CARDIOVASCULAR AUTONOMIC FUNCTION IN ASTHMA: A STUDY IN EASTERN INDIA

Introduction: Any abnormality in the autonomic control of the airway can result in bronchospasm, airway edema and excessive mucous secretion, which are characteristic of bronchial asthma. There is scarcity of literatures on cardiovascular autonomic dysfunction in asthma. Some of the studies have suggested increased vagal drive while others have reported sympathetic dominance to the heart. Aims: Evaluation of cardiovascular autonomic function in asthma by simple non-invasive tests Methods: A case control study was carried out involving 18-50 yrs old previously diagnosed asthma patients and same number of age and sex-matched controls. Electrocardiogram (ECG) and blood pressure were obtained from multi-parameter monitor (BPL Excello). Parasympathetic function was evaluated by heart rate response to Valsalva maneuver (Valsalva ratio), heart rate response to deep breathing for 1 minute and heart rate response to standing (30:15 ratio). Sympathetic function was assessed by blood pressure response to standing and sustained hand-grip test (HGT). HGT was performed using a handgrip dynamometer (Inco, Ambala, India, 0-60 kg). Mann Whitney test and Spearman’s test were used for data analysis. P value less than 0.05 was considered significant. Results: Out of 39 patients, 17 were female. Asthma patients had significantly higher systolic and diastolic blood pressure (DBP). 30:15 ratio and DBP change in response to HGT were significantly lower in patients compared to controls. Twenty three patients (59%) had at least one abnormal or two borderline test results indicating autonomic impairment. Conclusion: Autonomic dysfunction is common in asthma with affection of bothparasympathetic and sympathetic components.