The relationship between fragmanted QRS complex, terminal ST changes and angiographical findings in patients with acute ST elevated miyocardial infarction

Introduction and Aim: QRS fragmentation (fQRS) and QRS distortion were seperately showed to be related with increased morbiditiy and mortality in patients with acute myocardial infarction. To our knowledge there is no study in literature evaluating these two parameters together in acute STEMI. Aims of our study are to determine factors affecting fQRS and QRS distortion development in patients diagnosed with acute STEMI for the first time, compare these parameters with clinical and angiographical findings and to find out whether patients with high risk profile can be determined by this way. Methods: 248 patients who admitted to Dokuz Eylül University Cardiology department with acute STEMI for the first time between 01 Januray 2009 and 01 July 2011 were included in our study and data was evaluated retrospectively. Demographical features, routine laboratory parameters were obtained. 116 patients were treated with thrombolytic therapy and 132 patients were treated with primary PCI. Results of 12 derivation ECG taken in 48 hours were evaluated and analysed for fQRS presence and QRS distortion. Also coronary angiography images were evaluated to determine infarct related artery, lesion localisation and number vessels with crtical stenosis (>70%). Findings: Fragmanted QRS was found in total of 91 (36.7%) patients and QRS distortion in 98 (39.5%) patients. Infarct localisation and infarct related artery distribution did not differ between patients with fragmented QRS and patients without it (anterior infarction: 38,5% vs 45,2%; p=0.3), (LAD: 37.4% vs 45.9 %, CX: 12.1% vs 12.1%, RCA: 50.5% vs 42%; p=0.387). However patients with fQRS were found to have more frequent proximal segment lesions (81.3% vs 38.2%; p<0.001) and more frequent three vessel disease (61,5% vs 14,6%; p<0.001). Additionally patients with fragmented QRS were determined to have lower left ventricular ejection fraction (35±7% vs 47±6%; p<0.001), higher leukocyte counts (12.958±3.07 vs 10.780±3.38; p<0.001), higher maximum troponin levels (62.73±53.49 vs 29.71±16.17; p<0.001), longer QRS durations (107.86±8.95 msn vs 102.77±9.21 msn; p<0.001) and lower ST segment resolution ratios (46.31% ±20.42 vs 70.16% ±13.53; p<0.001) Failed thrombolysis was found higher (40% vs 4.2%; p<0.001) and number of stents used were lower (0.75±0.66 vs 1.10±0.55; p<0.001) in patients with fragmented QRS. When patients with QRS distoriton were comapred with patients without it, no significant difference between infarct localisation (anterior infarction: 45.9% vs 40.7%; p=0.414) and infarct related artery distribution (LAD: 45.9% vs 40.7%; CX: 9.2% vs 14%; RCA: 44.9% vs 45.3%; p=0.467) was observed. Besides patients with QRS distortion, same as the fQRS phenomenon, had more frequent proximal lesion localisation compared to patinets without QRS distortion (68.4% vs 44.7%; p<0.001), but presence three vessel disease did not differ between two groups which was contradictory to fQRS findings (33.7% vs 30.7%; p=0.619). Also patients with QRS distortion were found to have lower left ventricular ejection fraction (39±9% vs 45±8%; p<0.001), higher maximum troponin levels (54.54±52.55 vs 33.54±21.22; p<0.001), higher number of derivations with ST segment elevation (5.57±1.62 vs 4.55±1.44; p<0.001), higher ST segment deviation scores (19.42±9.87 mm vs 13.18±6.38 mm; p<0.001) and lower ST resolution ratios (57.12% ±18.67 vs 64.22% ±20.41; p=0.006). In hospital mortality was found to be higher in patients with fQRS and with QRS distortion seperately when compared to patients without those features (fQRS: 14.3% vs 4.5%; p=0.006; QRS distortion: 13.3% vs 4.7%; p=0.015). Patients with both these ECG findings were observed to have again higher in hospital mortality compared to the ones without them. (15.7% vs 6.1%; p=0.039). Result: In patients with acute STEMI presence of fQRS or QRS distortion on surface ECG is not related to MI localisation and infarct related artery. fQRS can foresee thrombolytic therapy failure or three vessel disease while QRS distortion does not possess such quality. In addition to this both these ECG features can seperately aid to determine high risk patients with myocardium under greater threat . Also presence of both fQRS and QRS distortion is related to worse prognosis and increased in hospital mortality. Key Words: Fragmanted QRS, QRS distortion, Three vessel disease, Proximal vessel disease, Thrombolytic therapy failure.