Correlation of heart rate variability parameters and QT interval in patients after PTCA of infarct related coronary artery as an indicator of improved autonomic regulation.

UNLABELLED: The purpose of this study was to determine if PTCA of the infarct related coronary artery (IRA) in the late phase of myocardial infarction (MI) can improve autonomic regulation of sinus rhythm and electrical stability of the myocardium measured by heart rate variability (HRV), QT, QTc, and its dispersion (QTd) and if any correlation exists among these measures. The study was performed in 25 patients (21 male, age: 50 +/- 9 years, EF: 52% +/- 11%) in the late phase of MI (2.5 +/- 1.5 months). HRV parameters were calculated automatically. QT, QTc, and QTd were measured manually from a 12-lead surface ECG (50 mm/s). All measurements were made before and 3-5 days after PTCA. Day and night parameters of HRV were sampled over two periods: 2 pm to 10 pm (day) and 10 pm to 6 am (night). Parameters of HRV measured from whole recordings were significantly higher after successful PTCA: SDRR (116 +/- 31 vs 128 +/- 38 ms), SD (55 +/- 17 vs 62 +/- 22 ms), rMSSD (30 +/- 13 vs 36 +/- 14 ms) and HF (246 +/- 103 vs 417 +/- 224 ms2). Significant differences were found during daytime for SD, rMSSD, and HF, and during nighttime for SDRR, SDANN. QT interval duration, QT corrected to the heart rate, and QT dispersion were significantly lower after PTCA (QTd: 54 +/- 15 vs 39 +/- 12 ms). There was no correlation between HRV and QT values before PTCA. High correlations were found after the procedure, particularly between QTd and nighttime HRV. CONCLUSIONS: PTCA of IRA in the late phase of MI enhances sympathovagal regulation of the cardiac rhythm and the electrical stability of the heart, which may be prognostically important.

[Left ventricular systolic function after PTCA--recent and late assessment by exercise echocardiography]. / Funkcja skurczowa lewej komory po plastyce tetnicy wiencowej--wczesna i odlegla ocena metoda echokardiografii wysilkowej.

The purpose of this study was to determine whether global and segmental left ventricle (LV) systolic function, assessed by exercise echocardiography (EE), improves after PTCA in patients without previous myocardial infarction (MI) and after infarction and angioplasty of infarct related coronary artery. 32 patients without MI and 35 patients with previous (4 +/- 3 months) MI were examined before PTCA (percutaneous transluminal coronary angioplasty), 3-5 days after successful elective PTCA and 6 months later with EE (modified Bruce protocol). LV ejection fraction (EF) and wall motion score index (WMSI) at the baseline and immediately after exercise were assessed. Following angioplasty (after 3-5 days and 6 months later), exercise duration was significantly (p < 0.001) increased in both groups of patients. Resting EF and WMSI did not change after angioplasty of infarct-related artery, but in patients without prior MI resting EF increased (p < 0.001) after PTCA in comparison with pre-PTCA values. Significant improvement of exercise EF and WMSI were observed in both groups of patients. In 25 of 35 patients with old MI wall motion improvement in the infarcted region after PTCA was observed. Twenty of these 25 patients developed exercise-induced akinesia in this area during pre-PTCA EE. Among 10 patients without improvement of the regional contractility were 9 after type Q-wave infarction and only 2 developed angina during EE. These data demonstrate improvement in global and regional systolic LV function and better exercise tolerance following successful PTCA both in patients without prior MI and with old MI after angioplasty of a stenosis in an infarct-related coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

[PTCA and left ventricular systolic function (evaluation by exercise two-dimensional echocardiography)]. / Przezskórna plastyka tetnic wiencowych a funkcja skurczowa lewej komory (ocena metoda echokardiografii wyslkowej).

Successful transluminal coronary angioplasty (PTCA) should improve left ventricular systolic function. To assess the effect of this procedure 25 patients with coronary heart disease were examined before and 3-to 5 days after successful PTCA with electrocardiographic treadmill exercise test, and exercise two-dimensional echocardiography (modified Bruce protocol). Echocardiographic examination was obtained prior to and immediately following exercise. Left ventricular ejection fraction and segmental wall motion at the baseline and immediately after exercise were assessed. Electrocardiographic evidence of ischemia was found in 16 of 25 patients prior to PTCA and in 9 patients after PTCA. Following angioplasty, exercise duration was increased and the exercise-induced angina rate was significantly decreased. Ejection fraction did not change significantly in patients prior and after PTCA (52 +/- 10% versus 55 +/- 16%, p = NS). Following angioplasty, ejection fraction increased from 55 +/- 10% (rest) to 64 +/- 11% (exercise) (p less than 0.001). New exercise-induced echocardiographic segmental wall motion abnormalities were found in 16 of 25 patients prior to PTCA and in only one patient following PTCA. Significant improvement of ejection fraction and segmental wall motion were also observed in 11 patients with old myocardial infarction subjected to successful angioplasty of infarct-related coronary artery. Opposite to post-exercise results, the resting mean values of these echocardiographic parameters did not differ significantly between pre and post-PTCA examinations. These data demonstrate an improvement in systolic left ventricular function and better exercise tolerance following successful PTCA. This occurs also in patients with old myocardial infarction after angioplasty of infarct-related coronary artery. Two-dimensional exercise echocardiography may be helpful in assessing the early results of successful angioplasty.

[Late right and left ventricular potentials using inter-cardiac recording in patients with ischemic heart disease--methodologic and clinical problems]. / Opóznione potencjaly prawo- i lewokomorowe rejestrowane z wnetrza serca u chorych z choroba niedokrwienna serca--problemy metodologiczne i kliniczne.

The aim of the study was to compare detection frequency of late inter-cardiac potentials recorded from the right and left ventricle. There was also estimated relationship between their incidence and ventricular tachycardia or fibrillation occurrence. 41 patients with ischemic heart disease underwent the study. Electrophysiologic examination were performed because of ventricular tachycardia and/or fibrillation attacks or complex ventricular arrhythmias recorded in ECG Holter monitoring. In 11 patients intracardiac electrocardiograms were recorded from both ventricles, in 29 only from the right and in 1 from the left one. All patients underwent programmed right and/or left ventricular stimulation. Left ventricular end-diastolic diameter, segmental contractility and ejection fraction were echocardiographically estimated. Study results were statistically analyzed by means of CHI2 and t-Student tests for unpaired variables. Late potentials were more frequently observed in patients with left ventricular dyskinesis (p less than 0.01) and decreased ejection fraction. Late potentials recorded in patients with a history of ventricular tachycardia or fibrillation were more delayed to proceeded QRS complex and had a greater amplitude. This prolongation of ventricular activation can make an anatomic substrate for dangerous ventricular arrhythmias occurrence. Since the presence of late potentials in patients with contractility disorders is connected with more frequent incidence of spontaneous and provoked ventricular arrhythmias, endocardial late potentials recording may be of a prognostic value, if it is performed from both ventricles.