Right ventricular infarction mimicking anterior infarction

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.

Precordial ST-Segment Elevation Caused by Proximal Occlusion of a Non-Dominant Right Coronary Artery

For patients with ST-segment elevation myocardial infarction, primary percutaneous coronary intervention to the culprit lesion via electrocardiographic guidance is essential. We herein report the rare case of a 49-year-old man who presented with ST-segment elevation in the precordial leads, while coronary angiography results indicated total occlusion of the proximal non-dominant right coronary artery. We evaluated its possible pathophysiologic mechanisms and thoroughly discussed isolated right ventricular infarction and its electrocardiography findings.

KEY WORDS

Coronary angiography; Myocardial infarction; Total occlusions.

Isolated right ventricular infarct presenting as ventricular fibrillation arrest and confirmed by delayed-enhancement cardiac MRI

Malignant ventricular arrhythmias resulting from isolated right ventricular myocardial infarction (RVMI) without left ventricular myocardial ischaemia or infarction occur rarely. We present a case of a 61 year-old male with acute onset of chest pain and ventricular fibrillation cardiac arrest requiring prompt defibrillation. Subsequent 15-lead EKG, showed ST-segment elevation in the anterior and right precordial leads without ST-segment elevation in the inferior leads. Angiography documented occlusion of a large RV marginal branch. Delayed enhancement cardiac magnetic resonance imaging (DE-CMR) with gadolinium performed two days post-infarct showed isolated RVMI. Patient remained symptom free and haemodynamically stable throughout his hospital stay. The clinical presentation of isolated RV infarct can be misleading and diagnosis difficult. EKG findings can resemble acute anterior wall myocardial infarction, while its course can be accompanied by life-threatening ventricular arrhythmias. This case uniquely combines this rare clinical sequence with DE-CMR images using gadolinium to confirm isolated RVMI. A brief review of RVMI presentation and associated EKG patterns is also discussed.

Magnitude and consequences of missing the acute infarct-related circumflex artery

Emergent reperfusion strategies are integral to providing optimal patient outcomes in the setting of acute coronary artery occlusion. ST-segment elevation on the surface 12-lead electrocardiogram, although specific as a surrogate marker, is insensitive to acute posterior circulation coronary artery occlusion. Studies of non-ST-segment elevation acute coronary syndrome consistently identify patients who have epicardial vessel occlusion at the time of initial angiography, which is usually delayed for hours or days after the initial presentation. In addition, studies of ST-segment elevation myocardial infarction often divulge a disparity in identification of the infarct-related artery, with an underrepresentation of the left circumflex artery. Taken together, it is likely that many patients with left circumflex artery occlusion are "missed" during the early phases of myocardial infarction due to the electrocardiographically silent nature of the posterior territory, resulting in delayed myocardial salvage and worse cardiovascular outcomes. In this review, we report on the magnitude of missed left circumflex infarction and the consequences of this delay in diagnosis. We review the electrocardiographic findings of left circumflex occlusion and discuss strategies to enhance early identification. Heightened awareness of this clinical scenario and the available methods to avoid missing this elusive diagnosis are imperative in our quest to further improve the outcomes of patients with acute myocardial infarction.