Incidence of syncope and cardiac arrest in patients with severe aortic stenosis

Syncope and sudden cardiac arrest are known complications of aortic stenosis (AS).

The aim of the study was to investigate the incidence of these complications in patients with severe symptomatic AS and to analyze whether basic clinical data and electrocardiographic (ECG) and echocardiographic parameters can be the markers of these complications.

The incidence of syncope and sudden cardiac arrest and its correlations with clinical and diagnostic data (ECG, echocardiography, Holter monitoring) were analyzed in 514 patients (mean age, 60 ±11 y) with severe symptomatic AS before valve replacement.

Syncope was reported in 167 patients (32%), and aborted cardiac arrest in 14 (2.7%; ventricular fibrillation, 13 patients; third-degree atrioventricular block, 1 patient). None of the analyzed parameters was related to syncope. Patients with a history of sudden cardiac arrest had higher New York Heart Association class (P = 0.01), more frequent history of syncope (P = 0.017), higher left ventricular mass index (P = 0.02), lower ejection fraction (P = 0.004), longer QRS duration (P = 0.048), corrected QT (P = 0.002), QT dispersion (P = 0.007), and a higher number of ventricular arrhythmias in 24-hour Holter monitoring (P = 0.002). A multivariate analysis showed correlations between syncope, ejection fraction of less than 45%, and QTd exceeding 60 ms and aborted cardiac arrest. At least 2 of these parameters were observed in 8 of 14 patients (P <0.001): sensitivity, 57%; specificity, 86%; positive predictive value, 10%; and negative predictive value, 98%.

The incidence of sudden cardiac arrest in severe symptomatic AS is low. It is higher in patients with a history of syncope, prolongation of QTd, and reduced ejection fraction. None of the clinical and diagnostic parameters were associated with a history of syncope in patients with AS.