Abstract 4665: CASPER: Study Design and Preliminary Results in Probands from the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry
Cardiac arrest without evident cardiac disease may be caused by uncommon genetic conditions, including primary electrical disease and latent cardiomyopathy. The CASPER study was designed to assess the results of systematic assessment of patients with unexplained cardiac arrest (UCA - probands), their 1st degree relatives, 1st degree relatives of sudden cardiac death victims before age 35 with a negative autopsy, and patients with syncope and documented polymorphic VT. Patients with UCA and no evident cardiac disease (normal LV, no evidence of CAD and a resting QTc<480 msec for females, <460 msec for males) underwent systematic evaluation including cardiac MRI, SAECG, exercise testing, adrenaline and procainamide challenge, selective EP testing, voltage mapping, RV angiography and biopsy to unmask subclinical primary electrical or structural disease. Family members underwent non-invasive testing, with directed provocative and invasive testing. Standard diagnostic criteria were based on published criteria for ARVC, a positive drug challenge for LQTS or Brugada Syndrome (LQTS, BS), exercise or adrenaline-induced PMVT or bidirectional VT for CPVT, spontaneous transient ST segment elevation with ventricular arrhythmia for coronary spasm. Targeted genetic testing based on phenotype assessment is underway. 128 patients in 1 pediatric and 8 adult centers were enrolled (age 41±16 years, range 9 –79 years, 66 female). 66 patients received an ICD prior to or after enrollment. Enrollment to date has included 58 UCA patients, 25 first-degree relatives of the UCA proband, 27 first-degree relatives of sudden cardiac death victims, 7 first-degree relatives of primary electrical disease patients, and 9 patients with syncope and documented polymorphic VT. In the first 51 UCA probands, a diagnosis was obtained in 43% of patients: LQTS in 16%, CPVT in 12%, ARVC and coronary spasm in 6%, and BS in 4%. Systematic testing is useful in unmasking the etiology of apparent unexplained cardiac arrest or sudden death. The CASPER study approach helps to diagnose primary electrical diseases as well as latent structural causes of cardiac arrest.