Case Presentation: 65 year old female with history of rheumatoid arthritis on methotrexate and hydroxychloroquine, prior gastric ulcers on EGD, who was admitted to the hospital with bloody diarrhea, epigastric pain, acute blood loss anemia found to have duodenal ulcer. Patient received 2 units of blood products on hospitals day one and four. Course had been complicated by new hypoxia, sepsis secondary to pneumonia on hospital day 5, for which she was started on antibiotics and received 1 unit of fluids. Given concern for hypoxia, patient received diuretics on hospital day 7. On hospital day 8, patient with progressive hypoxic respiratory failure, requiring ICU transfer, found to have multifocal ground glass and consolidative opacities concerning for pulmonary edema. Her echocardiogram showed severe concentric left ventricular hypertrophy (LVH), anterior mitral valve leaflet systolic anterior motion (SAM) at rest, with LVOT gradient of up to 71 mmHg provoked with Valsalva. She was ultimately diagnosed with hypertrophic cardiomyopathy (HCM) with left ventricular outflow tract obstruction. She was fluid resuscitated with 3L of IV fluids with improvement in her LVOTO and clinical status.
Discussion: HCM is an autosomal dominant disease with mutations in genes encoding proteins of the cardiac sarcomere or sarcomere-related structures causing LVH. Although it was previously known as “HOCM”, one-third of patients are nonobstructive (Maron et al). It is characterized by LVH in the absence of another cardiac, systemic, or metabolic disease capable of producing hypertrophy (Maron). Diagnosis is made with echocardiogram, which shows an unexplained increased LV wall thickness ≥15 mm anywhere in the LV wall and the presence of a peak LVOT gradient of ≥30 mmHg indicates obstruction (Maron). Systolic displacement of the distal portion of the anterior leaflet of the mitral valve (SAM) towards the outflow tract of the left ventricle and can cause LVOTO and mitral valve regurgitation. LVOTO is dynamic and sensitive to ventricular load and contractility and is worsened by increased myocardial contractility, decreased preload, or decreased afterload (Nickson). Treatment of HCM in the acute setting is focused on minimizing the effect of the obstruction and utilizing pure alpha agonists to reduce cardiac contractility, heart rate and LVOT velocity. Short acting beta blockers can further decrease the heart rate and cardiac contractility. Chronic management includes avoiding intense exercise, dehydration and exposures that can cause vasodilation and decreased preload. Surgery or septal ablation is indicated for patients with an outflow tract gradient of >50 mm Hg and continuing symptoms despite maximal drug therapy (Maron et al, Ommen et al).
Conclusions: LVOTO and SAM are important to identify as they can contribute to a low output state that paradoxically worsens with increased inotropic support (Nickson). This case illustrates the effects of intravascular hypovolemia via acute blood loss and vasodilation, such as that seen in sepsis, on worsening SAM and LVOTO. In this case, the obstruction caused acute pulmonary edema, mimicking a state of volume overload; however, the treatment with additional fluid was critical to overcome the obstruction, as opposed to diuresis such as in classic heart failure.