Evaluation of 1-minute heart rate variability during deep breathing as a prognostic indicator in patients with acute myocardial infarction

Authors:Pai N, Adhikari PMR, Madi D, Achappa B, Pai S, Unnikrishnan B
Int J Biol Med Res. 2012; 3(3): 2103-2106  |  PDF File

Abstract

Background and objective- Heart rate variability (HRV) is a noninvasive electrocardiographic marker reflecting the activity of the sympathetic and vagal components of the autonomic nervous system on the sinus node of the heart. Decreased HRV is a risk factor for both arrhythmic and non-arrhythmic deaths following acute myocardial infarction (MI) .Our aim was to find out the utility of heart rate variability (during deep breathing over 1 minute ) in predicting end point cardiac events (risk stratification) in patients after an episode of acute myocardial infarction. Material and methods- Bedside heart rate variability (HRV) during deep breathing was assessed in 100 patients after a first episode of myocardial infarction.. This test was performed between 6-48 hours after the first attack of myocardial infarction. We defined low HRV as HRV < 10 beats/minute. The patients were followed up over a duration of 3 months to document end point cardiac events. Statistical analysis was done using the student ‘t’ test . Results- Heart rate variability (HRV) < 10 beats/minute was seen in 44 (44%) patients. 16 patients died in the follow up period. Among the 16 patients who died 15 (93.75%) patients had HRV < 10 beats/minute. Conclusion- Heart rate variability (HRV) during deep breathing is a simple, cost effective bedside test in risk stratification of patients who present with myocardial infarction.