Ventricular Arrhythmia at a Cardiopulmonary Exercise Test as Predictor for Severe Arrhythmic Events in Patients with Complex Congenital Heart Disease on 36 Months Follow-up

Objective: Cardiopulmonary exercise testing (CPET) in patients with complex congenital heart disease (CHD) provides relevant information for clinical evaluation and risk stratification. The goal of this retrospective study was to assess predictability of ventricular arrhythmias during CPET for severe arrhythmic events (SAEs) later in life.

Methods: Number of premature ventricular complexes and occurrence of couplets, triplets, bigeminy, trigeminy, and nonsustained or sustained ventricular tachycardia (VT) were recorded from CPET data. Outcome during 36 months follow-up after CPET was recorded from medical chart review. SAEs were defined as a composite of sudden death, aborted sudden death, appropriate discharge of implantable cardioverter-defibrillator (ICD), hospitalization for ventricular arrhythmias, and occurrence of nonsustained or sustained VT on Holter, pacemaker, or ICD read.

Results: Clinical data from 371 patients (42.6% female) were analyzed. Diagnoses were single ventricle physiology in 68, tetralogy of Fallot in 131, transposition of the great arteries in 116, Ebstein anomaly in 35, and truncus arteriosus in 21 patients. Age at the time of CPET was 25.0 ± 10.7 years.

The table shows the comparison of patients with and without SAEs on follow-up with regard to ventricular rhythm disturbances during CPET. Patients with no ventricular arrhythmia at CPET had a lower occurrence of SAEs. Frequency and mean duration of bigeminy and trigeminy and presence of couplets and triplets were not different between patients with and without SAEs on follow-up. No patient experienced VT during CPET.

Conclusion: Patients with complex CHD and no ventricular arrhythmia during CPET are at a slightly lower risk for SAEs during follow-up. Severity of ventricular rhythm disturbances did not seem to influence outcome in this cohort. Risk stratification for SAEs in patients with complex CHD should include evaluation of rhythm disturbances during CPET, but more sensitive markers are warranted.

	No severe arrhythmic event	Severe arrhythmic event	p-Value
Abbreviations: PVC, premature ventricular complex; std, standard deviation.
aBigeminy and trigeminy length defined as number of beats in longest episode that occurred.
No ventricular arrhythmia, N/n (%)	176/319 (55.2)	20/52 (38.5)	0.035
PVC number (mean ± std)	5.1 ± 13.2	10.0 ± 21.3	0.115
Bigeminy, N/n (%)	14/319 (4.4)	3/52 (5.8)	0.717
Bigeminy lengtha (mean ± std)	12.1 ± 14.6	17.0 ± 9.2	0.587
Trigeminy, N/n (%)	3/319 (0.9)	2/52 (3.9)	0.146
Trigeminy lengtha (mean ± std)	26.7 ± 29.0	3 ± 0	0.354
Couplets, N/n (%)	30/319 (9.4)	10/52 (19.2)	0.186
Triplets, N/n (%)	6/319 (1.9)	1/52 (1.9)	1