Objective: Takotsubo syndrome (TTS) is characterized by transient left ventricular dysfunction, often elevated myocardial enzymes, and electrocardiographic changes. Previous studies suggested that an overstimulation of the sympathetic nervous system might cause TTS. However, the pathogenesis of TTS is largely unknown. Therefore, we investigated physiological stress reactivity with a standardized stress test in monozygotic twin sisters, only one of whom had experienced TTS.
Methods: The 60-year-old Caucasian monozygotic twins, one with and one without a previous episode of TTS, were recruited in the Department of Cardiology at the University Hospital Zurich, Switzerland. We applied the Trier Social Stress Test (TSST) to investigate stress reactivity six weeks after the TTS. Hemodynamic measures (heart rate (HR), blood pressure (BP)), heart rate variability (HRV), plasma norepinephrine and epinephrine and salivary cortisol levels were collected immediately before and after the TSST, and 15, 45, and 90 min after TSST. The monozygotic twins differed in their hemodynamic stress response with the TTS twin showing blunted HR and BP reactivity and vagal withdrawal beyond the acute phase of stress. In contrast, the TTS twin showed a higher catecholamine and cortisol stress response with a steady increase in norepinephrine during the recovery period from stress compared to her non-TTS twin sister.
Conclusion: Large studies applying a case-control design are needed to confirm blunted hemodynamic reactivity, increased catecholamine reactivity, vagal withdrawal, and increased cortisol reactivity to stress in TTS. This may advance the knowledge of psychophysiological mechanisms in TTS.
Keywords: blood pressure; case report; heart rate variability; monozygotic twins; stress reactivity; takotsubo syndrome; trier social stress test.