Defibrillation safety margin (DSM) testing is being performed less frequently over time and may be safe in patients with congenital heart disease (CHD) who have ICDs, according to a study published April 28 in JACC: Clinical Electrophysiology.

Jordan M. Prutkin, MD, MHS, FACC, et al., used data from ACC’s EP Device Implant Registry, formerly known as the ICD Registry, to look at predictors of DSM testing at the time of ICD insertion and factors associated with inadequate DSM, defined as a lowest successful energy tested <10 J than the maximum output of the ICD generator, in CHD patients with atrial or ventricular septal defect, tetralogy of Fallot, transposition of the great vessels, Ebstein anomaly or common ventricular undergoing a transvenous ICD procedure. The researchers also examined prevalence of DSM testing and the rate of in-hospital adverse events associated with DSM testing.

Over time, DSM testing decreased, from 64% when the study began in 2010 to 31.4% in 2016. Of 7,024 ICD recipients, DSM testing was performed on 3,654 (52%). The lowest average successful energy tested was 20.7 ± 7.3 J. Patients who underwent DSM testing were more likely to be younger and have private insurance. Other factors associated with DSM testing include nonischemic cardiomyopathy, prior syncope, prior ventricular tachycardia arrest, higher ejection fraction, worse kidney function and first-time ICD insertion. Inadequate DSM occurred in 501 (13.8%) of those receiving DSM testing. Patients with inadequate DSM had higher NYHA function class. There was no difference in presence of inadequate DSM in those with the most common types of CHD, except for common ventricle (1.6% vs. 0.7%) and Ebstein anomaly (4.6% vs. 2.2%).

There were no differences between patients who received DSM vs. those who did not in in-hospital mortality (0.33% vs. 0.50%) or complications (2.30 vs. 2.31%). After adjustment, DSM testing was associated with reduced odds of a prolonged hospital stay of more than three days (OR: 0.71; 95% CI: 0.60-0.84). In addition, inadequate DSM was not associated with in-hospital death or complications (OR: 1.27; 95% CI: 0.79-2.04) or a prolonged hospital stay (OR: 1.34; 95% CI: 0.995-1.81).

According to the authors, DSM testing decreased over the study period and patients undergoing DSM testing represented an overall healthier cohort. They conclude that the findings demonstrate no association between DSM testing or inadequate DSM and in-hospital adverse events. “Overall, the lack of complications is a reassuring finding for those who conduct DSM testing,” they write.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Cardiovascular Care Team, Congenital Heart Disease and Pediatric Cardiology, Heart Failure and Cardiomyopathies, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Aortic Surgery, Cardiac Surgery and Arrhythmias, Cardiac Surgery and CHD and Pediatrics, Cardiac Surgery and Heart Failure, Congenital Heart Disease, CHD and Pediatrics and Arrhythmias, CHD and Pediatrics and Quality Improvement

Keywords: Hospital Mortality, Length of Stay, Ebstein Anomaly, Stroke Volume, Tetralogy of Fallot, Tachycardia, Ventricular, Arrhythmias, Cardiac, Defibrillators, Implantable, Heart Defects, Congenital, Registries, Cardiomyopathy, Hypertrophic, Cardiomyopathies, Hospitals, Heart Septal Defects, Ventricular, Syncope, Electrophysiology, Insurance, Kidney, National Cardiovascular Data Registries, EP Device Implant Registry

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