EVALUATION OF THE Q WAVE BY COMPARISON WITH THE RESULTS OF ECHOCARDIOGRAPHY AND CMR AND ANGIOGRAPHY.

Background:Q waves on the electrocardiogram are often considered to be reflective of irreversibly scarred Myocardium due to antecedent transmural myocardial infarction. However, there are some indications that residual viable tissue may be present in Q wave infracted regions. It is clinically relevant to know how many Q-wave regions contain viable tissue because these patients may benefit from revascularization in terms of improvement of function and long-term survival. A technical advance in contrast-enhanced magnetic resonance imaging (MRI) has significantly improved image quality. We investigated whether healed myocardial infarction can be visualized as hyper enhanced regions with this new technique, and whether assessment of the transmural extent of infarction yields new physiological data. Methods:100 MRI examinations were carried out in two groups: patients with Q wave and patients without Q wave at the electrocardiogram. Patients with healed myocardial infarction were prospectively enrolled after enyzmatically proven necrosis and imaged by the echocardiography. The MRI procedure used a segmented inversion-recovery gradient-echo sequence after gadolinium administration. Findings were compared with those of coronary angiography, electrocardiography, cine MRI, and Echocardiography. Results:The mean age of patients with cardiac MRI was 57.9 ? 12.9 years, with extremes of 28 and 85 years. A male predominance with 56 men (56%) and 44 women (44%) is a sex ratio of 1.3. One or more cardiovascular risk factors were found in 86 patients (86%). Thirteen patients (13%) were coronary patients known or followed for effort angina, And finally 5 patients (5%) had a field of coronary heredity. 47 patients had NYHA Stage II or III Dyspnea (47%) and worsened to become NYHA Stage IV in 20 patients (20%) with Paroxysmal Night Dyspnea in 27 patients (27%). ) and an orthopnea in 26 patients (26%).78 patients had chest pain (78%), 14% of patients had palpitations (n = 14); The delay between onset of symptoms of our patients and their hospitalizations varied between the same day and 180 days with an average of 24 days +/- 36 days and a median of 7 days and this can be explained by the variety of clinical presentation between Acute chest pain that pushes the patient consulted on the field and a flare of heart failure that settles gradually. The initial clinical evaluation shows that the patients were all aware, with a GCS at 15; The signs of right heart failure were present in 20% of cases, Crackling Rails in 29% of cases. Chest x-ray: 30% of patients (n = 30) already had cardiomegaly. The electrocardiogram show Q Wave in 42% of cases (n = 42), The result of Echocardiography and cardiac magnetic resonance was compared between the two group of patient (Q wave and non Q wave) The results of our comparison were significant between the two group of patient with P <0.05 in most times which indirectly means that the presence of a Q wave corresponds to more akinesia on MRI and echocardiography. Coronarography was performed in 73% of patients (n = 73), Although the presence of a Q wave at the ECG corresponds to more occlusion at the coronarography, the comparison was not statistically significant, and this can be explained either by coronary reperfusion or by the presence of collaterality or following MINOCA? The CMR was able to detect sequelae of necrosis in 81% (n = 81) of cases, of which 34% (n = 34) was viable vs. 47% (n=47) not viable. Finally we deduce that the presence of necrosis Q wave corresponds to more necrosis in echocardiography and cardiac magnetic resonance imaging, but despite this the territory remains viable in 42% of cases. And the results are statistically significant. The comparison of different methods of exploration respectively to coronary angiography showed statistically significant results, as far as the ECG and the ETT are concerned, it means that the 2 methods can miss the affected territories, on the other hand the MRI despite the difference in outcome with coronary angiography but the statistic was not significant, and this can be explained by the number of coronary angiography performed that was less than MRI and the ability of MRI to detect non visible lesions at the coronarography to see MINOCA whose number in our series was not negligible. Conclusions:Chronic Q waves on electrocardiography do not exclude the presence of viable myocardium; in 38% of the Q-wave regions in 55 patients, viable tissue was present. Thus patients with a previous Q-wave infarction, severely depressed left ventricular function, and heart failure should be referred for viability testing.