Implantable cardioverter-defibrillator therapy in the very young - Patient characteristics procedural outcome and one-year follow-up - A subgroup analysis of the german DEVICE registry
Authors: Chung D , Hochadel M , Senges J , Kleemann T , Eckhardt L , Brachmann J , Steinbeck G , Larbig R , Butter C , Schulz E , Willems S , Hakmi S 
Published: May 2022

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
The implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) are well-established and essential therapeutic pillars for patients with heart failure and survivors of sudden cardiac death. The number of young patients receiving ICD or CRT-D has been increasing in the last decades. Understanding the key differences between the typically older ICD population and younger patients is paramount to optimized patient care.

Methods
The DEVICE registry prospectively enrolled patients undergoing ICD/CRT implantation or revision from 50 German centers between 2007–2014. Data on patient characteristics, procedural outcome, adverse events and mortality during the initial stay and follow-up was collected. All patients under the age of 45 years were identified and included into a comparative analysis with the remaining population.

Results
A total number of 4181 patients were enrolled into the registry, of which 236 patients (5.6%) were under the age of 45 years. Median age was 38.0 [31.0; 42.0] vs. 69.0 [60.0; 75.0] years, p&lt;0.001), compared to older patients. Young patients were more likely to receive an ICD (91.5 vs. 69.4%, p&lt;0.001), than CRT device and were less likely to suffer from non-cardiac comorbidities (20.3 vs. 67.4%, p&lt;0.001). Coronary artery disease was less common in young patients (15.7 vs. 63.6%, p&lt;0.001), whereas hypertrophic cardiomyopathy (11.0 vs. 2.5%, p&lt;0.001) and primary cardiac electrical diseases (14.0 vs. 1.6%, p&lt; 0.001) were encountered more often. Mean left-ventricular ejection fractions were 42.4±18.5 vs. 31.5±11.8%, respectively (p&lt;0.001) with less young patients in NYHA functional class III/IV (19.5 vs. 45.3%, p&lt;0.001). Primary symptom at presentation was chronic heart failure for older patients (19.5 vs. 34.8%, p&lt;0.001) and survived sudden cardiac death (30.9 vs. 15.6%, p&lt;0.001) for young patients. Thus, ICD for secondary prevention was more common in young patients (53.8 vs. 43.2%, p&lt;0.001). There were no detectable differences in postoperative complications (3.0 vs. 4.1%, p=0.500) or in-hospital mortality (0.0 vs. 0.3%, p=1.000). Median follow-up time was 514 [398; 669] vs. 458 [391; 563] days (p=0.006). Device-associated complications requiring revision were more common in young patients (16.3 vs. 8.2%, p&lt;0.001) and all-cause 1-year-mortality after implantation was lower (3.1 vs. 7.3%, p=0.029; HR 0.42, 95%CI: 0.19-0.94). Even though there was no difference in rates of rehospitalization between groups (32.1 vs. 32.4%, p=0.93), young patients were re-admitted more often for "cardiac" reasons (82.7 vs. 58.9%, p&lt;0.001).

Conclusion
Rates for procedural complications and in-hospital mortality were very low and without differences between both age groups. However younger patients experienced a higher rate of postoperative complications requiring revision and had higher readmission rates for cardiac reasons, potentially due to a more active lifestyle.