Acute Right Coronary Artery Occlusion Research Articles

Right ventricle injury in RCA occlusion: Exploration using precordial bipolar leads and surrogate vectorcardiograms.

Precordial Bipolar Leads (PBL) provide new electrocardiographic information derived from standard 12‑lead ECG recordings. To explore the usefulness of PBL in patients with acute right coronary artery (RCA) occlusion. Sixteen patients undergoing elective percutaneous transluminal coronary angioplasty (PTCA) were studied before and after RCA occlusion and their data were processed with new methods based on PBL. The findings were: 1. In PBL V2-V1, strong systolic currents of injury moving in the left to right direction coexist with those directed towards leads II, III and aVF. 2. Changes in the time of the peaks of the QRS waves do not alter the duration of the QRS. 3. The QRS loops of the surrogate VCG generated show that, during ischemia, the time changes in the peak of the QRS waves displayed in one axis are the consequence of an increase in the amplitude of the waves observed in the perpendicular axis. 4. The use of two simultaneous dimensions (transverse and frontal planes) facilitates the location of the J-point. 5. In the surrogate VCGs of this group of patients, J-point and ST segment shifts produced an image that reminded the Greek letter omega (Ω). 6. The QRS wave changes, in time and amplitude, explained the rotational changes and the ischemic distortions of the surrogate VCG loops. Computerized processing of ECG data appears to provide new and valuable diagnostic data in patients with acute RCA occlusion. The loops revealed important information related to systolic currents of injury. Because these methods use routine 12‑lead ECG data, the procedure is based only in software applications.

The evaluation of an electrocardiographic myocardial ischemia acuteness score to predict the amount of myocardial salvage achieved by early percutaneous coronary intervention: Clinical validation with myocardial perfusion single photon emission computed tomography and cardiac magnetic resonance

Background The time from symptom onset to reperfusion in acute myocardial infarction (MI) has been shown to be a poor predictor of patient outcome. Acute electrocardiographic (ECG) changes, however, have been shown useful for estimated acuteness of myocardial ischemia using the Anderson-Wilkins ECG ischemia acuteness score (AW-acuteness score). The aim was to study whether acute ischemic ECG changes can predict the amount of salvageable myocardium in patients with acute ST-elevation MI. Methods Thirty-eight patients treated with primary percutaneous coronary intervention for first-time ST-elevation MI were retrospectively enrolled. Myocardium at risk (MaR) was determined by myocardial perfusion single photon emission computed tomography acutely or by T2-weighted cardiac magnetic resonance after 1 week, at the same time when final MI size was determined by late gadolinium enhancement. Myocardial salvage was calculated as (MaR − MI size)/MaR and compared with AW-acuteness score and time from symptom onset to primary percutaneous coronary intervention. Results The AW-acuteness score correlated significantly with salvageable myocardium for right coronary artery (RCA) occlusions ( r = −0.57; P = .02) but not for left anterior descending artery (LAD) occlusions ( r = −0.04; P = .88). Time from symptom onset did not correlate with the amount of salvageable myocardium (LAD, r = 0.04 and P = .87; RCA, r = −0.40 and P = .13). Conclusions There is a moderate correlation between AW-acuteness score and salvageable myocardium in patients with acute RCA occlusion but not in patients with LAD occlusion.

Spatial Distribution of Right Ventricular Perfusion Abnormalities Following Acute Right Coronary Artery Occlusion: A Study by Myocardial Contrast Echocardiography and Blue Dye Staining

Although echocardiography is used for diagnosing right ventricular (RV) infarction produced by right coronary artery (RCA) occlusion, there has been no data on the spatial distribution of RV perfusion abnormalities following acute RCA occlusion. We examined this distribution by myocardial contrast echocardiography (MCE) and blue dye staining in canine models. The RCA was occluded in 10 open-chest dogs. MCE was performed with 0.27 g/min Levovist infusion by harmonic power Doppler with electrocardiogram gated intermittent triggered imaging at baseline and at 90 min after RCA occlusion. The opacification defects were assessed at the basal, middle, and apical levels of the RV free wall by short-axis view. The extent of the risk area of the occluded RCA, expressed as a percentage of the RV free wall, was measured at each level by injecting blue dye at the end of the experiments. In 10 other dogs, the left anterior descending coronary artery (LAD) was occluded by ligating the proximal portion of the LAD to examine the territory of the LAD on the same levels of the RV free wall by injecting blue dye. Although patchy opacification defects accompanying RV dilation were observed at the basal and middle levels during RCA occlusion, no apical defects were observed in any dogs by MCE. The risk area of the occluded RCA, as delineated by blue dye, was larger in the basal than apical level of the RV free wall in all 10 dogs (basal: 79 +/- 9%; middle: 48 +/- 14%; apical: 3 +/- 6%, p < 0.0001). The risk area of the occluded LAD (basal: 17 +/- 7%; middle: 12 +/- 6%; apical: 6 +/- 6%) was smaller than the risk area of the occluded RCA at the basal and middle levels of the RV free wall (p < 0.0001), and no significant difference was observed at the apical level. RV perfusion abnormalities produced by RCA occlusion are larger in the basal than apical level of the RV free wall. This finding elucidates the spatial distribution of the territory of the RCA on the RV free wall, and may help in identifying and assessing RV ischemia by echocardiography in humans. Moreover, the data in the current study indicate that RV infarction may be produced by occlusion of the coronary arteries except RCA, because the territory of the LAD on the RV free wall is clearly delineated.