Paroxysmal atrial fibrillation in myotonic dystrophy type 1 patients: P wave duration and dispersion analysis

V. Russo, F. Di Meo, A. Rago, A.A. Papa, A. Molino, M. Mosella, L. Politano, M.G. Russo, G. Nigro

Chair of Cardiology, Second University of Naples, Monaldi Hospital, Naples, Italy. f_dimeo@hotmail.it

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• Cardiology

OBJECTIVE: Myotonic dystrophy type 1 (MD1) is characterized by cardiac involvement, in about 80% of case, that predominantly affects the conduction system. Aim of our study was to evaluate the P-wave duration and dispersion (PD) in MD1 patients underwent pacemaker implantation with conserved systolic and diastolic function.

PATIENTS AND METHODS: We enrolled 60 MD1 patients (age 51.3 ± 5 years; 11 females) underwent dual chamber pacemaker implantation for various grade of atrioventricular (AV) block. Sixty sex-and age matched non-MD1 subjects were recruited as controls. P-wave duration and dispersion were carefully measured using 12-lead electrocardiogram.

RESULTS: Compared with healthy control group, MD1 patients presented increased maximum P wave duration (106.4 ± 20.9 vs 65.9 ± 8.2 ms, p = 0.03) and PD values (40.1 ± 11 vs 27.1 ± 4.2 ms, p = 0.003). No statistically significant difference was found in minimum P wave duration (69.7 ± 11.8 vs 65.4 ± 8.1 ms, p = 0.4). The MD1 patients with paroxysmal atrial fibrillation, compared with MD1 patients without evidence of atrial fibrillation, presented increased maximum P wave duration (108.1 ± 10.4 vs 78.1 ± 7.9 ms, p = 0.001) and PD values (41.1 ± 8.5 vs 33.2 ± 4.2 ms, p = 0.003). Minimum P wave duration (68.4 ± 8.2 vs 67.1 ± 4.9 ms, p = 0.5) didn’t differ between the two groups.

CONCLUSIONS: Our data showed a significantly increased P wave duration and dispersion in MD1 patients compared with age and sex-matched healthy controls. We showed a statistically significant increase in PD and P max in MD1 patients subgroup with AF compared to MD1 patients with no arrhythmias.

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