Patients and Angioplasty Technique
The study group consisted of 34 patients, 21 men and 13 women with a mean age of 58 ±9 years who underwent proximal or mid LAD angioplasties. Inclusion required the following: (1) ST segment elevation of 1 mm or more in at least one precordial lead V, through V4 during a coronary occlusion; (2) corresponding measurements of left ventricular (LV) hemodynamics; and (3) absence of acute myocardial infarction, hemodynamic or respiratory instability; left main disease, ventricular hypertrophy, and bundle branch blocks present before or during angioplasty. All LAD lesions to be angioplastied had 70 percent or greater narrowing of the luminal diameter. The study was approved by the Institutional Review Board at Maimonides Medical Center as part of a larger prospective study to evaluate hemodynamics and ECG with coronary angioplasty. All patients gave informed written consent to participate in the study.
Patients had a right heart catheter placed via the femoral vein prior to the angioplasty procedure. Baseline hemodynamic pressures obtained were right atrial, right ventricular systolic and end- diastolic, pulmonary artery systolic and diastolic, and PW. Repeated hemodynamic measurements were obtained during coronary occlusion at the time suggestive of peak ST changes on the ECG. For the purpose of this investigation, only the data on PVVs is reported. canadian cialis
Complete 12-lead ECGs were recorded at baseline and every 30 to 45 s during coronary occlusion using a paper speed of 25 mm/s and a standardization of 10 mm per 1 MV. Precordial leads were monitored by use of radiolucent electrodes. The ECG most closely associated with the hemodynamic measurements was used for analysis. R-wave amplitude was measured as the vertical distance from the PR segment to the peak of the R wave; S-wave amplitude was measured as the vertical distance from the PR segment to the peak of the S wave. Determination of the magnitude of ST segment elevation was made at the J point with the PR segment as the baseline. All measurements were performed manually to the nearest 0.5 mm. Analyzed were R- and S-wave changes and ST elevations in the anterior precordial leads (V, through V4), in the precordial lead with the most prominent ST elevations, and in lead V5.
Data are expressed as means and SDs in the text and means and SE in the figure. Students two-tailed t tests were used to study the statistical significance between baseline and occlusion hemodynamics. Linear regression analysis was used to correlate changes in R and S waves to ST elevations, and changes in R and S waves and ST elevations to changes in PW. Statistical significance was assumed when p<0.05. tadalis sx