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Paradoxical Pulmonary Congestion After Mavacamten in Obstructive HCM: A Case Illustrating Hemodynamic Transition
Noriaki Tabata1, Yasuhiro Izumiya2, Noriko Nomura3
1Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan; Tabata Internal Medicine and Heart Clinic, Kumamoto, Japan.
Background:
Mavacamten effectively reduces left ventricular outflow tract (LVOT) obstruction in hypertrophic cardiomyopathy (HCM).
Case Summary:
A 51-year-old man with obstructive HCM developed paradoxical pulmonary congestion after successful LVOT relief with mavacamten. Despite a dramatic reduction in LVOT gradient and preserved ejection fraction, he experienced dyspnea and pleural effusion in week 6. Notably, an increase in tricuspid regurgitation pressure gradient and E/A ratio preceded clinical congestion. Initiation of an SGLT2 inhibitor led to clinical stabilization and hemodynamic re-equilibration by week 8.
Discussion:
This case illustrates a "functional dam" mechanism, where rapid LVOT obstruction relief may increase forward flow, potentially overwhelming a noncompliant left ventricle.
Take-Home Messages:
Relief of LVOT obstruction can be associated with paradoxical pulmonary congestion despite apparent left-sided unloading. This observation highlights the importance of comprehensive noninvasive hemodynamic assessment during the early treatment phases of obstructive HCM.
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