Nondominant right coronary artery occlusion and ventricular tachyarrythmias

A case report of non-dominant right coronary artery occlusion: not always benign!

Background

Non-dominant right coronary artery (RCA) occlusion is uncommon and usually affects a small area of the myocardium. Rarely, it can complicate fatal outcomes such as shock, cardiac arrest, bradyarrhythmia, or tachyarrhythmia.

Case summary

A 50-year-old man with no significant medical history presented with ventricular fibrillation (VF) cardiac arrest. He required prolonged cardiopulmonary resuscitation and multiple defibrillation shocks to achieve return of spontaneous circulation. ST elevation was noted on inferior leads. Due to refractory VF, extracorporeal membrane oxygenation (ECMO) was initiated followed by coronary angiography which demonstrated 100% acute occlusion of proximal RCA (small non-dominant), 90% stenosis of ramus intermedius (RI), and 80% stenosis of obtuse marginal (OM) arteries. Left ventricular ejection fraction was 35%. Percutaneous coronary intervention (PCI) of the RCA was performed with drug eluting stent. He had excellent clinical recovery without any neurological deficits. The ECMO was weaned off and decannulated within three days. Guideline directed medical therapy was administered. He remained hemodynamically stable and underwent staged PCI of RI and OM to achieve complete revascularization.

Discussion

Non-dominant RCA lesions are usually considered benign. However, when acute RCA occlusion results in cardiac arrest as seen in our patient, prompt revascularization is necessary. Treatment of cardiogenic shock with appropriate pharmacological and mechanical therapies is important, such as ECMO in our patient.

Isolated Right Ventricular Infarction Mimicking Anterior ST-Segment Elevation

Acute coronary syndromes in patients with presence of ST-segment elevation in the anterior precordial leads indicates left anterior descending coronary artery occlusion. However, anterior ST-segment elevation has also been described in right ventricular myocardial infarction and is thought to be due to right coronary artery (RCA) occlusion. We present a rare case of isolated RVMI presenting with anterior ST-segment elevation due to proximal occlusion of a right coronary artery that was treated by primary coronary angioplasty. Primary coronary angioplasty and stenting of this artery was performed resulting in resolution of the chest pain and ST- segment elevation.

Symptomatic right ventricular ischemia secondary to a critical stenosis in a nondominant right coronary artery

Stable angina pectoris owing to isolated right ventricular ischemia from a critical stenosis in a nondominant right coronary artery is a rare entity and documentation of isolated right ventricular ischemia even rarer. We present a case of isolated right ventricular ischemia documented by fractional flow reserve (FFR) and resolution of symptoms after percutaneous coronary intervention.

Isolated right ventricular infarction presenting with anterior ST-segment elevation: a case for careful assessment of right ventricular branch occlusion

We describe the case of a 61-year-old man who presented with chest pain and ST-segment elevation in the anterior precordial leads (V1-V5) due to proximal occlusion of the right ventricular branch of a codominant right coronary artery. Primary coronary angioplasty and stenting of this branch was performed resulting in resolution of the chest pain and ST-segment elevation. Our description illustrates a case of isolated right ventricular infarction as an uncommon but important differential diagnosis of anterior ST-segment elevation. In addition, it highlights the value of careful review of the angiographic images in this context, as the culprit lesion may be a right ventricular branch occlusion. To the best of our knowledge, this is the first reported case of primary percutaneous coronary intervention treatment of a right ventricular branch occlusion causing isolated acute right ventricular myocardial infarction and anterior ST-segment elevation.

Catheter-based intracoronary myocardial adenoviral gene delivery: importance of intraluminal seal and infusion flow rate

Although percutaneous, adenoviral-mediated intracoronary gene delivery to the heart has been demonstrated in some species, consistent and safe methodology is needed before clinical applicability is possible. In this study, we examine the effects of altering intracoronary flow rate and obtaining an adequate seal between the catheter and the coronary lumen on successful cardiac gene delivery and myocardial injury in both piglets and adult rabbits. To study the efficacy of in vivo myocardial gene transfer, we utilized adenoviral vectors containing either the beta(2)-adrenergic receptor or beta-galactosidase. The left circumflex coronary artery of piglets and the right coronary artery of rabbits were catheterized under fluoroscopic guidance and adenovirus solutions were injected using varying flow rates with or without balloon inflation. Successful transgene delivery to the heart was determined approximately 1 week after coronary infusions. Histologic analysis was also performed in all animals to determine the extent of myocardial injury. Our results indicate that efficient and reproducible cardiac transgene expression utilizing intracoronary delivery is dependent upon the infusion flow rate and, in larger animals, requires an intraluminal seal. Excessive flow rate is associated with greater myocardial injury. Thus, conditions can be established and controlled to improve future investigational and clinical application of catheter-based intracoronary myocardial gene therapy.