Andrzej Cieśliński

QT Interval Dispersion as a New Marker of Restenosis after Percutaneous Transluminal Coronary Angioplasty of Isolated Single-Vessel Coronary Artery Stenosis

Background: There are no reliable non-invasive markers of restenosis after percutaneous transluminal coronary angioplasty (PTCA). The aim of our study was to measure changes in QT interval dispersion after PTCA and to determine whether restenosis subsequently affects QT interval dispersion. Methods and Results: Fifty-six consecutive patients – 41 men and 15 women (mean age: 56.2 ±8.3 years) – with isolated stenosis of the left anterior descending artery who underwent successful PTCA were studied. A symptom-limited treadmill exercise test was performed within 7 days after PTCA and then again before repeated angiography. Repeated coronary angiography revealed restenosis in 15 patients (26.8%) and no signs of significant stenosis in 41 patients (73.2%). QT interval dispersion in the group of patients with restenosis measured before exercise increased from baseline 34 ± 7 to 49 ± 15 ms after 6 months (p < 0.01) and QT interval dispersion measured immediately after exercise increased from baseline 38 ± 4 to 68 ± 21 ms after 6 months (p < 0.001). In contrast, patients without restenosis showed no significant changes in QT interval dispersion measured before (baseline: 34 ± 9 ms; after 6 months 33 ± 12 ms; p = NS) and immediately after exercise (baseline: 34 ± 12 ms; after 6 months: 33 ± 10; p = NS). When QT interval dispersion ≧60 ms (measured 6 months after PTCA procedure) was considered as a potential marker of restenosis, this indicator had very high sensitivity and specificity when measured immediately after exercise (80 and 95% respectively). Conclusions: QT interval dispersion significantly increases in the group of patients with documented restenosis and may be a simple, non-invasive marker of restenosis. However, further studies are needed to confirm this observation.

Correlation of ST-segment depression during ambulatory electrocardiographic monitoring with myocardial perfusion and left ventricular function

To assess the relation between silent ischemia and objective markers of ischemia we compared ambulatory electrocardiographic (AECG) monitoring, exercise stress testing, and technetium-99m methoxyisobutyl isonitrile single-photon emission computed tomography (SPECT) in 68 patients with coronary artery disease. ST-segment depression at AECG monitoring occurred in 40%, exercise testing was positive in 88%, and SPECT was abnormal in 98% of patients. Patients with ST-segment depression had a higher incidence of 3-vessel disease (70% vs 45%, p = 0.04), shorter duration of exercise (267 +/- 109 vs 416 +/- 167 seconds, p < 0.01), lower workload achieved (5.1 +/- 1.9 vs 7.6 +/- 2.8 METs, p < 0.0002), and a greater extent of ischemia at scintigraphy (p = 0.01). Patients with a total ischemic time of >30 minutes in a 24-hour period had a lower ejection fraction (48 +/- 21% vs 70 +/- 9%, p = 0.001), a higher perfusion index at rest (2.4 +/- 0.6 vs 1.6 +/- 0.6, p = 0.001), and a greater number of segments with fixed perfusion defects (4.1 +/- 3.7 vs 1.3 +/- 1.8, p = 0.02) in comparison with those who had a shorter ischemic time. We conclude that AECG monitoring fails to identify a substantial proportion of patients with objective markers of ischemia; however, ST-segment depression reflects more significant disease. Longer total ischemic time correlates with the area of myocardial damage but not with other markers of ischemia.

Restoration of Mechanical Atrial Function after Electrical Cardioversion of Chronic Atrial Fibrillation in Patients after Surgical Treatment of Mitral Valve Disease – Hemodynamic Effects and Prognostic Value of Maintenance of Sinus Rhythm

There are controversies regarding the possibility of returning of A wave (mitral flow at left atrial contraction) after electroconversion (EC) in patients with persisting chronic atrial fibrillation in spite of successful surgical treatment of mitral valve disease. Twenty-four hours before successful EC, thereafter daily for 1 week and then on the 14th, 21st and 28th day and 6 months after EC, ECG, M-mode, two-dimensional and Doppler echocardiography were performed in 55 patients. A wave (>0.1 m/s) appeared on the 1st day in 31 patients, on the 2nd day in the next 6, on the 3rd in 5 patients, on the 4th and 5th days in 1 patient and on the 7th day in 4 patients. In 7 patients A wave did not restore. Maximum velocity of A wave increased from 0.48 +/- 0.22 to 0.86 +/- 0.28 m/s (p < 0.05) during the follow-up. In 92% of patients with A wave 24 h after EC, significant increases in stroke index from 35 +/- 12 to 47 +/- 15 ml/m2 (p < 0.04), ejection fraction from 46 +/- 9 to 55 +/- 8% (p < 0.01) and pulmonary acceleration time from 94 +/- 26 to 107 +/- 22 ms (p < 0.05) were observed. Sinus rhythm was still present on the 28th day in 34 patients (62%) and after 6 months in 31 patients (57%), all of them with A wave. observation shows the increase in pulmonary acceleration time, the decrease in the left atrial area and the increase in its systolic function in patients with A wave. Appearance of A wave determined the hemodynamic improvement, but we did not observe a correlation between maximal velocity of A wave and hemodynamic improvement. Appearance of A wave had a low predictive value for maintaining sinus rhythm (sensitivity 58% and specificity 45%). Relative increase in A wave velocity during the 1st week after EC correlated positively with long-term maintenance of sinus rhythm (r = 0.62; p < 0.001).