Relationship Between Dominant Prolongation of the Filtered QRS Duration in the Right Precordial Leads and Clinical Characteristics in Brugada Syndrome
ABSTRACT 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.
- Journal of Cardiovascular Electrophysiology 04/2006; 17(3):276-8. DOI:10.1111/j.1540-8167.2006.00406.x · 2.88 Impact Factor
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ABSTRACT: A reliable alternative method for detecting Brugada syndrome is desirable because the diagnosis of Brugada syndrome using 12-lead ECG is not optimal. The purpose of this study was to assess the usefulness of the wavelet-transformed ECG in detecting Brugada syndrome. The study consisted of 15 patients with Brugada syndrome and 15 healthy subjects (control group). The parameters on the signal-averaged ECG and the frequency components recorded from the wavelet-transformed ECG were compared between the two groups. Measurements were repeated after pilsicainide infusion in the two groups of patients, after an isoproterenol infusion following pilsicainide injection, and after administration of cilostazol in the group of patients with Brugada syndrome. The positive rate of late potentials was 80% in the Brugada syndrome group and 0% in the control group (P <.01). The high-frequency components (80-150 Hz) were developed in the Brugada syndrome group to a greater extent than in the control group, but the low-frequency components (10-50 Hz) did not differ (mean peak power at 80 Hz; 713 +/- 36 vs 488 +/- 60, P <.001). After pilsicainide injection, high-frequency components significantly increased in both groups. However, after isoproterenol and cilostazol administration, high-frequency components significantly decreased but remained higher than in the control group (80 Hz; 655 +/- 40 vs 488 +/- 60, P <.001). The sensitivity of the development of high-frequency components in detecting Brugada syndrome was higher than that of signal-averaged ECG (100% vs 80%), but specificity remained high and similar (100% for both methods). Abnormally high-frequency components recorded from the wavelet-transformed ECG might be a novel factor in detecting Brugada syndrome.Heart Rhythm 01/2007; 3(12):1436-44. DOI:10.1016/j.hrthm.2006.08.027 · 4.92 Impact Factor
- Journal of Cardiovascular Electrophysiology 05/2007; 18(4):422-4. DOI:10.1111/j.1540-8167.2006.00759.x · 2.88 Impact Factor