CARDIAC TAMPONADE WITHOUT CHARACTERISTIC ECHOCARDIOGRAPHIC FEATURES DUE TO HIGH RIGHT HEART PRESSURE FROM PULMONARY HYPERTENSION

Abstract

TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: Introduction: Cardiac tamponade occurs when pericardial effusion leads to equalization of intrapericardial pressure and diastolic intracardiac pressure, which reduces the systemic venous-to-right atrial pressure gradient, leading to depression in cardiac output. The lower this gradient, the greater the risk for cardiac tamponade. Cardiac tamponade manifests clinically as shock, jugular venous distention, and muffled heart sounds, known collectively as Beck's triad. Typical findings on echocardiogram are right atrial and ventricular collapse.[2] These findings may not be seen in patients with elevated right-sided intracardiac pressure and can lead to misdiagnosis or delay in diagnosis of cardiac tamponade.[1] We present a patient with a cardiac tamponade to highlight this point. CASE PRESENTATION: Case presentation: A 46 year old male with hypoxia and respiratory failure from COVID-19 pneumonia supported with mechanical ventilation for several weeks developed refractory shock of multifactorial etiology. The patient was known to have pulmonary hypertension with dilated right atrial and ventricular pressure in addition to paradoxical septal motion, as seen on echocardiogram of recent past. Clinical examination revealed jugular venous distention and muffled heart sounds. Electrocardiogram detected sinus tachycardia and low cardiac voltage. Echocardiogram revealed large pericardial effusion without right atrial or ventricular collapse, and therefore cardiac tamponade was not considered as the cause of shock. As shock remained refractory to multiple vasopressors and inspiratory variation of the mitral valve inflow was noted on echocardiogram, it was decided to initiate pericardial drainage. However, the patient went into cardiac arrest before it could be performed. DISCUSSION: Discussion: A clinical diagnosis of cardiac tamponade can be made in the presence of Beck's triad. However, echocardiogram is most often relied on to make the diagnosis. The most sensitive echocardiographic findings of cardiac tamponade are right atrial and ventricular collapse.[2] Though sensitive, these changes may not be present in a patient who has preexisting elevated right sided intracardiac pressure. In such cases, the diagnosis must be based on clinical evidence and can be aided by the findings of exaggerated changes in mitral/tricuspid inflow during respiration. CONCLUSIONS: Conclusion: A hallmark finding of cardiac tamponade is right atrial or ventricular collapse on echocardiogram. However, these findings may be absent in the setting of elevated right-sided intracardiac pressure. The absence of right atrial or ventricular collapse in our patient can be attributed to the elevated right-sided intracardiac pressure due to pulmonary hypertension.[3] In such cases, the diagnosis of cardiac tamponade should be made on clinical grounds and pericardial drainage should not be delayed. REFERENCE #1: 1. Adams JR, Tonelli AR, Rokadia HK, Duggal A. Cardiac tamponade in severe pulmonary hypertension. A therapeutic challenge revisited. Ann Am Thorac Soc. 2015;12(3):455-460. REFERENCE #2: 2. Spodick DH. Acute cardiac tamponade. N Engl J Med. 2003;349(7):684-690. REFERENCE #3: 3. Vallabhajosyula, S., Kanuri, S., Sundaragiri, P., & Alla, V. (2014). Management of cardiac tamponade in severe pulmonary hypertension. Chest, 146(4). DISCLOSURES: No relevant relationships by George Apergis, source=Web Response No relevant relationships by Dushyant Damania, source=Web Response No relevant relationships by Aaron Douen, source=Web Response No relevant relationships by Padmanabhan Krishnan, source=Web Response No relevant relationships by George Mbolu, source=Web Response No relevant relationships by Ryan Panetti, source=Web Response