C. Jan Willem Borleffs

Infarct tissue heterogeneity assessed with contrast-enhanced MRI predicts spontaneous ventricular arrhythmia in patients with ischemic cardiomyopathy and implantable cardioverter-defibrillator.

Background—The relation between infarct tissue heterogeneity on contrast-enhanced MRI and the occurrence of spontaneous ventricular arrhythmia (or sudden cardiac death) is unknown. Therefore, the study purpose was to evaluate the predictive value of infarct tissue heterogeneity assessed with contrast-enhanced MRI on the occurrence of spontaneous ventricular arrhythmia with subsequent implantable cardioverter-defibrillator (ICD) therapy (as surrogate of sudden cardiac death) in patients with previous myocardial infarction. Methods and Results—Ninety-one patients (age, 65±11 years) with previous myocardial infarction scheduled for ICD implantation underwent cine MRI to evaluate left ventricular function and volumes and contrast-enhanced MRI for characterization of scar tissue (infarct gray zone as measure of infarct tissue heterogeneity, infarct core, and total infarct size). Appropriate ICD therapy was documented in 18 patients (20%) during a median follow-up of 8.5 months (interquartile range, 2.1 to 20.3). Multivariable Cox proportional hazards analysis revealed that infarct gray zone was the strongest predictor of the occurrence of spontaneous ventricular arrhythmia with subsequent ICD therapy (hazard ratio, 1.49/10 g; CI, 1.01 to 2.20; &khgr;2=4.0; P=0.04). Conclusions—Infarct tissue heterogeneity on contrast-enhanced MRI is the strongest predictor of spontaneous ventricular arrhythmia with subsequent ICD therapy (as surrogate of sudden cardiac death) among other clinical and MRI variables, that is, total infarct size and left ventricular function and volumes, in patients with previous myocardial infarction.

Long-term prognosis after cardiac resynchronization therapy is related to the extent of left ventricular reverse remodeling at midterm follow-up.

OBJECTIVES The aim of the current study was to evaluate the relation between the extent of left ventricular (LV) reverse remodeling and clinical/echocardiographic improvement after 6 months of cardiac resynchronization therapy (CRT) as well as long-term outcome. BACKGROUND Despite the current selection criteria, individual response to CRT varies significantly. Furthermore, it has been suggested that reduction in left ventricular end-systolic volume (LVESV) after CRT is related to outcome. METHODS A total of 302 CRT candidates were included. Clinical status and echocardiographic evaluation were performed before implantation and after 6 months of CRT. Long-term follow-up included all-cause mortality and hospitalizations for heart failure. RESULTS Based on different extents of LV reverse remodeling, 22% of patients were classified as super-responders (decrease in LVESV > or =30%), 35% as responders (decrease in LVESV 15% to 29%), 21% as nonresponders (decrease in LVESV 0% to 14%), and 22% negative responders (increase in LVESV). More extensive LV reverse remodeling resulted in more clinical improvement, with a larger increase in LV function and more reduction in mitral regurgitation. In addition, more LV reverse remodeling resulted in less heart failure hospitalizations and lower mortality during long-term follow-up (22 +/- 11 months); 1- and 2-year hospitalization-free survival rates were 90% and 70% in the negative responder group compared with 98% and 96% in the super-responder group (log-rank p value <0.001). CONCLUSIONS The extent of LV reverse remodeling at midterm follow-up is predictive for long-term outcome in CRT patients.

Inappropriate implantable cardioverter-defibrillator shocks: incidence, predictors, and impact on mortality.

OBJECTIVES The purpose of this study was to assess the incidence, predictors, and outcome of inappropriate shocks in implantable cardioverter-defibrillator (ICD) patients. BACKGROUND Despite the benefits of ICD therapy, inappropriate defibrillator shocks continue to be a significant drawback. The prognostic importance of inappropriate shocks outside the setting of a clinical trial remains unclear. METHODS From 1996 to 2006, all recipients of defibrillator devices equipped with intracardiac electrogram storage were included in the current analysis and clinically assessed at implantation. During follow-up, the occurrence of inappropriate ICD shocks and all-cause mortality was noted. RESULTS A total of 1,544 ICD patients (79% male, age 61 ± 13 years) were included in the analysis. During the follow-up period of 41 ± 18 months, 13% experienced ≥1 inappropriate shocks. The cumulative incidence steadily increased to 18% at 5-year follow-up. Independent predictors of the occurrence of inappropriate shocks included a history of atrial fibrillation (hazard ratio [HR]: 2.0, p < 0.01) and age younger than 70 years (HR: 1.8, p = 0.01). Experiencing a single inappropriate shock resulted in an increased risk of all-cause mortality (HR: 1.6, p = 0.01). Mortality risk increased with every subsequent shock, up to an HR of 3.7 after 5 inappropriate shocks. CONCLUSIONS In a large cohort of ICD patients, inappropriate shocks were common. The most important finding is the association between inappropriate shocks and mortality, independent of interim appropriate shocks.

Infarct Tissue Heterogeneity Assessed with Contrast-Enhanced Magnetic Resonance Imaging Predicts Spontaneous Ventricular Arrhythmia in Patients with Ischemic Cardiomyopathy and Implantable Cardioverter-Defibrillator

Background—The relation between infarct tissue heterogeneity on contrast-enhanced MRI and the occurrence of spontaneous ventricular arrhythmia (or sudden cardiac death) is unknown. Therefore, the study purpose was to evaluate the predictive value of infarct tissue heterogeneity assessed with contrast-enhanced MRI on the occurrence of spontaneous ventricular arrhythmia with subsequent implantable cardioverter-defibrillator (ICD) therapy (as surrogate of sudden cardiac death) in patients with previous myocardial infarction. Methods and Results—Ninety-one patients (age, 65±11 years) with previous myocardial infarction scheduled for ICD implantation underwent cine MRI to evaluate left ventricular function and volumes and contrast-enhanced MRI for characterization of scar tissue (infarct gray zone as measure of infarct tissue heterogeneity, infarct core, and total infarct size). Appropriate ICD therapy was documented in 18 patients (20%) during a median follow-up of 8.5 months (interquartile range, 2.1 to 20.3). Multivariable Cox proportional hazards analysis revealed that infarct gray zone was the strongest predictor of the occurrence of spontaneous ventricular arrhythmia with subsequent ICD therapy (hazard ratio, 1.49/10 g; CI, 1.01 to 2.20; &khgr;2=4.0; P=0.04). Conclusions—Infarct tissue heterogeneity on contrast-enhanced MRI is the strongest predictor of spontaneous ventricular arrhythmia with subsequent ICD therapy (as surrogate of sudden cardiac death) among other clinical and MRI variables, that is, total infarct size and left ventricular function and volumes, in patients with previous myocardial infarction.

Cardiac Sympathetic Denervation Assessed With 123-Iodine Metaiodobenzylguanidine Imaging Predicts Ventricular Arrhythmias in Implantable Cardioverter-Defibrillator Patients

OBJECTIVES The purpose of this study was to evaluate whether 123-iodine metaiodobenzylguanidine (123-I MIBG) imaging predicts ventricular arrhythmias causing appropriate implantable cardioverter-defibrillator (ICD) therapy (primary end point) and the composite of appropriate ICD therapy or cardiac death (secondary end point). BACKGROUND Although cardiac sympathetic denervation is associated with ventricular arrhythmias, limited data are available on the predictive value of sympathetic nerve imaging with 123-I MIBG on the occurrence of arrhythmias. METHODS Before ICD implantation, patients underwent 123-I MIBG and myocardial perfusion imaging. Early and late 123-I MIBG (planar and single-photon emission computed tomography [SPECT]) imaging was performed to assess cardiac innervation (heart-to-mediastinum ratio, cardiac washout rate, and 123-I MIBG SPECT defect score). Stress-rest myocardial perfusion imaging was performed to assess myocardial infarction and perfusion abnormalities (perfusion defect scores). During follow-up, appropriate ICD therapy and cardiac death were documented. RESULTS One-hundred sixteen heart failure patients referred for ICD therapy were enrolled. During a mean follow-up of 23 +/- 15 months, appropriate ICD therapy (primary end point) was documented in 24 (21%) patients and appropriate ICD therapy or cardiac death (secondary end point) in 32 (28%) patients. Late 123-I MIBG SPECT defect score was an independent predictor for both end points. Patients with a large late 123-I MIBG SPECT defect (summed score >26) showed significantly more appropriate ICD therapy (52% vs. 5%, p < 0.01) and appropriate ICD therapy or cardiac death (57% vs. 10%, p < 0.01) than patients with a small defect (summed score </=26) at 3-year follow-up. CONCLUSIONS Cardiac sympathetic denervation predicts ventricular arrhythmias causing appropriate ICD therapy as well as the composite of appropriate ICD therapy or cardiac death.

Relative Merits of Left Ventricular Dyssynchrony, Left Ventricular Lead Position, and Myocardial Scar to Predict Long-Term Survival of Ischemic Heart Failure Patients Undergoing Cardiac Resynchronization Therapy

Background— The relative merits of left ventricular (LV) dyssynchrony, LV lead position, and myocardial scar to predict long-term outcome after cardiac resynchronization therapy remain unknown and were evaluated in the present study. Methods and Results— In 397 ischemic heart failure patients, 2-dimensional speckle tracking imaging was performed, with comprehensive assessment of LV radial dyssynchrony, identification of the segment with latest mechanical activation, and detection of myocardial scar in the segment where the LV lead was positioned. For LV dyssynchrony, a cutoff value of 130 milliseconds was used. Segments with <16.5% radial strain in the region of the LV pacing lead were considered to have extensive myocardial scar (>50% transmurality, validated in a subgroup with contrast-enhanced magnetic resonance imaging). The LV lead position was derived from chest x-ray. Long-term follow-up included all-cause mortality and hospitalizations for heart failure. Mean baseline LV radial dyssynchrony was 133±98 milliseconds. In 271 patients (68%), the LV lead was placed at the latest activated segment (concordant LV lead position), and the mean value of peak radial strain at the targeted segment was 18.9±12.6%. Larger LV radial dyssynchrony at baseline was an independent predictor of superior long-term survival (hazard ratio, 0.995; P=0.001), whereas a discordant LV lead position (hazard ratio, 2.086; P=0.001) and myocardial scar in the segment targeted by the LV lead (hazard ratio, 2.913; P<0.001) were independent predictors of worse outcome. Addition of these 3 parameters yielded incremental prognostic value over the combination of clinical parameters. Conclusions— Baseline LV radial dyssynchrony, discordant LV lead position, and myocardial scar in the region of the LV pacing lead were independent determinants of long-term prognosis in ischemic heart failure patients treated with cardiac resynchronization therapy. Larger baseline LV dyssynchrony predicted superior long-term survival, whereas discordant LV lead position and myocardial scar predicted worse outcome.

Implantation-Related Complications of Implantable Cardioverter-Defibrillators and Cardiac Resynchronization Therapy Devices: A Systematic Review of Randomized Clinical Trials

The number of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy (CRT) implantations is increasing drastically worldwide, and hence, the number of implanting centers is also increasing. Despite abundant data on the beneficial effect of these devices, little is known regarding safety and complication rates. Eleven ICD and 7 CRT trials were systematically reviewed to provide data on the frequency of in-hospital mortality and complications related to the implantation. Average in-hospital mortality was 2.7% in trials using both thoracotomy and nonthoracotomy ICDs, 0.2% in trials using nonthoracotomy ICDs, and 0.3% in CRT trials. The pneumothorax rate was similar between the nonthoracotomy ICD and CRT trials (0.9%) Coronary sinus complications occurred in 2.0% of patients undergoing CRT. Lead dislodgement rates were higher in CRT trials (5.7%) than in nonthoracotomy ICD trials (1.8%).

Analysis of Ventricular Activation Using Surface Electrocardiography to Predict Left Ventricular Reverse Volumetric Remodeling During Cardiac Resynchronization Therapy

Background— Cardiac resynchronization therapy for heart failure with left bundle branch block reduces left ventricular (LV) conduction delay, contraction asynchrony, and LV end-systolic volume (“reverse remodeling”). Up to one third of patients do not improve, and the electric requirements for reverse remodeling are unclear. We hypothesized that reverse remodeling is predicted by the left bundle branch block ventricular activation sequence, the paced activation sequence, and interactions between these 2 conditions. Methods and Results— Twelve-lead ECGs during left bundle branch block and cardiac resynchronization therapy were analyzed in 202 consecutive patients (New York Heart Association class III to IV heart failure, ejection fraction ≤35%) for predictors of reverse remodeling (≥10% reduction in end-systolic volume) at 6 months. Greater longest baseline LV activation time predicted increased odds of reverse remodeling (odds ratio [confidence interval]=1.30 [1.11, 1.52] per 10-ms increase), whereas higher QRS scores for LV scar predicted reduced reverse remodeling (odds ratio [confidence interval]=0.49 [0.27, 0.88] for each 1-point increase from 0 to 4; 0.92 [0.83, 1.01] for each 1-point increase >4). After cardiac resynchronization therapy, increasing R amplitudes in leads V1 through V2 (odds ratio [confidence interval]=2.76 [1.01, 7.51] for each 1× increase over [baseline R×4.5]) and left→right frontal axis shift (odds ratio [confidence interval]=2.00 [0.99, 4.02]), indicators of ventricular activation wavefront fusion, were positive predictors of reverse remodeling. Predicted probability of reverse remodeling ranged from <20% for patients with adverse predictors to 99% for those with positive predictors. Conclusions— Ventricular activation with the use of the ECG accurately predicts LV reverse remodeling during cardiac resynchronization therapy. Greater longest baseline LV activation time and smaller scar volume combined with wavefront fusion on the paced ECG, anticipate higher probability of reverse remodeling.

Prognostic importance of strain and strain rate after acute myocardial infarction

AIMS Recently, strain and strain rate have been introduced as novel parameters reflecting left ventricular (LV) function. The purpose of the current study was to assess the prognostic importance of strain and strain rate after acute myocardial infarction (AMI). METHODS AND RESULTS A total of 659 patients after AMI were evaluated. Baseline echocardiography was performed to assess LV function with traditional parameters and strain and strain rate. During follow-up, 51 patients (8%) reached the primary endpoint (all-cause mortality) and 142 patients (22%) the secondary endpoint (a composite of revascularization, re-infarction, and hospitalization for heart failure). Strain and strain rate were both significantly related with all endpoints. After adjusting for clinical and echocardiographic parameters, strain was independent related to all endpoints and was found to be superior to LV ejection fraction (LVEF) and wall motion score index (WMSI). Patients with global strain and strain rate higher than -15.1% and -1.06 s(-1) demonstrated HRs of 4.5 (95% CI 2.1-9.7) and 4.4 (95% CI 2.0-9.5) for all-cause mortality, respectively. CONCLUSION Strain and strain rate provide strong prognostic information in patients after AMI. These novel parameters were superior to LVEF and WMSI in the risk stratification for long-term outcome.

Cardiac Resynchronization Therapy as a Therapeutic Option in Patients With Moderate-Severe Functional Mitral Regurgitation and High Operative Risk

Background— Functional mitral regurgitation (MR) is a common finding in heart failure patients with dilated cardiomyopathy and has important prognostic implications. However, the increased operative risk of these patients may result in low referral or high denial rate for mitral valve surgery. Cardiac resynchronization therapy (CRT) has been shown to have a favorable effect on MR. Aims of this study were to (1) evaluate CRT as a therapeutic option in heart failure patients with functional MR and high operative risk and (2) investigate the effect of MR improvement after CRT on prognosis. Methods and Results— A total of 98 consecutive patients with moderate-severe functional MR and high operative risk underwent CRT according to current guidelines. Echocardiography was performed at baseline and 6-month follow-up; severity of MR was graded according to a multiparametric approach. Significant improvement of MR was defined as a reduction ≥1 grade. All-cause mortality was assessed during follow-up (median 32 [range 6.0 to 116] months). Thirteen patients (13%) died before 6-months follow-up. In the remaining 85 patients, significant reduction in MR was observed in all evaluated parameters. In particular, 42 patients (49%) improved ≥1 grade of MR and were considered MR improvers. Survival was superior in MR improvers compared to MR nonimprovers (log rank P<0.001). Mitral regurgitation improvement was an independent prognostic factor for survival (hazard ratio 0.35, confidence interval 0.13 to 0.94; P=0.043). Conclusions— Cardiac resynchronization therapy is a potential therapeutic option in heart failure patients with moderate-severe functional MR and high risk for surgery. Improvement in MR results in superior survival after CRT.