Abstract 128: Evolution of Clinical Diagnosis in Patients Presenting with Unexplained Cardiac Arrest
Background Systematic evaluation of patients with unexplained cardiac arrest can lead to a diagnosis in 50% of cases. However; evolution of clinical phenotype, identification of new disease-causing mutations and description of new syndromes may result in a change in diagnosis
Methods Diagnoses were reviewed for all patients with at least one year of follow-up in the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER), who presented with unexplained cardiac arrest or symptomatic polymorphic VT and had no significant coronary disease, normal ventricular function and a normal electrocardiogram (ECG).
Results A total of 68 patients were included, with an average age of and 45 ± 15 years. Twenty-five (37%) were female. Their diagnosis following initial investigations was: idiopathic VF (34); long QT syndrome (9); CPVT (7); ARVC (5); myocarditis (3); coronary spasm (4); early repolarization (3); Brugada syndrome (2) and myocardial infarction (1). Patients were followed for 30 ± 17 months, during which time, the clinical diagnosis changed in 12 (18%) patients. In 6 cases, a diagnosis of idiopathic VF was changed to early repolarization syndrome, after the publication of the Haissaguerre series and re-analysis of baseline ECGs. Conversely, one diagnosis of early repolarization was changed to idiopathic VF. In another case, a diagnosis of early repolarization syndrome was changed to long QT syndrome based on new ECG abnormalities. A case of ARVC was re-classified as sarcoidosis based on autopsy findings and a case diagnosed as CPVT was changed to cardiomyopathy, based on evolution of left ventricular dysfunction and detection of a disease-causing phospholambin mutation In a final case, a diagnosis of long QT syndrome was changed to ARVC, based on the demonstration of a class I genetic mutation. At the time of last follow-up, 30% of diagnoses were classified as definite, 34% as probable and 36% as possible. Diagnosis was based on phenotype alone in 81%, both phenotype and genotype in 12% and genotype alone in 7%.
Conclusions Re-evaluation of patients presenting with unexplained cardiac arrest may lead to a change in diagnosis in up to 20%; which could have implications for the treatment of these patients and the screening of their relatives.
- © 2011 by American Heart Association, Inc.