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

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 88-129-Acromegaly & Prolactinoma
Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-115
Muhammet Dural1, Giray Kabakci1, Nese Cinar1, Tomris Erbas*1, Ugur Canpolat2, Murat K Gurses1, Lale Tokgozoglu1, Ali Oto1, Baris E Kaya1, Hikmet Yorgun1, Levent Sahiner2, Selcuk Dagdelen1 and Kudret Aytemir2
1Hacettepe University Medical School, Ankara, Turkey, 2Hacettepe University School of Medicine, Ankara, Turkey
Background: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.

Methods:We enrolled 20 newly diagnosed acromegalic patients (11 female, 55.0%; age: 45.7±12.6 years) and 32 healhty subjects. All participants underwent 24 hours Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting first, second and third minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV) and QT dynamicity analysis.

Results:Baseline characteristics were similar except diabetes mellitus and hypertension among groups. Exercise test duration and peak exercise capacity were similar between acromegaly and control 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 (43.7 vs 81.9, p=0.001), SDANN (91.4±37.2 vs 182.1±35.1, p=0.001), RMSSD (18.6 vs 69.0, p=0.001), PNN50 (1.46 vs 33.0, p=0.001) and HF (14.0 vs 45.3, p=0.001) were significantly decreased in patients with acromegaly; but LF (63.0±16.9 vs 54.7±12.6, p=0.046) and LF/HF (4.6 vs 1.2, p=0.001) were significantly higher in acromegaly patients. Also, QTec (435.78±32.0 vs 416.9±17.0, p=0.009), QTac/RR slope (0.19±0.05 vs 0.16±0.03, p=0.017) and QTec/RR slope (0.20±0.06 vs 0.17±0.04, p=0.01) were significantly higher in patients with acromegaly. Additionally, there were significant negative correlation between disease duration and HRR2 (r=-0.65, p=0.002), HRR3 (r=-0.70, p=0.001), SDNN (r=-0.65, p=0.003), PNNN50 (r=-0.56, p=0.01), RMSSD (r=-0.53, p=0.02), variability index (r=-0.48, p=0.04).

In conclusion, we observed that cardiac autonomic functions are impaired in patients with acromegaly. Increased incidence of sudden cardiac death and arrhythmias in acromegalic patients may be explained by these results. Because of the significant relationship between derangement in autonomic functions and cardiovascular mortality indicates that the early identification of acromegalic patients at higher risk is essential. Further large scale studies are needed to exhibit the prognostic significance of impaired autonomic functions in patients with acromegaly.

Nothing to Disclose: MD, GK, NC, TE, UC, MKG, LT, AO, BEK, HY, LS, SD, KA

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm