Abnormal Cardiac MRI

The patient is a 33-year-old male with hypertrophic cardiomyopathy (HCM), congenital perimembranous ventricular septal defect, and hypertension who presents to clinic for consultation of primary prevention implantable cardioverter-defibrillator (ICD). He has a family history of HCM in his mother, sister, and maternal uncle. His maternal uncle experienced sudden cardiac death (SCD) status post ICD placement and subsequently underwent orthotopic heart transplantation. His mother and sister both have an ICD in place. He denies experiencing any chest pain, shortness of breath, paroxysmal nocturnal dyspnea, orthopnea, palpitations, dizziness, lightheadedness, syncope, near syncope, or pedal edema. He is currently prescribed losartan 50mg daily.

His electrocardiogram (ECG) showed normal sinus rhythm with a heart rate of 80 beats per minute. There is a possible old septal infarction of undetermined age. The QT interval is 406 milliseconds.

Figure 1

Figure 1

A Holter monitor showed 2 premature ventricular contractions (PVCs), 1 premature atrial contraction (PAC), and no arrhythmias.

A transthoracic echocardiogram showed concentric left ventricular hypertrophy (LVH) with septal thickness of 1.5 cm. 

A cardiac magnetic resonance imaging (MRI) showed asymmetric septal hypertrophy (ASH) that was at maximum 2.4 cm without evidence of left ventricular outflow tract (LVOT) obstruction, a small perimembranous ventricular septal defect (VSD), normal biventricular function, and diffuse patchy midwall fibrosis involving more than 15% of the myocardium.

Figure 2a and b

Figure 2
Figure 2a and b: Cardiac MRI short axis and long axis views showing late gadolinium enhanced fibrosis (see arrows).

What is the most appropriate next step?

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