Purpose: In this study, we aimed to examine the evolution of electrocardiographic abnormalities in a cohort of 47 patients with TM as well as the incidence of new-onset arrhythmias during a 12-month follow-up period.
Methods: We studied 47 adult TM patients (median age 36 [31-42] years, 57% men) without systolic heart failure. Baseline demographic and clinical characteristics were recorded while 12-lead electrocardiograms, 24-hour ECG Holter recordings, and treadmill exercise stress tests were analyzed at baseline and after 12 months in each patient. Classical electrocardiographic measurements (complexes duration and intervals), as well as novel indexes of depolarization and repolarization/dispersion of repolarization (QRS fragmentation; T peak-to-end; T peak-to-end/QT), were performed. Also, indexes of autonomic dysfunction, heart rate variability in Holter recordings, and heart rate recovery after exercise testing were assessed.
Results: Electrocardiographic indexes of atrial and ventricular depolarization and indexes of ventricular repolarization/dispersion of repolarization were not significantly changed during the short-term follow-up. The same was true with regard to indexes of autonomic imbalance. No significant variation was observed in paroxysmal atrial fibrillation (PAF) detection (4/47 at baseline vs. 8/47 at 12 months; p=0.32). However, 3/8 patients that were diagnosed with PAF at the second evaluation did not have the arrhythmia at the initial screening. Thus, in total 12/47 (25%) of TM patients had PAF while 1/3 of these events was silent.
Conclusions: TM patients without overt heart failure exhibit electrocardiographic repolarization and autonomic dysfunction abnormalities that do not significantly alter during a short-term follow-up period. Of note, the AF burden in this population seems to be considerable. Undoubtedly, studies with a longer follow-up may elucidate the exact prognostic significance of specific electrocardiographic and arrhythmic parameters in this setting.