Darryl P. Leong

Outcome of Ventricular Tachycardia Ablation in Patients with Nonischemic Cardiomyopathy: The Impact of Noninducibility

Background—Ablation failure and recurrence rates after ventricular tachycardia (VT) ablation in nonischemic cardiomyopathy are high and the optimal procedural end point is not well defined. This study assessed the outcome after ablation, the impact of noninducibility, and other potential predictors of VT recurrence. Methods and Results—Forty-five patients with nonischemic cardiomyopathy (60±16 years; left ventricular ejection fraction, 44±14%) accepted for VT ablation were included. Epicardial mapping was performed in 29 (64%). A median of 2 (first-to-third quartile, 2–4) VTs (cycle length, 342±77 ms) were induced per patient. After ablation, the complete programmed electric stimulation protocol (3 drive cycle length, 3 extrastimuli ≥200 ms, and burst≥2 sites) was repeated. Complete success (noninducibility of any monomorphic VT) was achieved in 17 patients (38%), partial success (elimination of clinical VT, persistent inducibility of nonclinical VT) in 17 patients (38%), and failure (persistent inducibility of clinical VT) in 11 patients (24%). During 25±15 months of follow-up, VT occurred in 24 patients (53%), but the 6-month VT burden was reduced by ≥75% in 79%. Recurrence rates were low after complete procedural success (18%), but high after both partial success (77%) and failure (73%). Non-complete procedural success was the strongest predictor of VT recurrence (hazard ratio, 8.20; 95% confidence interval, 2.37–28.43; P=0.001). Conclusions—Although 53% of patients had VT during follow-up, the 6-month VT burden was decreased by ≥75% in 79%. Recurrence rates are low after complete procedural success, but high after both partial success and failure. Non-complete procedural success was the strongest predictor of VT recurrence.

Right ventricular function and survival following cardiac resynchronisation therapy

Objectives Right ventricular (RV) function is an important prognostic marker in heart failure. However, its impact on all-cause mortality following cardiac resynchronisation therapy (CRT) independent of confounding factors has not been evaluated. Furthermore, evidence concerning the effect of CRT on RV function is limited. The studys aims were to: (1) assess the prognostic importance of RV function among CRT recipients, and (2) characterise RV functional change following CRT and its determinants. Design Retrospective observational study. Setting Single tertiary centre. Patients A total of 848 CRT recipients (median age 65u2005years, 78% male, 60% ischaemic) underwent echocardiography before and 6u2005months after CRT. RV function was evaluated using tricuspid annular plane systolic excursion (TAPSE), with a ≤14u2005mm threshold indicating severe RV impairment. The primary endpoint was long-term all-cause mortality. Results Significant baseline RV dysfunction was observed in 286 (34%) individuals. After a median 44u2005months, 288 deaths occurred. RV impairment was associated with a greater incidence of all-cause mortality (log-rank p<0.001). Independent predictors of this endpoint were functional class, ischaemic aetiology, diabetes, atrial fibrillation, renal dysfunction, bigger left ventricular (LV) end-systolic volume, less LV dyssynchrony and reduced TAPSE. Importantly, TAPSE added prognostic value to these recognised prognostic parameters (likelihood-ratio test p<0.001). Furthermore, improvement in RV function after CRT was independent of the improvement in LV systolic function but significantly associated with the improvement in LV diastolic function. Importantly, a favourable RV functional response to CRT was associated with superior survival. Conclusions RV function is an independent predictor of long-term outcome following CRT.

Unrecognized Failure of a Narrow Caliber Defibrillation Lead: The Role of Defibrillation Threshold Testing in Identifying an Unprotected Individual

In this case report we describe a short circuit in the Riata 1570 defibrillator lead (Riata 1570, St. Jude Medical, St. Paul, MN, USA) that was unsuspected owing to normal lead parameters until defibrillator threshold testing at the time of elective generator change. On this occasion, the short circuit manifested as unsuccessful defibrillation of ventricular fibrillation with immediate battery depletion. This report adds weight to existing concerns over narrow caliber leads, it draws attention to the possibility of lead malfunction despite unremarkable interrogation, and lastly it highlights the potential role of routine defibrillator threshold testing, particularly at elective generator change (an issue that remains sparingly addressed in the existing literature). (PACE 2012; 35:e154–e155)

Global longitudinal strain and left atrial volume index improve prediction of appropriate implantable cardioverter defibrillator therapy in hypertrophic cardiomyopathy patients

Accurate predictors of appropriate implantable cardioverter defibrillator (ICD) therapy in hypertrophic cardiomyopathy (HCM) patients are lacking. Both left atrial volume index (LAVI) and global longitudinal strain (GLS) have been proposed as prognostic markers in HCM patients. The specific value of LAVI and GLS to predict appropriate ICD therapy in high-risk HCM patients was studied. LAVI and 2-dimensional speckle tracking-derived GLS were assessed in 92 HCM patients undergoing ICD implantation (69xa0% men, mean age 50xa0±xa014xa0years). During long-term follow-up, appropriate ICD therapies, defined as antitachycardia pacing and/or shock for ventricular arrhythmia, were recorded. Appropriate ICD therapy occurred in 21 patients (23xa0%) during a median follow-up of 4.7 (2.2–8.2) years. Multivariate analysis revealed LAVI (pxa0=xa00.03) and GLS (pxa0=xa00.04) to be independent predictors of appropriate ICD therapy. Both LAVI and GLS showed higher accuracy to predict appropriate ICD therapy compared to presence of ≥1 conventional sudden cardiac death (SCD) risk factor(s) [area under the curve 0.76 (95xa0% CI 0.65–0.87) and 0.65 (95xa0% CI 0.54–0.77) versus 0.52 (95xa0% CI 0.43–0.58) respectively, pxa0<xa00.001]. No patient with both LAVI <34xa0mL/m2 and GLS <−14xa0% experienced appropriate ICD therapy. Assessment of both LAVI and GLS on top of conventional SCD risk factors provided incremental clinical predictive value for appropriate ICD therapy, as shown by likelihood ratio test (pxa0<xa00.001) and integrated discrimination improvement index (0.17, pxa0<xa00.001). LAVI and GLS provide high negative predictive value for appropriate ICD therapy in high-risk HCM patients. Additionally to conventional SCD risk factors, both parameters may be useful to optimize criteria and timing for ICD implantation in these patients.

Leaflet remodelling in functional mitral valve regurgitation: characteristics, determinants, and relation to regurgitation severity

BACKGROUNDnRecently, it has been hypothesized that mitral leaflet remodelling may play a role in the pathophysiology of functional mitral regurgitation (FMR). We investigated the characteristics, determinants, and relation of mitral leaflet remodelling to FMR severity.nnnMETHODS AND RESULTSnThree-dimensional transoesophageal echocardiographic data of the mitral valve (MV) were studied in 30 patients with FMR ≥ grade 3 (≥3), 24 patients with FMR < grade 3 (<3), and 22 controls with normal MV. FMR <3 and ≥3 patients showed leaflet remodelling compared with control subjects with larger overall MV leaflet areas (11.47 ± 3.16 and 9.58 ± 1.99 vs. 7.30 ± 1.57 cm(2)/m(2), respectively; all P < 0.01). Tenting volume (r(2) = 0.55), left ventricular (LV) ejection fraction (r(2) = 0.20), annulus area (r(2) = 0.87), and LV sphericity index (r(2) = 0.25) were correlated with overall MV leaflet area (all P < 0.001). Although these correlates were similar between FMR <3 and ≥3 patients (all P > 0.05), the overall MV leaflet area was smaller in FMR ≥3 compared with FMR <3 patients (P = 0.01), indicating less remodelling despite similar tethering degree. Particularly, coaptation/overall MV leaflet area ratio ≤0.24, reflecting insufficient leaflet remodelling, was associated with FMR ≥3 [area under receiver operating characteristic (ROC) curve = 0.93, sensitivity 90%, and specificity 91%]. This ratio was independently associated with FMR ≥3 (odds ratio 70.0, 95% confidence interval 11.7-419.9, P < 0.001) and showed significant correlation with effective regurgitant orifice area (r(2) = 0.38, P < 0.001).nnnCONCLUSIONnMV leaflet remodelling in FMR is common and relates to LV function, LV sphericity, MV tenting volume, and annulus dilatation. Insufficient leaflet remodelling relative to the mitral annular and LV changes is independently associated with FMR severity.

Predictors of long-term benefit of cardiac resynchronization therapy in patients with right bundle branch block

AIMSnThe aims of this study were: (i) to characterize consecutive cardiac resynchronization therapy (CRT) recipients with right bundle branch block (RBBB) in comparison with left bundle branch block (LBBB) and (ii) to identify independent predictors of long-term outcome among CRT recipients with RBBB. The presence of RBBB has been associated with poorer prognosis after CRT compared with LBBB; however, little is known about the differences in cardiac mechanics between RBBB and LBBB patients. Furthermore, predictors of favourable outcome after CRT in patients with RBBB have not been identified.nnnMETHODS AND RESULTSnFive hundred and sixty-one consecutive CRT recipients (89 with RBBB and 472 with LBBB) underwent echocardiography before and 6 months after CRT to determine left ventricular (LV) size and function, and interventricular and LV dyssynchrony (as measured by tissue Doppler imaging). Long-term follow-up to identify a composite endpoint of all-cause mortality or heart failure hospitalization was available. Right bundle branch block patients exhibited a higher prevalence of male gender, ischaemic heart disease, atrial fibrillation, and lower exercise capacity when compared with LBBB patients, despite smaller LV volumes. In addition, the extent of both interventricular and LV dyssynchrony was less in RBBB patients. Six months after CRT, RBBB patients also showed limited LV reverse remodelling. At long-term follow-up, LV dyssynchrony and mitral regurgitation were identified as independent predictors of all-cause mortality or heart failure hospitalization among RBBB patients.nnnCONCLUSIONnLeft ventricular dyssynchrony may be an important determinant of outcome following CRT in patients with RBBB and may help in the selection of CRT candidates.

Effect of Induced LV Dyssynchrony by Right Ventricular Apical Pacing on All‐Cause Mortality and Heart Failure Hospitalization Rates at Long‐Term Follow‐Up

Right ventricular apical (RVA) pacing may induce left ventricular (LV) dyssynchrony. The long‐term prognostic implications of induction of LV dyssynchrony were retrospectively evaluated in a cohort of patients who underwent RVA pacing.

Outcome of Ventricular Tachycardia Ablation in Patients With Nonischemic CardiomyopathyClinical Perspective: The Impact of Noninducibility

Background—Ablation failure and recurrence rates after ventricular tachycardia (VT) ablation in nonischemic cardiomyopathy are high and the optimal procedural end point is not well defined. This study assessed the outcome after ablation, the impact of noninducibility, and other potential predictors of VT recurrence. Methods and Results—Forty-five patients with nonischemic cardiomyopathy (60±16 years; left ventricular ejection fraction, 44±14%) accepted for VT ablation were included. Epicardial mapping was performed in 29 (64%). A median of 2 (first-to-third quartile, 2–4) VTs (cycle length, 342±77 ms) were induced per patient. After ablation, the complete programmed electric stimulation protocol (3 drive cycle length, 3 extrastimuli ≥200 ms, and burst≥2 sites) was repeated. Complete success (noninducibility of any monomorphic VT) was achieved in 17 patients (38%), partial success (elimination of clinical VT, persistent inducibility of nonclinical VT) in 17 patients (38%), and failure (persistent inducibility of clinical VT) in 11 patients (24%). During 25±15 months of follow-up, VT occurred in 24 patients (53%), but the 6-month VT burden was reduced by ≥75% in 79%. Recurrence rates were low after complete procedural success (18%), but high after both partial success (77%) and failure (73%). Non-complete procedural success was the strongest predictor of VT recurrence (hazard ratio, 8.20; 95% confidence interval, 2.37–28.43; P=0.001). Conclusions—Although 53% of patients had VT during follow-up, the 6-month VT burden was decreased by ≥75% in 79%. Recurrence rates are low after complete procedural success, but high after both partial success and failure. Non-complete procedural success was the strongest predictor of VT recurrence.

Outcome of Ventricular Tachycardia Ablation in Patients With Nonischemic CardiomyopathyClinical Perspective

Background—Ablation failure and recurrence rates after ventricular tachycardia (VT) ablation in nonischemic cardiomyopathy are high and the optimal procedural end point is not well defined. This study assessed the outcome after ablation, the impact of noninducibility, and other potential predictors of VT recurrence. Methods and Results—Forty-five patients with nonischemic cardiomyopathy (60±16 years; left ventricular ejection fraction, 44±14%) accepted for VT ablation were included. Epicardial mapping was performed in 29 (64%). A median of 2 (first-to-third quartile, 2–4) VTs (cycle length, 342±77 ms) were induced per patient. After ablation, the complete programmed electric stimulation protocol (3 drive cycle length, 3 extrastimuli ≥200 ms, and burst≥2 sites) was repeated. Complete success (noninducibility of any monomorphic VT) was achieved in 17 patients (38%), partial success (elimination of clinical VT, persistent inducibility of nonclinical VT) in 17 patients (38%), and failure (persistent inducibility of clinical VT) in 11 patients (24%). During 25±15 months of follow-up, VT occurred in 24 patients (53%), but the 6-month VT burden was reduced by ≥75% in 79%. Recurrence rates were low after complete procedural success (18%), but high after both partial success (77%) and failure (73%). Non-complete procedural success was the strongest predictor of VT recurrence (hazard ratio, 8.20; 95% confidence interval, 2.37–28.43; P=0.001). Conclusions—Although 53% of patients had VT during follow-up, the 6-month VT burden was decreased by ≥75% in 79%. Recurrence rates are low after complete procedural success, but high after both partial success and failure. Non-complete procedural success was the strongest predictor of VT recurrence.

Young Investigator Award session - Clinical * Clinical applications

# 66 3D speckle-tracking echocardiography in acute myocardial infarction: relationship between contrast-enhanced magnetic resonance imaging and myocardial deformation {#article-title-2}nnSpeckle analysis of 3D echocardiography improves information on left ventricle (LV) segmental and global deformation by avoiding loss of speckles as it is the case in monoplane 2D analysis. Our goal was to evaluate the accuracy of 3D deformation parameters to detect myocardial delayed enhancement (MDE) transmural extent by cardiac magnetic resonance imaging (CMR) in myocardial infarction (MI).nnMethods: We included 72 patients (57.3±12.4yo) with first acute MI who underwent within 3 days following revascularization both CMR (GE 3T) and echocardiography (GE Vivid E9) including a 3D acquisition of full LV volume. Furthermore, 31 normal subjects (56.5±8.2yo) underwent a complete echocardiography. Automated analysis of 3D allowed the calculation of 3D global LV area (3DGAS), longitudinal (3DGLS), circumferential (3DGCS) and radial (3DGRS) strains (S%). Peak systolic 2D and 3D S values from the 17 LV myocardial segments were recorded. For each segment MDE was defined as transmural (MDE>66%), intermediate (33–66%) and subendocardial (<33%). Pearson was used to study correlation between 2D, 3DTTE and CMR measurements. ROC analysis identified strain cutoff value predicting scar extent.nnResults: The 72 MI pts show a slightly decreased CMR-LVEF (47.1±8.8%) with a small infarct size (global scar extent 20±13%). CMR identified 920 non-infarcted segments (75.2%) and 199 segments with transmural (16.2%), 86 with intermediate (7.0%) and 19 with subendocardial MDE (1.6%). A good tracking quality was obtained respectively in 87% and 93% of the segments in control and MI pts with good inter observer reproducibility (ICC 0.824 for 3DGLS and 0.945 for 3DGAS). All S values were significantly higher in control than in MI pts (3DGAS: −36.4±7.1 vs −25.9±5.8; 3DGLS: −21.7±5.6 vs −14.84±3.8; 3DGCS: −20.4±6.2 vs −14.18%±4.3; 3DGRS: 60.9±19.3 vs 39.2±11.8, p<.0001). All 3DGS values were correlated with CMR-LVEF (3DGLAS r=−0.715; 3DGLS r=0.602; 3DGCS r=−0.64; 3DGRS r=0.66; 2DGLS r=−0.652; all p<0.0001). All 3D S values were significantly different between non-infarcted, subendocardial, intermediate and transmurally infarcted segments (p<0.0001) and were significantly lower in non-infarcted segments of MI patients than in segments of control pts except for 3DGRS.The optimal cut-off value for segmental 3DAS to predict a transmural extent was −27.5% with a sensitivity of 89.5% and a specificity of 88.3% (AUC:0.94).nn3D speckle imaging is an interesting tool in the acute phase of MI and 3D area strain seems the most valuable parameter, both as a global marker of LV dysfunction and as a regional marker of transmural scar extent.nn# 67 Left atrial strain for prediction of cardiovascular outcomes {#article-title-3}nnBackground: The incremental value of left atrial (LA) deformation analysis by speckle tracking echocardiography (STE) compared with LA volume or LA ejection fraction as a cardiovascular risk marker has not been evaluated prospectively. We sought to compare LA function by STE to other conventional LA parameters for the prediction of adverse cardiovascular outcomes.nnMethods: This prospective study includedxa0425 adults (mean age 70±6 years, 55% males) in sinus rhythm who were followed for development of first AF, congestive heart failure, stroke, transient ischemic attack, myocardial infarction, coronary revascularization, and cardiovascular death. Global peak atrial longitudinal strain (global PALS) by STE was measured in all subjects by averaging all atrial segments. Left atrium was assessed with biplane LA volume, LA ejection fraction, four-chamber LA area, and M-mode dimension.nnResults: Of thexa0425 subjects at baseline,xa054 hadxa071 new events during a mean follow-up of 3.3 ± 1.5 years. All LA parameters, traditional ones and STE derived, were independently predictive of combined outcomes (all p < 0.0001). The overall performance for the prediction of cardiovascular events was greatest for global PALS (area under the receiver operator characteristic curve: global PALS 0.84; indexed LA volume 0.71; LA ejection fraction 0.70; LA area 0.62; LA diameter 0.59). A graded association between the degree of LA enlargement and risk of cardiovascular events was only evident for global PALS and indexed LA volume.nnConclusions: Global PALS is a strong and an independent predictor of cardiovascular events and appears to be superior to conventional parameters of LA analysis.[⇓][1] nn![Figure][2] nn# 68 Left ventricular subepicardial twist represents a novel marker of contractile reserve in patients after acute myocardial infarction: a speckle-tracking dobutamine stress echocardiography study {#article-title-4}nnPurpose: Dobutamine stress echocardiography (DSE) remains the most widely used method of assessing contractile reserve (CR) in patients with left ventricular (LV) dysfunction following myocardial infarction. LV twist, an emerging parameter of global LV function, has not been systematically evaluated on DSE. In particular, the potential value of multiple layer (subepicardial and subendocardial) twist assessment has not been explored despite the knowledge that each are affected differently after STEMI. The aim of the current study was to investigate whether response of subepicardial LV twist – known to be impaired only in transmural infarctions - on full protocol DSE may serve as a marker of CR in STEMI patients.nnMethods: Consecutive STEMI patients undergoing primary percutaneous coronary intervention and standard protocol DSE at 3 months with abnormal wall motion score index (WMSI) at rest were selected. Studies positive for ischemia were excluded. Two-dimensional speckle-tracking was used to calculate subepicardial and subendocardial LV twist – defined as the net difference (in degrees) of the apical and basal rotation for each sub layer – at rest and peak-dose stages. Improvement in WMSI by ≥1 grade in ≥ 1 segment was also determined. Primary endpoint of the study was an absolute increase in LV ejection fraction (LVEF) by ≥ 5% at 6-month follow-up and its predictors were investigated.nnResults: In total 69 patients (mean age 61 ± 13, 87% male, mean LVEF 49 ± 9%, mean WMSI 1.4 ± 0.3) had complete DSE studies feasible for speckle-tracking at each stage. Improved LVEF at follow-up occurred in 41% (n=28). The mean change in both subepicardial (Δsubepi) and subendocardial (Δsubendo) LV twist from rest to peak-stress was significantly higher in LVEF improvers: 2.76 versus 0.91°, p=0.009 and 3.76 versus 1.45°, p=0.04 respectively. On multivariate analysis higher Δsubepi twist (OR 1.4 95% CI 1.1–1.7, p=0.009), and lower baseline LVEF (OR 0.88 95% CI 0.80-0.96) were independently associated with improved LVEF at 6 months while subendo and WMSI improvement were not. Area under the receiver operating characteristics curve for Δsubepi twist to predict LVEF improvement was 0.70.nnConclusions: In post-STEMI patients with persistent wall motion abnormalities, the response of subepicardial LV twist on full-protocol DSE predicts improvement in LVEF at follow-up, supporting previous studies suggesting preserved subepicardial rotation reflects less extensive infarction. This finding suggests a novel, clinical use for LV twist as a marker of contractile reserve in patients following STEMI.nn [1]: #F1n [2]: pending:yes