Diminishing proportional risk of sudden death with advancing age: implications for prevention of sudden death

Is it time to consider a "time-out" before primary prevention implantable cardioverter-defibrillator placement in currently or recently hospitalized older patients with heart failure?

BACKGROUND

Trajectories of mortality after primary prevention implantable cardioverter-defibrillator (ICD) placement for older patients with heart failure during or soon after acute hospitalization have not been assessed.

OBJECTIVE

The purpose of this study was to compare trajectories of mortality after primary prevention ICD placement during or soon after acute cardiac or non-cardiac hospitalization.

METHODS

We identified older patients with heart failure undergoing primary prevention ICD placement using 20% Medicare data (2008-2018). Placement settings were as follows: (1) Current-H-during current hospitalization, (2) Recent-H-within 90 days of hospitalization, or (3) Chronic stable. Hospitalization was categorized as cardiac vs non-cardiac. Interval mortality rates and hazard ratios (HRs) using Cox regression were estimated at 0-30, 31-90, and 91-365 days after ICD placement.

RESULTS

Of the 61,710 patients (mean age 76 years; 35% female; 85% white), 19% (11,947), 25% (15,147), and 56% (34,616) had ICDs in Current-H, Recent-H, and Chronic stable settings. Mortality rates (per 100 person-years) were highest during 0-30 days, with 38 (34-42) and 22 (19-24) for Current-H and Recent-H, which declined to 21 (20-22) and 16 (15-17) during 91-365 days, respectively. Compared to Chronic stable, HRs were highest during 0-30 days post-ICD placement (5.5 [4.5-6.8] for Current-H and 3.4 [2.8-4.2] for Recent-H) and decreased during 91-365 days (2.0 [1.8-2.1] for Current-H and 1.6 [1.5-1.7] for Recent-H). HR pattens were similar for cardiac and non-cardiac hospitalizations.

CONCLUSION

Primary prevention ICD placement during or soon after hospitalization for any reason was associated with worse mortality with diminishing risks after 90 days. Hospitalization likely identifies a sicker population in whom early mortality with or without ICD may be higher. Our results support careful consideration regarding ICD placement during the 90 days after hospitalization.

Cardiac resynchronization therapy with a defibrillator in non-ischemic and ischemic patients for primary and secondary prevention of sudden cardiac death: Analysis of the Japan cardiac device treatment registry database

Background

Panoramic studies in patients with cardiac resynchronization therapy with a defibrillator (CRT-D) focusing on the etiology and indication are scarce. Besides, a controversy exists regarding requirement of a defibrillator in non-ischemic patients for primary prevention with CRT.

Methods

Annual trends of de novo CRT-D implantations from 2011 to 2020 and outcomes of those between January 2011 and August 2015 were analyzed from the Japan cardiac device treatment registry (JCDTR) and New JCDTR database.

Results

From 2011 to 2020, 8062 CRT-D recipients were registered, whose dominant indication was primary prevention of sudden cardiac death with a steady rate of about 70%. There was no significant temporal change of the proportion of non-ischemic patients being about 70% and 65% for primary and secondary prevention, respectively. Non-ischemic patients for primary prevention were associated with increased odds of appropriate ICD therapy [adjusted hazard ratio (aHR): 1.66; 95% confidence interval (CI): 1.01-2.75; p = .047] and reduced odds of any death (aHR: 0.66; 95% CI: 0.44-0.99; p = .046) as compared to ischemic patients.

Conclusions

Proportion of non-ischemic etiology was much higher than that of ischemic one in the CRT-D cohort. Based on the higher odds of appropriate ICD therapy, non-ischemic patients for primary prevention appear to be prudently selected in Japan.

Impact of age on the prognosis of patients with ventricular tachyarrhythmias and aborted cardiac arrest

BACKGROUND

This study evaluated the prognostic impact of age on patients presenting with ventricular tachyarrhythmias (VTA) and aborted cardiac arrest.

MATERIAL AND METHODS

The present registry-based, monocentric cohort study included all consecutive patients presenting at the University Medical Center Mannheim (UMM) between 2002 and 2016 with ventricular tachycardia (VT), ventricular fibrillation (VF) and aborted cardiac arrest. Middle-aged (40-60 years old) were compared to older patients (> 60 years old). Furthermore, age was analyzed as a continuous variable. The primary endpoint was all-cause mortality at 2.5 years. The secondary endpoints were cardiac death at 24 h, all-cause mortality at index hospitalization, all-cause mortality after index hospitalization and the composite endpoint at 2.5 years of cardiac death at 24 h, recurrent VTA, and appropriate implantable cardioverter defibrillator (ICD) treatment.

RESULTS

A total of 2259 consecutive patients were included (28% middle-aged, 72% older). Older patients were more often associated with all-cause mortality at 2.5 years (27% vs. 50%; hazard ratio, HR = 2.137; 95% confidence interval, CI 1.809-2.523, p = 0.001) and the secondary endpoints. Even patient age as a continuous variable was independently associated with mortality at 2.5 years in all types of VTA. Adverse prognosis in older patients was demonstrated by multivariate Cox regression analyses and propensity score matching. Chronic kidney disease (CKD), systolic left ventricular dysfunction (LVEF) < 35%, cardiopulmonary resuscitation (CPR) and cardiogenic shock worsened the prognosis for both age groups, whereas acute myocardial infarction (STEMI/NSTEMI) and the presence of an ICD improved prognosis.

CONCLUSION

The results of this study suggest that increasing age is associated with increased mortality in VTA patients. Compared to the middle-aged, older patients were associated with higher all-cause mortality at 2.5 years and the secondary endpoints.

Long-term outcome of cardiac resynchronization therapy patients in the elderly

Heart failure (HF) is a leading cause of mortality and hospitalization in the elderly. However, data are scarce about their response to device treatment such as cardiac resynchronization therapy (CRT). We aimed to evaluate the age-related differences in the effectiveness of CRT, procedure-related complications, and long-term outcome. Between 2000 and 2020, 2656 patients undergoing CRT implantation were registered and analyzed retrospectively. Patients were divided into 3 groups according to their age: group I, < 65; group II, 65-75; and group III, > 75 years. The primary endpoint was the echocardiographic response defined as a relative increase > 15% in left ventricular ejection fraction (LVEF) within 6 months, and the secondary endpoint was the composite of all-cause mortality, heart transplantation, or left ventricular assist device implantation. Procedure-related complications were also assessed. After implantation, LVEF showed significant improvement both in the total cohort [28% (IQR 24/33) vs. 35% (IQR 28/40); p < 0.01)] and in each subgroup (27% vs. 34%; p < 0.01, 29% vs. 35%; p < 0.01, 30% vs. 35%; p < 0.01). Response rate was similar in the 3 groups (64% vs. 62% vs. 56%; p = 0.41). During the follow-up, 1574 (59%) patients died. Kaplan-Meier curves revealed a significantly lower survival rate in the older groups (log-rank p < 0.001). The cumulative complication rates were similar among the three age groups (27% vs. 28% vs. 24%; p = 0.15). Our results demonstrate that CRT is as effective and safe therapy in the elderly as for young ones. The present data suggest that patients with appropriate indications benefit from CRT in the long term, regardless of age.

Sudden death in the southern region of Saudi Arabia: A retrospective study

BACKGROUND

Sudden death is unanticipated, non-violent death taking place within the first 24 h after the onset of symptoms. It is a major public health problem worldwide. Moreover, the effects of living at moderate altitude on mortality are poorly understood.

AIM

To retrospectively report the frequency and the main causes of sudden deaths in relation to total deaths at Asir Central Hospital, 2255 m above sea level, in the southern region of Saudi Arabia over a period of 4 years from 2013 to 2016.

METHODS

The medical records of 1821 deaths were examined and showed 353 cases (19.4%) of sudden death.

RESULTS

The highest incidence of sudden death was among the elderly (51%), whereas, the lowest was among children and adolescents (6.5%). With regard to gender, the incidence of sudden death was higher in males (54.4%) compared to 45.6% in females. In this study, we found that the most common direct causes of sudden death were cardiovascular diseases (29.2%), respiratory disease (22.7%), infectious disease (12.2%), cancer (9.4%) and hematological diseases (6.2%). With respect to seasonal variation, the highest incidence was during winter (31.32%) followed by summer (25.8%).

CONCLUSION

The results of this study will help emergency physicians and health care providers to exercise due care to reduce the incidence of sudden death and raise public awareness about the impact of sudden death.

Sudden death in the southern region of Saudi Arabia: A retrospective study

BACKGROUND

Sudden death is unanticipated, non-violent death taking place within the first 24 h after the onset of symptoms. It is a major public health problem worldwide. Moreover, the effects of living at moderate altitude on mortality are poorly understood.

AIM

To retrospectively report the frequency and the main causes of sudden deaths in relation to total deaths at Asir Central Hospital, 2255 m above sea level, in the southern region of Saudi Arabia over a period of 4 years from 2013 to 2016.

METHODS

The medical records of 1821 deaths were examined and showed 353 cases (19.4%) of sudden death.

RESULTS

The highest incidence of sudden death was among the elderly (51%), whereas, the lowest was among children and adolescents (6.5%). With regard to gender, the incidence of sudden death was higher in males (54.4%) compared to 45.6% in females. In this study, we found that the most common direct causes of sudden death were cardiovascular diseases (29.2%), respiratory disease (22.7%), infectious disease (12.2%), cancer (9.4%) and hematological diseases (6.2%). With respect to seasonal variation, the highest incidence was during winter (31.32%) followed by summer (25.8%).

CONCLUSION

The results of this study will help emergency physicians and health care providers to exercise due care to reduce the incidence of sudden death and raise public awareness about the impact of sudden death.

Age and the Risk of Ventricular Tachyarrhythmia in Patients With an Implantable Cardioverter-Defibrillator

BACKGROUND

The benefit of implantable cardioverter-defibrillators (ICDs) in elderly patients is controversial.

OBJECTIVES

The aims of this study were to evaluate the risk for ventricular tachyarrhythmia (VTA) and ICD shocks by age groups and to assess the competing risk for VTA and death without prior VTA.

METHODS

The study included 5,170 primary prevention ICD recipients enrolled in 5 landmark ICD trials (MADIT [Multicenter Automatic Defibrillator Implantation Trial] II, MADIT-Risk, MADIT-CRT [MADIT Cardiac Resynchronization Therapy], MADIT-RIT [MADIT Reduce Inappropriate Therapy], and RAID [Ranolazine in High-Risk Patients With Implanted Cardioverter-Defibrillator]). Fine and Gray regression analysis was used to evaluate the risk for fast VTA (ventricular tachycardia ≥200 beats/min or ventricular fibrillation) vs death without prior fast VTA in 3 prespecified age groups: <65, 65 to <75, and ≥75 years.

RESULTS

The cumulative incidence of fast VTA at 3 years was similar for patients <65 years of age and those 65 to <75 years of age (17% vs 15%) and was lowest among patients ≥75 years of age (10%) (P < 0.001). Multivariate Fine and Gray analysis showed a 40% lower risk for fast VTA in patients ≥75 years of age (HR: 0.60; 95% CI: 0.46-0.78; P < 0.001) compared with patients <65 years of age. In patients ≥75 years of age, a risk reversal was observed whereby the risk for death without prior fast VTA exceeded the risk for developing fast VTA. A history of nonsustained ventricular tachycardia, male sex, and the presence of nonischemic cardiomyopathy were identified as predictors of fast VTA in patients ≥75 years of age.

CONCLUSIONS

Patients ≥75 years of age have a significantly lower risk for VTA and ICD shocks compared with younger patients. Aging is associated with a higher risk for death compared with the risk for fast VTA, the reverse of what is seen in younger patients.

Usefulness of the MADIT-ICD Benefit Score in a Large Mixed Patient Cohort of Primary Prevention of Sudden Cardiac Death

Background: Decision-making in primary prevention is not always trivial and many clinical scenarios are not reflected in current guidelines. To help evaluate a patient’s individual risk, a new score to predict the benefit of an implantable defibrillator (ICD) for primary prevention, the MADIT-ICD benefit score, has recently been proposed. The score tries to predict occurrence of ventricular arrhythmias and non-arrhythmic death based on data from four previous MADIT trials. We aimed at examining its usefulness in a large single-center register of S-ICD patients with various underlying cardiomyopathies. Methods and results: All S-ICD patients with a primary preventive indication for ICD implantation from our large single-center database were included in the analysis (n = 173). During a follow-up of 1227 ± 978 days, 27 patients developed sustained ventricular arrhythmias, while 6 patients died for non-arrhythmic reasons. There was a significant correlation for patients with ischemic cardiomyopathy (ICM) (n = 29, p = 0.04) to the occurrence of ventricular arrhythmia. However, the occurrence of ventricular arrhythmias could not sufficiently be predicted by the MADIT-ICD VT/VF score (p = 0.3) in patients with (n = 142, p = 0.19) as well as patients without structural heart disease (n = 31, p = 0.88) and patients with LV-EF < 35%. Of the risk factors included in the risk score calculation, only non-sustained ventricular tachycardias were significantly associated with sustained ventricular arrhythmias (p = 0.02). Of note, non-arrhythmic death could effectively be predicted by the proposed non-arrhythmic mortality score as part of the benefit score (p = 0.001, r = 0.3) also mainly driven by ICM patients. Age, diabetes mellitus, and a BMI < 23 kg/m2 were key predictors of non-arrhythmic death implemented in the score. Conclusion: The MADIT-ICD benefit score adds a new option to evaluate expected benefit of ICD implantation for primary prevention. In a large S-ICD cohort of primary prevention, the value of the score was limited to patients with ischemic cardiomyopathy. Future research should evaluate the performance of the score in different subgroups and compare it to other risk scores to assess its value for daily clinical practice.

NT-proBNP and ICD in Nonischemic Systolic Heart Failure: Extended Follow-Up of the DANISH Trial

OBJECTIVES

In this extended follow-up study of the DANISH (Danish Study to Assess the Efficacy of Implantable Cardioverter Defibrillators in Patients with Non-ischemic Systolic Heart Failure on Mortality) trial, adding 4 years of additional follow-up, we examined the effect of implantable cardioverter-defibrillator (ICD) implantation according to baseline N-terminal pro-B-type natriuretic peptide (NT-proBNP) level.

BACKGROUND

In the DANISH trial, NT-proBNP level at baseline appeared to modify the response to ICD implantation.

METHODS

In the DANISH trial, 1,116 patients with nonischemic systolic HF were randomized to receive an ICD (N = 556) or usual clinical care (N = 550). Outcomes were analyzed according to NT-proBNP levels (below/above median) at baseline. The primary outcome was death from any cause.

RESULTS

All 1,116 patients in the DANISH trial had an available NT-proBNP measurement at baseline (median: 1,177 pg/mL; range: 200-22,918 pg/mL). There was a trend toward a reduction in all-cause death with ICD implantation, compared with usual clinical care, in patients with NT-proBNP levels lower than the median (HR: 0.75 [95% CI: 0.55-1.03]), but not in those with higher NT-proBNP levels (HR: 0.95 [95% CI: 0.74-1.21]) (P_interaction = 0.28). Similarly, ICD implantation significantly reduced the rate of cardiovascular (CV) and sudden cardiovascular death (SCD) in patients with NT-proBNP levels lower than the median (CV death, HR: 0.69 [95% CI: 0.47-1.00]; SCD, HR: 0.37 [95% CI: 0.19-0.75]), but not in those with higher levels (CV death, HR: 0.94 [95% CI: 0.70-1.25]; SCD, HR: 0.86 [95% CI: 0.49-1.51]) (P_interaction = 0.20 and 0.08 for CV death and SCD, respectively).

CONCLUSIONS

Lower baseline NT-proBNP levels could identify patients with nonischemic systolic HF who may derive benefit from ICD implantation. (Danish Study to Assess the Efficacy of Implantable Cardioverter Defibrillators in Patients with Non-ischemic Systolic Heart Failure on Mortality [DANISH]; NCT00542945).

Prevalence of sudden cardiac death in dogs with atrial fibrillation

Background

Atrial fibrillation (AF) is associated with increased risk of sudden cardiac death (SCD) in humans, independent of secondary risk factors such as thrombogenic disorders. In dogs, SCD is described in a number of heart diseases, but an association between AF and SCD is unreported.

Hypothesis

(a) A higher proportion of dogs with AF will experience SCD, and (b) SCD will be associated with complex ventricular arrhythmias.

Animals

One‐hundred forty‐two dogs with AF, and 127 dogs without AF.

Methods

Retrospective, multicenter, case‐control study. Dogs included in the AF group were compared to a control group of dogs in sinus rhythm, matched for echocardiographic diagnosis. Descriptive statistics were used to identify proportions of each group suffering SCD, compared using chi‐squared testing. Risk factors for SCD in dogs with AF were evaluated at the univariable and multivariable level using binary logistic regression. Significance was P < .05.

Results

A significantly higher proportion of dogs with AF suffered SCD than dogs in the control group (14.8% vs 5.5%; P = .01). Younger age at diagnosis, larger left atrial size, and a history of syncope all were independent predictors of SCD in dogs with AF (χ², 16.3; P = .04).

Conclusions and Clinical Importance

Atrial fibrillation was associated with a higher prevalence of SCD in dogs. A history of syncope may be a useful predictor of SCD risk.

Prospective evaluation of health status, quality of life and clinical outcomes following implantable defibrillator generator exchange

BACKGROUND

Little is known about health status and quality of life (QoL) after implantable cardioverter-defibrillator (ICD) generator exchange (GE).

METHODS

We prospectively followed patients undergoing first-time ICD GE. Serial assessments of health status were performed by administering the 36-Item Short Form Survey (SF-36).

RESULTS

Mean age was 67.5 ± 14.3 years, left ventricle ejection fraction (LVEF) was 36.5% ± 15.0% and over 40% of the cohort had improved LVEF to > 35% at the time of GE. SF-36 scores were significantly worse in physical/general health domains compared to domains of emotional/social well-being ( P < 0.001 for each comparison). Physical health scores were significantly worse among those with medical comorbidities including diabetes, chronic obstructive pulmonary disease and atrial fibrillation. Mean follow-up was 1.6 ± 0.5 years after GE. Overall SF-36 scores remained stable across all domains during follow-up. Survival at 3 years post-GE was estimated at 80%. Five patients died during follow-up and most deaths were adjudicated as non-arrhythmic in origin. Four patients experienced appropriate ICD shocks after GE, three of whom had LVEF which remains impaired LVEF (i.e., < 35%) at the time of GE.

CONCLUSION

Patients undergoing ICD GE have significantly worse physical health compared to emotional/social well-being, which is associated with the presence of medical comorbidities. In terms of clinical outcomes, the incidence of appropriate shocks after GE among those with improvement in LVEF is very low, and most deaths post-procedure appear to be non-arrhythmic in origin. These data represent an attempt to more fully characterize the spectrum of QoL and clinical outcomes after GE.

ICD therapy in the elderly: a retrospective single-center analysis of mortality

BACKGROUND

Current implantable cardioverter-defibrillator (ICD) guidelines do not impose age limitations for ICD implantation (IMPL) and generator exchange (GE); however, patients (pts) should be expected to survive for 1 year. With higher age, comorbidity and mortality due to non-sudden cardiac death increase. Thus, the benefit of ICD therapy in elderly pts remains unclear. Mortality after ICD IMPL or GE in pts ≥ 75 years was assessed.

METHODS

Consecutive pts aged ≥ 75 years with ICD IMPL or GE at the University Hospital Cologne, Germany, between 01/2013 and 12/2017 were included in this retrospective analysis.

RESULTS

Of 418 pts, 82 (20%) fulfilled the inclusion criteria; in 70 (55 = IMPL, 79%, 15 = GE, 21%) follow-up (FU) was available. The median FU was 3.1 years. During FU, 40 pts (57%) died (29/55 [53%] IMPL; 11/15 [73%] GE). Mean survival after surgery was 561 ± 462 days. The 1‑year mortality rate was 19/70 (27%) overall, 9/52 (17%) in pts ≥ 75 and 10/18 (56%) in pts ≥ 80 years. Deceased pts were more likely to suffer from chronic renal failure (85% vs. 53%, p = 0.004) and peripheral artery disease (18% vs. 0%, p = 0.02). During FU, seven pts experienced ICD shocks (four appropriate, three inappropriate). In primary prevention (n = 35) mortality was 46% and four pts experienced ICD therapies (two adequate); in secondary prevention (n = 35) mortality was 69% (p = 0.053) with three ICD therapies (two adequate).

CONCLUSION

Mortality in ICD pts aged ≥ 80 years was 56% at 1 and 72% at 2 years in this retrospective analysis. The decision to implant an ICD in elderly pts should be made carefully and individually.

Downgrade of cardiac defibrillator devices to pacemakers in elderly heart failure patients: clinical considerations and the importance of shared decision-making

Implantable cardioverter defibrillators are implanted on a large scale in patients with heart failure (HF) for the prevention of sudden cardiac death. There are different scenarios in which defibrillator therapy is no longer desired or indicated, and this is occurring increasingly in elderly patients. Usually device therapy is continued until the device has reached battery depletion. At that time, the decision needs to be made to either replace it or to downgrade to a pacing-only device. This decision is dependent on many factors, including the vitality of the patient and his/her preferences, but may also be influenced by changes in recommendations in guidelines. In the last few years, there has been an increased awareness that discussions around these decisions are important and useful. Advanced care planning and shared decision-making have become important and are increasingly recognised as such. In this short review we describe six elderly patients with HF, in whose cases we discussed these issues, and we aim to provide some scientific and ethical rationale for clinical decision-making in this context. Current guidelines advocate the discussion of end-of-life options at the time of device implantation, and physicians should realise that their choices influence patients’ options in this critical phase of their illness.

Developing and validating models to predict sudden death and pump failure death in patients with heart failure and preserved ejection fraction

BACKGROUND

Sudden death (SD) and pump failure death (PFD) are leading modes of death in heart failure and preserved ejection fraction (HFpEF). Risk stratification for mode-specific death may aid in patient enrichment for new device trials in HFpEF.

METHODS

Models were derived in 4116 patients in the Irbesartan in Heart Failure with Preserved Ejection Fraction trial (I-Preserve), using competing risks regression analysis. A series of models were built in a stepwise manner, and were validated in the Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity (CHARM)-Preserved and Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trials.

RESULTS

The clinical model for SD included older age, men, lower LVEF, higher heart rate, history of diabetes or myocardial infarction, and HF hospitalization within previous 6 months, all of which were associated with a higher SD risk. The clinical model predicting PFD included older age, men, lower LVEF or diastolic blood pressure, higher heart rate, and history of diabetes or atrial fibrillation, all for a higher PFD risk, and dyslipidaemia for a lower risk of PFD. In each model, the observed and predicted incidences were similar in each risk subgroup, suggesting good calibration. Model discrimination was good for SD and excellent for PFD with Harrell's C of 0.71 (95% CI 0.68-0.75) and 0.78 (95% CI 0.75-0.82), respectively. Both models were robust in external validation. Adding ECG and biochemical parameters, model performance improved little in the derivation cohort but decreased in validation. Including NT-proBNP substantially increased discrimination of the SD model, and simplified the PFD model with marginal increase in discrimination.

CONCLUSIONS

The clinical models can predict risks for SD and PFD separately with good discrimination and calibration in HFpEF and are robust in external validation. Adding NT-proBNP further improved model performance. These models may help to identify high-risk individuals for device intervention in future trials.

CLINICAL TRIAL REGISTRATION

I-Preserve: ClinicalTrials.gov NCT00095238; TOPCAT: ClinicalTrials.gov NCT00094302; CHARM-Preserved: ClinicalTrials.gov NCT00634712.

Trends in the use of implantable cardioverter-defibrillator and cardiac resynchronization therapy device in advancing age: Analysis of the Japan cardiac device treatment registry database

BACKGROUND

Trends of de novo implantation of cardiac implantable electronic devices (CIEDs) including implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy with a defibrillator (CRT-D) or pacemaker (CRT-P) in advancing age are unknown.

METHODS

Analysis of data from the Japan cardiac device treatment registry (JCDTR) with an implantation date between January 2006 and December 2016 was performed focusing on advancing age of ≧75 years.

RESULTS

The cohort included 17 564 ICD, 9470 CRT-D and 1087 CRT-P recipients for de novo implantation. The rate of patients ≧75 years of age increased from 17.1% to 20.5% in ICD implantation (P = .052), from 19.7% to 30.0% in CRT-D implantation (P < .0001), and from 40.0% to 64.0% in CRT-P implantation (P = .17). There was an apparent increase in the percentage of nonischemic patients aged ≧75 years receiving ICD (10.9% in 2006 to 16.4% in 2016, P = .0008) and CRT-D (17.1% in 2006 to 27.8% in 2016, P = .0001). The implantation for primary prevention ICD (P = .059) and CRT-D (P = .012) was also associated with a temporal increase in the percentage of patients aged ≧75 years.

CONCLUSIONS

Proportion of patients ≧75 years of age for de novo CIED implantation gradually increased from 2006 to 2016, presumably because of the growing number of nonischemic cardiomyopathy and heart failure patients requiring primary prevention of sudden cardiac death.

Duration of Heart Failure and Effect of Defibrillator Implantation in Patients With Nonischemic Systolic Heart Failure

BACKGROUND

Patients with nonischemic systolic heart failure (HF) have increased risk of sudden cardiac death (SCD) and death from progressive pump failure. Whether the risk of SCD changes over time is unknown. We seek here to investigate the relation between duration of HF, mode of death, and effect of implantable cardioverter-defibrillator implantation.

METHODS AND RESULTS

We examined the risk of all-cause death and SCD according to the duration of HF among patients with nonischemic systolic HF enrolled in the DANISH (Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischemic Systolic Heart Failure on Mortality). In all, 1116 patients were included. Patients were divided according to quartiles of HF duration (≤8, 9≤18, 19≤65, and ≥66 months). Patients with the longest duration of HF were older, more often men, had more comorbidity, and more often received a cardiac resynchronization therapy device. Doubling of HF duration was an independent predictor of both all-cause mortality (hazard ratio [HR], 1.27; 95% CI, 1.17-1.38; P<0.0001), and SCD (HR, 1.29; 95% CI, 1.11-1.50; P=0.0007). The proportion of deaths caused by SCD was not different between HF quartiles (P=0.91), and the effect of implantable cardioverter-defibrillator implantation on all-cause mortality was not modified by the duration of HF (P=0.59).

CONCLUSIONS

Duration of HF predicted both all-cause mortality and risk of SCD independently of other risk indicators. However, the proportion of death caused by SCD did not change with longer duration of HF, and the effect of implantable cardioverter-defibrillator was not modified by the duration of HF.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00542945.

Association of diabetes and kidney function according to age and systolic function with the incidence of sudden cardiac death and non-sudden cardiac death in myocardial infarction survivors with heart failure

AIMS

An implantable cardioverter-defibrillator (ICD) is recommended for reducing the risk of sudden cardiac death (SCD) in myocardial infarction (MI) patients with a left ventricular ejection fraction (LVEF) ≤ 30%, as well as patients with a LVEF ≤ 35% and heart failure symptoms. Diabetes and/or impaired kidney function may confer additional SCD risk. We assessed the association between these two risk factors with SCD and non-SCD among MI survivors taking account of age and LVEF.

METHODS AND RESULTS

A total of 17 773 patients from the High-Risk MI Database were evaluated. Overall, diabetes and estimated glomerular filtration rate < 60 mL/min/1.73 m² , individually and together, conferred a higher risk of SCD [adjusted competing risk: hazard ratio (HR) 1.23, 1.23, and 1.32, respectively; all P < 0.03] and non-SCD (HR 1.34, 1.52, and 2.13, respectively; all P < 0.0001). Annual SCD rates in patients with LVEF > 35% and with diabetes, impaired kidney function, or both (2.0%, 2.5% and 2.7%, respectively) were comparable to rates observed in patients with LVEF 30-35% but no such risk factors (1.7%). However, these patients had also similarly higher non-SCD rates, such that the ratio of SCD to non-SCD was not increased. Importantly, this ratio was mostly dependent on age, with higher overall ratios in youngest subgroups (0.89 in patients < 55 years vs. 0.38 in patients ≥ 75 years), regardless of risk factors.

CONCLUSION

Although MI survivors with LVEF > 35% with diabetes, impaired kidney function, or both are at increased risk of SCD, the risk of non-SCD risk is even higher, suggesting an extension of the current indication for an ICD to them is unlikely to be worthwhile. MI survivors with low LVEF and aged < 55 years are likely to have the greatest potential benefit from ICD implantation.

Arrhythmias in Patients ≥80 Years of Age: Pathophysiology, Management, and Outcomes

Advances in medical care have led to an increase in the number of octogenarians and even older patients, forming an important and unique patient subgroup. It is clear that advancing age is an independent risk factor for the development of most arrhythmias, causing substantial morbidity and mortality. Patients ≥80 years of age have significant structural and electrical remodeling of cardiac tissue; accrue competing comorbidities; react differently to drug therapy; and may experience falls, frailty, and cognitive impairment, presenting significant therapeutic challenges. Unfortunately, very old patients are under-represented in clinical trials, leading to critical gaps in evidence to guide effective and safe treatment of arrhythmias. In this state-of-the-art review, we examine the pathophysiology of aging and arrhythmias and then present the available evidence on age-specific management of the most common arrhythmias, including drugs, catheter ablation, and cardiac implantable electronic devices.

[Continuation of ICD treatment at the time of device exchange without adequate treatment?]

INTRODUCTION

Due to improved treatment of heart failure, patients are older and have more comorbidities at the time of an elective device exchange. This leads to higher rates of complications and represents an opportunity for re-evaluation of the implantable cardioverter defibrillator (ICD) treatment.

OBJECTIVE

This article reviews the current literature regarding the indications for continued ICD therapy and device exchange in patients who have never received adequate treatment through the ICD.

MATERIAL AND METHODS

Patients with primarily prophylactic indications, who have not received adequate treatment and have shown significant improvement in the left ventricular ejection fraction (LVEF) >35%, have a significantly lower risk of ventricular arrythmia (VA) after device exchange. Although further ventricular events can occur in these patients, the continuation of ICD treatment should be individually discussed in cases of high age and increased comorbidities. In female patients with a non-ischemic cardiac myopathy and an almost normalized LVEF, mostly during cardiac resynchronization therapy (CRT), a discontinuation of ICD treatment or downgrading to CRT with pacemaker (CRT-P) treatment should be discussed.

CONCLUSION

At the time of an elective device exchange for primarily prophylactic indications, the possibility to discontinue ICD treatment can be discussed with patients who have not experienced adequate treatment. Additional factors, such as LVEF, age, sex and comorbidities of the patient should be taken into consideration in order to make an individualized decision. As prospective randomized studies are lacking, it is not possible to give generally valid recommendations.

Incidence of appropriate implantable cardioverter-defibrillator therapy and mortality after implantable cardioverter-defibrillator generator replacement: results from a real-world nationwide cohort

Aims

The safety of omitting implantable cardioverter-defibrillator (ICD) generator replacement in patients with no prior appropriate therapy, comorbid conditions, and advanced age is unclear. The aim was to investigate incidence of appropriate ICD therapy after generator replacement.

Methods and results

We identified patients implanted with a primary prevention ICD (n = 4630) from 2007 to 2016, who subsequently underwent an elective ICD generator replacement (n = 670) from the Danish Pacemaker and ICD Register. The data were linked to other databases and evaluated the outcomes of appropriate therapy and death. Predictors of ICD therapy were identified using multivariate Cox regression analyses. A total of 670 patients underwent elective ICD generator replacement. Of these, 197 (29.4%) patients had experienced appropriate therapy in their 1st generator period. During follow-up of 2.0 ± 1.6 years, 95 (14.2%) patients experienced appropriate therapy. Predictors of appropriate therapy in 2nd generator period was low initial left ventricular ejection fraction (≤25%) [hazard ratio (HR) 1.87, confidence interval (CI) 1.13–1.95] and appropriate therapy in 1st generator period (HR 3.95, CI 2.57–6.06). For patients with appropriate therapy in 1st generator period, 4-year incidence of appropriate therapy was 50.6% vs. 16.4% in those without (P < 0.001). Among patients >80 years with no prior appropriate therapy 8.8% of patients experienced appropriate therapy after replacement. Comorbidity burden and advanced age were associated with reduced device utilization after replacement and a high competing risk of death without preceding appropriate therapy.

Conclusion

A significant residual risk of appropriate therapy in the 2nd generator was present even among patients with advanced age and with a full prior generator period without any appropriate ICD events.

Prophylactic implantable cardioverter-defibrillator in the very elderly

Aims

Current guidelines do not propose any age cut-off for the primary prevention implantable cardioverter-defibrillator (ICD). However, the risk/benefit balance in the very elderly population has not been well studied.

Methods and results

In a multicentre French study assessing patients implanted with an ICD for primary prevention, outcomes among patients aged ≥80 years were compared with <80 years old controls matched for sex and underlying heart disease (ischaemic and dilated cardiomyopathy). A total of 300 ICD recipients were enrolled in this specific analysis, including 150 patients ≥80 years (mean age 81.9 ± 2.0 years; 86.7% males) and 150 controls (mean age 61.8 ± 10.8 years). Among older patients, 92 (75.6%) had no more than one associated comorbidity. Most subjects in the elderly group got an ICD as part of a cardiac resynchronization therapy procedure (74% vs. 46%, P < 0.0001). After a mean follow-up of 3.0 ± 2 years, 53 patients (35%) in the elderly group died, including 38.2% from non cardiovascular causes of death. Similar proportion of patients received ≥1 appropriate therapy (19.4% vs. 21.6%; P = 0.65) in the elderly group and controls, respectively. There was a trend towards more early perioperative events (P = 0.10) in the elderly, with no significant increase in late complications (P = 0.73).

Conclusion

Primary prevention ICD recipients ≥80 years in the real world had relatively low associated comorbidity. Rates of appropriate therapies and device-related complications were similar, compared with younger subjects. Nevertheless, the inherent limitations in interpreting observational data on this particular competing risk situation call for randomized controlled trials to provide definitive answers. Meanwhile, a careful multidisciplinary evaluation is needed to guide patient selection for ICD implantation in the elderly population.

Implantable Cardioverter-Defibrillators are the Main Link in the Modern Concept of Sudden Cardiac Death Prevention. Problems and Prospects of the Development of the Method

The article covers the development of the problem of sudden cardiac death prevention with the implantable cardioverter-defibrillators from the moment of creation of these devices to our days. The current concept of primary prevention of sudden cardiac death, based on the severity of manifestation of heart failure and left ventricular dysfunction, is not effective enough. Its practical application is difficult because it requires mass application of implantable defibrillators, with low predictive accuracy of these criteria in terms of development of life-threatening arrhythmias. The development of methods for visualizing the myocardium, allowing to assess the severity of myocardial fibrosis, as well as the possibilities of medical genetics, at the present stage, allows us to clarify indications for implantation of cardioverter-defibrillators and thereby significantly improve the concept of preventing sudden cardiac death with these instruments.

Natural History of Implantable Cardioverter-Defibrillator Implanted at or after the Age of 70 years in a Veteran Population: A Single Center Study

Background

The median age of patients in major Implantable Cardioverter-defibrillator (ICD)trials (MUSTT, MADIT-I, MADIT-II, and SCD-HeFT) was 63-67 years; with only 11% ≥70 years. There is little follow-up data on patients over 70 years of age who received an ICD for primary/secondary prevention of sudden cardiac death, particularly for veterans.

Objective

The aim of this study was to study the natural history of ICD implantation for veterans over 70 years of age.

Methods

We retrospectively reviewed single center ICD data in 216 patients with a mean age at implantation 76 ± 4 years. The ICD indication was primary prevention in 161 patients and secondary prevention in 55 patients. The ICD indication was unavailable in 4 patients.

Results

Mean duration of follow up was 1686 ± 1244 days during which 114 (52%) patients died. Of these, 31% died without receiving any appropriate ICD therapy. Overall, 60/216 (28%) received appropriate therapy and 28/216 (13%) received inappropriate therapy. Patients who had ICD implantation for secondary prophylaxis had statistically more (p= 0.02) appropriate therapies compared to patients who had ICD implantation for primary prevention. Indication for implantation and hypertension predicted appropriate therapy, while age at the time of implantation and presence of atrial fibrillation predicted inappropriate therapies. Overall, 7.7% had device related complications.

Conclusions

Although 28% septuagenarians in this study received appropriate ICD therapy, they had high rates of mortality, inappropriate therapy, and device complications. ICD implantation in the elderly merits individualized consideration, with higher benefit for secondary prevention.

[Sudden cardiac death : Epidemiology, pathophysiology and risk stratification]

Sudden cardiac death (SCD) remains a major public health burden despite revolutionary progress in the last three decades in the treatment of ventricular tachyarrhythmia with the use of implantable cardioverter defibrillator (ICD) therapy. Survivors of sudden cardiac arrest are at high risk for recurrent tachyarrhythmia events. Early recognition of low left ventricular ejection fractions (≤35%) as a strong predictor of mortality and the causal association between ventricular tachyarrhythmia and SCD has led to a significant development of not only pharmacological antiarrhythmic therapy but also device-based prevention of SCD. The ICD therapy is nowadays routinely used for primary prevention of SCD in patients with significant structural cardiomyopathy and primary electrical arrhythmia syndromes, which are associated with high a risk and secondary prevention in survivors of sudden cardiac arrest. Additionally, effective approaches exist to significantly reduce the recurrence rate of ventricular tachyarrhythmia of various origins by complex electrophysiological endocardial and epicardial catheter ablation procedures.

Implantable cardioverter-defibrillator in the elderly: Predictors of appropriate interventions and mortality at 12-month follow-up

BACKGROUND

The effectiveness of implantable cardioverter-defibrillator (ICD) in the elderly is uncertain, given their competing risk of nonarrhythmic death. Guidelines state that an ICD should be implanted if the expectation of survival is at least 1 year. However, survival is not easy to predict in elderly patients with severe cardiac disease.

AIM

To assess 12-month survival after ICD implantation in patients aged ≥75 years, to identify predictors of 12-month mortality, and to evaluate the incidence of ICD therapy during follow-up.

METHODS

We retrospectively analyzed all clinical, instrumental, and survival data of patients ≥75 years old who received an ICD in our center from 2000 to 2013.

RESULTS

We included 127 patients (mean age 78 years). ICD was implanted for primary prevention in 61%. The 12-month survival rate was 87.4%. At both univariate and multivariate analyses, left ventricular ejection fraction (EF) ≤ 25%, and moderate to severe impaired renal function (IRF) independently predicted 12-month mortality that was as high as 45.5% in patients with both risk factors. During a median follow-up of 38 months, 30 patients (23.6%) received ≥1 appropriate ICD interventions, but only 3.1% of shocks occurred during the first year, and none in the subgroup of patients with EF ≤ 25% and IRF.

CONCLUSION

Twelve-month survival in elderly patients after ICD implantation is good and the indication for ICD should not be based on age alone. However, the subgroup with EF ≤ 25% and IRF showed a high 12-month nonarrhythmic mortality and did not benefit from ICD implantation.

Age and Outcomes of Primary Prevention Implantable Cardioverter-Defibrillators in Patients With Nonischemic Systolic Heart Failure

BACKGROUND

The DANISH study (Danish Study to Assess the Efficacy of ICDs [Implantable Cardioverter Defibrillators] in Patients With Non-Ischemic Systolic Heart Failure on Mortality) did not demonstrate an overall effect on all-cause mortality with ICD implantation. However, the prespecified subgroup analysis suggested a possible age-dependent association between ICD implantation and mortality with survival benefit seen only in the youngest patients. The nature of this relationship between age and outcome of a primary prevention ICD in patients with nonischemic systolic heart failure warrants further investigation.

METHODS

All 1116 patients from the DANISH study were included in this prespecified subgroup analysis. We assessed the relationship between ICD implantation and mortality by age, and an optimal age cutoff was estimated nonparametrically with selection impact curves. Modes of death were divided into sudden cardiac death and nonsudden death and compared between patients younger and older than this age cutoff with the use of χ² analysis.

RESULTS

Median age of the study population was 63 years (range, 21-84 years). There was a linearly decreasing relationship between ICD and mortality with age (hazard ratio [HR], 1.03; 95% confidence interval [CI], 1.003-1.06; P=0.03). An optimal age cutoff for ICD implantation was present at ≤70 years. There was an association between reduced all-cause mortality and ICD in patients ≤70 years of age (HR, 0.70; 95% CI, 0.51-0.96; P=0.03) but not in patients >70 years of age (HR, 1.05; 95% CI, 0.68-1.62; P=0.84). For patients ≤70 years old, the sudden cardiac death rate was 1.8 (95% CI, 1.3-2.5) and nonsudden death rate was 2.7 (95% CI, 2.1-3.5) events per 100 patient-years, whereas for patients >70 years old, the sudden cardiac death rate was 1.6 (95% CI, 0.8-3.2) and nonsudden death rate was 5.4 (95% CI, 3.7-7.8) events per 100 patient-years. This difference in modes of death between the 2 age groups was statistically significant (P=0.01).

CONCLUSIONS

In patients with systolic heart failure not caused by ischemic heart disease, the association between the ICD and survival decreased linearly with increasing age. In this study population, an age cutoff for ICD implantation at ≤70 years yielded the highest survival for the population as a whole.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00542945.

Denervated Myocardium Is Preferentially Associated With Sudden Cardiac Arrest in Ischemic Cardiomyopathy: A Pilot Competing Risks Analysis of Cause-Specific Mortality

BACKGROUND

Previous studies have identified multiple risk factors that are associated with total cardiac mortality. Nevertheless, identifying specific factors that distinguish patients at risk of arrhythmic death versus heart failure could better target patients likely to benefit from implantable cardiac defibrillators, which have no impact on nonsudden cardiac death.

METHODS AND RESULTS

We performed a pilot competing risks analysis of the National Institutes of Health-sponsored PAREPET trial (Prediction of Arrhythmic Events with Positron Emission Tomography). Death from cardiac causes was ascertained in subjects with ischemic cardiomyopathy (n=204) eligible for an implantable cardiac defibrillator for the primary prevention of sudden cardiac arrest after baseline clinical evaluation and imaging at enrollment (positron emission tomography and 2-dimensional echo). Mean age was 67±11 years with an ejection fraction of 27±9%, and 90% were men. During 4.1 years of follow-up, there were 33 sudden cardiac arrests (arrhythmic death or implantable cardiac defibrillator discharge for ventricular fibrillation or ventricular tachycardia >240 bpm) and 36 nonsudden cardiac deaths. Sudden cardiac arrest was correlated with a greater volume of denervated myocardium (defect of the positron emission tomography norepinephrine analog ¹¹C-hydroxyephedrine), lack of angiotensin inhibition therapy, elevated B-type natriuretic peptide, and larger left ventricular end-diastolic volume index. In contrast, nonsudden cardiac death was associated with a higher resting heart rate, older age, elevated creatinine, larger left atrial volume index, and larger left ventricular end-diastolic volume index.

CONCLUSIONS

Distinct clinical, laboratory, and imaging variables are associated with cause-specific cardiac mortality in primary-prevention candidates with ischemic cardiomyopathy. If prospectively validated, these multivariable associations may help target specific therapies to those at the greatest risk of sudden and nonsudden cardiac death.

CLINICAL TRIAL REGISTRATION

URL: https://clinicaltrials.gov. Unique identifier: NCT01400334.

Treatment of Ventricular Arrhythmias and Use of Implantable Cardioverter-Defibrillators to Improve Survival in Older Adult Patients with Cardiac Disease

Ventricular arrhythmia (VA) and sudden cardiac death (SCD) are well-recognized problems in the overall heart failure population, but treatment decisions can be more complex and nuanced in older patients. Sustained VA does not always lead to SCD, but identifies a higher risk population and may cause significant symptoms. Antiarrhythmic drugs (AAD) and catheter ablation are the mainstays for prevention of VA, but have not been shown to improve mortality. The value of implantable cardiac defibrillators (ICDs) may be influenced by patient age. This article discusses long-term treatment of VA and the use of ICDs in the elderly.

Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators: Groupe de Rythmologie et Stimulation Cardiaque de la Société Française de Cardiologie and Société Française de Gériatrie et Gérontologie

Despite the increasingly high rate of implantation of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety and effectiveness of conventional pacing, ICDs and cardiac resynchronization therapy (CRT) in elderly patients. Although periprocedural risk may be slightly higher in the elderly, the implantation procedure for PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, the general consensus is that DDD pacing with the programming of an algorithm to minimize ventricular pacing is preferred. In very old patients presenting with intermittent or suspected atrioventricular block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is similar in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantageous effect of the device on arrhythmic death may be attenuated by higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live more than 5-7years after implantation. Elderly patients usually experience significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non-responders remains globally the same, while considering a less aggressive approach in terms of reinterventions (revision of left ventricular [LV] lead placement, addition of a right ventricular or LV lead, LV endocardial pacing configuration). Overall, physiological age, general status and comorbidities rather than chronological age per se should be the decisive factors in making a decision about device implantation selection for survival and well-being benefit in elderly patients.

Trends and determinant factors in the use of cardiac resynchronization therapy devices in Japan: Analysis of the Japan cardiac device treatment registry database

Background

The choice of cardiac resynchronization therapy device, with (CRT-D) or without (CRT-P) a defibrillator, in patients with heart failure largely depends on the physician׳s discretion, because it has not been established which subjects benefit most from a defibrillator.

Methods

We examined the annual trend of CRT device implantations between 2006 and 2014, and evaluated the factors related to the device selection (CRT-D or CRT-P) for primary prevention of sudden cardiac death in patients with heart failure by analyzing the Japan Cardiac Device Treatment Registry (JCDTR) database from January 2011 and August 2015 (CRT-D, n=2714; CRT-P, n=555).

Results

The proportion of CRT-D implantations for primary prevention among all the CRT-D recipients was more than 70% during the study period. The number of CRT-D implantations for primary prevention reached a maximum in 2011 and decreased gradually between 2011 and 2014, whereas CRT-P implantations increased year by year until 2011 and remained unchanged in recent years. Multivariate analysis identified age (odds ratio [OR] 0.92, 95% confidence interval [CI] 0.90–0.95, P<0.0001), male sex (OR 1.99, 95% CI 1.28–3.11, P<0.005), reduced left ventricular ejection fraction (LVEF) (OR 0.96, 95% CI 0.94–0.98, P<0.0001), and non-sustained ventricular tachycardia (NSVT) (OR 2.85, 95% CI 1.87–4.35, P<0.0001) as independent factors favoring the choice of CRT-D.

Conclusions

Younger age, male sex, reduced LVEF, and a history of NSVT were independently associated with the choice of CRT-D for primary prevention of sudden cardiac death in patients with heart failure in Japan.

A Patient Presents with Longstanding, Severe LV Dysfunction. Is There a Role for Additional Risk Stratification Before ICD?

Increased longevity of patients with systolic heart failure caused by the use of implantable cardioverter-defibrillators (ICDs) is one of the most successful achievements in contemporary medicine. During the last 2 decades, the scientific community has striven to increase the benefits of ICD usage by specifying indications for primary prevention ICD implantation. Left ventricular ejection fraction is neither highly specific nor is it a highly sensitive risk marker of sudden cardiac death. The authors discuss risk-stratification approaches in different patient populations with structural heart disease and systolic heart failure.

Primary prevention implantable cardioverter-defibrillator and cardiac resynchronization therapy-defibrillator in elderly patients: results of a Spanish multicentre study

AIMS

Currently, there continues to be a lack of evidence regarding outcomes associated with device-based therapy for ventricular arrhythmias in elderly patients, even more in primary-prevention indications. We aimed to describe the follow-up in terms of efficacy and safety of implantable cardioverter-defibrillator (ICD) therapy in a large cohort of elderly patients.

METHODS AND RESULTS

Retrospective multicentre study performed in 15 Spanish hospitals. Consecutive patients referred for ICD implantation before 2011 were included. One hundred and sixty-two of 1174 patients (13.8%) ≥75 years were considered as 'elderly'. When compared with those patients <75, this subgroup presented more co-morbid conditions, including hypertension, chronic obstructive pulmonary disease , and renal failure, and more previous hospitalizations due to heart failure (HF). During a mean follow-up of 104.4 ± 3.3 months, 162 patients (14%) died, 120 in the younger age (12.4%), and 42 (24.4%) in the elderly. Kaplan-Meier analysis showed an increased probability of death with increasing age (17, 24, 28, and 69% at 12, 24, 48, and 60 months of follow-up in the elderly group). There was neither difference regarding the rate of appropriate nor inappropriate ICD intervention.

CONCLUSION

In a real-world scenario, elderly patients comprise ∼15% of ICD implantations for primary prevention of sudden cardiac death (SCD). Although the rate of appropriate therapy is similar between groups, the benefit of ICD is attenuated for a major increase in mortality risk among those patients ≥75 years at the moment of device implantation.

The spectrum of epidemiology underlying sudden cardiac death

Sudden cardiac death (SCD) from cardiac arrest is a major international public health problem accounting for an estimated 15%-20% of all deaths. Although resuscitation rates are generally improving throughout the world, the majority of individuals who experience a sudden cardiac arrest will not survive. SCD most often develops in older adults with acquired structural heart disease, but it also rarely occurs in the young, where it is more commonly because of inherited disorders. Coronary heart disease is known to be the most common pathology underlying SCD, followed by cardiomyopathies, inherited arrhythmia syndromes, and valvular heart disease. During the past 3 decades, declines in SCD rates have not been as steep as for other causes of coronary heart disease deaths, and there is a growing fraction of SCDs not due to coronary heart disease and ventricular arrhythmias, particularly among certain subsets of the population. The growing heterogeneity of the pathologies and mechanisms underlying SCD present major challenges for SCD prevention, which are magnified further by a frequent lack of recognition of the underlying cardiac condition before death. Multifaceted preventative approaches, which address risk factors in seemingly low-risk and known high-risk populations, will be required to decrease the burden of SCD. In this Compendium, we review the wide-ranging spectrum of epidemiology underlying SCD within both the general population and in high-risk subsets with established cardiac disease placing an emphasis on recent global trends, remaining uncertainties, and potential targeted preventive strategies.

[ICD therapy in the primary prevention of sudden cardiac death: Risk stratification and patient selection]

Without the concept of primary prevention of sudden cardiac death, therapy with implantable defibrillators would not have reached the current distribution and clinical importance. Most of the scientific evidence of the concept is based on clinical studies from 1996-2005. More than 75 % of all defibrillator implantations are currently indicated as primary prevention. Implantable converter-defibrillator (ICD) therapy in the primary prevention of sudden cardiac death was incorporated into scientific guidelines starting in 1998. The historical development of the indications for ICD therapy in the primary prevention of sudden cardiac death is presented, reflecting major results of controlled, randomized clinical studies and guideline discussions.

Effect of age on survival and causes of death after primary prevention implantable cardioverter-defibrillator implantation

The benefit of implantable cardioverter-defibrillators (ICDs) remains controversial in elderly patients and may be attenuated by a greater risk of nonarrhythmic death. We examined the effect of age on outcomes after prophylactic ICD implantation. All patients with coronary artery disease or dilated cardiomyopathy implanted with an ICD for primary prevention of sudden cardiac death in 12 French medical centers were included in a retrospective observational study. The 5,534 ICD recipients were divided according to age: 18 to 59 years (n = 2,139), 60 to 74 years (n = 2,693), and ≥75 years (n = 702). Greater prevalences of coronary artery disease and atrial fibrillation at the time of implant were observed with increasing age (both p <0.0001). During a mean follow-up of 3.1 ± 2.0 years, the annual mortality rate increased with age: 3.1% per year for age 18 to 59 years, 5.7% per year for age 60 to 74 years, and 7.5% per year for age ≥75 years (p <0.001). Older age was independently associated with a greater risk of death (adjusted odds ratio 1.43, 95% confidence interval 1.14 to 1.80 for age 60 to 74 years; and adjusted odds ratio 1.65, 95% confidence interval 1.22 to 2.22 for age >75 years). Proportions of cardiac deaths (55.2%, 57.6%, and 57.0%, p = 0.84), including ICD-unresponsive sudden death (9.9%, 6.0%, and 10.6%, p = 0.08), and rates of appropriate ICD therapies were similar in the 3 age groups. Older age was independently associated with a higher rate of early complications and a lower rate of inappropriate therapies. In conclusion, older patients exhibited higher global mortality after ICD implantation for primary prevention, whereas rates of sudden deaths and of appropriate device therapies were similar across age groups.

Survival benefit of the primary prevention implantable cardioverter-defibrillator among older patients: does age matter? An analysis of pooled data from 5 clinical trials

BACKGROUND

The impact of patient age on the risks of death or rehospitalization after primary prevention implantable cardioverter-defibrillator (ICD) placement is uncertain.

METHODS AND RESULTS

Data from 5 major ICD trials were merged: the Multicenter Automatic Defibrillator Implantation Trial I (MADIT-I), the Multicenter UnSustained Tachycardia Trial (MUSTT), the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II), the Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation Trial (DEFINITE), and the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT). Median age at enrollment was 62 (interquartile range 53-70) years. Compared with their younger counterparts, older patients had a greater burden of comorbid illness. In unadjusted exploratory analyses, ICD recipients were less likely to die than nonrecipients in all age groups: among patients aged <55 years: hazard ratio 0.48, 95% posterior credible interval 0.33 to 0.69; among patients aged 55 to 64 years: hazard ratio 0.69, 95% posterior credible interval 0.53 to 0.90; among patients aged 65 to 74 years: hazard ratio 0.67, 95% posterior credible interval, 0.53 to 0.85; and among patients aged ≥75 years: hazard ratio 0.54, 95% posterior credible interval 0.37 to 0.78. Sample sizes were limited among patients aged ≥75 years. In adjusted Bayesian-Weibull modeling, point estimates indicate ICD efficacy persists but is attenuated with increasing age. There was evidence of an interaction between age and ICD treatment on survival (two-sided posterior tail probability of no interaction <0.01). Using an adjusted Bayesian logistic regression model, there was no evidence of an interaction between age and ICD treatment on rehospitalization (two-sided posterior tail probability of no interaction 0.44).

CONCLUSIONS

In this analysis, the survival benefit of the ICD exists but is attenuated with increasing age. The latter finding may be because of the higher burden of comorbid illness, competing causes of death, or limited sample size of older patients. There was no evidence that age modifies the association between ICD treatment and rehospitalization.