Relationship Between Dominant Prolongation of the Filtered QRS Duration in the Right Precordial Leads and Clinical Characteristics in Brugada Syndrome

First Department of Internal Medicine, Niigata University School of Medicine, Niigata, Japan.
Journal of Cardiovascular Electrophysiology (Impact Factor: 2.96). 12/2005; 16(12):1311-7. DOI: 10.1111/j.1540-8167.2005.00262.x
Source: PubMed


Electrical abnormalities in the RVOT may be involved in Brugada syndrome.
We investigated the relationship between the signal-averaged ECG (SAECG) and electrophysiologic study (EPS), especially focusing on conduction delay in the outflow tract of the right ventricle (RVOT) and its contribution to clinical characteristics.
Twenty-four patients with Brugada syndrome (23 men and 1 woman; 61 +/- 16 years old) were studied. We assessed the presence of late potential (LP) in SAECG and the filtered QRS duration in the right precordial leads (V1 or V2; RfQRS) and in the left precordial leads (V5 or V6; LfQRS) and the difference between them. In 18 patients, SAECG was evaluated for an LP on three separate occasions.
SAECG was positive for LP in 15 patients at least once; and in 7 patients, SAECG was positive for an LP on multiple occasions, and 6 of 7 patients (86%) had a history of cardiac arrest. The difference between RfQRS and LfQRS was significantly greater in patients with cardiac arrest than in patients with syncope or in asymptomatic patients; 29 +/- 10, 14 +/- 11 (P < 0.01), and 7 +/- 5 msec (P < 0.001), respectively. All patients were alive and one patient with cardiac arrest had an appropriate VF therapy delivered by the ICD.
The dominant prolongation of the filtered QRS duration in the right precordial leads may be related to the risk of arrhythmic event in Brugada syndrome.

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