Diagnostic Value of Isoproterenol Testing in Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)
Background—Although the Task Force Criteria (TFC) for ARVC have recently been updated the diagnosis remains challenging in the early stages. The aim of this study was to evaluate the diagnostic value of β-adrenergic stimulation in arrhythmogenic right ventricular cardiomyopathy (ARVC).
Methods and Results—We evaluated 412 consecutive patients (213 men, age 41.5±16 years) referred for premature ventricular contractions (PVCs) evaluation or suspected ARVC. Isoproterenol testing was performed with continuous infusion of isoproterenol (45 μg/min) over 3 minutes). It was considered positive if there were either (1) polymorphic PVCs with at least one couplet or (2) sustained or non-sustained ventricular tachycardia (VT) with LBBB excluding right ventricular outflow tract VT. ARVC was diagnosed in 35 patients at initial evaluation (23 men, aged 42±15 years). Isoproterenol testing was positive in 32/35 (91.4%) ARVC patients and in 42/377 (11.1%) patients without ARVC (p<0.0001). Sensitivity, specificity, positive and negative predictive values of isoproterenol testing to diagnose ARVC were 91.4%, 88.9%, 43.2% and 99.1% respectively. During a mean follow-up period of 5.6±4.4 years, 6 additional patients met diagnostic criteria for ARVC. Importantly initial isoproterenol testing was positive in 6/6 (100%) of these patients. Survival free from ARVC diagnosis was significantly lower in the positive isoproterenol group than in the negative isoproterenol group (p<0.0001, exact log-rank test).
Conclusions—Ventricular arrhythmogenicity during isoproterenol testing is highly sensitive (sensitivity 91.4%) for the diagnosis of ARVC, particularly in its early stages.
- arrhythmogenic right ventricular dysplasia/cardiomyopathy
- ventricular arrhythmia
- Received November 2, 2011.
- Revision received May 30, 2014.
- Accepted June 2, 2014.