Patients and Methodology
306 consecutive patients diagnosed with acute inferior MI were enrolled in this study after discharge following the review of their records. MI was diagnosed according to ACC / AHA 2012 guidelines. 32 patients were excluded due to problems in the follow-up process. In addition, patients who had a heart attack and had a previous heart attack were not included in the study. The remaining 274 patients with a median age of 56.8 ± 9.8 years and with TIMI 2-3 after PPCI were included in the study. The patients were divided into two groups as MBG 0-1 and MBG 2-3.
ECG records were taken to assess the fragmented QRS and ST segment resolution was assessed in the first hour ECG routinely taken after the procedure. A 12-lead ECG with a paper speed of 25 mm/sec was recorded in each patient at admission and 60 minutes after primary PCI. The fragmented QRS includes different morphologies of the QRS, and the S wave in two adjacent leads contains an additional R wave (R ’) or notching at the lowest end of the damaged area. The presence of fragmented QRS in 2 adjacent inferior leads (II, III and aVF) indicated myocardial scar and necrosis in the inferior region. For ST segment resolution, the largest ST segment elevation on the baseline ECG was taken as a reference for subsequent assessment of ST segment elevation. ST segment measurement was made 60 milliseconds after J point at the ST segment point. QRS duration was calculated manually according to the clinical condition of the patients and was measured from the earliest beginning to the end of the last QRS deflection. QT was defined as the interval between the beginning of the QRS and the end of the T wave. QT dispersion was calculated as the maximum QT interval minus the minimum QT interval. All ECGs were analyzed manually by a single experienced cardiologist who was blinded to this study.
Blood samples were taken from all patients and measurements were made using a standard Beckman Coulter LH 780 Analyzer.
All patients were given 300 mg aspirin and 600 mg loading dose of clopidogrel before the procedure, and intravenous heparin 10,000 U and intracoronary nitroglycerin were administered at the beginning of the procedure. The use of glycoprotein IIb / IIIa inhibitor (tirofiban) was at the discretion of the operator. First balloon angioplasty and then coronary artery stenting were performed in all patients.
All coronary angiographies were recorded using Philips AlluraXper FD 10/10 device. First balloon angioplasty and then coronary artery stenting were performed in all patients. The contrast injector was set at 4 mL/sec for the left coronary artery (8 mL bolus) and 3 mL/sec for the right coronary artery (6 mL bolus). MBG was used to assess myocardial blush during angiography (9). Myocardial blush grading was performed visually in a catheterization lab with a sinus film at a rate of 25 fps. This should have been sufficient to assess the length of the coronary angiography. In this study, coronary angiography was sufficient to see the venous phase of the contrast passage, and coronary angiography was performed with the same images as the infarct-related artery. In the assessment of MBG, a single image was selected from multiple orthogonal views to minimize overlapping of non-infarction areas. In most of the patients, right anterior oblique (RAO) was used for the right coronary artery, and laterolateral or RAO was used for the circumflex coronary artery. Two experienced cardiologists blinded to the study performed the MBG classification. The reproducibility of MBG was assessed by 2 observers who examined 40 coronary angiograms. Inter-observer and intra-observer agreement was 90% and 90%, respectively. TIMI flow grades were assessed as previously described (10) and coronary atherosclerosis density was assessed using the Gensini score (11).
Echocardiographic evaluation using the Hewlett Packard SONOS 4500 and 2.5 to 3.5 mHz transducer according to the American Echocardiographic Association criteria was performed within the first 24 hours after primary PCI by two cardiologists blinded to this study. Left ventricular ejection fraction (EF) was measured using the modified Simpson method. The study was approved by the local Ethics Committee.