Characteristics and mechanism of reciprocal ST-segment depression in acute ST segment elevation myocardial infarction

Background: At present, the mechanism of reciprocal ST-segment depression(RSTD) is still not clear.Methods: The electrocardiogram and angiography of 85 STEMI patients were retrospectively analyzed to summarize the characteristics of ST segment changes and explore the mechanism of RSTD.Results: A total of 85 patients were included, of which 75 were patients with RSTD (10 patients with anterior myocardial infarction had no RSTD), all 45 patients with inferior myocardial infarction had limb leads RSTD, and 37 of them had anterior lead ST segment depression.Thirty patients with anterior myocardial infarction were accompanied by mild ST segment changes in the limb leads. According to the characteristics of RSTD, it is speculated that the mechanism of RSTD is that the action potential of infarct area decreased , which could not offset the action potential in non-infarct area.Conclusion: the mechanism of RSTD in acute myocardial infarction maybe that the negative electrode action potential of the lead was weakened or disappeared, and the positive electrode action potential could not be completely offset, resulting in ST segment depression.

Angiographic Significance of ST Depression in Anterior Leads in Acute Inferior ST Elevation Myocardial Infarction.

Background and aims: Electrocardiogram of acute ST elevation inferior myocardial infarction can show concomitant ST depression in anterior leads. We aimed to see its significance on coronary angiogram. Methods: Cross sectional study conducted in Department of Cardiology of Shahid Gangalal National Heart Centre from March 2021 to June 2021. Total of 64 patients of acute inferior myocardial infarction were included consecutively. Electrocardiogram were analyzed for the presence of ST depression in anterior leads (V1-V6). Coronary angiogram were obtained. Linear regression analysis was applied to see correlations. Results: Thirty-four (53.12%) participants had significant ST depression in anterior leads. Their mean age was 64.53±11.67 years. Twenty-two (64.70%) were male. Out of them, 13 (38.23%) were hypertensive, 9 (26.47%) were smoker and 7 (20.58%) were diabetic. Among 30 (46.88%) participants without ST depression, mean age was 56.73±13.31 years and 21 (70%) were male. Out of them, 11 (36.66%) were hypertensive, 12 (40%) were smoker and 11 (33.66%) were diabetic. Culprit vessel was right coronary artery in 22 (64.70%) of those with ST depression and 22 (73.33%) of those without ST depression. Significant left anterior descending artery lesion was seen in 19 (55.88%) of those with ST depression and 3 (10%) of those without depression. Anterior ST depression showed positive correlation with left anterior descending artery lesion. Conclusion: ST depression in anterior leads in acute inferior myocardial infarction can be due to presence of concomitant left anterior descending coronary artery disease.

Case Report: Area of Focus of Myocardial Infarction With Non-obstructive Coronary Arteries in Eosinophilic Granulomatosis With Polyangiitis

Background: Eosinophilic granulomatosis with polyangitis manifested as myocardial infarction with non-obstructed coronary arteries (MINOCA) is rarely reported.Case: We report a 43-year-old male patient without any cardiovascular risk factors presenting with acute chest pain. Electrocardiogram was suggestive of acute anterior and inferior myocardial infarction. MINOCA was confirmed based on significant elevated cardiac troponin and normal coronary arteries. Cardiac magnetic resonance (CMR) imaging revealed extended late gadolinium enhancement (LGE). Further diagnosis of eosinophilic granulomatosis with polyangitis (EGPA) was based on clinical manifestations and auxiliary examination. Subsequent immunosuppressive therapy led to regression of symptoms and significant resolution of LGE on CMR.Conclusion: Our case highlights that EGPA can be a rare cause of MINOCA. CMR is useful for differentiation diagnosis and evaluation of cardiac involvement.

А new electrocardiographic criterion in diagnosis right ventricular myocardial infarction

The aim of this study is to identify the features of ST-changes in 12-leads surface ECG, which help to diagnose the right ventricular involvement in inferior myocardial infarction. The study included 145 patients with inferior myocardial infarction, the right ventricular infarction (RVI) was detected by echocardiography in 62 (42.8%) patients. ST segment depression in lead aVL was deeper than in lead V3 in 93.5% of patients with RVI. This feature is revealed in 4.9% patients with inferior myocardial infarction without RVI only. The sensitivity of this criterion for diagnosis RVI is 93.5%, the specificity is 95.2%, the predictive value of positive and negative results make up 93.5 and 95.2%.

Characteristics and mechanism of reciprocal ST-segment depression in acute ST segment elevation myocardial infarction

Background:At present, the mechanism of reciprocal ST-segment depression(RSTD) is still not clear. Purpose : We proposed the mechanism of RSTD: the action potential of negative electrode of the lead was weakened or disappeared, and the AP of positive electrode could not be completely offset. The electrocardiograms of patients with acute STEMI were analyzed to explore the mechanism of RSTD. Methods: The electrocardiogram and angiography of 85 STEMI patients were retrospectively analyzed to summarize the characteristics of ST segment changes. Results: A total of 85 patients were included, of which 75 were patients with RSTD (10 patients with anterior myocardial infarction had no RSTD), all 45 patients with inferior myocardial infarction had limb leads RSTD, and 37 of them had anterior lead ST segment depression.Thirty patients with anterior myocardial infarction were accompanied by mild ST segment changes in the limb leads. According to the characteristics of RSTD, it is speculated that the mechanism of RSTD is that the action potential of infarct area decreased , which could not offset the action potential in non-infarct area. By using this mechanism, all ST segment changes in STEMI can be explained by the proposed mechanism, and the value of the ST segment changes can be calculated in limb leads. Conclusion: the mechanism of RSTD in acute myocardial infarction is that the negative electrode action potential of the lead was weakened or disappeared, and the positive electrode action potential could not be completely offset, resulting in ST segment depression.

Total atrioventricular block in patient with late onset acute inferior myocardial infarction

TAVB is common complication of acute inferior myocardial infarction (AMI). Total atrioventricular block (TAVB) occurs when none of the impulses are conducted from atrium to ventricles and move independently without coordination. In our case, A 61-year-old woman came to the emergency room (ER) with chief complaint of general weakness and nausea without any other complaints since 4 days before going to ER. She had TAVB which is a complication of undiagnosed AMI due to silent ischemia. She didn't get reperfusion therapy because of patient delay and limited resources. Pharmacological therapy had been given while awaiting implantation of temporary pacemaker (TPM). Two days after insertion, the heart rhythm returned to sinus rhythm, therefore permanent pacemaker implantation was not required. TAVB in AMI usually resolves spontaneously. Therefore, it is important to identify TAVB in AMI, so we can quickly diagnose and promptly treat the patient. Thus, it can reduce mortality and increase the probability of spontaneous resolution of TAVB, so physician practice management (PPM) insertion can be avoided.