Effect of sodium-channel blockade on early repolarization in inferior/lateral leads in patients with idiopathic ventricular fibrillation and Brugada syndrome.

Abstract

BACKGROUND:

A high incidence of early repolarization (ER) pattern in the inferolateral leads has been reported in patients with idiopathic ventricular fibrillation (IVF). Brugada syndrome (BS) is characterized by J-point or ST-segment elevation in the right precordial leads and ventricular fibrillation, and some patients with BS also have ER in the inferolateral leads.

OBJECTIVE:

To compare the clinical characteristics and effects of sodium-channel blockade on ER between IVF patients with ER (early repolarization syndrome [ERS]) and BS patients with or without ER.

METHODS:

Fourteen patients with ERS and 21 patients with BS were included in this study. ER was defined as an elevation of at least 0.1 mV from baseline in the QRS-T junction in the inferorolateral leads. Provocative tests with sodium-channel blockers were conducted in all patients with ERS to distinguish ERS from BS.

RESULTS:

In the ERS group, all patients were male and most patients experienced ventricular fibrillation during sleep or low activity (79%). ER was attenuated by sodium-channel blockers in most patients with ERS (13/14, 93%) and BS (5/5, 100%), whereas ST-segment elevation was augmented in the right precordial leads in the BS group. The rates of positive late potentials were significantly higher in the BS group (60%) than in the ERS group (7%) (P <.01).

CONCLUSIONS:

Some similarities were observed between ERS and BS, including gender, arrhythmia triggers, and response of ER to sodium-channel blockers. Unlike the ST segment in the right precordial leads in BS, ER was attenuated in patients with both ERS and BS, suggesting a differential mechanism between ER in the inferolateral leads and ST elevation in the right precordial leads.

• Authors: Hiro Kawata, Takashi Noda, Yuko Yamada, Hideo Okamura, Kazuhiro Satomi, Takeshi Aiba, Hiroshi Takaki, Naohiko Aihara, Mitsuaki Isobe, Shiro Kamakura, Wataru Shimizu
• Journal: Heart rhythm (Heart Rhythm) Vol. 9 Issue 1 Pg. 77-83 (Jan 2012) ISSN: 1556-3871 [Electronic] United States
• PMID: 21855521 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Chemical References

• Sodium Channel Blockers

Topics

• Adult
• Arrhythmias, Cardiac (drug therapy, physiopathology)
• Brugada Syndrome (drug therapy, physiopathology)
• Electrocardiography (drug effects)
• Humans
• Male
• Middle Aged
• Sodium Channel Blockers (pharmacology, therapeutic use)
• Ventricular Fibrillation (drug therapy, physiopathology)