QT interval dispersion and autonomic modulation in subjects with anxiety

This study was designed to assess Q-T interval dispersion as a marker of el ectrical instability in subjects with anxiety. Recent observations have sho wn that the presence of anxiety symptoms increases the risk of sudden death . The Kawachi anxiety questionnaire identified 29 subjects (male/female rat io 13:16) who scored 0, 22 subjects (male/female ratio 14:8) who scored 1,a nd 37 subjects (male/female ratio 13:24) who scored 2 or more, In all subje cts we measured electrocardiographic interlead QT dispersion and autonomic function through spectral analysis of R-R interval and blood pressure varia bilities and left ventricular mass. Compared with subjects who scored 0, th ose reporting 2 or more symptoms showed increased heart rate-corrected QT d ispersion (54.9 +/- 1,7 ms vs 34.9 +/- 3.2 ms, P < .001), sympathetic modul ation (normal logorithm low-frequency power/high-frequency power 0.59 +/- 0 .1 vs 0.12 +/- 0.04, P < .05), and left ventricular mass (120.7 +/- 3.5 g/m (2) vs 97.9 +/- 2.8 g/m(2), P < .001), Probably because it augments sympath etic activity, anxiety causes left ventricular mass to increase and, like h ypertension, increases heart rate-corrected Q-T interval dispersion. The co nsequent electrical instability could be the substrate responsible for indu cing fatal ventricular arrhythmias.