Impact of Percutaneous Mitral Valve Repair Using the MitraClipTM System on Ventricular Arrhythmias and ICD Therapies

Transcatheter edge-to-edge repair (TEER) using the MitraClip™ device has been established as a suitable alternative to mitral valve surgery in patients with severe mitral regurgitation (MR) and high or prohibitive surgical risk. Only limited information regarding the impact of TEER on ventricular arrhythmias (VA) has been reported. The aim of the present study was to assess the impact of TEER using the MitraClip^TM device on the burden of VA and ICD (Implantable Cardioverter Defibrillator) therapies. Among 600 MitraClip^TM implantations performed in our clinic between September 2009 and October 2018, we identified 86 patients with successful TEER and an active implantable cardiac device (pacemaker, ICD, CRT-P/D (Cardiac Resynchronization Therapy-Pacemaker/Defibrillator)) eligible for retrospective VA analyses. These patients presented with mainly functional MR (81.4%) and severely reduced left ventricular ejection fraction (mean LVEF 22.1% ± 10.3%). The observation period comprised 456 ± 313 days before and 424 ± 287 days after TEER. The burden of ventricular arrhythmias (sustained ventricular tachycardia (sVT) and ventricular fibrillation (VF)) was significantly reduced after TEER (0.85 ± 3.47 vs. 0.43 ± 2.03 events per patient per month, p = 0.01). Furthermore, the rate of ICD therapies (anti-tachycardia pacing (ATP) and ICD shock) decreased significantly after MitraClip^TM implantation (1.0 ± 3.87 vs. 0.32 ± 1.41, p = 0.014). However, reduction of VA burden did not result in improved two-year survival in this patient cohort with severely reduced LVEF. Mitral valve TEER using the MitraClip™ device was associated with a significant reduction of ventricular arrhythmias and ICD therapies.

Ventricular arrhythmias in patients with functional mitral regurgitation and implantable cardiac devices: implications of mitral valve repair with Mitraclip®

Background

Limited information has been reported regarding the impact of percutaneous mitral valve repair (PMVR) on ventricular arrhythmic (VA) burden. The aim of this study was to address the incidence of VA and appropriate antitachycardia implantable cardiac defibrillator (ICD) therapies before and after PMVR.

Methods

We retrospectively analyzed all consecutive patients with heart failure with reduce left ventricular ejection fraction (LVEF), functional mitral regurgitation (FMR) grade 3+ or 4+ and an active ICD or cardiac resynchronizer who underwent PMVR in any of the eleven recruiting centers. Only patients with complete available device VA monitoring from one-year before to one year after PMVR were included. Baseline clinical and echocardiographic characteristics were collected before PMVR and at 12-months follow-up.

Results

Ninety-three patients (68.2±10.9 years old, male 88.2%) were enrolled. PMVR was successfully performed in all patients and device success at discharge was 91.4%. At 12-month follow-up, we observed a significant reduction in mitral regurgitation severity, NT-proBNP and prevalence of severe pulmonary hypertension and severe kidney disease. Patients also referred a significant improvement in NYHA functional class and showed a non-significant trend to reserve left ventricular remodeling. After PMVR a significant decrease in the incidence of non-sustained ventricular tachycardia (VT) (5.0±17.8 vs. 2.7±13.5, P=0.002), sustained VT or ventricular fibrillation (0.9±2.5 vs. 0.5±2.9, P=0.012) and ICD antitachycardia therapies (2.5±12.0 vs. 0.9±5.0, P=0.033) were observed.

Conclusions

PMVR was related to a reduction in arrhythmic burden and ICD therapies in our cohort.

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.

Outcome of Primary Prevention Implantable Cardioverter Defibrillator Therapy According to New York Heart Association Functional Classification

We aimed to assess if the outcome of primary prevention implantable cardioverter defibrillators (ICDs) without cardiac resynchronization therapy is dependent on New York Heart Association (NYHA) class. Among the participants of Défibrillateur Automatique Implantable-Prévention Primaire (DAI-PP; NCT01992458) multicenter cohort study, 155 patients in NYHA class I, 504 in NYHA class II, and 188 in NYHA class III had a QRS width <120 ms and were implanted with an ICD without cardiac resynchronization therapy and, thus, were eligible for the purpose of this analysis. Total and specific mortalities and the incidence of appropriate therapies were assessed for every NYHA. During 2,606 patient-years (3.1 ± 2.1 years), 104 (12.3%) subjects died and 188 (22.2%) experienced appropriate therapies. After adjustment, overall mortality increased with NYHA class (adjusted hazard ratio [HR] 1.63, 95% confidence interval [CI] 1.11 to 2.41, p = 0.014), driven by an increase in cardiovascular death. Conversely, incidence of appropriate ICD intervention was comparable among the 3 NYHA groups (NYHA class I 7.43, NYHA class II 7.91, and NYHA class III 12.10 per 100 patient-years; HR 1.19, 95% CI 0.89 to 1.59, p = 0.231). Incidence of ICD-unresponsive sudden death was very low and also comparable (NYHA class I 0.22, NYHA class II 0.36, and NYHA class III 0.83 per 100 patient-years (HR 6.34, 95% CI 0.32 to 124.49, p = 0.224). No significant differences were observed in the other specific modes of death. In conclusion, although patients in NYHA class III have higher overall mortality, they experience a comparable incidence of appropriate ICD therapies. The low incidence of ICD-unresponsive sudden death in all assessed NYHA classes also supports the efficacy of ICDs, irrespective of NYHA class.

Differences in predictors of implantable cardioverter-defibrillator therapies in patients with ischaemic and non-ischaemic cardiomyopathies

AIMS

Implantable cardioverter-defibrillators (ICDs) have been shown to reduce mortality in patients with both ischaemic and non-ischaemic cardiomyopathy by terminating life-threatening arrhythmias. However, such arrhythmic events are unequally distributed among different patient subgroups. We aimed to evaluate predictors of appropriate ICD therapies as a step towards risk stratification in a real-world cohort.

METHODS AND RESULTS

The prevalence and predictors of appropriate ICD therapies were analysed in 330 consecutive patients (mean age 65 ± 11, 81% male) with implanted ICDs due to ischaemic (n = 204) or dilated (n = 126) cardiomyopathy. During a mean follow-up of 19 ± 9 months, 1545 appropriate ICD therapies (antitachycardia pacing and shocks) were detected in 94 patients (29%). In multivariate analysis applied on the whole cohort, the presence of atrial fibrillation [AF: odds ratio (OR) = 1.906, confidence interval (CI) = 1.143-3.177, P = 0.013] and secondary prevention indication (OR = 1.963, CI = 1.123-3.432, P = 0.018) was associated with ICD therapy. The presence of cardiac resynchronization therapy (CRT) had a protective value (OR = 0.563, CI = 0.327-0.968, P = 0.038). Moreover, the predictors were different depending on the aetiology of the cardiomyopathy: in the ischaemic group, only secondary prevention indication (OR = 2.0, CI = 1.029-3.891, P = 0.041) and the presence of a biventricular system (OR = 0.359, CI = 0.163-0.794, P = 0.011) remained significant, while in the non-ischaemic group, an association with AF was observed (OR = 4.281, CI = 1.632-11.231, P = 0.003).

CONCLUSION

The aetiology of cardiomyopathy should be taken into consideration for the therapy of ICD patients. The protective role of CRT devices should be pointed out in ischaemic cardiomyopathy (ICM) and a more rigorous antiarrhythmic treatment should be considered for ICM patients with secondary prevention or for dilated cardiomyopathy patients with AF.

Influence of renal function on mortality and ventricular arrhythmias in patients undergoing first implantable cardioverter-defibrillator generator replacement

BACKGROUND

Impaired renal function is associated with increased mortality among patients with implantable cardioverter-defibrillators (ICDs). The relationship between renal function at time of ICD generator replacement and subsequent appropriate ICD therapies is not known.

METHODS AND RESULTS

We identified 441 patients who underwent first ICD generator replacement between 2000 and 2011 and had serum creatinine measured within 30 days of their procedure. Patients were divided into tertiles based on estimated glomerular filtration rate (eGFR). Adjusted Cox proportional hazard and competing risk models were used to assess relationships between eGFR and subsequent mortality and appropriate ICD therapy. Median eGFR was 37.6, 59.3, and 84.8 mL/min/1.73 m(2) for tertiles 1-3, respectively. Five-year Kaplan-Meier survival probability was 34.8%, 61.4%, and 84.5% for tertiles 1-3, respectively (P < 0.001). After multivariable adjustment, compared to tertile 3, worse eGFR tertile was associated with increased mortality (HR 2.84, 95% CI [1.36-5.94] for tertile 2; HR 3.84, 95% CI [1.81-8.12] for tertile 1). At 5 years, 57.0%, 58.1%, and 60.2% of patients remained free of appropriate ICD therapy in tertiles 1-3, respectively (P = 0.82). After adjustment, eGFR tertile was not associated with future appropriate ICD therapy. Results were unchanged in an adjusted competing risk model accounting for death.

CONCLUSIONS

At time of first ICD generator replacement, lower eGFR is associated with higher mortality, but not with appropriate ICD therapies. The poorer survival of ICD patients with reduced eGFR does not appear to be influenced by arrhythmia status, and there is no clear proarrhythmic effect of renal dysfunction, even after accounting for the competing risk of death.

Is CRT pro-arrhythmic? A comparative analysis of the occurrence of ventricular arrhythmias between patients implanted with CRTs and ICDs

Aim and Hypothesis: Despite the proven symptomatic and mortality benefit of cardiac resynchronization therapy (CRT), there is anecdotal evidence it may be pro-arrhythmic in some patients. We aimed to identify if there were significant differences in the incidence of ventricular arrhythmias (VAs) in patients undergoing CRT-D and implantable cardioverter-defibrillators (ICD) implantation for primary prevention indication. We hypothesized that CRT is unlikely to be pro-arrhythmic based on the positive mortality and morbidity data from large randomized trials.

Methods and Results: A retrospective analysis of device therapies for VA in a primary prevention device cohort was performed. Patients with ischemic (IHD) and non-ischemic (DCM) cardiomyopathy and ICD or CRT+ICD devices (CRT-D) implanted between 2005 and 2007 without prior history of sustained VA were included for analysis. VA episodes were identified from stored electrograms and defined as sustained (VT/VF) if therapy [anti-tachycardia pacing (ATP) or shocks] was delivered or non-sustained (NSVT) if not. Of a total of 180 patients, 117 (68% male) were in the CRT-D group, 42% IHD, ejection fraction (EF) 24.5 ± 8.2% and mean follow-up 23.9 ± 9.8 months. 63 patients (84% male) were in the ICD group, 60% IHD, EF 27.7 ± 7.2% and mean follow-up 24.6 ± 10.8 months. Overall, there was no significant difference in the incidence of VA (35.0 vs. 38.1%, p = 0.74), sustained VT (21.3 vs. 28.5%, p = 0.36) or NSVT (12.8 vs. 9.5%, p = 0.63) and no significant difference in type of therapy received for VT/VF: ATP (68 vs. 66.6%, p = 0.73) and shocks (32 vs. 33.3%, p = 0.71) between the CRT-D and ICD groups, respectively.

Conclusion: In patients with cardiomyopathy receiving CRT-D and ICDs for primary prophylaxis, there was no significant difference in the incidence of VA. From this single center retrospective analysis, there is no evidence to support cardiac resynchronization causing pro-arrhythmia.

Usefulness of sleep-disordered breathing to predict occurrence of appropriate and inappropriate implantable-cardioverter defibrillator therapy in patients with implantable cardioverter-defibrillator for primary prevention of sudden cardiac death

Advanced heart failure (HF) is associated with severe sleep-disordered breathing (SDB). In addition, most patients with HF are treated with an implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death. The incidence of ICD therapy in such a patient cohort with SDB has never been investigated. The present study sought to determine the effect of SDB on the incidence of appropriate and inappropriate ICD therapy in patients with a categorical primary prevention ICD indication. A total of 133 consecutive ICD patients with New York Heart Association class II-III HF and depressed left ventricular function (≤35%) with no history of ventricular arrhythmia underwent a sleep study before ICD implantation and were followed for 24 ± 8 months, prospectively. A relevant SDB was defined as an apnea-hypopnea index of ≥10 events/hour. Of these 133 patients, 82 (62%) had SDB. Overweight (body mass index >29.1 vs 24.7 kg/m(2); p <0.001) was identified as the only independent risk factor for SDB. Appropriate ICD therapy intervention was significantly greater among patients with SDB than among patients without SDB (54% vs 34%, p = 0.03). Inappropriate ICD therapy intervention was documented more often in patients with SDB (n = 24 [29%] vs 7 [14%]; p = 0.04). An apnea-hypopnea index >10 events/hour was an independent predictor of appropriate ICD therapy on multivariate analysis (odds ratio 2.5, 95% confidence interval 1.8 to 4.04; p = 0.01). In conclusion, the present study is the first trial exploring the effect of SDB on the incidence of appropriate and inappropriate ICD therapy in patients with HF with a primary prevention indication. These results indicate that a preimplantation sleep study will identify patients with HF prone to receive appropriate and inappropriate ICD therapy.

Kidney dysfunction and deterioration of ejection fraction pose independent risk factors for mortality in implantable cardioverter-defibrillator recipients for primary prevention

BACKGROUND

A growing number of patients with advanced heart failure fulfill a primary-prevention indication for an implantable cardioverter-defibrillator (ICD). This study seeks to identify new predictors of overall mortality in a Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT)-like collective to enhance risk stratification.

HYPOTHESIS

An impaired renal function and severely depressed left ventricular ejection fraction pose relevant risk factors for mortality in primary prevention ICD recipients.

METHODS

Ninety-four consecutive ICD patients with New York Heart Association class II-III heart failure and depressed left ventricular function (left ventricular ejection fraction [LVEF] ≤ 35%) with no history of malignant ventricular arrhythmias were followed for 34 ± 20 months.

RESULTS

During this period, 30 patients died (32%). Deceased patients revealed a significantly worse renal function before ICD implantation (1.55 ± 0.7 mg/dL vs 1.1 ± 0.4 mg/dL; P = 0.007), suffered more often from coronary artery disease (53 vs 29; P = 0.006), and were older (69.5 ± 8 y vs 67 ± 12 y; P = 0.0002) than surviving patients. Furthermore, increased serum creatinine at baseline (2 mg/dL vs 1 mg/dL; odds ratio [OR]: 3.96, 95% confidence interval [CI]: 1.2-13.04, P = 0.02), presence of coronary artery disease (OR: 8.6, 95% CI: 1.1-65, P = 0.036), and low LVEF (OR per 5% baseline LVEF deterioration: 1.4, 95% CI: 1-1.8, P = 0.034) represented strong and independent predictors for overall mortality.

CONCLUSIONS

Impaired renal function, the presence of coronary artery disease, and reduced LVEF before implantation represent independent predictors for mortality in a cohort of patients with advanced systolic heart failure. These conditions still bear a high mortality risk, even if ICD implantation effectively prevents sudden arrhythmic death. Indeed, in patients suffering from several of the identified "high-risk" comorbidities, primary-prevention ICD implantation might have a limited survival benefit. The possible adverse effects of these comorbidities should be openly discussed with the potential ICD recipient and his or her close relatives.