“Dead” Pregnant Pt with Hypertrophic Cardiomyopathy delivers baby, survives
Traditionally, mention a clinical vignette featuring a “20-something year-old male basketball player with no known medical or surgical history suddenly collapsing during a game” to any medical student and he or she will enthusiastically respond “Hypertrophic cardiomyopathy.”
After news released this weekend, a different vignette may be used to describe this rare but fascinating disease: A 32-year-old pregnant teacher collapses, experiences a seizure, and loses her pulse. After CPR is performed and a defibrillator is used, she temporarily regains a pulse only to lose it upon arrival to the hospital. An emergent Cesarean section is performed and the mother regains her pulse. A post-delivery workup reveals that the patient has hypertrophic cardiomyopathy.
News outlets, beginning with CNN last Friday, noted that since the 36-weeks pregnant patient Erica Nigrelli lacked a pulse, technically speaking, she delivered her baby while dead.
Given the miraculous news, let’s take a moment to review hypertrophic cardiomyopathy.
DEMOGRAPHICS The condition follows an autosomal dominant inheritance pattern in about 50% of cases, which is why after the fact, it may be found during a thorough family history that an uncle or other relative experienced sudden cardiac death. Males are affected more frequently than females in a 2:1 ratio, and blacks are affected more frequently than whites.
PATHOPHYSIOLOGY At a pathophysiologic level, abnormal myocardial structural proteins lead to heart muscle thickening and the cascade of events that jeopardize the normal beating of the heart.
SIGNS & SYMPTOMS Like Nigrelli, most patients are typically asymptomatic for years. When symptoms occur, the patient can suddenly experience a variety of dyspnea, chest pain, syncope, palpitations or dizziness.
The murmur of hypertrophic cardiomyopathy is systolic, while the left ventricle pumps blood through a partially obstructed outflow tract that develops due to a thickened interventricular septum. The classic description is crescendo-decrescendo.
Provocative maneuvers help to distinguish this murmur from others. Squatting, lifting the legs, or hand grip result in a less intense murmur. This is because squatting and passive leg lift cause an increase in the left ventricular volume and chamber size. Therefore, a reduction in the degree of outflow obstruction and turbulence results. Thus, the murmur is less intense. Handgrip increases afterload which decreases the pressure gradient across the aortic valve and thus also decreases murmur intensity.
On the flip side, maneuvers that decrease the left ventricular volume and chamber size –such as standing or performing a Valsalva–intensify the murmur.
DIAGNOSIS The diagnosis of hypertrophic cardiomyopathy is confirmed by transthoracic echocardiography showing left ventricular hypertrophy (LVH) and left ventricular outflow tract obstruction. On ECG, LVH and left atrial enlargement may be appreciated.
MANAGEMENT CNN and other news outlets didn’t discuss Nigrelli’s current treatment after she spent several weeks in the ICU. Medical management typically consists of beta blockers or the calcium channel blocker verapamil. These agents slow the heart rate, providing additional filling time. They also decrease the outflow tract gradient. Surgical removal of the excess, hypertrophied tissue in the septum–myectomy–can relieve the outflow obstruction and provide symptomatic relief. A more recent approach is to inject alcohol into the septum by percutaneous route, ablating and infarcting the excess tissue.