Peak oxygen uptake, ventilatory efficiency and QRS-duration predict event free survival in patients late after surgical repair of tetralogy of Fallot.

Abstract

OBJECTIVE:

Patients with repaired tetralogy of Fallot (ToF) have an increased long-term risk of cardiovascular morbidity and mortality. Risk stratification in this population is difficult. Initial evidence suggests that cardiopulmonary exercise testing (CPET) may be helpful to risk-stratify patients with repaired ToF.

METHODS AND RESULTS:

We studied 875 patients after surgical repair for ToF (358 females, age 25.5 ± 11.7 year, range 7-75 years) who underwent CPET between 1999 and 2009. During a mean follow-up of 4.1 ± 2.6 years after CPET, 30 patients (3.4%) died or had sustained ventricular tachycardia (VT). 225 patients (25.7%) had other cardiac related events (emergency admission, surgery, or catheter interventions). On multivariable Cox regression-analysis, %predicted peak oxygen uptake (V˙O2 %) (p=0.001), resting QRS duration (p=0.030) and age (p<0.001) emerged as independent predictors of mortality or sustained VT. Patients with a peak V˙O2 ≤ 65% of predicted and a resting QRS duration ≥ 170 ms had a 11.4-fold risk of death or sustained VT. Ventilatory efficiency expressed as V˙E/V˙CO2 slope (p<0.001), peak V˙O2 % (p=.001), QRS duration (p=.001) and age (p=0.046) independently predicted event free survival. V˙E/V˙CO2 slope ≥ 31.0, peak V˙O2 % ≤ 65% and QRS duration ≥ 170 ms were the cut-off points with best sensitivity and specificity to detect an unfavorable outcome.

CONCLUSIONS:

CPET is an important predictive tool that may assist in the risk stratification of patients with ToF. Subjects with a poor exercise capacity in addition to a prolonged QRS duration have a substantially increased risk for death or sustained ventricular tachycardia, as well as for cardiac-related hospitalizations.

• Authors: Jan Müller, Alfred Hager, Gerhard-Paul Diller, Graham Derrick, Roselien Buys, Karl-Otto Dubowy, Tim Takken, Stefan Orwat, Ryo Inuzuka, Luc Vanhees, Michael Gatzoulis, Alessandro Giardini
• Journal: International journal of cardiology (Int J Cardiol) Vol. 196 Pg. 158-64 (Oct 01 2015) ISSN: 1874-1754 [Electronic] Netherlands
• PMID: 26114442 (Publication Type: Journal Article, Multicenter Study)
• Copyright: Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Topics

• Adolescent
• Adult
• Aged
• Child
• Disease-Free Survival
• Electrocardiography
• Exercise Test
• Exercise Tolerance (physiology)
• Female
• Humans
• Male
• Middle Aged
• Oxygen Consumption (physiology)
• Pulmonary Ventilation (physiology)
• Retrospective Studies
• Risk Factors
• Tachycardia, Ventricular (epidemiology)
• Tetralogy of Fallot (mortality, physiopathology, surgery)
• Young Adult