Background: There is growing evidence that mitral valve prolapse (MVP) is an important cause of unexplained cardiac arrest (UCA). However, this evidence is limited by selection bias and/or the absence of a systematic assessment for potential causes
Objective: To report the prevalence and characteristics of patients with MVP in the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER)
Methods: Patients were enrolled following an UCA, defined as no significant coronary disease and a normal ejection fraction. A comprehensive work-up including provocative testing, cardiac imaging, and genetic testing were performed. Working diagnoses were divided into definite, probable and possible diagnoses based on standardized criteria. For the current study, those with identifiable or reversible causes were excluded. Echocardiography reports were systematically reviewed for MVP and exercise treadmill tests (ETT) were examined for ventricular arrhythmia
Results: Among 385 patients with no identifiable or reversible cause of UCA, 24 patients had MVP (6%). Patients with MVP had similar clinical characteristics but were less likely to have an alternative diagnosis (p=0.05) and more likely to have T-wave inversions on ECG (p=0.04); compared to those without MVP (Table 1). UCA occurred during mild activity or exercise in the majority of MVP patients (55%) and ETT was abnormal in 4/14 patients (29%)
Conclusion: The prevalence of MVP in a national registry of UCA survivors who underwent systematic evaluation was 6%. MVP patients typically presented with cardiac arrest during activity. T-wave inversions on ECG and ventricular arrhythmia on ETT were found in a significant proportion