SYMPATHOVAGAL IMBALANCE IN TAKOTSUBO CARDIOMYOPATHY

Abstract

Takotsubo cardiomyopathy is an acute reversible cardiac dysfunction syndrome associated with high circulating catecholamine levels. Our objective was to investigate whether abnormal cardiovascular control might play a role in the pathophysiology.We studied autonomic cardiovascular reflexes in 10 women who had takotsubo (33±7 months after being hospitalized) and 10 age/BMI matched healthy women.In the women with takotsubo, indices of vagal modulation of heart rate induced by respiration were uniformly reduced (expiratory:inspiratory ratio: p<0.01, pnn50%: p<0.02, rMSSD: p<0.03). Cognitive (stroop test: p<0.03) and emotional arousal (event recall: p<0.05) produced exaggerated pressor responses, without detectable ECG changes. Pressor responses to hemodynamic stimuli were also amplified (Valsalva SBP overshoot: p<0.05). Takotsubo women had increased BP variability in the short‐term (St. Dev. SBP: p<0.01). Ambulatory recordings captured an exaggerated morning surge in SBP after awakening from sleep (p<0.05). Cardiovagal baroreflex gain was significantly lower in the takotsubo women (sequence analysis: p<0.01, regression method: p<0.001, transfer function gain: p<0.001).Women with takotsubo have heightened sympathetic responsiveness, labile BP and reduced vagal modulation of the heart. This shift in sympathovagal balance could play a role in the pathophysiology.