Recurrent hypotension induced by sacubitril/valsartan in cardiomyopathy secondary to Duchenne muscular dystrophy: A case report

Abstract

Background: Duchenne muscular dystrophy (DMD), which is caused by a mutation/deletion in the dystrophin gene on the X-chromosome, is the most common type of neuromuscular disorder in pediatrics. Skeletal muscle weakness progressively develops in DMD patients and usually leads to respiratory failure in the early adolescent years. Cardiac muscle is frequently affected in DMD patients, which leads to a high burden of cardiomyopathy and heart failure. In the era of improved respiratory care, cardiac deaths are becoming the major cause of mortality in DMD patients.

Case summary: We report the case of a 15-year-old boy who presented to the hospital due to recurrent orthopnea for 6 mo and palpitations for 4 mo. He was diagnosed with progressive muscular dystrophy at the age of 3 years and was confined to a wheelchair at 12 years. He was prescribed diuretics and digoxin at the outpatient clinic; however, his symptoms did not resolve. Sacubitril/valsartan was added 1 mo prior to presentation, but he experienced recurrent episodes of palpitations. The electrocardiogram showed atrial tachycardia with a heart rate of 201 bpm, and he was then hospitalized. Hypotension was found following the administration of sacubitril/valsartan tablets; he could not tolerate even a small dose, always developing tachyarrhythmia. His symptoms were relieved after discontinuing sacubitril/valsartan, and his heart rate was controlled by a small dose of metoprolol tartrate and digoxin. Atrial tachycardia spontaneously converted in this patient, and his symptoms attenuated in the following 6 mo, without palpitation episodes.

Conclusion: Blood pressure should be closely monitored in DMD patients with advanced heart failure when taking sacubitril/valsartan.

Keywords: Case report; Duchenne muscular dystrophy; Heart failure; Hypotension; Sacubitril/valsartan.

Figure 1

Electrocardiogram recorded at the Emergency Department. The electrocardiogram shows atrial tachycardia with Wenckebach block, Q waves in leads I, V₅ and V₆, and large R waves in leads V₁ and V₂.

Figure 2

Echocardiogram of the patient. A: Parasternal long axis view; B: Apical four-chamber view. Whole heart enlargement with cardiac dysfunction was found with mild mitral regurgitation, mild to moderate tricuspid regurgitation and moderate pulmonary hypertension (PASP = 51 mmHg). The left ventricular ejection fraction was 23% as calculated using Simpson’s Formula.

Figure 3

Cardiac magnetic resonance imaging of the patient. A, B: Long-axis view of the heart, in diastole (A) and systole (B); C, D: With late gadolinium enhancement imaging, the short-axis view (C) and long-axis view (D) demonstrated multi-segmental abnormal enhancement at lateral, anterolateral and part of the inferior wall of the left ventricle.

Figure 4

Electrocardiogram at the time of symptom relief. Electrocardiogram shows sinus rhythm, right heart hypertrophy, Q waves in leads I, V₅ and V₆, and large R waves in leads V₁ and V₂.