Hyperacute Myocardial Infarction and One Minute Heart Rate Variability Test

We evaluated the use of a simple, bedside test of 1-minute heart rate variability (HRV) during deep breathing as a prognostic index after hyperacute myocardial infarction (MI). Bedside HRV was assessed in 50 patients who were hospitalized due to hyperacute MI (Group I) and 50 age and sex matched control subjects without ischemic heart disease (Group II). Patients and control subjects were instructed to take 6 deep respirations in 1-minute while changes in RR intervals were measured and calculated by an electrocardiographic recorder (50 mm/sec velocity). The shortest and longest RR interval was calculated manually; HRV was defined as the difference between the longest and shortest RR interval. HRV in group I was significantly less than group II (144±101 msec vs 278±152 msec, p<0.0001). In group I, there was a strong linear correlation of HRV with left ventricular ejection fraction (p<0.05, r= 0.876); HRV in patients with acute pulmonary edema was significantly less than in patients without acute pulmonary edema (24±25 msec, 178±86 msec, p<0.0001). HRV in patients with anterior MI was significantly less than in patients with inferior MI (94±78 msec, 195±96 msec, p=0.001). Decreased one minute HRV test is associated with presence of acute pulmonary edema, anterior MI and depressed ejection fraction.