SEVERE ARTERIAL AND CHRONIC THROMBOEMBOLIC PULMONARY HYPERTENSION RESULTS IN CARDIAC AUTONOMIC NERVOUS SYSTEM DYSFUNCTION ASSESSED BY HEART RATE VARIABILITY AND HEART RATE TURBULENCE
Introduction: Severe pulmonary hypertension (PH) is associated with poor prognosis. Heart rate variability (HRV) or turbulence (HRT) impairment is an independent risk factor for malignant ventricular arrhythmias occurrence and sudden cardiac death, especially in postmyocardial infarction patients. There are limited data on HRV and HRT in PH patients.
Methods: Out of 41 PH patients, 33 subjects were enrolled in the study (25F, 8M) aged 49.7 ± 15.9 years (mean disease duration 4.85 ± 4.72 years). In 22 arterial PH and in 11 chronic thromboembolic PH was diagnosed. Most of PH patients (84.4 %) underwent right heart catheterization. Control group (CG) consisted of 25 aged-matched healthy subjects (20F, 5M). In addition to conventional evaluations, 24-hour ECG Holter monitoring with assessment of time domain HRV and HRT was performed.
Results: In PH patients mean pulmonary arterial pressure was 59.00 ± 16.58 mmHg and pulmonary vascular resistance was 11.84 ± 6.72 Wood`s units.
As compared to controls, in PH subjects time domain HRV analysis revealed significant lower values of SDNN (104.39 vs 152.12 ms, p<0.0001), SDANN (98.03 vs 138.77 ms, p<0.0001) and SDNN-I (31.82 vs 59.26 ms, p<0,0001), but not RMS-SD (28.31 vs 29.03 ms, p=0.79) and pNN50 (6.29 vs 7.83 %, p=0.33).
HRT was significantly impaired in PH patients, as compared to CG: TO was -0.27 ± 2.30 vs -2.60 ± 1.43 % (p<0.0001), and TS was 4.06 ± 4.78 vs 19.96 ± 13.61 msRR (p<0.0001). Abnormal HRT (TO 0.0% and/or TS #2.5 ms/RR) was found in 21 (63.3%) of PH patients and in nobody in CG.
Conclusion: Patients with arterial and chronic thromboembolic PH are characterized by significant impairment of HRV and HRT indicating cardiac autonomic nervous system dysfunction. The hypothesis that this imbalance could be considered as an independent risk factor for mortality in PH needs further investigation.