Case presentation
A 46 year old female with a reported history of HCM, but poor cardiology follow up, presented to the hospital with progressively worsening symptoms of congestive heart failure. Prior to presentation, she experienced flu-like symptoms for a week which were treated by her primary care physician with oral antibiotics and as needed albuterol inhaler. She reported an initial improvement of her symptoms, however, soon noted development of rapid-onset palpitations, presyncope, dyspnea on exertion, and lower extremity edema prior to presenting to the emergency department. On arrival she was hemodynamically stable but found to be in atrial fibrillation with rapid ventricular response. She was noted to have mild pulmonary edema, otherwise with a warm and well perfusing clinical profile, and oxygenating well on room air. She was admitted and started on rate control with a diltiazem infusion along with systemic anticoagulation and intravenous diuresis.
TTE obtained on hospitalization day 1 raised significant concerns for HCM given the findings of asymmetric basal septal hypertrophy with a maximum width of 2.2 cm, hyperdynamic LV systolic function, and peak LV outflow tract (LVOT) gradient of 70 mm Hg at rest. Systolic anterior motion of the anterior mitral valve leaflet and moderate mitral regurgitation were also noted.
Given the TTE findings, as well as episodes of non-sustained ventricular tachycardia on telemetry, a CMR was obtained on hospital day 3 to look for risk factors for sudden cardiac death (Figure 1). The latter revealed marked basal anterior LV hypertrophy with shifting geometry symmetrically towards the apex in a counter-clockwise, spiral pattern, characteristic of spiral variant HCM (Figure 1). Late gadolinium enhancement (LGE) of greater than 20% of the myocardium was noted. Due to poorly tolerated atrial fibrillation, the patient was cardioverted back to normal sinus rhythm and was started on oral metoprolol to reduce inotropy and LVOT gradients. After successful cardioversion, a repeat TTE with the administration of (UEA) was performed on hospital day 6 to reassess the peak LVOT gradient and attempt to visualize the spiral variant HCM (Figure). The peak LVOT was noted to improve to 51 mm Hg and the spiral HCM geometry was well visualized but only appreciated after administration of UEA to define the endomyocardial borders (Figure).