Autonomic neuropathy and prolongation of QT interval in human immunodeficiency virus infection

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Abstract
Autonomic neuropathy has been reported in human immunodeficiency virus positive (HIV+) patients. Since alterations in cardiac innervation may determine QT interval prolongation, this interval was studied in a group of HIV+ subjects to evaluate if it is prolonged and to compare this measurement with other diagnostic tests for autonomic neuropathy. Fifty-seven HIV+ and 23 human immunodeficiency virus negative (HIV−) subjects were studied. Autonomic function was tested by noninvasive cardiovascular reflex tests, and the QT interval on the electrocardiogram was measured at rest, at maximum tachycardia during Valsalva manoeuvre, and afterwards at maximum bradycardia. QT intervals were corrected for heart rate according to Bazzett's formula (QTc). Autonomic neuropathy was found in 37 HIV+ subjects: 25 had moderate autonomic neuropathy (HIV+/mAN) and twelve had severe autonomic neuropathy (HIV+/sAN). The 23 HIV− and 20 HIV+ (HIV+/AN−) patients did not have autonomic neuropathy. QTc intervals were significantly longer in HIV+/sAN and HIV+/mAN than in HIV− at rest; in HIV+/sAN than in HIV− at maximum tachycardia; in HIV+/sAN and HIV+/mAN than in HIV+, in HIV+/sAN and HIV+/mAN than in HIV+/AN− and in HIV+/sAN than in HIV+/mAN at maximum bradycardia. QTc was ≥ 440 ms in 24 out of 37 (64.8%) patients with autonomic neuropathy and in five out of 20 (25%) HIV+/AN− patients (sensitivity 65%, specificity 75%). A significant correlation was observed between scores of autonomic involvement and QTc interval prolongation. This study confirms that the QTc measurement is a reliable parameter indicating the presence of autonomic neuropathy. Since QT prolongation may determine ventricular arrhythmias, such patients must be followed because they may be at increased risk of sudden death.