Autonomic modulation and QT interval dispersion in hypertensive subjects with anxiety

Anxiety is associated with an increased risk of sudden death. QT dispersion is a marker of cardiac repolarization instability and is seen in condition s of high risk of sudden death. The purpose of this study was to evaluate a utonomic nervous system control and QT dispersion in hypertensive subjects with anxiety symptoms. In a recent preliminary study, we observed that hype rtensive individuals reporting high scores on a self-assessment anxiety sca le had more marked left ventricular hypertrophy. In 105 hypertensive subjec ts divided into 3 groups according to severity of anxiety, we evaluated aut onomic control by short-term power spectral analysis of RR and arterial pre ssure variability at rest (baseline) and during sympathetic stress (tilt te st), left ventricular mass index, and heart rate-corrected QT (QTc) dispers ion. At baseline, hypertensive subjects with higher anxiety symptom scores had significantly lower high-frequency RR values expressed in absolute term s (P<0.05) and in normalized units (P<0.05) than their counterparts without anxiety symptoms. Hypertensive subjects with anxiety also had a higher mea n left ventricular mass index (P<0.001) and greater QTc dispersion (P<0.001 ). Both indexes and high frequency (P<0.05) correlated with severity of anx iety. These findings suggest that anxiety is associated with autonomic imba lance. This condition could favor an increase in left ventricular mass. Myo cardial hypertrophy alone or combined with neuroautonomic imbalance may lea d to QT dispersion.