Conus artery occlusion causing isolated right ventricular outflow tract infarction: novel application of cardiac magnetic resonance in anterior STEMI

Clinical significance of R-wave amplitude in lead V1 and inferobasal myocardial infarction in patients with inferior wall myocardial infarction

OBJECTIVE

To assess electrocardiogram (ECG) for risk stratification in inferior ST-elevation myocardial infarction (STEMI) patients within 24 h.

METHODS

Three hundred thirty-four patients were divided into four ECG-based groups: Group A: R V1 <0.3 mV with ST-segment elevation (ST↑) V7-V9, Group B: R V1 <0.3 mV without ST↑ V7-V9, Group C: R V1 ≥0.3 mV with ST↑ V7-V9, and Group D: R V1 ≥0.3 mV without ST↑ V7-V9.

RESULTS

Group A demonstrated the longest QRS duration, followed by Groups B, C, and D. ECG signs for right ventricle (RV) infarction were more common in Groups A and B (p < .01). ST elevation in V6, indicative of left ventricle (LV) lateral injury, was more higher in Group C than in Group A, while the ∑ST↑ V3R + V4R + V5R, representing RV infarction, showed the opposite trend (p < .05). The estimated LV infarct size from ECG was similar between Groups A and C, yet Group A had higher creatine kinase MB isoform (CK-MB; p < .05). Cardiac troponin I (cTNI) was higher in Groups A and C than in B and D (p < .05 and p = .16, respectively). NT-proBNP decreased across groups (p = .20), with the highest left ventricular ejection fraction (LVEF) observed in Group D (p < .05). Group A notably demonstrated more cardiac dysfunction within 4 h post-onset.

CONCLUSIONS

For inferior STEMI patients, concurrent R V1 <0.3 mV with ST↑ V7-V9 suggests prolonged ventricular activation and notable myocardial damage. RV infarction's dominance over LV lateral injury might explain these observations.

Right ventricular infarction: epidemiological, clinical, and angiographic characteristics and the outcomes through the experience of a Moroccan cardiology department

Background

Acute myocardial infarction (MI) is a major cause of cardiovascular mortality, which is the leading cause of death in the world. Our objective in this study was to evaluate the epidemiological, clinical, and angiographic features of right ventricular infarction (RVI), as well as its complications and its therapeutic approaches.

Patients and methods

It is a single-centered retrospective descriptive study conducted over a period of 2 years from November 2018 to October 2020. The authors included 82 patients with RVI hospitalized in the cardiovascular ICU during the initial phase of acute coronary syndrome with persistent ST segment elevation. Patients who were diagnosed with RVI at electrocardiogram and echocardiography were recruited.

Results

The authors included 500 patients hospitalized for STEMI, 82 had MI extended to the RV, reflecting a rate of 16.4%. The mean age in our study was 64±12.3 years. Dyslipidemia, diabetes mellitus, and hypertension were the most common cardiovascular risk factors among these patients. RVI co-existed with inferior MI in 62.2 of cases and in 37.8% of anterior MI, while isolated RVI was seen in only one patient. Transthoracic echocardiography showed right ventricular (RV) systolic dysfunction in 24.39% of cases, while RV dilatation was seen in only 10.9% of patients. Therapeutic approach was based essentially on revascularization with thrombolysis and coronary angiography +/- PCI. The percentage of mortality was 2.4%.

Conclusion

RVI is relatively rare and is mostly related to an extension of an inferior MI. Early diagnosis, prompt treatment, and appropriate are the keys to improve prognosis, and reduce complications.

Acute Isolated Right Ventricular Infarction: Unusual Presentation of Anterior ST-Segment-Elevation Myocardial Infarction

. Emergency coronary angiograms revealed that acute thrombotic occlusion of the right ventricular marginal branch of the dominant right coronary artery caused the clinical manifestations in the first patient, whereas occlusion of the proximal nondominant right coronary artery was the culprit lesion in the second patient. Both lesions caused right ventricular myocardial infarction. The patients underwent successful primary percutaneous coronary intervention. These cases illustrate the importance of carefully reviewing angiographic findings to accurately diagnose an acute isolated right ventricular myocardial infarction, which may mimic the electrocardiographic features of an anterior-wall myocardial infarction.

Correlation of anteroseptal ST elevation with myocardial infarction territories through cardiovascular magnetic resonance imaging

BACKGROUND

Anteroseptal ST elevation myocardial infarction (STEMI) is traditionally defined on the electrocardiogram (ECG) by ST elevation (STE) in leads V1-V3, with or without involvement of lead V4. It is commonly taught that such infarcts affect the basal anteroseptal myocardial segment. While there are suggestions in the literature that Q waves limited to V1-V4 represent predominantly apical infarction, none have evaluated anteroseptal ST elevation territories. We compared the distribution of the myocardium at risk (MaR) in STEMI patients presenting with STE limited to V1-V4 and those with more extensive STE (V1-V6).

METHODS

We identified patients in the MITOCARE study presenting with a first acute STEMI and new STE in at least two contiguous anterior leads from V1 to V6. Patients underwent cardiac magnetic resonance (CMR) imaging three to five days after acute infarction.

RESULTS

Thirty-two patients met inclusion criteria. In patients with STE in V1-V4 (n = 20), myocardium at risk (MaR) > 50% was seen in 0%, 85%, 75%, 100%, and 90% in the basal anteroseptal, mid anteroseptal, apical anterior, apical septal segments, and apex, respectively. The group with STE in V1-V6 (n = 12), MaR > 50% was seen in 8%, 83%, 83%, 92%, and 83% of the same segments.

CONCLUSIONS

Patients with acute STEMI and STE in leads V1-V4, exhibit MaR in predominantly apical territories and rarely in the basal anteroseptum. We found no evidence to support existence of isolated basal anteroseptal or septal STEMI. "Anteroapical" infarction is a more precise description than "anteroseptal" infarction for acute STEMI patients exhibiting STE in V1-V4.