SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation: A 58 year-old woman with known hypertrophic cardiomyopathy (HCM) was hospitalized for clinical heart failure. Her HCM phenotype was concentric hypertrophy with mid-cavitary obstruction (MCO) and an associated large apical aneurysm. Her salient past medical history includes presentation for resuscitated sudden cardiac arrest with subsequent implantable cardioverter-defibrillator (ICD), and ventricular tachycardia (VT) endocardial and epicardial ablation for appropriate ICD shocks during VT storm. During her admission, she underwent transapical myectomy of her midventricle, resection of her apical aneurysm with endocardial cryoablation of its orifice, and Dacron patch aneurysmorrhaphy. She underwent pre- and post-operative cardiac magnetic resonance (CMR) studies, the latter revealing a large apical thrombus that was suspected with transthoracic echocardiography. Currently, she is being evaluated for cardiac transplantation.
Diagnostic Techniques and Their Most Important Findings:
CMR was performed using a 1.5T scanner (Avanto, Siemens, Erlangen, Germany). Electrocardiographic gated breath-hold steady-state free precession cine images were obtained in short axis slices at 10-mm intervals (slice thickness 6-mm, 4-mm gap) and 2-, 3-, and 4-chamber views. Gadolinium-based contrast agent (Dotarem, Guerbet, Villepinte, France) was injected in a 0.2 mmol/kg bolus and late gadolinium enhancement images were acquired ten minutes later using gradient echo sequences with inversion recovery in multiple slices. A long inversion time (TI) sequence (TI = 600 ms) was used to assess for the presence of intracardiac thrombus. Midcavity obstruction with apposition of left ventricular walls (Figure 1) as well as transmural scarring of the apical aneurysmal segments (Figure 2) were demonstrated pre-operatively, whereas a large de novo apical thrombus was revealed after cardiac surgery (Figure 3).
Learning Points from this Case: HCM with MCO is a well-established HCM phenotype that occurs in a minority of HCM patients.1,2 The presence of MCO has been associated with adverse outcomes in large HCM cohorts, including progression to end stage heart failure, sudden cardiac death, and ventricular arrhythmias. Apical aneurysms are a characteristic feature of HCM with MCO, occurring in an estimated 25-30% of such patients and thought to contribute to their poorer prognosis.1,2 Current data support transapical myectomy as an effective surgical therapy to relieve MVO and intracavitary gradients, with intermediate-term survival comparable to age and sex matched controls.3 While thrombus formation is a known complication of apical aneurysms, the incidence of postoperative thrombus after aneurysmectomy and endocardial cryoablation has not been reported in available surgical case series.3 Our case demonstrates dramatic CMR features of HCM with MCO before and after surgical management.