Shorter minimum p-wave duration is associated with paroxysmal lone atrial fibrillation.

BACKGROUND AND PURPOSE: Prolonged P-wave dispersion (PWD) and P-wave duration (PWdur) have been found to be associated with common atrial fibrillation (AF), but the association of P-wave indices with lone atrial fibrillation (LAF) is unclear. METHODS: We enrolled 61 paroxysmal LAF cases and 150 controls without AF. P-wave indices were measured from a 12-lead ECG. Multivariable logistic regression was used to assess the association between P-wave indices and LAF. RESULTS: PWD was longer in LAF patients (median, IQR; 54.1 [42.9-63.2] ms) than controls (46.0 [38.5-57.7] ms), P=0.03. MinPWdur was shorter in LAF patients (60.5 [50.7-72.6] ms) than controls (66.0 [55.5-76.4] ms), P=0.03. In multivariable models, only the association between shorter minPWdur and LAF remained statistically significant (OR [95% CI] per tertile increment in minPWdur, 0.64 [0.42-0.95], P=0.03). CONCLUSIONS: Unlike common AF, paroxysmal LAF is independently associated with shorter minPWdur. This finding suggests that both shorter and prolonged PWdur may be associated with increased risk of AF.

Prevalence of Brugada sign and syndrome in patients presenting with arrhythmic symptoms at a Heart Rhythm Clinic in Singapore.

AIMS: Southeast Asia is endemic for Brugada syndrome; however, its prevalence in Singapore is unknown. We aimed to determine the prevalence of Brugada sign [Types 1, 2, and 3 Brugada electrocardiogram (ECG)] and syndrome at an arrhythmia clinic in Singapore. METHODS AND RESULTS: Patients who presented with pre-syncope, syncope, and/or palpitations without a known cause at an arrhythmia clinic between 2005 and 2007 were included in the study. The study criteria were met by 392 patients (age: 49.6 +/- 19.1 years, 55.9% male); 675 patients were excluded because they were referred for the management of known diagnoses. The 12-lead ECGs of these patients were analysed and clinical information was abstracted. Brugada sign was observed in 28 patients, and 12 patients were determined to have Brugada syndrome (age: 36.3 +/- 15.4 years, 100% male), yielding a prevalence of 7.1% [95% confidence interval (CI): 4.8-10.2] and 3.1% (95% CI: 1.6-5.3), respectively. The prevalence rates of patients with Type 1, Type 2, and Type 3 Brugada signs were 4.8% (95% CI: 2.9-7.5), 1.8% (95% CI: 0.7-3.6), and 0.5% (95% CI: 0.06-1.8), respectively. Over 30.4 person-years of follow-up, there was one inappropriate defibrillation shock but no appropriate shocks or sudden cardiac deaths among patients with Brugada sign or syndrome. CONCLUSION: The prevalence of both Brugada sign and syndrome in a hospital-based population in Singapore was found to be high. Further population-based investigation is warranted to confirm these findings.