Features of heart rate variability in patients with takotsubo syndrome

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Main funding source(s): North-Western State Medical University named after I.I. Mechnikov Objective to study the features of autonomic regulation of sinus rhythm features of autonomic regulation of cardiac sinus rhythm in patients with Takotsubo syndrome (TTS) during inpatient stay in hospital. Materials and methods. The study included 25 female patients (the median age 57.5 ± 28.5 years) with TTS, diagnosis was based on the InterTAK criteria. On the 5-7th day after admission, the heart rate variability (HRV) was assessed both at rest and cardiac autonomic function tests: the deep breathing test (DBT) and active orthostatic test (AOT) with the usage of a computer diagnostic system «Valenta». RESULTS According to HRV data, initially at rest, the majority of the studied patients predominantly had a parasympathetic impact on the heart rate regulation: in 70% - increased parasympathetic influence, in 17% - increased sympathetic influence, in 13% - a balanced heart rate regulation. When performing a DBT, the predominance of the parasympathetic influence on the heart rate was noted both in spectral parameters and according to the data of time analysis (HF during DBT increased 1.8 times up to 489.6 ± 114.2 ms2 (p <0.05) ; LF decreased 1.7 times up to 254.1 ± 70.3 ms2 (p <0.05); VLF increased 2.8 times up to 402.3 ± 101.8 ms2 (p <0, 05); TP increased 1.4 times up to 1145.9 ± 251.3 ms2; CV increased 1.3 times up to 6.5 ± 0.7% (p <0.05); SDNN increased 1.3 times up to - 58.7 ± 6.6 ms (p <0.05). HRV measured during an AOT showed a paradoxical evaluation in the parasympathetic impact on the heart rate (HF increased by 1.8 times and reached - 488.0 ± 104.7 ms2 (p <0.05); LF decreased by 1.1 times up to 408 , 4 ± 103.6 ms2; VLF increased 1.2 times up to 166.4 ± 52.2 ms2; TP increased 1.3 times up to 1062.8 ± 181.1 ms2 (p <0.05); CV increased 1.6 times up to 8.0 ± 0.9% (p <0.05); SDNN increased 1.4 times up to 62.6 ± 7.5 ms (p <0.05)). Conclusions During the index hospital inpatient stays the majority of patients with TTS have a vegetative imbalance due to increased parasympathetic influence on the heart rate, both at rest and during a deep breathing test and an active orthostatic test. This fact is quite unexpected and requires further study.