Autonomic Modulation and QT Interval Dispersion in Hypertensive Subjects With Anxiety

Abstract

Abstract-Anxiety is associated with an increased risk of sudden death. QT dispersion is a marker of cardiac repolarization instability and is seen in conditions of high risk of sudden death. The purpose of this study was to evaluate autonomic nervous system control and QT dispersion in hypertensive subjects with anxiety symptoms. In a recent preliminary study, we observed that hypertensive individuals reporting high scores on a self-assessment anxiety scale had more marked left ventricular hypertrophy. In 105 hypertensive subjects divided into 3 groups according to severity of anxiety, we evaluated autonomic control by short-term power spectral analysis of RR and arterial pressure variability at rest (baseline) and during sympathetic stress (tilt test), left ventricular mass index, and heart rate-corrected QT (QTc) dispersion. At baseline, hypertensive subjects with higher anxiety symptom scores had significantly lower highfrequency RR values expressed in absolute terms (PϽ0.05) and in normalized units (PϽ0.05) than their counterparts without anxiety symptoms. Hypertensive subjects with anxiety also had a higher mean left ventricular mass index (PϽ0.001) and greater QTc dispersion (PϽ0.001). Both indexes and high frequency (PϽ0.05) correlated with severity of anxiety. These findings suggest that anxiety is associated with autonomic imbalance. This condition could favor an increase in left ventricular mass. Myocardial hypertrophy alone or combined with neuroautonomic imbalance may lead to QT dispersion. (Hypertension. 1999;34:242-246.)Key Words: autonomic nervous system Ⅲ spectrum analysis Ⅲ anxiety Ⅲ death, sudden, cardiac Ⅲ hypertension Ⅲ hypertrophy, left ventricular Ⅲ QT dispersion A nxiety, 1-3 worry, 4 and anger 5 are among the psychological conditions associated with increased risk of death from coronary artery disease or indicated as a possible trigger of acute coronary episodes. Recent evidence also shows that depression can worsen the follow-up of postinfarction patients. 6 Clinical studies and experiments in animals have shown that anxiety is associated with changes in neuroautonomic control. 7-9 Spectral analysis of heart rate variability has confirmed increased indexes of sympathetic modulation, 10 -13 reduced indexes of parasympathetic modulation, or both 10,11 in subjects with phobic anxiety. Similar changes have been described in subjects with expression of anger 12 and panic attacks. 13,14 In preliminary studies, we recently observed that subjects with hypertension and high scores on a self-rated anxiety scale had more marked left ventricular hypertrophy and decreased parasympathetic and increased sympathetic modulation of sinus activity. 15 Hence, our aim in this study was to confirm these findings in a larger population of hypertensive subjects. Because subjects with high scores on the Cornell anxiety subscale proposed by Kawachi et al 1 have a greater risk of sudden death, we also studied QT dispersion, a marker of electrical instability in subjects with left ventricular hypertrophy. 16 Recent...

Modulation of the QT interval duration in hypertension with antihypertensive treatment

“…Despite their comparable BPs, hypertensive patients with anxiety exhibit significantly longer QT intervals and broader QT dispersion than their counterparts without anxiety. 33 This finding is supported by evidence that the magnitude of beat-to-beat QT variability is related to cardiac sympathetic activation in hypertensive patients. 47 Marfella and colleagues 54 determined that both the prolongation of cardiac repolarization and morning sympathetic overactivity coexist in hypertensive patients at the time of each patient's maximum morning BP.…”

“…28 Previous investigations describing QT abnormalities in the hypertensive population focused primarily on QT dispersion, whereas others focused on QT duration. As the two phenomena are linked by their relationship with both LVH and BP in the majority of studies, 8,[25][26][27][29][30][31][32][33][34][35][36] they will be discussed together in this review. Piccirillo and colleagues 37 described their findings of QT abnormalities in hypertensive subjects with LVH and speculated that greater ventricular mass results in decreased repolarization synchronization in myocardial cells.…”

“…33,51 Systemic catecholamines may alter ventricular repolarization 52 and prolong the duration of the QT interval, and also increase QT dispersion, even among healthy subjects. 52,53 The regulation of the QT interval by the autonomic nervous system has been demonstrated by several studies.…”

Predictors of sudden cardiac death in never previously treated patients with essential hypertension: long-term follow-up

“…[4][5][6][7][8] The long term significance of increased QT dispersion in hypertensive patients and its relationship to sudden cardiac death has not been determined previously although QT dispersion in hypertension has been studied on many occasions. [18][19][20][21][22][23] However the relationship between increased QT dispersion, LVH and ventricular arrhythmias as determined by 24-h ambulatory electrocardiographic recordings over long-term followup has not been studied previously in completely untreated patients. Within the limitations of this study the findings indicate that LVH and high grade ventricular arrhythmias are the only predictors of sudden cardiac death in hypertensive patients.…”

Autonomic cardiovascular control and diastolic dysfunction in hypertensive subjects

“…The severity of anxiety was rated with the Kawachi Symptoms Score [16]. The questionnaire comprises five items: ''Do strange people or places make you afraid?…”