Utility of exercise testing in children and teenagers with arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is increasingly recognized as an important cause of exertional sudden death in otherwise healthy young individuals and athletes. Graded exercise testing is routinely included in the evaluation of patients with suspected ARVC, but its diagnostic utility has not been systematically assessed. Using a single-center retrospective design, the rhythm response to graded exercise testing was examined in 33 tests performed in 16 young (aged <18 years) patients with established diagnosis of ARVC. Ventricular premature complexes (VPCs) were classified as absent (graded 0), as being isolated or in couplets (graded 1), or as comprising nonsustained ventricular tachycardia (graded 2) during pretest rest, at peak exercise, and during postexercise recovery. VPCs were absent at rest in 21 of 33 studies, subsequently appearing at peak exercise in 4 studies and during recovery in 2 studies. Isolated VPCs and couplets were present at rest in 9 of 33 studies, with subsequent exercise provoking higher grade ectopic activity in 2 instances at peak exercise and in 1 case during recovery, while VPCs decreased or remained unchanged in all other cases. In all 3 instances in which ventricular tachycardia was observed during pretest rest, there was either suppression (3 at peak exercise, 2 during recovery) or no change (1 case during recovery) in VPC grade. In conclusion, the exercise response of ventricular ectopic activity is highly variable in young patients with ARVC. The diagnostic utility of graded exercise testing is thus questionable in young patients with suspected ARVC, and the absence or suppression of VPCs during exercise should not be considered reassuring in terms of its diagnostic exclusion.

Diagnosis and treatment of idiopathic ventricular tachycardia.

Idiopathic ventricular tachycardia in patients with an anatomically normal heart is a distinct entity whose management and prognosis differs from ventricular tachycardia associated with structural heart disease. The tachycardia's QRS morphology on surface electrocardiogram (ECG) predicts the site of origin and is commonly classified as right ventricular tachycardia or left ventricular tachycardia. The tachycardia is further characterized by clinical features such as repetitive monomorphic ventricular tachycardia (VT), paroxysmal sustained VT, or catecholamine dependent VT. The responsiveness of VT to adenosine or verapamil is useful in differentiating the mechanism, which may be reentry or triggered activity. Patients generally tolerate the tachycardia but may present with dizziness, syncope, or palpitations. Sudden cardiac death is rare in this patient population. Patient work-up should include 12-lead ECG, signal-averaged ECG, ambulatory ECG recording, stress testing, and tests to rule out structural heart disease such as echocardiography, cardiac angiography, endomyocardial biopsy, or magnetic resonance imaging. Treatment options include pharmacotherapy or catheter ablation. Although the prognosis of these patients remains excellent, they should continue to have periodic cardiac follow-up to rule out latent progressive heart disease such as arrhythmogenic right ventricular dysplasia or cardiomyopathy or other forms of cardiomyopathies.