Cardiac arrest and Brugada syndrome: Is drug-induced type 1 ECG pattern always a marker of low risk?

Abstract

Background: Patients diagnosed as affected by Brugada syndrome (BrS) on the basis of a drug-induced type 1 ECG pattern (type1) are regarded as at low risk for cardiac arrest. We tested whether this assumption matches reality.

Methods: The study population included 26 patients from our group and 217 patients from three studies published between 2002 and 2013, all of them with aborted cardiac arrest (ACA) and in whom a previously unrecognized type1 (spontaneous or drug-induced) was discovered after the event, thus leading to the diagnosis of BrS.

Results: Among our 26 patients, a drug-induced type1 was detected in 11 (42%) and only 1/11 showed a spontaneous pattern during follow-up; of 6 patients with syncope before ACA, 4 (67%) had only a drug-induced pattern. ICD shocks rates were similar in both spontaneous and drug-induced groups (57% and 45%). Early on, year 2002, the percentage of drug-induced type1 after ACA was much lower (14%) and has progressively increased to approximately 50%.

Conclusions: If drug-induced type1 carries low arrhythmic risk, it should seldom be the only marker for BrS after an ACA. In studies on patients after an unexpected ACA, a drug-induced type1 leads to the diagnosis of BrS more often than anticipated. This contrasts with prospective studies focusing on patients already diagnosed as BrS and which consider drug-induced type1 as a marker of low risk. Contrary to current views, it is possible that not all patients with a drug-induced BrS type1 are at low risk of future events.

Keywords: Aborted cardiac arrest; Brugada syndrome; Brugada type 1 ECG pattern; Sudden death.