an imaging modality in clinical practice is rapidly increasing. More evidence from randomized studies establishing clinical safety and performance of pacing systems in patients undergoing a cMRI scan is needed. Objectives The purpose of this prospective, multi-center, randomized study was to demonstrate safety and efficacy of the Accent MRI conditional pacing systems in patients undergoing cMRI scan. Methods Patients (n = 283) indicated for dual-chamber pacemaker implant were randomized to either the MRI Group (MG) (n = 140) or the Control Group (CG) (n = 143) after successful device implantation of the Accent MRI system. Clinical evaluation and device interrogation were performed at pre- and post-MRI scan, and one month post-MRI for all patients. At 9–12 weeks post-implant, patients in MG underwent a non-diagnostic cMRI scan at 1.5 Tesla (T) while patients in CG underwent device interrogation and clinical evaluation twice with a 45-minute waiting period in between. The safety endpoint was freedom from MRI scan-related complications and that for efficacy was significant changes in right atrial/ventricular (RA/RV) capture threshold and sensing amplitude between right before MRI, immediately after MRI and one month post-MRI. Results Results showed 100% freedom from MRI scan related complications. There were no significant changes in device performance between pre-MRI scan and one month post MRI scan time points in both study groups. Conclusions cMRI scanning with 1.5 T scanners is safe in patients implanted with the Accent MRI conditional pacing system and has no significant effect on the electrical parameters of the device and leads. This article is protected by copyright. All rights reserved

Cardiac contractility modulation (CCM) has been shown to be effective in improving symptoms and cardiac function in heart failure (HF). However, there is limited data on the role of CCM on long-term survival, which was explored in the present study.Forty-one consecutive HF patients with left ventricular ejection fraction (EF)40% received CCM and were followed for approximately 6 years. They were compared with another 41 HF patients who were enrolled into the HF registry in the same period, and had similar age, gender, EF and etiology of HF. The primary end-point was all cause-mortality. This was stratified by EF. Secondary end-points included HF hospitalization, cardiovascular death, and the composite outcome of death or heart failure hospitalization.The CCM and control groups were well balanced for demographic data, medications and baseline left ventricular EF (27 ± 6 vs 27 ± 7%, p=NS). The mean follow-up duration was 75 ± 19 months in the CCM group and 69 ± 17 months in the control group. All-cause mortality was lower in the CCM group than the control group (39% vs. 71%, respectively; Log-rank χ(2)=11.23, p=0.001). Of note, the improvement of all-cause mortality is more dramatic in patients with EF ≥ 25-40% (36% vs. 80%, Log-rank χ(2)=15.8, p0.001) than those with EF25% (50% vs. 56%, p=NS), CCM vs. control respectively. Similar results were shown for the benefit of CCM in the secondary endpoints of cardiovascular death, and the composite outcome of death or heart failure hospitalization. The occurrence of HF hospitalization showed no significant difference between CCM and control groups in the whole cohort (41% vs. 49%, p=NS), but was significantly lower with CCM in subjects with EF ≥ 25-40% at baseline (36% vs. 64%, Log-rank χ(2)=7.79, p=0.005).CCM resulted in significant improvement of long-term survival, in particular in those with EF ≥ 25-40%. A reduction in heart failure hospitalizations was also seen in this group of patients with less severely reduced EF.

Cremation of implanted cardiac electronic devices can be associated with explosion from rapid gas formation causing potential hazard to the crematoria staffs and facilities. We present four patients who had undergone cremation with a leadless pacemaker (MicraTM , Medtronic Inc., Minneapolis, MN, USA) left inside their bodies. There was neither reported explosion nor damage to the cremation chamber during the cremation process. In this small series, cremation of MicraTM is not associated with noticeable explosion.

Background Cardiac resynchronization therapy utilizing biventricular pacing is an effective therapy for patients with left ventricular (LV) systolic dysfunction, left bundle branch block, and heart failure. Benefits of biventricular pacing may be limited in patients with right bundle branch block (RBBB). Permanent His bundle pacing (HBP) has recently been reported as an option for cardiac resynchronization therapy. The aim of the study was to assess the feasibility and outcomes of HBP in patients with RBBB and heart failure. Methods HBP was attempted as a primary or rescue (failed LV lead implant) strategy in patients with reduced LV ejection fraction, RBBB, QRS duration ≥120 ms, and New York Heart Association class II to IV heart failure. Implant characteristics, New York Heart Association functional class, and echocardiographic data were assessed in follow-up. Results Mean age was 72±10 years, female 15%, with an average LV ejection fraction of 31±10%. HBP was successful in 37 of 39 patients (95%) with narrowing of RBBB in 78% cases. His capture and bundle branch block correction thresholds were 1.1±0.6 V and 1.4±0.7 V at 1 ms, respectively. During a mean follow-up of 15±23 months, there was a significant narrowing of QRS from 158±24 to 127±17 ms ( P =0.0001), increase in LV ejection fraction from 31±10% to 39±13% ( P =0.004), and improvement in New York Heart Association functional class from 2.8±0.6 to 2±0.7 ( P =0.0001) with HBP. Increase in capture threshold occurred in 3 patients. Conclusions Permanent HBP was associated with significant narrowing of QRS duration and improvement in LV function in patients with RBBB and reduced LV ejection fraction. Permanent HBP is a promising option for cardiac resynchronization therapy in patients with RBBB and reduced LV ejection fraction.

Coronary blood flow (CBF) is improved by cardiac resynchronization therapy (CRT) and impaired by right ventricular apical (RVA) pacing in patients with heart failure. However, the underlying mechanism remains unclear.Twenty-nine non-ischemic heart failure patients who responded to CRT underwent transthoracic echocardiography examination including both left anterior descending (LAD) CBF and tissue Doppler imaging in 3 pacing modes: intrinsic conduction, RVA pacing and biventricular (BiV) pacing. LAD velocity-temporal integral (LAD-VTI) and duration were measured. Systolic dyssynchrony was assessed with the standard deviation of a 12-left ventricular segmental model (Ts-SD).BiV pacing improved while RVA pacing reduced CBF compared to intrinsic conduction (all p0.05). Both Ts-SD and ventricular septal velocity deteriorated during RVA pacing but improved during BiV pacing (all p0.05). When systolic dyssynchrony was induced, lower LAD-VTI (9.5 ± 3.4 versus 12.7 ± 5.1cm, p=0.001) and shorter LAD diastolic duration (483 ± 92 versus 542 ± 106 ms, p=0.010) were detected than synchronous status. Systolic dyssynchrony was inversely related to septal velocity (r=-0.41), p0.001 and LAD-VTI (r=-0.30, p=0.007), with the latter found to be moderately correlated to septal velocity (r=0.30, p=0.007).Regional LAD flow was improved in patients subjected to BiV but worsened in those treated with RVA pacing in non-ischemic heart failure CRT responders. Systolic dyssynchrony was more commonly observed in patients subjected to RVA pacing. Reduction of septal velocity with dyssynchrony may directly lead to reduced LAD flow. Improvement of septal velocity by CRT and hence LAD flow may be an important mechanism in determining the response to CRT.

Right ventricular apical (RVA) pacing is associated with adverse left ventricular (LV) remodeling and biventricular (BiV) pacing may prevent it although the mechanisms remain unclear. The current study aimed to assess the role of early pacing-induced systolic dyssynchrony (DYS) to predict adverse LV remodeling.Patients with standard pacing indications and normal LV ejection fraction were randomized either to BiV (n=89) or RVA pacing (n=88). Pacing-induced DYS, defined as the standard deviation of the time to peak systolic velocity (Dyssynchrony Index)33 ms in a 12-segmental model of LV, was measured by tissue Doppler echocardiography at 1 month.At 1 month, 59 patients (33%) had DYS which was more prevalent in RVA than BiV pacing group (52% vs. 15%, χ(2)=28.3, p0.001), though Dyssynchrony Index was similar at baseline (30 ± 14 vs. 26 ± 11 ms, p=0.06). At 12 months, those developing DYS had significantly lower LV ejection fraction (55.1 ± 9.7 vs. 62.2 ± 7.9%, p0.001) and larger LV end-systolic volume (35.3 ± 14.3 vs. 27.0 ± 10.4 ml, p0.001) when compared to those without DYS. Reduction of ejection fraction ≥ 5% occurred in 67% (39 out of 58) of patients with DYS, but only in 18% (21 out of 115) in those without DYS (χ(2)=40.8, p0.001). Both DYS at 1 month (odds ratio [OR]: 4.725, p=0.001) and RVA pacing (OR: 3.427, p=0.009) were independent predictors for reduction of ejection fraction at 12 months.Early pacing-induced DYS is a significant predictor of LV adverse remodeling and the observed benefit of BiV pacing may be related to the prevention of DYS.Centre for Clinical Trials number, CUHK_CCT00037 (URL: http://www.cct.cuhk.edu.hk/Registry/publictrialrecord.aspx?trialid=CUHK_CCT00037).

Background: The acute effects of right ventricular apical (RVA) pacing on left atrial (LA) function in patients with normal ejection fraction are not clear. Methods: A total of 94 patients (age 68.1 ± 11.1 years, 26 men) with implanted RVA-based dual-chamber pacemakers were recruited into this study. Patients who were pacemaker-dependent, in persistent atrial fibrillation or left ventricular ejection fraction

Atrial Dysfunction and Dyssynchrony Predict Atrial High Rate Episodes. Introduction: Right atrial (RA) appendage pacing may prolong atrial conduction time (ACT). This study aimed to investigate if RA appendage pacing can induce intra- and interatrial dyssynchrony and if atrial dysfunction and dyssynchrony can predict atrial high rate episodes (AHREs) in the first year after pacing. Methods and Results: Patients implanted with dual-chamber pacemakers for symptomatic bradycardia were enrolled. Cumulative percentage of RA appendage pacing (Cum%AP) during 1-year follow-up and AHREs were recorded. Full Doppler echocardiography studies were performed before implantation and 1 year after pacing. ACT and peak atrial velocities (Sm-la, Em-la, Am-la) were measured. One hundred ten patients (age 70.5 ± 11 years; 53 males) were recruited and completed 1-year follow-up. ACT of both RA and left atrial (LA) were more prolonged in patients with Cum%AP > 75% than those with 75% (22.3 ± 12.2 milliseconds vs 9.5 ± 6.2 milliseconds; 53.9 ± 29.7 milliseconds vs 19.7 ± 17.3 milliseconds; both P < 0.001). AHREs occurred in 29% of patients. Atrial pump function and interatrial dyssynchrony independently predicted AHREs in multivariate analysis. Receiver operating characteristic curve provided a cutoff value of Am-la

Background: Elevated admission glucose level is a strong predictor of short-term adverse outcome in patients with acute coronary syndrome (ACS). However, the prognostic value of diabetic control (ie, hemoglobin A1c levels) in patients with ACS is still undefined. Hypothesis: Hemoglobin A1c level may predict short-term outcome in patients with ACS. Methods: We conducted a retrospective study with prospective follow-up in 317 diabetic patients with ACS. Patients were stratified into 2 groups based on HbA1c level, checked within 8 weeks of the index admission (optimal control group, HbA1c ≤7%; suboptimal control group, HbA1c >7%). All patients were followed up prospectively for major adverse cardiovascular events (MACE) and mortality for 6 months. Short-term clinical outcomes were also compared between the 2 study groups. Results: In our cohort, 27.4%, 46.4%, and 26.2% patients had unstable angina, non–ST-segment elevation myocardial infarction, and ST-segment elevation myocardial infarction, respectively. In-hospital mortality was similar in both HbA1c groups (3.37% vs 2.88%, P = 0.803). Six-month MACE was also similar (26.40% vs 26.47%, P = 0.919). All-cause mortality, cardiovascular mortality, symptom-driven revascularization, rehospitalization for angina, and hospitalization for heart failure were also similar in both groups. The hazard ratios for 6-month MACE and individual endpoints were also similar in both groups. Conclusions: This study suggests that HbA1c levels before admission are not associated with short-term cardiovascular outcome in diabetic patients subsequently admitted with ACS. © 2011 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.

Functional mitral regurgitation (MR) at different phases of the regurgitant period may respond differently to cardiac resynchronization therapy (CRT). The aims of this study were to examine the impact of CRT on the phasic changes of MR (early vs late systole) and to explore the mechanisms of such changes.Instantaneous MR flow rate and total MR volume were evaluated in 60 patients who had more than mild functional MR before and 3 months after CRT. In addition, indices of global left ventricular (LV) remodeling, mitral deformation, and LV systolic dyssynchrony were assessed.CRT diminished MR volume (38 ± 18 vs 32 ± 20 mL) by reducing both the early (72 ± 47 vs 58 ± 48 mL/sec) and late (48 ± 42 vs 40 ± 42 mL/sec) systolic components (all p values.01). In patients with ≥10% reductions in total MR volume but not in patients without this improvement, there were significant reductions in LV end-systolic volume, increases in LV +dP/dt, decreases in mitral valvular tenting, and improvements of systolic dyssynchrony at 3 months (all P values.05). By multivariate regression, the reductions in LV end-systolic volume and tenting area were independent determinants of a reduction in total MR volume: the reductions in LV end-systolic volume and global dyssynchrony determined the reduction in early systolic MR, and the reductions in tenting area and global dyssynchrony determined reduction in late systolic MR.CRT decreases MR volume by reducing both early and late systolic MR. The determinants of the phasic improvement in functional MR are different.

Aims To examine whether the presence of pre-pacing functional mitral regurgitation (MR) and its improvement would affect the extent of left ventricular (LV) reverse remodelling after cardiac resynchronization therapy (CRT). Methods and results Echocardiographic assessment was performed in 83 patients before and 3 months after CRT. Total MR volume and the early- and late-systolic MR flow rate were assessed. At 3 months, there was reduction in total MR volume (38 ± 20 vs. 33 ± 21 mL) with decrease in both early- (71 ± 52 vs. 60 ± 51 mL/s) and late-systolic (49 ± 46 vs. 42 ± 46 mL/s) MR flow rate (all P < 0.05). Receiver-operating characteristic curve found that an 11% decrease in total MR volume was associated with LV reverse remodelling \[defined by the reduction in LV end-systolic volume (LVESV) of ≥15%\] \[sensitivity, 90%; specificity, 80%; area under the curve (AUC), 0.85; P < 0.001\]. The improvement in early- and late-systolic MR was also associated with LV reverse remodelling, in which improvement in early-systolic MR had higher sensitivity, specificity, and AUC than late-systolic MR. The extent of reverse remodelling with gain in LV ejection fraction and forward stroke volume was greatest in patients with improvement in total MR, intermediate in those with mild or no MR at baseline, and the least in those without improvement in total MR (LVESV, −29.8 ± 12.0 vs. −18.6 ± 16.6 vs. −5.5 ± 8.6%; ejection fraction, 11.8 ± 6.2 vs. 7.0 ± 6.8 vs. 3.0 ± 5.0%; forward stroke volume, 43.1 ± 37.9 vs. 21.1 ± 26.1 vs. 6.8 ± 34.6%; all P < 0.05). Conclusion Improvement of functional MR contributes to LV reverse remodelling after CRT, whereas reduction of early-systolic MR is more powerful than late-systolic MR.

Right ventricular apical (RVA) pacing may induce mechanical dyssynchrony. However, its impact on patients with normal ejection fraction (EF) is not fully understood. This study examined the prevalence and predictors of RVA pacing-induced systolic dyssynchrony by real-time three-dimensional echocardiography (RT3DE), and evaluated its impact on left ventricular (LV) function.Ninety-three patients with sinus node dysfunction and normal EF (50%) received RVA-based dual-chamber pacing were assessed by RT3DE during RVA pacing (V-pace) and intrinsic conduction (V-sense). Systolic dyssynchrony was evaluated using the standard deviation of the time to minimal regional volume of 16 LV segments (Tmsv-16SD), and a cutoff value of 16 ms was determined from 93 normal controls. Systolic dyssynchrony was induced in 49.5% of patients at V-pace with significant increase in LV end-systolic volume (LVESV), decrease in EF, and worsening of Tmsv-16SD (all P0.001). Furthermore, patients who developed dyssynchrony had larger LVESV (P0.001), lower EF (P0.001) at V-pace mode, and higher cumulative percentage of RVA pacing in the past 6 months (P0.001) than those without systolic dyssynchrony. In multivariate logistic regression analysis, independent predictors of developing LV systolic dyssynchrony during V-pace included a low normal EF at V-sense, pre-existing LV hypertrophy, and cumulative RVA pacing40% in the past 6 months.For patients with preserved EF received RVA pacing, half of them would develop systolic dyssynchrony which was associated with EF deterioration and LV enlargement. A low normal EF, a high cumulative percentage of RVA pacing, and pre-existing LV hypertrophy were predictors of developing dyssynchrony.

We sought to determine whether early assessment of left ventricular (LV) dyssynchrony by tissue Doppler imaging may predict progressive ventricular enlargement and cardiac dysfunction after acute myocardial infarction (MI).Forty-seven patients (mean age 59.9 +/- 11.6 years) with normal QRS duration underwent tissue Doppler imaging and contrast-enhanced cardiac magnetic resonance imaging (Ce-MRI) at days 2 to 6, 3 months, and at 1 year after the index MI. Systolic dyssynchrony index (Ts-SD) was calculated from 12 LV segments, and infarct size (IS) by Ce-MRI.The remodeling group (n = 16) (defined as an increase in end-systolic volumeor =10% between 1 year and baseline) had greater initial IS (27.2 +/- 9.6 vs 13.7 +/- 4.1%, P.001) and Ts-SD (50.9 +/- 12.8 vs 33.6 +/- 7.7 milliseconds, P.001) than nonremodeling group (n = 31). At 1 year, the remodeling group had progressive increase in Ts-SD and decrease in LV ejection fraction (57.3 +/- 18.5 and 36.0 +/- 7.6%, respectively; both P.05 vs baseline). Both Ts-SD (odds ratio 1.19 [1.07-1.32], P = .001) and IS (odds ratio 1.65 [1.19-2.29], P = .003) were shown to be independent predictors of progressive LV remodeling. A cutoff value of Ts-SDor =45 milliseconds predicted LV remodeling at 1 year (sensitivity 90.5%, specificity 90.9%, Area-under-curve 0.907) (P = .0005).Left ventricular systolic dyssynchrony is a newly identified predictor of chronic LV remodeling after acute MI, which is independent and incremental to conventional assessment and IS as measured by Ce-MRI.

Background Left atrial (LA) volume is a predictor of cardiovascular events in patients with heart failure. Improvement of LA function and reverse remodeling was observed after cardiac resynchronization therapy (CRT). Objective The purpose of this study was to explore the clinical significance of improvement in LA function after CRT. Methods Echocardiographic studies were performed before and 3 months after CRT in 97 patients (72 men and 25 women; age 63.8 ± 13.3 years) with standard CRT indication but no history of atrial fibrillation (AF). LA active emptying fraction based on the change in volumes (LAV-EF) were calculated, and significant improvement in LA function (LA responder) was defined as a relative increase ≥50% from baseline LAV-EF. The primary end-points were newly developed AF detected by ECG or device and all-cause mortality. Results After 1,200 ± 705 days of follow-up, LA responders (n = 47 [48.5%]) had a significantly lower incidence of AF (12.8% vs 40%, P = .002) and mortality (17% vs 44%, P = .004) than did LA nonresponders. In Cox proportional hazard analysis, LA responders was the only independent predictor of lower risk of new-onset AF (hazard ratio 0.22, 95% confidence interval 0.08–0.61, P = .003), whereas both LA responders (hazard ratio 0.22, 95% confidence interval 0.09–0.53, P 10% reduction in left ventricular end-systolic volume at 3 months; hazard ratio 0.96, 95% confidence interval 0.93–0.99, P = .03) were independent predictors of lower risk of death after CRT. Conclusion Improvement of LA function after CRT was associated with a lower incidence of AF and mortality in AF naive patients with severe heart failure.

Renal insufficiency is prevalent in patients with heart failure and indicates poor prognosis. We examine (i) the relationship between left ventricular (LV) reverse remodeling (RR) and renal function and (ii) the prognostic value of renal function in patients receiving cardiac resynchronization therapy (CRT).The relationship between LV-RR, defined as a 10% reduction in LV end-systolic volume, and renal function was examined in 85 consecutive patients receiving CRT. Echocardiographic assessment and renal function tests were performed before and 3 months after CRT. All-cause mortality and the composite of mortality or heart failure hospitalization between those with preserved or deteriorated renal function at 3 months were assessed by Kaplan Meier analysis.There was a slight improvement in glomerular filtration rate (GFR) in those with LV-RR (n=44; 51.7+/-20.4 vs. 54.2+/-19.1 ml/min/1.73 m2; p=0.024) while a significant deterioration (n=41; 61.9+/-17 vs. 48.8+/-13.0 ml/min/1.73 m2; p0.001) was observed in those without LV-RR. The change (Delta) in GFR was significantly correlated with DeltaLV end-systolic/diastolic volumes and DeltaLV ejection fraction. After follow up of 856.4+/-576.8 days, patients with preserved renal function had significant lower all-cause mortality (log rank chi2=4.82, p=0.029) and the composite endpoints (log rank chi2=5.04, p=0.025).Preservation of renal function was observed in patients with systolic heart failure and renal insufficiency responding to CRT and provided prognostic information. A rapid decline in renal function after CRT was associated with worse clinical outcomes.

ObjectivesWe sought to examine whether cardiac resynchronization therapy (CRT) improves atrial function and induces atrial reverse remodeling.BackgroundCardiac resynchronization therapy is an established therapy for advanced heart failure with prolonged QRS duration, which improves left ventricle (LV) function and is associated with LV reverse remodeling.MethodsA total of 107 heart failure patients (66 ± 11 years) who received CRT and were followed up for 3 months were studied. Atrial function was assessed by M-mode, 2-dimensional echocardiography, transmitral Doppler, tissue Doppler velocity, and strain (ε) imaging. Left atrial (LA) emptying fraction based on the change in areas (LAA-EF) and volumes (LAV-EF) were calculated. The LV reverse remodeling was defined by a reduction of LV end-systolic volume >10%.ResultsIn the responders of LV reverse remodeling (n = 62), LAA-EF and LAV-EF were significantly increased (p < 0.001). Responders also had significant decrease in LA size area and volumetric measurements, both before (p < 0.05) and after atrial systole (p < 0.001). However, these parameters were unchanged in the nonresponders (n = 45, p = NS). In the responders, tissue Doppler velocity analysis showed improvement of contraction velocity in both left (p = 0.005) and right atria (p = 0.018), whereas ε in both atria were increased in all the phases of cardiac cycle, namely ventricular end-systole (p < 0.001), early diastole (p < 0.001), and late diastole (p = 0.007).ConclusionsCardiac resynchronization therapy improves both left and right atrial pump function. The increase in atrial ε throughout the cardiac cycle is likely reflecting the improvement of atrial compliance. These changes lead to LA reverse remodeling with reduction of LA size before and after atrial systole.

Background Deleterious effect on left ventricular (LV) function was observed with conventional right ventricular apical (RVA) pacing. Preliminary data suggested that biventricular pacing (BiV) may be superior to RVA pacing in patients with LV systolic dysfunction. However, the optimal pacing mode and site(s) for patients with normal LV systolic function remain controversial. Methods The Pacing to Avoid Cardiac Enlargement (PACE) trial is a prospective, multicenter, randomized, double blinded, parallel, controlled study aiming to determine if BiV pacing is better than conventional RVA pacing in preserving LV systolic function and preventing remodeling in patients with LV ejection fraction (EF) > or = 45% indicated for pacing. This study targets to recruit 200 patients from various centers in Asia, all of whom will receive BiV pacemaker implantation before being randomized to either atrial-based RVA or BiV pacing for 1 year. Their echocardiographic parameters including LV volumes, left ventricular ejection fraction (LVEF), and dyssynchrony index by tissue Doppler imaging, exercise capacity, quality of life assessment, neurohormone levels, and clinical events will be assessed before and after pacing. The primary endpoints are changes in LV end-systolic volume and LVEF 1 year after pacing. It is designed with 90% power to detect a 5% difference in the LVEF after 1 year of pacing. The enrollment began in 2006. It is expected to conclude at the end of 2008. Conclusion The PACE trial will determine whether atrial-based BiV pacing can preserve LV systolic function and prevent LV adverse remodeling induced by conventional RVA pacing in patients with normal LV systolic function and standard pacing indication.

Objective: To explore the left ventricular (LV) electrical activation pattern in heart failure (HF) and its implication to cardiac resynchronization therapy (CRT). Design and setting: Observational study at the University Teaching Hospital. Patients: 23 optimally treated patients with HF with New York Heart Association class III, QRS duration >120 ms and LV ejection fraction Interventions: The LV endocardial activation pattern and total activation time (Tat) was determined by non-contact mapping and the LV mechanical dys-synchrony was determined by standard deviation (Ts-SD) and maximal difference (Ts-diff) of time to peak systolic contraction (Ts) among 12 LV segments using tissue Doppler imaging before receiving CRT. Main outcome measures: Correlation between electrical and mechanical dys-synchrony; volumetric responder to CRT at 3 months; HF hospitalisation or death by Kaplan–Meier analysis. Results: Homogenous (type I, n = 8) and presence of conduction block (type II, n = 15) patterns were identified. Significant correlation between Tat and Ts-SD/Ts-diff was noted only in type II (r = 0.73/0.56, p = 0.002/0.03). Ts-SD and Ts-diff in type II were significantly longer than type I. 12 patients in type II and 2 in type I were CRT responders (p = 0.01). After 487 (447) days, patients with type II pattern had significantly lower risk of HF hospitalisation or death than those with type I (log rank χ 2 = 5.25; p = 0.02). Conclusion: Patients with type II LV endocardial activation pattern had a more favourable echocardiographic and clinical response to CRT than those with type I pattern.

Proven medical therapy is under-prescribed in heart failure (HF) for various reasons. Cardiac resynchronization therapy (CRT) is of proven value in selected patients with HF; however, the degree of benefit in those without the optimal therapy is not clear.This is a retrospective study comparing the effect of CRT in 30 patients without optimal combination therapy (group 1; 10 (33%) without ACEi or equivalent and 25 (83%) without beta-blockers) to an age, sex, ejection fraction (EF) and New York Heart Association (NYHA) class matched control but with the combination (group 2; n=30) at baseline. All patients were in NYHA class III or IV with EFor = 35% and QRS intervalor = 120 ms. Echocardiographic examination and N-terminal pro-brain natriuretic peptide (NT pro-BNP) levels before and 3 months after CRT were compared between the two groups. The composite endpoints of HF hospitalization or death during follow-up were compared by Kaplan-Meier analysis.There were significantly less improvement in EF (+4.0+/-2.5% vs +10.1+/-3.2%; p0.05) and degree of reverse remodeling in group 1 after 3 months. Patients in group 1 had significantly higher level of NT pro-BNP levels at 3 months (2221+/-2001 pg/mL vs 1038+/-905 pg/mL; p0.001) and higher rates of HF hospitalization or death (53.3% vs 23.3%; Log rank chi2 5.52; p=0.019).Patients receiving CRT but without optimal medical therapy were associated with less echocardiographic and clinical improvement. Optimal medical therapy, if tolerated, before CRT is necessary.

Currently, a clear definition of response to cardiac resynchronization therapy (CRT) is still lacking, and clinical and echocardiographic end points are used. It is also unclear whether patients with clinical responses also improve in echocardiographic end points (and vice versa). To better understand and define response to CRT, the relation between improvement in clinical and echocardiographic parameters was evaluated in 144 patients.

Prolongation of Atrial Effective Refractory Period. Background: A nonexcitatory, nonpropagating atrial extrastimulus delivered in the refractory period of the preceding cycle can prolong the atrial effective refractory period (AERP) and prevent the induction of atrial fibrillation by another AE introduced in the vulnerable period. Whether the effect of this nonexcitatory stimulation (NE) is confined only to its application site is unknown. Methods and Results: Sixteen consecutive patients were recruited into the study and 2 patients were excluded because of development of more sustained atrial fibrillation. NE was commenced by introduction of a 2.0 msec, 20-mA impulse at 50 msec after the preceding captured pacing impulse. AERP of right atrial septum, a distant site to NE application, was determined at baseline and after 5 minutes of steady pacing at six different protocols: protocol 1, 2, and 3 were conventional pacing at high right atrium, distal coronary sinus, and biatrial sites, respectively, and protocol 4, 5, and 6 were conventional pacing together with NE applied to the same sites as protocol 1, 2, and 3. Biatrial NE (protocol 6 with median AERP = 212.5 msec) significantly prolonged AERP compared with baseline (median AERP = 202.5 msec and P < 0.05), conventional pacing (protocol 1, 2, and 3 with median AERP = 205.0 msec, 205.0 msec, and 205.0 msec, respectively, and all P < 0.05), and single-site NE (protocol 4 and 5 with median AERP = 207.5 msec and 207.5 msec, respectively, and both P < 0.05). Conclusion: Biatrial NE resulted in AERP prolongation even at sites distant to NE application. The study result suggests that by adding NE to multi-sites pacing for atrial fibrillation prevention may have additional benefit.

Conventional activation or pacemapping is effective in guiding ablation of ventricular tachyarrhythmia originating from right ventricular outflow tract (RVOT). However, in selected patients with hemodynamically unstable or nonsustained tachycardia, noncontact mapping may be an effective alternative method to guide ablation in RVOT. Five patients with symptomatic hypotension during ventricular tachycardia (VT) or nonsustained tachyarrhythmia originating from the RVOT had radiofrequency ablation guided by noncontact mapping. All patients had a history of syncope and the tachyarrhythmias were refractory to antiarrhythmic therapy. Four patients had spontaneous sustained VT of a cycle length from 250 to 300 ms and one had symptomatic ventricular ectopic beats. Two patients were diagnosed to have arrhythmogenic right ventricular cardiomyopathy (ARVC). Sustained VT with hypotension was induced in two patients and nonsustained VT in three patients. Isopotential color maps were used to locate the earliest activation site of the tachyarrhythmia in RVOT. Three patients had tachyarrhythmia exit sites at the septal region and two at lateral region of RVOT. Low voltage area and diastolic activity were detected in the two patients with ARVC. Radiofrequency ablation guided by noncontact mapping was performed during sinus rhythm in all patients. The number of ablation attempts ranged from 1 to 14. After follow-up for 12 +/- 5.8 months, there was no recurrence of tachyarrhythmia and syncope in all five patients. Noncontact mapping is a safe and effective alternative method to guide ablation of hemodynamically unstable or nonsustained ventricular arrhythmia originating from RVOT.

Atrial fibrillation is related to increased risk of stroke and heart failure and is a growing health issue with the aging of the world population. Rate control strategy for atrial fibrillation is not inferior to rhythm control strategy in patients with and without heart failure, however could be difficult to achieve with pharmacological agent alone even with the latest, more lenient target of rate control of below 110 beats per minute. Atrial fibrillation especially with uncontrolled heart rate could be associated with tachycardia-mediated cardiomyopathy which can be reversible. Non-pharmacological method for rate control includes atrioventricular node modification, atrioventricular node ablation with permanent pacing, and selective vagal stimulation. Atrioventricular node ablation with permanent pacing is the most well-established method with evidence showing different degrees of improvement in left ventricular function. However, some of the early beneficial effect was cancelled out by the deleterious effect of dyssynchrony induced by right ventricular pacing. The beneficial effect is more pronounced and sustained in atrial fibrillation patients with heart failure receiving cardiac resynchronization therapy. Atrioventricular node ablation and biventricular pacing could turn out to be the superior non-pharmacological method of atrial fibrillation rate control.

[Figure][1] [![Graphic][3] ][3] A 52-year-old woman became hypotensive during radiofrequency ablation for paroxysmal atrial fibrillation. She received heparin 5,000 IU after transseptal puncture, and continued as an infusion to maintain an activated clotting time of 270 s during the

AIMS Right ventricular apex (RVA) pacing may have deleterious effects on left ventricular (LV) systolic function, but its impact on LV diastolic function has not been explored. METHODS AND RESULTS Ninety-seven patients with sinus node dysfunction and ejection fraction (EF) ≥ 50% with permanent RVA pacing were randomly programmed to V-sense and V-pace modes and examined by echocardiography. Tissue Doppler imaging was employed to assess myocardial systolic velocity (S') and early diastolic velocity (E') at the mitral annulus. Systolic dyssynchrony was assessed using 12 LV segmental model (Ts-SD). Switching from V-sense to V-pace resulted in the worsening of both diastolic and systolic functions as shown by the decreased EF, reduced mean E' and S' velocities, as well as increase in LV volume and Ts-SD (all P< 0.001). Reduction of mean E' and S' of ≥ 1 cm/s occurred in 35 (36%) and 45 (46%) patients, respectively. In pre-defined subgroup analysis, only patients with pre-existing LV diastolic dysfunction had a significant reduction of mean E' and S' (both P< 0.001) even after age adjustment. Multivariate logistic regression analysis showed that independent factors for the reduction of mean E' ≥ 1 cm/s or mean S' ≥ 1 cm/s at V-pace were pre-existing LV diastolic dysfunction [odds ratio (OR): 4.735, P= 0.007 for E'; OR: 3.307, P= 0.022 for S'] and systolic dyssynchrony at V-pace (OR: 5.459, P= 0.007 for E'; OR: 2.725, P= 0.035 for S'). CONCLUSION In patients with preserved EF, RVA pacing is associated with the deterioration of both LV diastolic and systolic functions, which is particularly obvious in those with pre-existing LV diastolic dysfunction and V-pace-induced systolic dyssynchrony.

This prospective study was to examine the impact of right ventricular apical (RVA) pacing on atrial remodeling and function.103 patients (age 70 ± 11 years; 53 men) with preserved left ventricular (LV) ejection fraction (LVEF45%) who received RVA pacing had Doppler echocardiography performed at baseline and after one year follow up. At one year follow up, left atrial (LA) volumes (pre-atrial contraction volume and the minimal volume) and their indexes were significantly increased with reduction in passive emptying fraction and total emptying fraction (all p0.05). LA segmental tissue velocities - mean peak systolic (Sm-la), peak early diastolic (Em-la) and late diastolic (Am-la) - were also significantly reduced (all p0.001). A reduction of Am-la30% occurred in 24% of patients, and was more prevalent in patients with an elevation of LV filling pressure (E/e'15) at one year (44.1% vs. 11.7%, χ(2)=12.75, p0.001) as well as those with a reduction of LVEF ≥ 5% (34.0% vs. 14.3%, χ(2)=5.140, p=0.023). By multivariate regression analysis, E/e'15 at one year (odds ratio [OR] 5.213; 95% confidence interval [CI] 1.778-15.281) and reduction of LVEF ≥ 5% (OR 3.181; 95% CI 1.045-9.686) were independent predictors of reduction of Am-la30%.Chronic RVA pacing results in LA remodeling and reduced atrial function. This is related to elevated filling pressures and impairment of LV systolic function.

ObjectivesThis study aimed to evaluate the impact of cardiac contractility modulation (CCM) on left ventricular (LV) size and myocardial function.BackgroundCCM is a device-based therapy for patients with advanced heart failure. Previous studies showed that CCM improved symptoms and exercise capacity; however, comprehensive assessment of LV structure, function, and reverse remodeling is not available.MethodsThirty patients (60 ± 11 years, 80% male) with New York Heart Association (NYHA) functional class III heart failure, ejection fraction

Aims To evaluate a novel atrial lead designed to reduce far-field sensing. Methods and results Sixty-three patients with standard pacing indications were randomized to receive an OptiSense™ 1699T (St Jude Medical, USA) or conventional pacing lead in the right atrium. Post-implant follow-up was conducted for all patients at 90 days and for a subset at 360 days. Standard electrical parameters were measured. Thresholds of sensing were determined for far-field ventricular signals. The number of inappropriate mode switches was determined from the stored intracardiac electrogram (IEGM). At 90 days, an IEGM Holter recorded 24 h of IEGM. With atrial sensitivity programmed at 0.3 mV, no far-field sensing occurred in the OptiSense™ group, but it did occur in 20% and 30% of the control group at 90 and 360 days, respectively. Inappropriate mode switching was observed in 4% of the OptiSense™ group in contrast to 23% of the control group. The IEGM Holter found no far-field sensing in the OptiSense™ group, but did find 83 023 far-field events from 22% of control patients. The standard electrical parameters of the OptiSense™ leads were acceptable. Conclusion The OptiSense™ lead reduced ventricular far-field sensing in the atrium while maintaining satisfactory pacing and sensing performance, resulting in less inappropriate mode switch.

Objective: To examine the predictive value of systolic dyssynchrony measured by tissue Doppler velocity versus tissue Doppler strain imaging on long-term outcome after cardiac resynchronisation therapy (CRT). Design: Cohort study. Setting: Two university hospitals. Patients: Two hundred and thirty-nine patients (65 (SD 12) years, 76% males) who underwent CRT. Interventions: Baseline echocardiography with tissue Doppler imaging (TDI) and clinical follow-up for 37 (20) months. Main outcome measures: The time to peak systolic velocity during ejection phase (T s ) and the time to peak systolic strain (T ϵ ) were assessed for dyssynchrony, that is the maximal delay in T s and the maximal delay in T ϵ among the four left ventricular basal segments. Occurrence of cardiovascular endpoints between patients with and without dyssynchrony was compared by Kaplan–Meier curves, followed by Cox regression analysis for potential predictor(s). Results: There were 78 (33%) deaths, with cardiovascular causes in 64 (27%) patients, while 136 (57%) patients were hospitalised for cardiovascular events, including decompensated heart failure in 87 (36%) patients. Patients with the maximal delay in T s of ⩾65 ms showed a lower event rate for cardiovascular mortality (19% vs 38%, logrank χ 2 = 7.803, p = 0.005) and other prognostic endpoints. In Cox regression analysis, the maximal delay in T s (hazard ratio (HR) 0.463, 95% CI 0.270 to 0.792, p = 0.005) and ischaemic aetiology (HR 2.716, 95% CI 1.505 to 4.901, p = 0.001) were independent predictors of cardiovascular mortality. In contrast, the maximal delay in T ϵ of ⩾80 ms failed to predict any cardiovascular event. Conclusions: Echocardiographic evidence of prepacing systolic dyssynchrony measured by TDI velocity, but not TDI strain, predicted lower long-term cardiovascular events after CRT.

INTRODUCTION The optimal left ventricular (LV) pacing site for cardiac resynchronization therapy (CRT) is unclear. The current study aims to explore the clinical significance of LV lead concordance to delayed contraction segment in CRT. METHODS AND RESULTS Concordant LV lead position was defined as the lead tip located by fluoroscopy at or immediately adjacent to the LV segment with latest contraction determined by tissue Doppler imaging. Echocardiographic and clinical outcomes among 101 consecutive patients with or without concordant LV lead positions were compared. There was no significant difference in changes in LV volumes and clinical parameters between patients with concordant (n = 46) or nonconcordant (n = 55) LV lead positions at 3 and 6 months. In multivariate analysis, the baseline asynchrony index (beta= 1.092, 95% CI: 1.050-1.114; P < 0.001), but not LV lead concordance, was the only independent predictor of LV reverse remodeling. By Cox regression analysis, ischemic etiology, and LV reverse remodeling, but not LV lead concordance, were independent predictors of mortality (beta= 2.475, 95% CI: 1.183-5.178; P = 0.016, and beta= 0.272, 95% CI: 0.130-0.567; P < 0.001, respectively), cardiovascular hospitalization (beta= 1.551, 95% CI: 1.032-2.333; P = 0.035, and beta= 0.460, 95% CI: 0.298-0.708; P < 0.001, respectively), and heart failure hospitalization (beta= 0.486, 95% CI: 0.320-0.738; P = 0.001 for LV reverse remodeling). CONCLUSION LV lead concordance to the delayed contraction segment may not be a major determining factor for favorable echocardiographic and clinical outcomes after CRT.

Several two-dimensional (2-D) tissue Doppler imaging (TDI) echocardiographic techniques have proved useful to identify responders to cardiac resynchronisation therapy (CRT). Recently a 3-D probe allowing simultaneous acquisition of TDI data in three imaging planes became available.To evaluate the value of triplane TDI to predict reverse left ventricular (LV) remodelling after CRT.Sixty patients with heart failure, scheduled for CRT, underwent triplane echocardiography with simultaneous TDI acquisition before and 6 months after implantation. From the triplane dataset a 3-D LV volume was generated and LV volumes and ejection fraction were calculated. Intraventricular dyssynchrony was quantitatively analysed by evaluating time from onset of the QRS complex to peak myocardial systolic velocity in 12 LV segments from the triplane dataset and calculation of the standard deviation (Ts-SD-12). Clinical response was defined as an improvement of at least one New York Heart Association class. Reverse LV remodelling was defined as/=15% decrease of LV end-systolic volume at 6 months' follow-up.Responders to CRT had significantly more LV dyssynchrony at baseline than non-responders (mean (SD) Ts-SD-12: 42 (14) vs 22 (12), p0.001). A cut-off value of 33 ms for baseline Ts-SD-12, acquired from the triplane TDI dataset, yielded a sensitivity of 89% with a specificity of 82% to predict clinical response to CRT; sensitivity and specificity to predict reverse LV remodelling were 90% and 83%, respectively.Triplane TDI echocardiography predicts clinical response and reverse LV remodelling 6 months after CRT implantation.

Background: Linear microwave ablation has been shown to be effective for treatment of atrial fibrillation during open-heart surgery by producing transmural lesions in the atrium to isolate the pulmonary veins. However, the safety and efficacy of percutaneous, transcatheter, linear microwave ablation for atrial arrhythmias, while demonstrated in animal models, is unknown in humans. Therefore, we studied the safety and efficacy of linear microwave ablation of the cavotricuspid isthmus (CTI) in humans with typical atrial flutter, utilizing a 2-cm long microwave antenna mounted on a steerable 9-French catheter. Methods and Results: In seven consecutive patients, multielectrode catheters were positioned at the His bundle (quadripolar) and around the TV annulus (duo-decapolar) for pacing and recording atrial activation sequence before and after ablation. The microwave antenna was withdrawn gradually from tricuspid annulus towards inferior vena cava to ablate the CTI. Intracardiac ultrasound was used to ensure adequate endocardial contact of the microwave ablation catheter with the CTI. Microwave energy was applied at a power of 18 to 21 W at each ablation point for 120 seconds. Ablation was repeated until bidirectional CTI block was confirmed by demonstrating a descending activation wavefront in the contralateral atrial wall during pacing from the coronary sinus ostium or low lateral right atrium, respectively. Bidirectional isthmus block was achieved in all patients, after a mean number of 27.4 ± 14.7 energy applications per patients. There were no acute procedural complications. Conclusions: Percutaneous, transcatheter microwave ablation of CTI dependent atrial flutter was demonstrated to be safe and effective in this preliminary feasibility study.

CRT in Moderate LV Systolic Dysfunction. Background: We sought to investigate the effect of cardiac resynchronization therapy (CRT) on disease progression in patients with moderate left ventricular (LV) systolic dysfunction. Methods and Results: This is a prospective study to explore the effect of CRT in 15 optimally treated patients (age: 66.1 ± 12.8 years; male = 13) with New York Heart Association (NYHA) class III, LV ejection fraction >35% and 120 msec. Echocardiographic examination and standard heart failure assessment was performed before and 3 months after CRT implantation. The magnitude of echocardiographic remodeling measurements was compared with 30 age, sex, NYHA class, and heart failure etiology matched patients with conventional CRT indication. There were significant reductions in LV end-systolic (86.2 ± 24.1 to 69.7 ± 22.2 mL, P < 0.01)/end-diastolic (135.5 ± 36.8 to 120.5 ± 34.6 mL, P < 0.01) volumes, improvement in LV ejection fraction (39.1 ± 2.2 to 44.2 ± 5.5%, P = 0.01), and NYHA class (3.0 ± 0.0 to 2.07 ± 0.46, P < 0.001). There was no difference in changes in LV volumes, ejection fraction, NYHA class, and exercise capacity before and after CRT between the study and conventional groups except for greater improvement in the quality of life score in the conventional group. Conclusion: In this prospective study, significant LV reverse remodeling by CRT in those with a wide QRS complex and moderate LV systolic dysfunction was observed. Further studies to explore the benefit of CRT in patients with less severe heart failure are recommended.