Double‐chambered right ventricle complicated by hypertrophic obstructive cardiomyopathy diagnosed as Noonan syndrome

Abstract

We present a case of double-chambered right ventricle (DCRV) complicated by hypertrophic obstructive cardiomyopathy (HOCM) in KRAS mutation-associated Noonan syndrome. The diagnosis was incidental and made during diagnostic testing for an intradural extramedullary tumour. Spinal compression, if not surgically treated, may cause paralysis of the extremities. We decided to pursue pharmacological therapy to control biventricular obstructions and reduce the perioperative complication rate. We initiated treatment with cibenzoline and bisoprolol; the doses were titrated according to the response. After 2 weeks, the peak pressure gradient of the two RV chambers decreased from 101 to 68 mmHg, and the LV peak pressure gradient decreased from 109 to 14 mmHg. Class 1A antiarrhythmic drugs and β-blockers decreased the severe pressure gradients of biventricular obstructions caused by DCRV and HOCM. The patient was able to undergo surgery to remove the intradural extramedullary tumour, which was diagnosed as schwannoma.

Case report: Double-chambered right ventricle diagnosed in a middle-aged female with hypertrophic cardiomyopathy and atrial flutter: A rare case

“…However, DCRV complicated by HCM is an extremely rare coexistence. Several cases reported this unique condition complicated with HCM (2,5,6). With respect to the combination of arrhythmias, Alvarez et al reported that, in two adult patients diagnosed with DCRV, complicated by sustained monomorphic ventricular tachycardia, tachycardia did not reoccur after surgical excision of the abnormal muscle bundles (7).…”

“…Since some patients with DCRV do not experience progressive RVOT blockage during the normal course of the disease, basic follow-up is sufficient for patients with no significant lesions and little or no pressure gradient in the RV (4,16,17). Negative inotropic drugs, such as beta-blockers and calcium channel antagonists, may be effective in improving symptoms (2,12). If the obstruction worsens during follow-up, surgical repair may be considered.…”

“…Double-chambered right ventricle (DCRV) is a rare congenital heart disease (CHD) characterized by abnormal muscle bundles, resulting in intra-cavity obstruction in which the right ventricle (RV) is divided into a high-pressure chamber near the tricuspid valve and a low-pressure chamber near the pulmonary valve (PV) (1). DCRV accounts for only 0.5-2% of all CHD cases (2). Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiac disease.…”

“…About 2/3 of patients experience left ventricular outflow tract obstruction, known as hypertrophic obstructive cardiomyopathy (HOCM) (3). Yamamoto et al first described HOCM in a DCRV patient with Noonan syndrome (2). Imaging examinations play an important role in the diagnosis of DCRV with HCM.…”

Double chambered right ventricle in a patient with hypertrophic cardiomyopathy. A unique coexistence

“…Park et al described an 80-year-old HCM-patient with DCRV who experienced recurrent hypotension and chest discomfort during hemodialysis [3]. Yamamoto reported most probably the first case of a 47-years-old DCRV-patient coexisting with severe left ventricle outflow tract obstruction (LVOTO) [4]. We describe a HCM-patient in whom DCRV was diagnosed in adulthood.…”