(Hypertension. 1996;28:16-21.)
© 1996 American Heart Association, Inc.
Articles |
Dispersion of the QT Interval and Autonomic Modulation of Heart Rate in Hypertensive Men With and Without Left Ventricular Hypertrophy
the Division of Cardiology, Department of Medicine, University of Oulu (Finland).
Correspondence to Juha S. Perkiomaki, MD, Division of Cardiology, Department of Medicine, Oulu University Central Hospital, 90220, Oulu, Finland.
Left ventricular hypertrophy is an independent risk factor for sudden cardiac death in hypertension, but the mechanisms of electrical instability associated with hypertrophy are not well known. We studied dispersion of the QT interval, an index of inhomogeneity of repolarization, and heart rate variability, a measure of cardiac autonomic modulation, in a randomly selected population of 162 men with systemic hypertension and made comparisons between the patients with echocardiographic evidence of left ventricular hypertrophy (left ventricular mass index 
131 g/m2, n=44) and those without hypertrophy (left ventricular mass index <131 g/m2, n=118). The heart rate-corrected QT dispersion (67±37 versus 53±21 milliseconds, P<.05) and QT apex dispersion (55±22 versus 44±16 milliseconds, P<.01) were significantly longer in the patients with left ventricular hypertrophy than in those without hypertrophy. Thirteen of the 44 patients (30%) with hypertrophy versus 7 of the 118 patients (6%) without hypertrophy had an abnormally long QT apex dispersion (>70 milliseconds) (P<.001). The time and frequency domain measures of heart rate variability did not differ significantly between the patient groups with and without left ventricular hypertrophy. The measures of heart rate variability were not related to QT dispersion or left ventricular mass index but had a negative correlation with blood pressure values (eg, r=-.30 between the low-frequency component of heart rate variability and systolic pressure, P<.001). Age, body mass index, antihypertensive medication, and the other demographic variables were similar between the groups, but the patients with left ventricular hypertrophy had higher systolic (P<.01) and diastolic (P<.01) pressures compared with the patients without hypertrophy. Left ventricular hypertrophy in hypertensive men is associated with inhomogeneity of the early phase of ventricular repolarization, favoring susceptibility to reentrant ventricular tachyarrhythmias. Abnormalities in cardiac autonomic function, which may trigger a spontaneous onset of arrhythmias, are related to elevated blood pressure but not specifically to left ventricular hypertrophy.
Key Words: electrocardiography • heart rate • hypertension, chronic • hypertrophy
This article has been cited by other articles:
 |
|
 |
|
  R. Marfella, P. Gualdiero, M. Siniscalchi, C. Carusone, M. Verza, S. Marzano, K. Esposito, and D. Giugliano Morning Blood Pressure Peak, QT Intervals, and Sympathetic Activity in Hypertensive Patients Hypertension, February 1, 2003; 41(2): 237 - 243. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A Yildirir, M. K Batur, and A Oto Hypertension and arrhythmia: blood pressure control and beyond Europace, January 1, 2002; 4(2): 175 - 182. [Abstract] [PDF]
|
|
|
|
 |
|
 M. Malik and V. N. Batchvarov Measurement, interpretation and clinical potential of QT dispersion J. Am. Coll. Cardiol., November 15, 2000; 36(6): 1749 - 1766. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Piccirillo, E. Viola, M. Nocco, E. Santagada, M. Durante, C. Bucca, and V. Marigliano Autonomic Modulation and QT Interval Dispersion in Hypertensive Subjects With Anxiety Hypertension, August 1, 1999; 34(2): 242 - 246. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D Darbar, C J Cherry, and D M Kerins QT dispersion is reduced after valve replacement in patients with aortic stenosis Heart, July 1, 1999; 82(1): 15 - 18. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L Oikarinen, L Toivonen, and M Viitasalo Electrocardiographic measures of ventricular repolarisation dispersion in patients with coronary artery disease susceptible to ventricular fibrillation Heart, June 1, 1998; 79(6): 554 - 559. [Abstract] [Full Text]
|
|
|
|
 |
|
 A. M. Choy, C. C. Lang, D. M. Chomsky, G. H. Rayos, J. R. Wilson, and D. M. Roden Normalization of Acquired QT Prolongation in Humans by Intravenous Potassium Circulation, October 7, 1997; 96(7): 2149 - 2154. [Abstract] [Full Text]
|
|