Rates of Sudden Cardiac Death Lower Than Expected in a Mediterranean HF Cohort

Sudden cardiac death (SCD) rates are lower than expected among a Mediterranean cohort of patients with heart failure (HF), according to results of a study published in the Journal of Cardiac Failure.

All ambulatory patients (N=2772) with HF who presented at the Hospital Universitari Germans Trial i Pujol in Spain between 2001 and 2021 were included in this Mediterranean HF cohort. Rates of SCD were compared with the expected rate based on the Seattle Proportional Risk Model (SPRM).

The patients had a mean age of 66.9 (SD, 12.9) years, 70.6% were men, 98.8% were White, the most common HF etiology was ischemic heart disease (45.5%), the median duration of HF was 7 (range, 2-47) months, and left ventricular ejection fraction (LVEF) was 36.4% (SD, 14.7%).

A total of 1421 patients survived to the end of follow-up. The survivors were younger (P <.001), fewer were White (P <.001), fewer had ischemic heart disease (P <.001), they had a shorter HF duration (P <.001), higher LVEF (P =.004), and fewer comorbidities than patients who did not survive.

Among the patients who did not survive (n=1351), 184 had SCD. The SCD cohort was younger (P <.001), more were men (P =.001), more had ischemic heart disease (P <.001), lower LVEF (P <.001), and more were smokers (P <.001) compared with patients who died from something other than SCD.

The overall observed SCD rate was 15.6% among patients with reduced ejection fraction (EF) with an annual rate of 1.4%, 9.6% among patients with mildly reduced EF with an annual rate of 0.7%, and 7.1% among patients with preserved EF with an annual rate of 0.9%.

In all cases, the predicted SCD rate was higher (range, 39.0%-43.2%) than observed (range, 9.1%-17.1%).

When appropriate shocks were also classified as SCD, the rate of SCD increased to 19.5%, which was still lower than the prediction including appropriate shocks (40.1%). Similarly, when including the patients who died of unknown cause in the SCD cohort, the observed value remained lower than predicted (24.7% vs 40.3%), respectively.

Overall, the SPRM performed poorly (area under the curve [AUC], 0.60) with a significant Hosmer-Lemeshow test outcome (P <.001). However, the SPRM outperformed predictions using guideline criteria for New York Heart Association II or II with EF of 35% or less (AUC, 0.54).

This study may have been limited, as the majority of the cohort had HF with reduced EF.

“The proportion of SCD over 20 years in a Mediterranean outpatient cohort with HF managed in a multidisciplinary HF clinic was significantly lower than that predicted with the SPRM, independent of the degree of predicted risk, ischemic etiology, the period of admission, and the presence of an implanted ICD,” the study authors wrote. “Differences in the SCD group of the derivation cohort of the SPRM and this multidisciplinary managed HF cohort may have had an impact on the lower observed rate of SCD than predicted.”

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.