Follow-up of implantable cardioverter-defibrillator therapy: comparison of coronary artery disease and dilated cardiomyopathy

Tachycardia Therapy Outcomes of Ischemic Versus Nonischemic Cardiomyopathy on Cardiac Resynchronization Therapy: A Propensity Score-matched Analysis

Objective

This investigation aimed to investigate differences between dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) patients treated with cardiac resynchronization therapy with defibrillator (CRT-D) for tachycardia therapy-related outcomes as well as mortality during follow-up of at least 1 year.

Methods

Seventy-eight patients with DCM (n = 42) and ICM (n = 36) with implantation or upgradation to CRT-D were included in this study and analyzed for incidence of non-sustained ventricular tachycardia (NSVT), non-sustained ventricular fibrillation (NSVF), defibrillator therapies, anti-tachycardia pacing (ATP), and mortality.

Results

DCM was the underlying etiology in 42 (53.84%) and ICM in 36 (46.15%). Time to first therapy was numerically longer in DCM than in ICM (9.5 ± 2.4 vs. 7.1 ± 3.2; P-value = 0.088). DCM patients had significantly higher therapy-free survival and mortality compared with ICM patients (OR (95%CI): 0.238 (0.155-0.424); log-rank P = 0.017) and (OR (95% CI): 0.612 (0.254-0.924); log-rank P = 0.029). ICM (HR (95%CI): 0.529 (0.243-0.925); P-value = 0.014) CAD (HR (95%CI): 0.326 (0.122-0.691): P-value = 0.003), and NSVT (HR (95%CI): 0.703 (0.513-0.849): P-value = 0.005) were demonstrated as independent predictors of the primary endpoint of appropriate therapy in CRT-D and ICM (HR (95%CI): 0.421 (0.321-0.524); P-value = 0.037), chronic kidney disease (CKD; HR (95%CI): 0.289 (0.198-0.380); P-value = 0.013), and CAD (HR (95%CI): 0.786 (0.531-0.967); P-value = 0.003) were predictors of mortality.

Conclusion

The clinical course of ICM and DCM cohorts who were treated with CRT-D differs significantly during follow-up, with increased tachycardia therapy and increased incidence of mortality in ICM patients.

Implantable Cardioverter Defibrillator in Primary and Secondary Prevention of SCD-What We Still Don't Know

Implantable cardioverter defibrillators (ICDs) are the cornerstone of primary and secondary prevention of sudden cardiac death (SCD) all around the globe. In almost 40 years of technological advances and multiple clinical trials, there has been a continuous increase in the implantation rate. The purpose of this review is to highlight the grey areas related to actual ICD recommendations, focusing specifically on the primary prevention of SCD. We will discuss the still-existing controversies strongly reflected in the differences between the international guidelines regarding ICD indication class in non-ischemic cardiomyopathy, and also address the question of early implantation after myocardial infarction in the absence of clear protocols for patients at high risk of life-threatening arrhythmias. Correlating the insufficient data in the literature for 40-day waiting times with the increased risk of SCD in the first month after myocardial infarction, we review the pros and cons of early ICD implantation.

Comparable Efficacy in Ischemic and Non-Ischemic ICD Recipients for the Primary Prevention of Sudden Cardiac Death

(1) Background: In patients suffering from heart failure, the main causes of death are either hemodynamic failure, or ventricular arrhythmias. The only tool to significantly reduce arrhythmic sudden death is the implantable cardioverter defibrillator (ICD), but not all patients benefit to the same extent from these devices. (2) Methods: The primary outcome of this single-center study was defined as cardiovascular death in patients with ischemic and non-ischemic heart failure who have benefited from ICD therapy. The secondary outcomes were death from any cause, sudden cardiac death, ICD-related therapies (appropriate antitachycardia pacing or shock therapy for ventricular tachycardia or fibrillation) and recurrences of ventricular tachyarrhythmias. (3) Results: A total of 403 consecutive ICD recipients—symptomatic heart failure patients with ICD for the primary prevention of sudden cardiac death—were included retrospectively: 59% ischemic cardiomyopathy (ICMP) and 41% non-ischemic cardiomyopathy (NICMP) patients. Within a median follow-up period of 36 months, the incidence of cardiovascular mortality was not significantly different in patients with NICMP and ICMP: the primary outcome had occurred in 9 patients (5.4%) in the NICMP group and in 14 patients (5.9%) in the ICMP group (hazard ratio 1; 95% confidence interval (CI) 0.45 to 2.28; p = 0.97). All-cause mortality occurred in 14 of 166 patients (8.4%) in the NICMP group and 18 of 237 patients (7.6%) in the ICMP group. Sudden cardiac death occurred in two patients (1.2%) in the NICMP group and in four patients (1.7%) in the ICMP group (hazard ratio 0.71; 95% CI, 0.13 to 3.88; p = 0.69). The rate of appropriate device therapies was comparable in both groups. (4) Conclusions: In this study, ICD implantation for primary prevention of sudden cardiac death in patients with symptomatic systolic heart failure was associated with similar rates of cardiovascular and all-cause mortality in patients with ischemic heart disease, and in patients with heart failure from other causes. NICMP and ICMP showed comparable rates of recurrent ventricular tachyarrhythmias and appropriate ICD therapies.

Non-ischemic compared to ischemic cardiomyopathy is associated with increasing recurrent ventricular tachyarrhythmias and ICD-related therapies

OBJECTIVE

The study sought to assess the impact of ischemic (ICMP) compared to non-ischemic cardiomyopathy (NICMP) on recurrences of ventricular tachyarrhythmias in implantable cardioverter defibrillator (ICD) recipients.

BACKGROUND

Data comparing recurrences of ventricular tachyarrhythmias in ICD recipients with ischemic or non-ischemic cardiomyopathy is limited.

METHODS

A large retrospective registry was used including all consecutive ICD recipients with first episodes of ventricular tachycardia (VT) or fibrillation (VF) from 2002 to 2016. Patients with ICMP were compared to patients with NICMP. The primary prognostic endpoint was first recurrences of ventricular tachyarrhythmias at one year. Secondary endpoints comprised ICD-related therapies, rehospitalization and all-cause mortality at one year. Statistics Kaplan-Meier survival and multivariable Cox regression analyses.

RESULTS

A total of 387 consecutive ICD recipients were included retrospectively (ICMP: 82%, NICMP: 18%). At one year of follow-up, freedom from first recurrences of ventricular tachyarrhythmias was lower in NICMP (81% vs. 71%, log-rank p = 0.063; HR = 1.760; 95% CI 0.985-3.002; p = 0.080), mainly attributed to higher rates of sustained VT (20% versus 12%, p = 0.054). Accordingly, freedom from first appropriate device therapies was lower in NICMP (74% vs. 85%, log rank p = 0.004; HR = 1.951; 95% CI 1.121-3.397; p = 0.028), especially in patients with sustained VT or VF at index. Both groups revealed comparable rates of rehospitalization and all-cause mortality at one year.

CONCLUSION

NICMP was associated with higher rates of recurrent ventricular tachyarrhythmias and appropriate ICD therapies compared to ICMP at one year of follow-up, whereas rates of rehospitalization and all-cause mortality were comparable.

CONDENSED ABSTRACT

This study retrospectively compared the impact of cardiomyopathy types (ICMP versus NICMP) on recurrences of ventricular tachyarrhythmias in 387 ICD recipients. Freedom from first episodes of ventricular tachyarrhythmias and first appropriate device therapies were lower in patients with NICMP compared to ICMP.

Increased mortality and ICD therapies in ischemic versus non-ischemic dilated cardiomyopathy patients with cardiac resynchronization having survived until first device replacement

INTRODUCTION

Cardiac resynchronization therapy combined with an implantable cardioverter defibrillator (CRT-D) is widely applied in heart failure patients. Sufficient data on arrhythmia and defibrillator therapies during long-term follow-up of more than 4 years are lacking and data on mortality are conflicting. We aimed to characterize the occurrence of ventricular arrhythmia, respective defibrillator therapies and mortality for several years following CRT-D implantation or upgrade.

MATERIAL AND METHODS

Eighty-eight patients with ischemic (ICM) or non-ischemic dilated cardiomyopathy (DCM) and at least one CRT-D replacement were included in this study and analyzed for incidence of non-sustained ventricular tachycardia (NSVT), defibrillator shocks, anti-tachycardia pacing (ATP) and mortality.

RESULTS

ICM was the underlying disease in 59%, DCM in 41% of patients. During a mean follow-up of 76.4 ±24.8 months the incidence of appropriate defibrillator therapies (shock or ATP) was 46.6% and was elevated in ICM compared to DCM patients (57.7% vs. 30.6%, respectively; p = 0.017). Kaplan-Meier analysis revealed significantly higher ICD therapy-free survival rates in DCM patients (p = 0.031). Left ventricular ejection fraction, NSVT per year and ICM (vs. DCM) were independent predictors of device intervention. The ICM patients showed increased mortality compared to DCM patients, with cumulative all-cause mortality at 9 years of follow-up of 45.4% and 10.6%, respectively. Chronic renal failure, peripheral artery disease and chronic obstructive pulmonary disease were independent predictors of mortality.

CONCLUSIONS

The clinical course of patients with ICM and DCM treated with CRT-D differs significantly during long-term follow-up, with increased mortality and incidence of ICD therapies in ICM patients.

Predicting appropriate shocks in patients with heart failure: Patient level meta-analysis from SCD-HeFT and MADIT II

BACKGROUND

No precise tools exist to predict appropriate shocks in patients with a primary prevention ICD. We sought to identify characteristics predictive of appropriate shocks in patients with a primary prevention implantable cardioverter defibrillator (ICD).

METHODS

Using patient-level data from the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) and the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), we identified patients with any appropriate shock. Clinical and demographic variables were included in a logistic regression model to predict appropriate shocks.

RESULTS

There were 1,463 patients randomized to an ICD, and 285 (19%) had ≥1 appropriate shock over a median follow-up of 2.59 years. Compared with patients without appropriate ICD shocks, patients who received any appropriate shock tended to have more severe heart failure. In a multiple logistic regression model, predictors of appropriate shocks included NYHA class (NYHA II vs. I: OR 1.65, 95% CI 1.07-2.55; NYHA III vs. I: OR 1.74, 95% CI 1.10-2.76), lower LVEF (per 1% change) (OR 1.04, 95% CI 1.02-1.06), absence of beta-blocker therapy (OR 1.61, 95% CI 1.23-2.12), and single chamber ICD (OR 1.67, 95% CI 1.13-2.45).

CONCLUSION

In this meta-analysis of patient level data from MADIT-II and SCD-HeFT, higher NYHA class, lower LVEF, no beta-blocker therapy, and single chamber ICD (vs. dual chamber) were significant predictors of appropriate shocks.

Echo response and clinical outcome in CRT patients

Background

Change in left ventricular end-systolic volume (∆LVESV) is the most frequently used surrogate marker in measuring response to cardiac resynchronisation therapy (CRT). We investigated whether ∆LVESV is the best measure to discriminate between a favourable and unfavourable outcome and whether this is equally applicable to non-ischaemic and ischaemic cardiomyopathy.

Methods

205 CRT patients (age 65 ± 12 years, 69 % men) were included. At baseline and 6 months echocardiographic studies, exercise testing and laboratory measurements were performed. CRT response was assessed by: ∆LVESV, ∆LV ejection fraction (LVEF), ∆ interventricular mechanical delay, ∆VO₂ peak, ∆VE/VCO₂, ∆BNP, ∆creatinine, ∆NYHA, and ∆QRS. These were correlated to the occurrence of major adverse cardiac events (MACE) between 6 and 24 months.

Results

MACE occurred in 19 % of the patients (non-ischaemic: 13 %, ischaemic: 24 %). ∆LVESV remained the only surrogate marker for CRT response for the total population and patients with non-ischaemic cardiomyopathy, showing areas under the curve (AUC) of 0.69 and 0.850, respectively. For ischaemic cardiomyopathy, ∆BNP was the best surrogate marker showing an AUC of 0.66.

Conclusion

∆LVESV is an excellent surrogate marker measuring CRT response concerning long-term outcome for non-ischaemic cardiomyopathy. ∆LVESV is not suitable for ischaemic cardiomyopathy in which measuring CRT response remains difficult.