Strong Emotions Could Lead to Sudden Cardiac Arrest

A new study claims that physiological changes brought on by anger and other types of mental stress can trigger potentially lethal ventricular arrhythmias.

Researchers at Yale School of Medicine (New Haven, CT, USA) studied 62 patients with implantable cardioverter-defibrillators (ICDs) and enlarged hearts to determine if anger-induced T-wave alternans (TWA) could predict future arrhythmias. TWA was analyzed using time-domain methods; the patients were monitored three months after the ICD was implanted and then given a mental stress test requiring them to recall a stressful situation that angered them; after a one year follow-up, ICD stored data was reviewed to determine incidence of ICD-terminated ventricular tachycardia and fibrillation.

The researchers found that patients with ICD-terminated arrhythmias during follow-up had higher TWA induced by anger, compared with those patients without future ventricular arrhythmias. Patients in the highest quartile of anger-induced TWA were more likely to experience arrhythmias by one year than those in the lower quartiles (33% versus 4%) and during extended follow-up (40% versus 9%). In multivariable regression controlling for ejection fraction, prior clinical arrhythmia, and wide QRS, anger-induced TWA remained a significant predictor of arrhythmia, with likelihood in the top quartile 10.8 times that of other patients. The study was published in the March 3, 2009, issue of the Journal of the American College of Cardiology (JACC).

"Anger-induced TWA predicts future ventricular arrhythmias in patients with ICDs, suggesting that emotion-induced repolarization instability may be one mechanism linking stress and sudden death,” concluded lead author Rachel Lampert, M.D., an associate professor of medicine at Yale, and colleagues. "Further studies are needed to determine whether there is a role for therapies which may reduce anger and the body's response to stress, thereby preventing arrhythmias in those at risk.”

T wave alternans are periodic beat-to-beat variations in the amplitude of the T wave in an electrocardiogram (ECG). TWA were first described in 1908; those "large” TWAs were associated with increased susceptibility to lethal ventricular tachyarrhythmias. Most modern references to TWA refer to microvolt T-wave alternans (MTWA), a noninvasive heart test that can identify patients who are at increased risk of developing a potentially lethal cardiac arrhythmia. The ECG test looks for the presence of variation in the vector and amplitude of the T-wave component of the ECG. The amount of variation is small, on the order of microvolts, so sensitive digital signal processing techniques are required to detect TWA.

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