Predicting Sudden Cardiac Death in Heart Failure with Mildly Reduced/Preserved Left Ventricular Ejection Fraction: A Clinical Review

Cardiac arrest is a way of demise of patients who are affected by heart failure (HF), being more frequent in those with HF with a reduced left ventricular ejection fraction (HFrEF), and is, as such, responsible for 30-50% of cardiac death. Specific data on the risk of sudden cardiac death (SCD) related to HF with a preserved ejection fraction (HFpEF) and HF with a mildly reduced ejection fraction (HFmrEF) are lacking, as well as data regarding ventricular arrhythmias in this population. Considering the 0.3% person/year incidence rate of investigator-reported ventricular tachycardia (VT) and ventricular fibrillation (VF), the rate of SCD in the analyzed population seems to be 1.3% per year. Age, gender, history of diabetes and myocardial infarction, left bundle branch block (LBBB) on electrocardiogram (ECG), and a natural logarithm of N-terminal pro B-type natriuretic peptide (NT-proBNP), identified a subgroup of HFpEF patients with a higher risk (5-year cumulative incidence of 11%) of sudden death (SD). In HFpEF patients, both glifozins and finerenone did not demonstrate a beneficial effect on SCD incidence in comparison to placebo. A significantly lower rate of SCD emerged in patients who were treated with dapaglifozin (10 vs. 26 pts) among patients with HF with an improved ejection fraction (HFimpEF), who were defined as patients with a previous left ventricular ejection fraction (LVEF) < 40%. Promising methods discussed include cardiac magnetic resonance, myocardial scintigraphy, genetic assessment, and electrophysiologic studies for predicting SCD in those patients. In conclusion, arrhythmic SCD in HFpEF patients should not be considered merely as an effect of VT/VF; bradyarrhythmia is probably more frequent and dangerous. The effects of drugs in preventing SCD in HFpEF have not been demonstrated yet.