Prognostic implications of muscle sympathetic nerve activity in takotsubo syndrome
I Leontsinis, M Mantzouranis, E Dri, A Sakalidis, S Soulaidopoulos, N Kazarian, I Dalakouras, C Fragkoulis, K Kasiakogias, K Dimitriadis, D Tsiachris, C Chrysochoou, K TsioufisAbstract
Introduction
Takotsubo syndrome (TTS) is characterized by marked heterogeneity in clinical presentation and outcomes, while its underlying pathophysiological mechanisms remain incompletely defined. Growing evidence implicates sympathetic nervous system activation as a key contributor to TTS development.
Purpose
To investigate whether sympathetic nervous system activity, assessed by microneurography-derived muscle sympathetic nerve activity (MSNA), is associated with long-term prognosis after an episode of TTS.
Methods
SYMPATAC is a prospective observational study evaluating the relationship between autonomic nervous system indices and subsequent functional or structural cardiac changes, as well as their prognostic significance. Thirty consecutive patients with confirmed TTS were included after exclusion of alternative diagnoses by cardiac magnetic resonance imaging. MSNA recordings were obtained during the subacute phase of TTS (days 1–14 after the acute event). Follow-up assessment at 12–24 months included echocardiography, 24-hour ambulatory heart rate monitoring, and ambulatory blood pressure monitoring.
Results
In most patients, MSNA values were higher at follow-up compared with subacute-phase measurements. No significant association was observed between change in left ventricular ejection fraction (ΔLVEF) and change in MSNA (ΔMSNA) (Spearman’s ρ = 0.226, p = 0.229). MSNA changes were not related to clinical outcome or type of triggering stressor (emotional, physical, or absent). However, higher baseline MSNA, expressed as bursts/min, was significantly associated with vascular adverse events at follow-up, including acute coronary syndromes and stroke, but not with heart failure events (p = 0.047).
Conclusion
A signal was observed between changes in MSNA and left ventricular functional recovery and prognosis, although statistical significance may have been limited by the small sample size. Higher baseline MSNA may identify a subgroup of patients with Takotsubo syndrome at increased risk for vascular adverse events.