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

Area of Science:

• Cardiology
• Genetics
• Neurology

Background:

• Noonan syndrome is a genetic disorder associated with various cardiac anomalies.
• Double-chambered right ventricle (DCRV) and hypertrophic obstructive cardiomyopathy (HOCM) are significant cardiac complications.
• KRAS mutations are increasingly recognized in Noonan syndrome, influencing clinical presentation.

Observation:

• A patient with KRAS mutation-associated Noonan syndrome was incidentally diagnosed with DCRV and HOCM during workup for an intradural extramedullary tumor.
• The patient presented with severe biventricular pressure gradients (RV: 101 mmHg, LV: 109 mmHg).
• Spinal compression from the tumor posed a risk of neurological deficits.

Findings:

• Pharmacological therapy using cibenzoline (Class 1A antiarrhythmic) and bisoprolol (beta-blocker) was initiated to manage the cardiac obstructions.
• After two weeks of treatment, significant reductions in pressure gradients were observed (RV: 68 mmHg, LV: 14 mmHg).
• The medical management successfully reduced the severity of biventricular outflow tract obstruction.

Implications:

• This approach highlights the potential of targeted pharmacotherapy in managing complex cardiac conditions in genetic syndromes.
• Controlling biventricular obstruction pharmacologically can mitigate perioperative risks, facilitating necessary non-cardiac surgeries.
• This case underscores the importance of comprehensive cardiac evaluation in patients with Noonan syndrome, even when presenting for unrelated conditions.