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).