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(Circulation. 2000;101:e213.)
© 2000 American Heart Association, Inc.

Circulation Electronic Pages

Mental Versus Physical Stress, QT Prolongation, and the Autonomic Nervous System

C. Noel Bairey Merz, MD; Yosef Pardo, MD

From the Division of Cardiology, Department of Medicine, Cedars-Sinai Research Institute, Cedars-Sinai Medical Center, and the Department of Medicine, University of California at Los Angeles School of Medicine, Los Angeles, Calif; and the Department of Cardiology, Sapir Medical Center, Meir Hospital, Kfar Saba, Israel.

Correspondence to C. Noel Bairey Merz, MD, 444 S San Vicente Blvd, Suite 901, Los Angeles, CA 90048. E-mail merz@cshs.org

	Introduction

 
A 56-year-old male physician with essential hypertension, elevated blood cholesterol, and irritable bowel syndrome underwent exercise radionuclide perfusion imaging and 24-hour Holter monitor because of palpitations at rest. The exercise perfusion test was within normal limits. During the Holter monitoring period, the subject was taking enalapril, simvastatin, and clonipine. The Holter study demonstrated no clinically significant arrhythmias. During the monitoring, the patient was awakened from sleep at 4:40 AM and told that his brother-in-law had suddenly died. The Holter ECG tracing at that time is shown in the Figure, panel A, demonstrating a sinus tachycardia heart rate elevation to 147 bpm and marked QT prolongation (400 ms), obliterating the p wave (arrow). Later the same morning, while still wearing the Holter monitor, the patient performed his usual morning aerobic exercise at 8:15 AM. The Holter ECG tracing during that time period is shown in the Figure, B. Notably, during exercise, the heart rate is again elevated to a sinus tachycardia at 150 bpm; however, the QT interval has shortened (220 ms), and clear demarcation between the T and p waves is evident (arrow). Neither strip demonstrates evidence of ST-segment depression or T-wave inversion, and the patient did not report any symptoms during either tachycardiac episode. Time duration, heart rate, and QT and QTc intervals before and after mental stress and physical exercise are shown in the Figure, C and D. Notably, mental stress triggered an abrupt heart rate elevation over 30 seconds that was not accompanied by . . . [Full Text of this Article]