gms | German Medical Science

A goal was to compare the arrhythmogenicity parameters in patients with previous myocardial infarction, depending on whether cardiac rehabilitation was performed or not. Two parameters were assessed: QT dispersion and QRST isointegral maps polarity, using 87-lead BSPM Fukuda Denshi system.

Material and methods: A study group consisted of 67 patients (age range: 47–72 years) with previous MI, treated with CABG, which was divided to the two subgroups: A – 34 patients subjected to 6-month cardiac training and B – 33 patients under permanent medical care, but not rehabilitated. The echocardiography data were: EF, 58.1±1.4%; LFDD, 53.1±0.4 mm; LVMI, 95.2±3.3 g/m2. Results: In the MI patients who underwent rehabilitation QT dispersion (dQT) decreased significantly: 77.5 ms vs 65.9 ms (p<0.01), whereas in the second group of MI patients, without rehabilitation, dQT was statistically unchanged: 76.8 vs 75.4 ms (NS). QRST isointegral maps were registered during sinus rhythm and nondipolarity (>2 extrema) was searched, using visual inspection. Initially, in A group, the mean extrema number was 5.3±2.9, similarly to B group: 5.2±2.6. As a result of rehabilitation, the extrema number decreased in A group from 5.3±2.9 to 4.1±1.8; in 5 of the patients QRST maps reversed to dipolar distribution. In A group, also median of QTd delta was assigned. Above the median, the mean QTd delta was –21.4±2.1 ms, and below the median –4.7±1.1 ms. The all patients, in whom polarity of QRST maps was reduced, fell into the range above the median. Contrarily, in the group B, not subjected to training, polarity of the QRST maps did not change significantly (5.2±2.6 vs 5.1±2.3).

Conclusion: Tendency of QT dispersion and QRST maps mutipolarity diminishing, observed in the MI patients subjected to cardiac rehabilitation, reflect a beneficial effect of physical training on heterogeneous repolarization, which reduces a risk of arrhythmia occurrence.