Heart rate turbulence in patients with previous myocardial infarction and history of malignant ventricular arrhythmias— with regard to left ventricle function

Abstract

Background: There is little information regarding the dynamics of electrocardiogram (ECG) parameters during any relaxation technique in post–myocardial infarction patients. We sought to determine whether there are any distinctive dynamics in ECG parameters variability during 2 different relaxation techniques. Methods: Twenty hospitalized men (age, 58.00 ± 7.07 years) participated in 2 laboratory sessions in which they practiced mindfulness body scan meditation (MBSM) and progressive muscular relaxation (PMR). A computerized ECG analysis system “Kaunas-load W03,” developed by the Institute of Cardiology of Kaunas Medical University, was applied for 12-lead ECG recording and analysis. Electrocardiogram was recorded for 30 minutes lying quietly: 5 minutes before, 20 minutes during, and 5 minutes after each performed technique. Participants listened via headphone to audiorecorded relaxation instructions: first practiced MBSM, during the second session participants practiced PMR. The dynamics in variability of durational indices (RR, dJT, dQRS) and amplitude indices (aR, aST1, aT1) were analyzed. All the data are presented as mean ± SEM. Results: Both relaxation techniques produce significant changes in analyzed ECG parameters. These changes in high-, low-, and very-low-frequency bands are significantly different from those produced by a period of just lying quietly. Total RR variability during MBSM increased 98.25 ± 20.72 ms, during PMR 107.25 ± 58.05 ms. Total dJT variability increased 16.8 ± 4.88 ms during MBSM and 19.8 ± 6.51 ms during PMR. Accordingly, total variability of dQRS increased 6.15 ± 1.48 and 11.55 ± 3.32 ms, with aR of 50.75 ± 10.96 and 101.75 ± 15.91 ms, aST1 of 22.15 ± 1.06 and 37.1 ± 7.78 ms, aT1 of 10.45 ± 3.01 and 19.8 ± 6.15 ms. Conclusion: Both relaxation techniques increase the variability of analyzed ECG parameters. The results indicate similarities in the ECG parameters variability responses to 2 different relaxation techniques.