A patient develops a drop in blood pressure after nitroglycerin administration and shows ST elevation in lead V4R. What is the likely diagnosis?

The scenario presented indicates a patient who experiences a drop in blood pressure after receiving nitroglycerin, accompanied by ST elevation in lead V4R. This specific elevation in V4R, which is a right precordial lead, is particularly significant for diagnosing a right-ventricular myocardial infarction (MI).

Nitroglycerin is a vasodilator commonly used to relieve chest pain by reducing myocardial oxygen demand, which may lead to hypotension, especially in patients who have inferior MIs with right ventricular involvement. When there is a right-ventricular MI, the right ventricle may already be compromised due to inadequate perfusion. The administration of nitroglycerin can exacerbate the drop in preload and subsequently result in a significant decrease in blood pressure.

The presence of ST elevation in lead V4R, specifically, suggests that the right ventricular wall is experiencing ischemia due to occlusion of the right coronary artery, which may also involve the right ventricular artery branches. In patients presenting with inferior MIs, it is critical to assess for right ventricular involvement, as it has distinct treatment implications, especially concerning the use of nitrates which can worsen hypotension in this context.

Other potential diagnoses like anteroseptal