Background: Short QT syndrome is a rare, inherited channelopathy associated with sudden cardiac arrest (SCA) but characteristics and prognosis of short QT interval (SQTI) in Asian patients remain unclear. This study aimed to determine clinical characteristics of and outcomes in patients with SQTI in an Asian population.
Methods: Consecutive patients with SQTI were recruited. SQTI was defined as a Bazett’s formula-corrected QT interval (QTc) ≤340 ms in serial electrocardiograms. Age- and sex-matched patients with a normal QTc and without overt cardiovascular disease were included at a 1:4 ratio. Clinical and ECG features and outcomes were compared between patients with and without SQTI.
Results: Thirty-four patients with SQTI [age, 23.5 (21–30.5) years; 31 male] were followed up for 4.8 (2.0–7.8) years. Early repolarization, tall T wave, and U wave were significantly more frequent in patients with SQTI than the patients without SQTI. QT dispersion [44.0 (28.0–73.0) vs. 20.0 (12.0–35.0) ms, P<0.001] was significantly wider and heart rate [52.0 (47.0–58.0) vs. 70.0 (62.3–84.0) /min, P<0.001] was significantly slower in patients with SQTI than patients without SQTI. Atrial fibrillation (AF, 11.8% vs. 2.2%, P=0.030) and ventricular arrhythmia (VA)/SCA (8.7% vs 0%, P=0.007) were significantly more frequent in patients with SQTI than patients without SQTI. SQTI was significantly associated with AF [odds ratio, 5.911; 95% confidence interval, 1.257–27.808; P=0.025] and VA/SCA.
Conclusions: In this Asian population, SQTI was associated with AF and VA/SCA.