Right ventricular myocardial infarction: a challenging diagnosis for residents, hospital physicians and cardiologists

  

Acute myocardial infarction is one of the common leading causes of death.

In the majority of cases the left ventricle of the heart is affected.

Less commonly, the right ventricle is infarcted, even though, it commonly occur with left ventricular infarction (in about half of cases), particularly the inferior wall.

Right ventricular infarction , when it’s isolated or predominant, it imposes different diagnostic and therapeutic approaches, that every hospital physician should be aware of.

The right ventricle is less susceptible to infarction than the left ventricle, because of its lower oxygen demand and because its myocardial blood supply  occurs during both systole and diastole, and not solely dependent on diastolic coronary blood flow as in the left ventricle.

This makes the right ventricular infarction quite unique, in that the right ventricular function may completely recover in surviving patients.

This is because the contractile dysfunction is largely a result of ischemia rather than infarction. Some authors consider the term “right ventricular infarction” as misnomer, owing to the fact that ischemia is responsible for the clinical manifestations in most of patients and not the infarction it self.

 

The in-hospital morbidity and mortality of right ventricular infarction is high, but the long term prognosis is good in survivals.

Immediate in-hospital complications are mainly hemodynamic instability and arrhythmias (Brady- and Tachyarrhytmias).

The diagnosis should be suspected in acute ST elevation myocardial infarction with hypotension , raised jugular venous pressure and clear lungs ( pulmonary embolism should be ruled out).

It’s particularly important to look for right ventricular infarction in all patients with inferior myocardial infarction.

Once suspected, ST elevation in lead V4R should be sought.

Symptoms include chest pain, nausea, vomiting, and excessive sweating.

Isolated (or predominant) right ventricular infarction doesn't cause dyspnea.

Urgent echocardiography is important for evaluating the extent of infarction, to look for alternative diagnosis like constructive pericarditis, and to detect complications like tamponade.

Although early administration of anti platelets and  reperfusion with either coronary intervention or thrombolysis is indicated, the  treatment of right ventricular infarction also differs in some aspects, in comparison to that of the left ventricular infarction.

Opioids, nitrates and beta blockers should be avoided or used with caution, as they decrease the already compromised preload and suppress the already slow heart rate.

Diuretics are not indicated. Instead, saline infusion must be initiated if there is clinical evidence of low cardiac output.

Atropine , dopamine or dobutamine may be used to increase heart rate and improve ventricular contractility and cardiac output.

In conclusion, right ventricular infarction, though less common than the left, when present , it's management may be challenging.

The two main management dilemmas are the early increased susceptibility to fatal arrhythmias, and the profound hemodynamic instability that, in some cases, requires invasive monitoring, which are largely distinct in management approach compared with the more common left ventricular infarction.