Procainamide infusion enables precise detection of BrS while maintaining an excellent safety profile. A study published in Circulation evaluated 947 individuals from the Canadian Hearts in Rhythm Organization (CHRO) registry who underwent procainamide infusion for suspected BrS. The study assessed infusion safety, diagnostic yield, and long-term arrhythmic outcomes compared with spontaneous type 1 Brugada electrocardiographic patterns.

Infusion-triggered ventricular arrhythmias were rare (0.2%) and resolved once procainamide was discontinued. Diagnostic positivity was 7.2% in unexplained cardiac arrest, 22.2% in individuals with a family history of BrS, and 6.9% in those with a family history of sudden unexplained death. Yield reached 46.6% in type 2 or type 3 Brugada patterns and 92% in intermittent spontaneous type 1 patterns, reflecting high diagnostic sensitivity and specificity.

No malignant ventricular arrhythmias occurred during a mean 5.9-year follow-up in the 137 individuals with a procainamide-induced type 1 pattern. One percent of spontaneous type 1 cases reached the arrhythmic endpoint. Implantable cardioverter defibrillator (ICD) use varied by clinical risk, and no ICD implanted during follow-up delivered appropriate therapy.

These data confirm procainamide infusion as a safe and reliable diagnostic tool for BrS. Asymptomatic individuals with induced type 1 Brugada patterns remain at minimal long-term arrhythmic risk.