Ventricular Fibrillation in a Patient with Marfan Syndrome without Severe Valvular Disease or Ventricular Dysfunction.

An increased incidence of ventricular fibrillation (VF) has been reported in patients with Marfan syndrome (MFS) compared with the general population. Although reduced left ventricular systolic function and severe valvular disease are recognized as major risk factors for ventricular arrhythmias (VAs) in MFS, we report a case of VF that developed despite the absence of these risk factors.A 22-year-old man with MFS who had previously undergone a valve-sparing aortic root replacement with the David procedure, lost consciousness and was diagnosed with VF. After resuscitation, no new abnormal findings were observed except for mild QT prolongation (QTc 471 msec) and a slightly elevated B-type natriuretic peptide level (89.0 pg/mL). An echocardiogram revealed no significant changes compared with the previous examination. It showed that the ejection fraction was preserved and that there was mild aortic valve regurgitation and mild-to-moderate mitral valve regurgitation. Whole-exome sequencing analysis revealed no pathogenic variants, except for an FBN1 variant that was already known to be present. He was diagnosed with idiopathic VF and was implanted a subcutaneous implantable cardioverter-defibrillator.This case underscores the risk of VAs in MFS even in the absence of ventricular dysfunction or severe valvular diseases. A combination of various factors, such as subtle depolarization abnormalities, moderate valvular abnormalities, and underlying myocardial damage, may contribute to the development of VF. More careful surveillance and precise identification of risk factors for arrhythmias are warranted.