Masked inherited primary arrhythmia syndromes in sudden cardiac death patients accompanied by coronary vasospasm.

BACKGROUND/AIMS: Coronary vasospasms are one of the important causes of sudden cardiac death (SCD). Provocation of coronary vasospasms can be useful, though some results may lead to false positives, with patients potentially experiencing recurrent SCD despite appropriate medical treatments. We hypothesized that it is not coronary vasospasms but inherited primary arrhythmia syndromes (IPAS) that underlie the development of SCD.

METHODS: We analyzed 74 consecutive patients (3.8%) who survived out-of-hospital cardiac arrest among 1,986 patients who had angiographically proven coronary vasospasms. Electrical abnormalities were evaluated in serial follow-up electrocardiograms (ECGs) during and after the index event for a 3.9 years median follow-up. Major clinical events were defined as the composite of death and recurrent SCD events.

RESULTS: Forty five patients (60.8%) displayed electrocardiographic abnormalities suggesting IPAS: Brugada type patterns in six (8.2%), arrhythmogenic right ventricular dysplasia patterns in three (4.1%), long QT syndrome pattern in one (2.2%), and early repolarization in 38 (51.4%). Patients having major clinical events showed more frequent Brugada type patterns, early repolarization, and more diffuse multivessel coronary vasospasms. Brugada type pattern ECGs (adjusted hazard ratio [HR], 4.22; 95% confidence interval [CI], 1.16 to 15.99; p = 0.034), and early repolarization (HR, 2.97; 95% CI, 1.09 to 8.10; p = 0.034) were ultimately associated with an increased risk of mortality.

CONCLUSIONS: Even though a number of aborted SCD survivors have coronary vasospasms, some also have IPAS, which has the potential to cause SCD. Therefore, meticulous evaluations and follow-ups for IPAS are required in those patients.