Older Persons with Diabetes Receive Fewer Inappropriate ICD Shocks: Results from the INTRINSIC RV Trial

Abstract

In patients with heart disease, diabetes and age predict adverse outcomes. It remains unclear whether persons with diabetes who have implantable cardioverter defibrillators (ICDs) have fewer appropriate and inappropriate ICD shocks. The objective of this study is to determine if persons with diabetes who have ICDs receive a similar amount of appropriate and inappropriate shocks compared to persons without diabetes. In a post hoc analysis of 1,528 patients enrolled in the INTRINSIC RV trial, all-cause mortality and ICD shocks between persons with and without diabetes, stratified by age, was compared. The relationship between shock and mortality was also assessed. Mortality 1 year after ICD implant was lower for persons without diabetes vs. persons with diabetes (3.5% vs. 7.9%, p < 0.001). Young and old persons with diabetes received a similar number of total and appropriate ICD shocks. However, older persons with diabetes were less likely to receive inappropriate ICD shocks vs. older persons without diabetes (1.9% vs. 6.9%, p < 0.01). ICD shocks were not temporally related to mortality regardless of diabetes status. In the INTRINSIC RV trial, persons with diabetes and older persons without diabetes undergoing ICD implant were at a higher risk of death. Older persons with diabetes received less inappropriate shocks and still had a similar amount of appropriate shocks compared to persons without diabetes of similar age.

Influence of Diabetes Mellitus on Inappropriate and Appropriate Implantable Cardioverter-Defibrillator Therapy and Mortality in the Multicenter Automatic Defibrillator Implantation Trial–Reduce Inappropriate Therapy (MADIT-RIT) Trial

“…In patients with diabetes mellitus, the decreased risk of inappropriate therapy is driven by a significant reduction in inappropriate ATP, with less SVT and sinus tachycardia in this patient group; the risk of inappropriate therapy caused by atrial fibrillation is similar in patients with and without diabetes mellitus. Our finding that diabetes mellitus is associated with an increased risk of appropriate therapy supports 2 previous studies, 7,11 but compared with the predictors of appropriate therapy previously found in the larger trials such as Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II), Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT), Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION), Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction (REVERSE), Cardiac Resynchronization-Heart Failure (CARE-HF), and others, this is a novel finding. [12][13][14][15][16][17][18][19][20][21] Our explanation for the risk association of diabetes mellitus with appropriate ICD therapy includes a vulnerable myocardium resulting from fibrosis, ischemia, and scar tissue; reduced autonomic function; and reduced coronary circulation in diabetics, [22][23][24][25] rendering the myocardium more prone to produce ventricular arrhythmias.…”

“…The prevalence of diabetes mellitus in our study (32%) was similar to that in the MADIT-II (35%), 26 MADIT-CRT (30%), 4,27 INTRINSIC-RV (27%), 7 and CARE-HF (29%) 21 trials, reflecting the close association between prevalent diabetes mellitus and heart failure.…”

“…In the Inhibition of Unnecessary RV Pacing With AV Search Hysteresis in ICDs (INTRINSIC-RV) trial, diabetes mellitus was associated with reduced risk of inappropriate shocks in the elderly, but the study did not find an association between inappropriate shocks and mortality. 7 Methods to better stratify patients who may have less inappropriate therapy and shocks are warranted.…”

Implantable cardioverter defibrillators in diabetics: efficacy and safety in patients at risk of sudden cardiac death

“…In a post hoc analysis of 1,528 patients enrolled in the INTRINSIC RV [73] trial, a lower risk of inappropriate shocks was described in older diabetics as compared to nondiabetics. The risk of appropriate shocks was similar.…”