HFrEF with a Specific Cardiomyopathy: Becker Muscular Dystrophy

A 36-year-old male patient who had been diagnosed as Becker muscular dystrophy (BMD) 25 years ago, presented with acute decompensated heart failure (ADHF), having had three hospitalizations in the last three months requiring high doses of diuretics. The patient reported a one-month history of progressively worsening exertional dyspnea and bilateral lower extremity edema.

Investigation on admission

• Blood pressure: 92/61 mmHg
• Heart rate: 101
• Cardiac auscultation revealed S1, S2 heart sounds with S3 and a holosystolic murmur by left parasternal border.
• Bilateral pretibial edema was present (+3).
• BNP:4500 pg/ml, creatinine:1.3 mg/dl, potassium:4.8 pg/ml
• ECG: 2nd day Electrocardiogram demonstrated sinus rhythm (SR) with a heart rate (HR) of 82 beats per minute with signs of atrial dilatation.
   

_{12-lead ECG of the patient at admission}

• Chest CT: Thoracic computed tomography (CT) revealed an increased cardiothoracic ratio. The pulmonary trunk diameter was enlarged at 35 mm. The trachea and main bronchi were patent. There was an increase in the amount of pleural effusion on the left hemithorax, measuring approximately 2 cm. Interlobular septal thickening was noted bilaterally. Additionally, peripheral predominant ground-glass opacities and consolidations were observed in the right lung, consistent with the findings on the patient’s previous imaging.

Clinical Assessment

The patient, along with his history in the last year is consistent with the European Society of Cardiology (ESC) 2021 guidelines criteria for advanced heart failure, including:

• New York Heart Association (NYHA) Class III symptoms
• LVEF <30%
• Elevated NT-proBNP levels
• Requirement for high-dose intravenous diuretics

Additionally, the patient met several markers of poor prognosis defined by the AHA’s 'I NEED HELP' criteria¹,  associated with an estimated one-year all-cause mortality rate of approximately 46.5%:

• NYHA Class III symptoms
• LVEF below 20%
• More than one heart failure hospitalization within the last year
• Persistent fluid overload and escalating diuretic requirement
• Persistent low systolic blood pressure (<90–100 mmHg)
• Inability to tolerate or uptitrate guideline-directed medical therapy

Powered by Quiz Maker 

Management and Decision-Making

The patient’s medical therapy for heart failure with reduced ejection fraction (HFrEF) has been optimized thoroughly along with succesful decongestion via intravenous infusion of furosemide at 5-10 mg/hour dose for 6 days. The patient was on low dose ARB before admission with no tolerance to beta blockers previously. He was on strict low salt diet.

Despite persistent low blood pressure with fluctuating hypotensive symptoms during the course of hospitalization, “start low go slow principle” has been implemented and doses were carefully adjusted according to the peak effect of each agent. 

As initial plan, low salt diet was abandoned and in order to control sinus tachycardia, ivabradine 5 mg was administered bid given that resting heart rate is elevated in the absence of significant secondary reason given that the patient was intolerant to beta blockers¹.

Additionally, digoxin was added for heart rate control (1)  to decrease further HF related hospitalization.

Of note, he was completely intolerant to each trial of different beta blockers. The patient was also anticoagulated parenterally during hospitalization not only related to spontaneous echo contrast within the heart but also to history of deep vein thrombsis and pulmonary embolism and then switched to apixaban 5 mg twice Daily: 10 a.m, 10 p.m (before discharge).

Furthermore, the patient was referred to the inpatient respiratory and mobilization physiotherapy program in order to improve muscle weakness and low peripheral vascular resistance.

Given the history of frequent hospitalization with intolerance to optimal medical therapy, the patient, who had an INTERMACS profile of 4, was evaluated for left ventricular assist device (LVAD) implantation. Neurology consultance was obtained and it yielded moderate to high perioperative neurological risk. Special precautions were advised regarding malignant hyperthermia susceptibility during anesthesia. The patient and his family are currently discussing the options. He was discharged from the hospital with an outpatient appointment at the 10th day. A very low dose selective beta blocker is planned at the first visit along with outpatient hospitalization.

Literature reports demonstrate successful outcomes of LVAD implantation and heart transplantation in selected patients with Becker muscular dystrophy². Critical factors influencing candidacy and postoperative prognosis include preserved respiratory function, adequate mobility, and swallowing capacity.

Specific cardiomyopathies which yield HFrEF phenotype are treated as such via quadruple GDMT though these patients are usually excluded from the clinical trials in which evidence is generated.

In these patients, several problems can potentially interfere with optimization of GDMT, and low blood pressure is a critical limiting factor.

However, as pointed out in the recent consensus statement of HFA³, it is possible to achieve much of the GDMT, and herein, SGLT2 inhibitors and MRA are potentially the most straightforward agents to begin with.

• Mustafa Goktug Erata: None 
• Mehmet Birhan Yilmaz: has received institutional fee from Bayer, Amgen, Novartis, Astra Zeneca, Boehringer Ingelheim, Novo Nordisk, Albert Health