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[Inhomogeneity of myocardial depolarization and repolarization in patients with chronic ischaemia undergoing coronary angioplasty].

AIM
The purpose of the study was to assess selected parameters of myocardial depolarization and repolarization, as well as other SCD risk factors before and after coronary angioplasty (PCI), especially in patients (pts) with increased risk of SCD.


METHODS
50 consecutive pts undergoing successful coronary angioplasty (39 men, 11 women, mean age 54 +/- 9.9 yrs) were included. Before PCI and 19.6 +/- 4.3 days after the procedure parameters of signal averaged ECG, QTd, heart rate variability--HRV, late potentials--LP and ejection fraction (LVEF) were assessed. Pts having at least one of the following: increased QTd (>80 ms), present LP, depressed HRV (SDNN <70 ms), significant ventricular arhythmia--VA (>10/h, >10 couplets/24h, VT), depressed LVEF (40%) were defined as having increased risk of SCD.


RESULTS
38 pts (76%) before PCI had increased risk of SCD. Increased QTd was observed in 46% pts, positive LP in 44% pts, depressed HRV in 20% pts, significant VA was present in 24% pts and depressed LVEF in 30% pts. After PCI there was a significant improvement in parameters of signal averaged ECG, especially in pts with LP present before PCI (QRS decreased from 120.8 +/- 25 to 100.4 +/- 19.4 ms, LAS from 57.3 +/- 23.8 to 37.7 +/- 15.3 ms, RMS40 increased from 9.3 +/- 5.8 to 26.8 +/- 22.1 ms; p < 0.005). In pts with increased risk similar improvement was seen in QT dispersion (decreased from 79.4 +/- 14.4 to 54.9 +/- 17.5 ms; p < 0.0005), in measures of autonomic tone (SDNN increased from 80.8 +/- 17.6 to 109.3 +/- 22.0 ms; p < 0.05) and in LVEF (increased from 45.7 +/- 10.3% to 50.6 +/- 10.9% p < 0.00005). In 15 (30%) patients with depressed LVEF there was no significant improvement in LP, QTd, HRV and VA.


CONCLUSIONS
Delayed ventricular activation, inhomogeneous ventricular repolarization, abnormal autonomic control and significant ventricular arrhythmia are common in pts currently undergoing PCI. There is a significant improvement in arrhythmia triggering factors after successful coronary angioplasty, except in pts with depressed LVEF.