Assessment of cardiac autonomic functions by heart rate recovery, heart rate variability and QT dynamicity parameters in patients with acromegaly

Abstract

Cardiovascular complications are the most common causes of morbidity and mortality in acromegaly. However, there is little data regarding cardiac autonomic functions in these patients. Herein, we aimed to investigate several parameters of cardiac autonomic functions in patients with acromegaly compared to healthy subjects. We enrolled 20 newly diagnosed acromegalic patients (55% female, age:45.7 ± 12.6 years) and 32 age- and gender-matched healthy subjects. All participants underwent 24 h Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting 1st, 2nd and 3rd minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV) and QT dynamicity analysis. Baseline characteristics were similar except diabetes mellitus and hypertension among groups. Mean HRR1 (29.2 ± 12.3 vs 42.6 ± 6.5, p = 0.001), HRR2 (43.5 ± 15.6 vs 61.1 ± 10.8, p = 0.001) and HRR3 (46.4 ± 16.2 vs 65.8 ± 9.8, p = 0.001) values were significantly higher in control group. HRV parameters as, SDNN [standard deviation of all NN intervals] (p = 0.001), SDANN [SD of the 5 min mean RR intervals] (p = 0.001), RMSSD [root square of successive differences in RR interval] (p = 0.001), PNN50 [proportion of differences in successive NN intervals >50 ms] (p = 0.001) and high-frequency [HF] (p = 0.001) were significantly decreased in patients with acromegaly; but low frequency [LF] (p = 0.046) and LF/HF (p = 0.001) were significantly higher in acromegaly patients. QTec (p = 0.009), QTac/RR slope (p = 0.017) and QTec/RR slope (p = 0.01) were significantly higher in patients with acromegaly. Additionally, there were significant negative correlation of disease duration with HRR2, HRR3, SDNN, PNN50, RMSSD, variability index. Our study results suggest that cardiac autonomic functions are impaired in patients with acromegaly. Further large scale studies are needed to exhibit the prognostic significance of impaired autonomic functions in patients with acromegaly.

Akromegalia może wiązać się z zaburzeniami rozkurczu dolnego zwieracza przełyku (LES)

“…LES is also stimulated by postganglionic sympathetic nerves, although vagal innervation is responsible for the main regulator action. Previous studies showed sympathetic hypertonia indicating sympathovagal imbalance in acromegaly patients [19]. In our study, the decreased percentage and duration of LES relaxation in acromegaly patients could be related to sympathovagal imbalance due to sympathetic hypertonia and decreased NO levels, which contribute to the impairment of relaxation and increase of LES basal tone in acromegaly [23].…”

“…Plausible mechanisms have been elucidated that might explain gastrointestinal motility alterations in acromegaly, and the underlying pathogenesis remains unclear. Motility disorders in acromegaly could be linked to the presence of autonomic dysfunction, similar to that which have been previously demonstrated in the cardiovascular system [8,19,20]. LES is comprised of smooth muscle, and vagal efferent nerve induces its relaxation mediated by NO, which is the main neurotransmitters in the gastrointestinal tract [21][22][23].…”

The Evaluation of QT Intervals During Diagnosis and After Follow-Up in Acromegaly Patients

“…15 The determination of clinical predictors of cardiac arrhythmias is important in patients with acromegaly. In literature, the number of studies showing lengthened QT intervals in patients with acromegaly is uncommon.…”

Impact of Successful Treatment of Acromegaly on Overnight Heart Rate Variability and Sleep Apnea

“…HRV is defined as the spontaneous fluctuations in the electrocardiographic (ECG) RR interval, generally studied in both the time and frequency domains (5)(6)(7)(8). To the best of our knowledge, only two HRV studies have focused on acromegalic patients (9,10). The authors found evidence of an impaired sympathovagal balance in acromegaly but reached opposite conclusions (9,10).…”

“…The authors found evidence of an impaired sympathovagal balance in acromegaly but reached opposite conclusions (9,10). Increased parasympathetic modulation of the heart rate was initially suggested, with no difference between patients with controlled and uncontrolled acromegaly (10), but a very recent study showed higher sympathetic tone over 24 hours in newly diagnosed acromegalic patients (9).…”