Abstract 4369971: A Hemodynamic Warning Sign: Continuous Mitral Regurgitation and Normal Sinus Rhythm

Introduction: Continuous mitral regurgitation (MR) is a rare echocardiographic finding. Diastolic MR, although uncommon, is typically associated with atrioventricular (AV) dissociation such as complete heart block, bradycardia, or ventricular pacing. It may also occur when elevated left ventricular end-diastolic pressure (LVEDP) reverses the normal transmitral gradient. We present a case of a critically ill patient with acute embolic stroke, found to have multivalvular infective endocarditis with severe aortic regurgitation (AR) and continuous MR attributed to elevated LVEDP. Case Description: A 37-year-old male with a history of intravenous drug use, tricuspid valve endocarditis (2022), and hepatitis C presented as a Code Stroke after being found unresponsive with left sided weakness. Imaging revealed a large right middle cerebral artery infarct. Blood cultures grew Enterococcus faecalis. Transthoracic echocardiogram showed mild LV dilation with preserved EF (55–60%), a small vegetation on the mitral valve with mild-to-moderate MR, and multiple large vegetations on the aortic valve with leaflet prolapse causing severe AR. Notably, MR persisted into diastole despite sinus rhythm, with no AV dissociation on ECG or telemetry. He was admitted to the ICU for stabilization and surgical planning. Discussion: While diastolic MR typically results from AV dissociation, in this case, the diastolic component was due to markedly elevated LVEDP from acute-on-chronic severe AR. Chronic AR likely led to LV dilation, and acute worsening from valve destruction reversed the diastolic mitral pressure gradient, producing regurgitation during filling. Though previously described in isolated reports, continuous MR (with both systolic and diastolic components) is rarely documented in the setting of native valve endocarditis. This finding reflects critical hemodynamic compromise and carries implications for urgent surgical intervention. Conclusion: This case highlights continuous MR as a marker of elevated LVEDP in the absence of AV dissociation, occurring due to acute worsening of chronic AR in the setting of infective endocarditis. Recognizing this pattern is essential, as it signifies significant volume overload and impending decompensation.