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


Yamamoto M, Takashio S, Nakashima N, Hanatani S, Arima Y, Sakamoto K, Yamamoto E, Kaikita K, Aoki Y, Tsujita K.

ESC Heart Fail. 2020 Apr;7(2):721-726. doi: 10.1002/ehf2.12650. Epub 2020 Feb 20.

PMID: 32078254 Free PMC Article

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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.



Figure 1 Gadolinium‐enhanced magnetic resonance imaging shows the intradural extramedullary tumour.

Figure 2 Electrocardiogram on admission.

Figure 3 Enhanced computed tomography shows (A) LV hypertrophy causing left LVOT obstruction (arrowhead), (B) cord‐like structure sequencing of the anterior tricuspid valve leaflet (arrowhead), and (C) RV (three arrowheads). LV, left ventricle; LVOT, left ventricular outflow tract; RV, right ventricle.

Figure 4 Gadolinium‐enhanced cardiovascular magnetic resonance imaging shows (A) late gadolinium enhancement at the RV junction (arrowhead) and (B,C) a flow void sign at the LV and RV outflow tracts (arrowhead). LV, left ventricle; RV, right ventricle.

Figure 5 Right ventriculography of the (A) systolic and (B) diastolic phases shows right ventricular hyperkinetic contraction and outflow obstruction.

Figure 6 Intracardiac pressure on heart catheterization: (A) control and (B) after intravenous injection of disopyramide (50 mg). Ao, aorta; LV, left ventricle; PA, pulmonary artery; RV, right ventricle; PG, pressure gradient.