Reduced coronary blood flow in cardiac tamponade: mystery solved

A 67-year-old male presented with several week history of progressive shortness of breath, lower extremity edema, and distended jugular veins. Transthoracic echocardiography showed moderate pericardial effusion with thickened visceral pericardium and septal bounce but no chamber collapse. Right and left cardiac catheterization showed discordance of the right and left ventricular systolic pressures during respiration and severely reduced cardiac output. There was near equalization of diastolic pressures in all four chambers suggestive of effusive-constrictive pericarditis with cardiac tamponade physiology. Simultaneous coronary angiography showed remarkably reduced coronary Thrombolysis in Myocardial Infarction (TIMI) flow (TIMI grade 2 flow). Coronary blood flow was restored to normal after pericardial drainage on repeat coronary angiography. This is the first report of reduced coronary blood flow on coronary angiography in patients with effusive-constrictive pericarditis and cardiac tamponade. Our finding complements the work of previous investigators as we show that elevated intrapericardial pressures in cardiac tamponade can reduce coronary blood flow. This is likely related to extrinsic epicardial coronary vessel compression and reduced perfusion pressures, which can lead to myocardial ischemia and eventually cardiogenic shock.