Knowledge of how the coronary arteries, cardiac topography, and the lead electrocardiogram (ECG) link together is imperative if the electrical tracing is to be. coronary artery (LAD), inferior wall infarction to dis- ease of the evaluate the value and limitations of the lead ECG in localizing relations were obtained. Correlation of ST-segment elevation on the lead ECG with the expected . LAD coronary artery obstruction most often results in ST-segment.
Localization of the ischemic area will now be discussed. The posterior third of the interventricular septum is supplied by the right coronary artery.
ECG localization of myocardial infarction / ischemia and coronary artery occlusion (culprit)
Occlusion in the right coronary artery Occlusion in the RCA causes inferior wall infarction in individuals with right-dominance i. If the occlusion occurs proximally, it may affect the blood supply to the right ventricle and thus cause right ventricular infarction this is uncommon.
Occlusion in the RCA may also cause posterior wall infarction. It is common that V1—V3 displays unusually high R-waves and positive T-waves during posterior wall infarction these are reciprocal changes to posterior Q-waves and T-wave inversions, respectively.
Inferior infarction and right ventricular infarction — None of the standard leads in the lead ECG is adequate to capture the injury currents arising in the right ventricle. It is a common misunderstanding that V1 and V2 records right ventricular activity V1 and V2 primarily observes the electrical activity of the interventricular septum.
However, V1 and V2 may occasionally display ST-segment elevations during right ventricular infarction the elevations should be higher in V1.12-15 Lead ECG: Coronary Anatomy Part 1
Since infarction of the right ventricle affects treatment alternatives, it is recommended that these right sided chest leads be used if there is suspicion of right ventricular infarction. Note that the ST-segment elevations in right ventricular infarction have much shorter duration than infarction of the left ventricle because the right ventricular wall is much thinner than the left, and therefore the infarction is completed faster.
The LAD supplies the large anteriosuperior wall often referred to as the anterior wall and the apical part of the lateral wall.
ECG changes and extension of the infarction depend heavily on the site of the occlusion. The more proximal the occlusion the greater the infarction and the more pronounced ECG changes.
Coronary anatomy and the lead electrocardiogram: how to tell who is hurting.
ST-segment elevations may be present in leads V1—V6, and frequently aVL, I the latter two may be affected because the diagonals given off by the LAD supplies the apical part of the lateral wall. In addition to fast diagnosis, immediate and accurate stratification of high-risk patients is also important in this situation.
The lead electrocardiogram ECG in emergency rooms is the most feasible and valuable test in patients with acute chest pain for diagnostic and therapeutic measures. Considerable numbers of patients with highly suspected MI have normal on-admission lead ECG, hence serial ECGs and also additional leads right and posterior leads may help physicians to deal with such cases 2.
Many studies in this field suggested stepwise algorithms and criteria to predict the culprit artery, like Fiol et alandTierala et al 34. In addition the relation of culprit lesion with ST segment deviation in posterior and right precordial leads were also analyzed in terms of odds ratio and confidence intervals. Methods In this retrospective study, of a total of studied patients, 25 had 3-vessel disease and 37 had two occluded arteries. Normal coronary was detected in one patient, which excluded based on the first decision of authors and the suggestion of similar studies.
We enrolled 76 consecutive patients with acute single vessel myocardial infarction who admitted in Tehran Heart Center THC from to and underwent clinically indicated percutaneous coronary interventions.
ECG changes (relating coronary artery involved, site of infarction and lead showing changes)
All of them fulfilled following criteria: Quantitative analysis of ST segment deviation was done. At the time of discrepancy, we re-evaluated the records at the presence of both cardiologists.
The maximum time between symptoms onset and coronary angiography in our patients was less than a week of hospitalization.