Temporal Incidence of Appropriate and Inappropriate Therapy and Mortality in Secondary Prevention ICD Patients by Cardiac Diagnosis

Global and Temporal Trends in Utilization and Outcomes of Implantable Cardioverter Defibrillators in Hypertrophic Cardiomyopathy

BACKGROUND

Over the past decades, hypertrophic cardiomyopathy has become a contemporary treatable disease. However, limited data exist on the global trends of implantable cardioverter defibrillator (ICD) utilization and its impact on mortality/morbidity burden reduction.

METHODS

Electronic databases were systematically searched up to March 2024 for studies reporting on ICD utilization rates in hypertrophic cardiomyopathy. A random effects model was used to pool study estimates across time-era, geographic region, and age group. Primary outcome was global trends in ICD utilization. Secondary outcomes included trends of sudden cardiac death, appropriate/inappropriate shocks, and ICD-related complications.

RESULTS

In total, 234 studies (N=92 500, 514 748 patient-years) met inclusion criteria. Mean age was 46.2 (12.4) years and 37.49% were women. A total of 12 139 patients (16.43%) received an ICD over 429 766 person-years of follow-up, with an ICD implantation rate of 2.79%/y ([95% CI, 2.35%-3.32%] I²=97.80%). Rates of ICD implantation steadily increased over time from 1990 (1.09%) to 2021 (4.01%; P=0.002), with noticeable geographic variation (P=0.008). The overall rate of appropriate ICD discharges and ICD-related complications was 3.44%/y ([95% CI, 3.08%-3.84%] I²=88.40%) and 1.98%/y ([95% CI, 1.52%-2.59%] I²=90.44%), respectively, with no significant trend over time. The overall rate of inappropriate discharges was 3.58%/y ([95% CI, 3.08%-4.16%] I2=88.03%), and declined significantly over time (P=0.044). There was a significant decline in the rates of sudden cardiac death from 1990 (0.84%/y) to 2020 (0.31%/y).

CONCLUSIONS

Dramatic increases in ICD utilization have occurred, representing a 3.7-fold increase, with appropriate therapies occurring in 3.44%/y. In parallel a significant reduction in sudden cardiac death was observed, but there are insufficient data to demonstrate that a causative relationship exists. Geographic disparities in ICD utilization were evident, highlighting the need to improve access to specialized care for patients with hypertrophic cardiomyopathy. Geographic disparities in ICD utilization were evident, highlighting the need to improve access to specialized care for patients with hypertrophic cardiomyopathy.

REGISTRATION

URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42023407126.

Long-Term Outcomes in ICD: All-Causes Mortality and First Appropriate Intervention in Ischemic and Nonischemic Etiologies

Real-life data comparing the long-term outcome in patients with different heart diseases carrying an implantable cardioverter defibrillator (ICD) are scarce. This study aimed to compare the long-term risk of the first appropriate ICD intervention and overall survival in patients with ICD and heart disease of different etiologies. Patients with an ICD implanted between January 1, 2010, and December 31, 2022, followed in our center were included. Study outcomes were all-cause mortality and first appropriate ICD intervention. A comparison between ischemic heart disease (IHD) and non-IHD (NIHD) was performed. In NIHD different etiologies of dilated cardiomyopathy (DCM) were analyzed. Overall, 1184 patients (592 IDH; 592 NIHD) were included. During a median follow-up of 53 months all-cause death occurred in 399 patients (34%) whereas first appropriate ICD intervention occurred in 320 (27%). All-cause mortality was significantly higher in IHD vs NIHD patients (60% vs 43%; p <0.0001) but no differences in appropriate ICD intervention rate at 10 years (34% vs 40%; p = 0.125) were observed. In patients with NIHD, a higher 10-year mortality rate was found in valvular heart disease, post-radio/chemotherapy DCM (rctDCM), and hypertensive DCM. Hypertrophic cardiomyopathy, alcoholic DCM, and rctDCM were the least arrhythmic phenotypes in NIHD. Of note, inappropriate interventions in alcoholic DCM and rctDCM were higher than appropriate ones. In conclusion, the rate of ICD-appropriate interventions and mortality is different according to the etiology of heart disease and cardiovascular risk profile; this should be taken into consideration in the prognostic stratification of these patients at the time of implantation.

Long-term outcomes among out-of-hospital cardiac arrest survivors with reversible vs. non-reversible causes

AIMS

A reversible cause of out-of-hospital cardiac arrest (OHCA) is vaguely defined in international guidelines as an identifiable transient or potentially correctable condition. However, studies evaluating long-term outcomes of patients experiencing OHCA due to reversible and non-reversible causes are lacking. We aimed to determine differences in long-term outcomes in OHCA survivors according to different aetiology.

METHODS AND RESULTS

From the British Columbia Cardiac Arrest registry, adults with non-traumatic OHCA (2009-2016) surviving to hospital discharge were identified. Patients were categorized by OHCA aetiology combining reversibility and underlying ischaemic aetiology. The primary outcome was a composite of all-cause mortality, recurrent OHCA, or re-hospitalization for sudden cardiac arrest or ventricular arrhythmias. Using the Kaplan-Meier method and multivariable Cox regression models, we compared the risk of the composite outcome according to different OHCA aetiology. Of 1325 OHCA hospital-discharge survivors (median age 62.8 years, 77.9% male), 431 (32.5%) had reversible ischaemic, 415 (31.3%), non-reversible ischaemic, 99 (7.5%), reversible non-ischaemic, and 380 (28.7%), non-reversible non-ischaemic aetiologies. At 3 years post discharge, the Kaplan-Meier event-free rate was highest in patients with a reversible ischaemic aetiology [91%, 95% confidence interval (CI) 87-94%], and lowest in those with a reversible non-ischaemic aetiology (62%, 95% CI 51-72%). In multivariate analyses, compared with non-reversible non-ischaemic cause, reversible ischaemic cause was associated with a significantly lower hazard ratio (HR; 0.52, 95% CI 0.33-0.81), reversible non-ischaemic cause with a significantly higher HR (1.53, 95% CI 1.03-2.32), and non-reversible ischaemic cause with a non-significant HR (0.92, 95% CI 0.64-1.33) for the composite outcome.

CONCLUSION

Compared to other aetiologies, the presence of a reversible ischaemic cause is associated with improved long-term OHCA outcomes.

Implantable cardioverter defibrillator therapy in paediatric patients for primary vs. secondary prevention

AIMS

The decisions about placing an ICD in a child are more difficult than in an adult due to longer expected lifespan and the complication risk. Young patients gain the most years from ICDs, despite higher risk of device-related complications. The secondary prevention ICD indication is clear, and device is implanted regardless of potential complications. For primary prevention, risk of sudden cardiac death and complications need to be evaluated. We aimed to compare outcomes for primary and secondary prevention ICDs.

METHODS AND RESULTS

Retrospective nationwide cohort study including paediatric patients identified from the Danish ICD registry with ICD implanted at an age ≤ 15 from 1982-21. Demographics, complications (composite of device-related infections or lead-failure requiring re-operation, mortality because of arrhythmia, or unknown cause), and mortality were retrieved from medical charts. Endpoint was appropriate therapy (shock or anti-tachycardia pacing for ventricular tachycardia or fibrillation). Of 72 receiving an ICD, the majority had channelopathies (n = 34) or structural heart diseases (n = 28). ICDs were implanted in 23 patients for primary prevention and 49 for secondary prevention, at median ages of 13.8 and 11.6 years (P-value 0.01), respectively. Median follow-up was 9.0 (interquartile ranges: 4.7-13.5) years. The 10-year cumulative incidence of first appropriate therapy was 70%, with complication and inappropriate therapy rates at 41% and 15%, respectively. No difference was observed between prevention groups for all outcomes. Six patients died during follow-up.

CONCLUSION

In children, two-thirds are secondary prevention ICDs. Children have higher appropriate therapy and complication rates than adults, while the inappropriate therapy rate was low.

Devices and Athletics: Decision-Making Around Return to Play

Until recently, implantable cardioverter defibrillators (ICDs) were considered a contraindication to competitive athletics. Recent prospective observational registry data in athletes with ICDs who participated in sports against the societal recommendations at the time have demonstrated the safety of sports participation. While athletes did receive both appropriate and inappropriate shocks, these were not more frequent during sports participation than other activity, and there were no sports-related deaths or need for external resuscitation in the 440 athlete cohort (median followup 44 months). Optimization of medical therapies, device settings and having an emergency action plan allow many athletes to safely continue athletic activity.

Integration of implantable device therapy in patients with heart failure. A clinical consensus statement from the Heart Failure Association (HFA) and European Heart Rhythm Association (EHRA) of the European Society of Cardiology (ESC)

Implantable devices form an integral part of the management of patients with heart failure (HF) and provide adjunctive therapies in addition to cornerstone drug treatment. Although the number of these devices is growing, only few are supported by robust evidence. Current devices aim to improve haemodynamics, improve reverse remodelling, or provide electrical therapy. A number of these devices have guideline recommendations and some have been shown to improve outcomes such as cardiac resynchronization therapy, implantable cardioverter-defibrillators and long-term mechanical support. For others, more evidence is still needed before large-scale implementation can be strongly advised. Of note, devices and drugs can work synergistically in HF as improved disease control with devices can allow for further optimization of drug therapy. Therefore, some devices might already be considered early in the disease trajectory of HF patients, while others might only be reserved for advanced HF. As such, device therapy should be integrated into HF care programmes. Unfortunately, implementation of devices, including those with the greatest evidence, in clinical care pathways is still suboptimal. This clinical consensus document of the Heart Failure Association (HFA) and European Heart Rhythm Association (EHRA) of the European Society of Cardiology (ESC) describes the physiological rationale behind device-provided therapy and also device-guided management, offers an overview of current implantable device options recommended by the guidelines and proposes a new integrated model of device therapy as a part of HF care.

Reduction in long-term mortality using remote device monitoring in a large real-world population of patients with implantable defibrillators

AIMS

Remote monitoring (RM) for implantable cardioverter-defibrillators (ICDs) is advocated for the potential of early detection of disease progression and device dysfunction. While studies have examined the effect of RM on clinical outcomes in carefully selected populations of heart failure patients implanted with ICDs from a single vendor, there is a paucity of data in real-world patients. We aimed to assess the long-term effect of RM in a representative ICD population using real-world data.

METHODS AND RESULTS

This is an observational retrospective longitudinal study of 1004 patients implanted with an ICD or cardiac resynchronization therapy device (CRT-D) from all device vendors between 2010 and 2021. Patients started on RM (N = 403) within 90 days following de novo device implantation and yearly in-office visits were compared with patients with only bi-yearly in-office follow-up (non-RM, N = 601). In a propensity score matched cohort of 430 patients (mean age 61.4 ± 14.3 years, 26.7% female), all-cause mortality at 4-year was 12.6% in the RM and 27.7% in the non-RM group [hazard ratio (HR) 0.52, 95% confidence interval (CI) 0.32-0.82; P = 0.005]. No difference in inappropriate ICD-therapy (HR 1.90, 95% CI 0.86-4.21; P = 0.122) was observed. The risk of appropriate ICD-therapy (HR 1.71, 95% CI 1.07-2.74; P = 0.026) was higher in the RM group.

CONCLUSION

Remote monitoring was associated with a reduction in long-term all-cause and cardiac mortality compared with traditional office visits in a real-world ICD population.

Driving following defibrillator implantation: a nationwide register-linked survey study

AIMS

Patients are restricted from driving following implantable cardioverter defibrillator (ICD) implantation or shock. We sought to investigate how many patients are aware of, and adhere to, the driving restrictions, and what proportion experience an ICD shock or other cardiac symptoms while driving.

METHODS AND RESULTS

We performed a nationwide survey of all living Danish residents 18 years or older who received a first-time ICD between 2013 and 2016 (n = 3913) and linked their responses with nationwide registers. Of 2741 respondents (47% primary prevention, 83% male, median age 67 years), 2513 (92%) held a valid driver's license at ICD implantation, 175 (7%) of whom had a license for professional driving. Many drivers were unaware of driving restrictions: primary prevention 58%; secondary prevention 36%; post-appropriate shock 28%; professional drivers 55%. Almost all (94%) resumed non-professional driving after ICD implantation, more than one-third during the restricted period; 35% resumed professional driving. During a median follow-up of 2.3 years, 5 (0.2%) reported receiving an ICD shock while driving, one of which resulted in a traffic accident. The estimated risk of harm was 0.0002% per person-year.

CONCLUSION

In this nationwide study, many ICD patients were unaware of driving restrictions, and more than one third resumed driving during a driving restriction period. However, the rate of reported ICD shocks while driving was very low.