Introduction: Ventricular arrhythmias are one of the most dangerous complications of ischemic heart disea-se. Ventricular tachycardia (VT) may occur frequently in patients with previous myocardial infarction (MI), both in the acute phase and long after acute ischemic injury. A favorable substrate for TV appearance is changes induced by left ventricular (LV) remodeling, including impaired systolic function, manifested by re-duction of the ejection fraction (EF), enlargement of LV and left atrium (LA), development of valvular re-gurgitation, especially of mitral valve (MV).
Objective: The purpose of this study was to highlight the particularities of electrocardiographic Holter mo-nitoring (Holter ECG) corresponding to echocardio-graphic parameters in patients with with late postin-farction ventricular tachycardia.
Methods: The study included 62 patients who develo-ped a documented VT event 6 weeks after an acute MI. The examinations included: the ECG Holter monito-ring with evidence of ventricular disturbances, espe-cially ventricular extrasystoles (VE) and heart rhythm variability (HRV) – SDNN – standard deviation of NN intervals (NN intervals – interbeat intervals from whi-ch artifacts have been removed, SDANN -standard deviation of the average NN intervals for each 5 min segment of a 24 h HRV recording, RMSSD – root mean square of successive NN interval differences; the echo-cardiographic examination with the assessment of the dimensions and volumes of the heart cavities; LV EF, MV regurgitation.
Results: Compared to patients with LV EF >35%, those with a pump function ≤35% had a higher percentage of ventricular extrasystoles (VE) (4.3 ± 1.1% vs. 3.4 ± 0.96%) and more ventricular bigeminism events (80% vs. 66.7%). EF ≤35% resulted in a moderate reducti-on for SDNN value (109.8 ± 35.2 ms vs. 121.3 ± 35.0 ms) and for SDANN (93.8 ± 27.2 ms vs. 109.0 ± 32.1ms). The LV telediastolic diameter (LVTDD) >58 mm was associated with approximately 2 times greater VE percentage – 4.8 ± 1.3% vs. 2.7 ± 4.8% in those with LVTDD ≤58 mm and with multiple cases of VE run (29% vs. 16.7%). Of the HRV indicators, the highest di-fferences were attested for SDANN – 96.2 ± 5.7 ms vs. 110.5 ± 6.6 ms. Similar characteristics were presented according to the degree of MV regurgitation – d. III-IV vs d. I-II, advanced mitral regurgitation being associa-ted with a double VE rate – 5.3 ± 1.6% vs. 2.7 ± 0.6%. The most significant reduction of HRV was attested for SDANN – 95.0 ± 6.7 ms vs. 109.3 ± 5.8 ms. LA volume >64 ml was associated with more VE / 24 hours (4.4 ± 1.4% vs. 2.7 ± 0.6%), HRV being comparable. Increased LA area > 32 mm2 confirmed an increased percentage of VE 6.0 ± 2.1% vs. 2.4 ± 0.6%. In HRV temporal in-dicators the highest difference was attested to RMSSD – 32.1 ± 3.8 ms vs. 43.2 ± 5.0 ms.
Conclusions: Evaluation of ventricular events and HRV during the Holter monitoring in patients with late postinfarction ventricular tachycardia correspon-ding to some echocardiographic parameters (LV EF, LV TDD, MV regurgitation d. III-IV, LA volume or area) has shown that their change is associated with a higher percentage of ventricular events and lower values of heart rhythm variability.