Long-term mortality risk in patients with an implantable cardioverter-defibrillator: Influence of heart rate and QRS duration

Anxiety and depression as risk factors for ICD shocks and mortality in patients with an implantable cardioverter defibrillator - A systematic review

OBJECTIVE

To examine associations between baseline anxiety and depression and occurrence of ICD shocks and risk of mortality in patients with an implantable cardioverter defibrillator (ICD).

METHOD

We systematically searched EMBASE, PubMed, PsycINFO, and CINAHL for eligible studies fulfilling the predefined criteria.

RESULTS

We included 37 studies based on 25 different cohorts following 35,003 participants for up to seven years. We observed no association between baseline anxiety nor depression and the occurrence of ICD shocks. More than half of the identified studies (respectively 56% and 60%) indicated a significant association between baseline anxiety or depression and increased risk of mortality (anxiety: n = 5, ranging from Hazard ratios (HR):1.02 [Confidence intervals (CI) 95% 1.00-1.03] to HR:3.45 [CI 95% 1.57-7.60]; depression: n = 6, ranging from HR:1.03 [CI 95% 1.00-1.06] to HR:2.10 [CI 95% 1.44-3.05]). We found a significant association between high methodological quality of the primary study and the detection of a significant association (p < 0.01).

CONCLUSIONS

Baseline anxiety and depression are associated with increased risk of mortality in patients with an ICD, but not with occurrence of ICD shocks. Inclusion of baseline anxiety and depression in risk stratification of mortality may be warranted.

Relation between resting heart rate and the risk of ventricular tachyarrhythmias in MADIT-RIT

AIMS

To explore the association between resting heart rate (RHR) and ventricular tachyarrhythmias (VTA) events among patients who were enrolled in MADIT-RIT.

METHODS AND RESULTS

Multivariate Cox proportional hazards regression modelling was employed to evaluate the association between baseline RHR [dichotomized at the lower quartile (≤63 b.p.m.) and further assessed as a continuous measure] and the risk for any VTA, fast VTA (>200 b.p.m.), and appropriate implantable cardioverter-defibrillator (ICD) therapy, among 1500 patients who were enrolled in MADIT-RIT. Kaplan-Meier survival analysis showed that at 2 years of follow-up the rate of any VTA was significantly lower among patients with low baseline RHR (≤63 b.p.m.) as compared with faster RHR (11% vs. 19%, respectively; P = 0.001 for the overall difference during follow-up). Similar results were shown for the association with the rate of fast VTA (8% vs. 14%, respectively; P = 0.016), and appropriate ICD therapy (10% vs. 18%, respectively; P = 0.004). Multivariate analysis, after adjustment for medical therapy, showed that low baseline RHR was associated with a significant 45% (P = 0.002) reduction in the VTA risk as compared with faster baseline RHRs. When assessed as a continuous measure, each 10 b.p.m. decrement in RHR was associated with a corresponding 13% (P = 0.014) reduction in the VTA risk.

CONCLUSION

In MADIT-RIT, low RHR was independently associated with a lower risk for life-threatening arrhythmic events. These findings suggest a possible role for RHR for improved selection of candidates for ICD therapy.

Anxiety disorders and all-cause mortality: systematic review and meta-analysis

PURPOSE

The purpose of this study was to perform a systematic review and meta-analysis of prospective cohort studies that examined the relationship between anxiety disorders, or clinically significant anxiety symptoms, at baseline and all-cause mortality at follow-up relative to control participants without clinically significant anxiety.

METHODS

PubMed, EMBASE, PsycInfo, and CINAHL were searched through July 2015, along with manual searches of published reviews and forward and backward snowball searches of included studies. Studies were excluded if anxiety was not defined with a standardized instrument, or if participants were followed-up for 1 year or less. The initial search yielded 7901 articles after the removal of duplicates, of which 328 underwent full-text screening.

RESULTS

Forty-two estimates from 36 articles were included in the meta-analysis with a total sample of 127,552 participants and over 11,573 deaths. The overall hazard ratio (HR) estimate of mortality in clinically anxious participants relative to controls was 1.09 (95 % CI 1.01-1.16); however, this was reduced after adjusting for publication bias (1.03; 95 % CI 0.95-1.13). There was no evidence of increased mortality risk among anxious participants derived from community samples (0.99; 95 % CI 0.96-1.02) and in studies that adjusted for a diagnosis of depression (1.01; 95 % CI 0.96-1.06).

CONCLUSIONS

These findings suggest that positive associations in the literature are attributable to studies in smaller samples, comorbid depression (or other psychiatric conditions) among participants, and possible confounding in medical patient samples followed-up for short durations.

The role of variability in night-time mean heart rate on the prediction of ventricular arrhythmias and all-cause mortality in implantable cardioverter defibrillator patients

AIMS

This study was to use implantable cardioverter defibrillator (ICD) home monitoring (HM) feature to evaluate the role of mean night-time heart rate (MNHR) in the occurrence of ventricular arrhythmias (VAs) and mortality.

METHODS AND RESULTS

This study retrospectively analysed clinical and ICD device data in 318 ICD patients. Data of the first 30-day MNHR (recorded 02:00-06:00 am) by HM were collected. The average and standard deviation of 30-day MNHR (AVHR and SDHR, respectively) were then determined in each patient. The primary endpoint was appropriate ICD treatment of VAs. The secondary endpoint was all-cause mortality. During a mean follow-up period of 32 ± 10 months, 179 of the 318 patients (56.3%) experienced VAs, 123 patients (38.7%) were treated by ICD shocks, and 37 patients (11.6%) died. The overall SDHR in this study cohort was 4.5 ± 3.0 bpm. Based on the receiver operating characteristic curve, the cut-off value of SDHR = 3.685 bpm was identified to predict VAs. In the Kaplan-Meier survival, SDHR ≥ 3.685 bpm was associated with increased VAs [hazard ratio (HR) = 1.885; 95% confidence interval (CI) = 1.362-2.609; P < 0.001], shock events (HR = 1.637; 95% CI = 1.11-2.414; P = 0.013), all-cause mortality (HR = 2.42; 95% CI = 1.266-4.627; P = 0.008), and the combined endpoints (HR = 1.872; 95% CI = 1.365-2.567; P < 0.001). In univariate and multivariate Cox models (adjusting for clinical factors), SDHR ≥ 3.685 bpm was still an independent predictor for all endpoints.

CONCLUSION

In ICD population, SDHR ≥ 3.685 bpm was an independent predictor for VAs and all-cause mortality.