The effect of deep breathing test on heart rate variability in obese and non-obese patients with myocardial infarction

Introduction and Aim:Obesity and metabolic syndrome increases the risk of cardiovascular diseases (CVD).The acute myocardial infarction may be associated with autonomic dysfunction and it may have a bearing on the prognosis. The objective of the study wasto examine the effect of deep breathing test on heart rate variability in obese and non-obese patients with myocardial infarction (MI).   Materials and Methods:The patients with acute myocardial infarction were confirmed by universal definition and treatment was administered. At 12 weeks of follow up, the MI patients were screened and divided into two groups. 30 patients of MI with BMI 25 to 30 kg/m2 formed the obese group.30 patients of MI with BMI 18.5 to 24.9 kg/m2 formed the non-obese group. The baseline ECG was taken for 5 minutes by using Niviqure B3 machine for HRV analysis. Then, deep breathing test (DBT) was performed in a standardized manner.   Results:The two groupswere well matched for the age (53.7±11.5 vs.55.2±9.2years).In the baseline there was a statistically significant decrease in the total power (TP) of the heart i.e., HF plus LF (2178±762ms2 vs2991±771ms2 with a ‘p’ value 0.001) in the obese group when compared to non-obese group. On DBT there was a significant decrease in heart rate (81bpm to 65bpm) in non-obese group. However, in obese group there was no significant decrease in heart rate (79bpm to 72bpm) on DBT.   Conclusion: Accordingly, we concludethat in obese patients with MI there is a reduction in respiratory vagal modulation of heart rate during DBT.