Elsevier

International Journal of Cardiology

Volume 168, Issue 2, 30 September 2013, Pages 1458-1465
International Journal of Cardiology

Arrhythmia and exercise intolerance in Fontan patients: Current status and future burden

https://doi.org/10.1016/j.ijcard.2012.12.055Get rights and content

Abstract

Background

Long-term survival after the Fontan procedure shows excellent results but is associated with a persistent risk of arrhythmias and exercise intolerance. We aimed to analyze the current burden of clinically relevant arrhythmia and severe exercise intolerance in Danish Fontan patients and furthermore, to estimate the future burden from analysis of mortality and the current burden related to age.

Methods

All Danish citizens with Fontan completion from 1981 to 2009 were identified (n = 235). Surviving patients performed exercise test, Holter monitoring, echocardiography, pulmonary function test, and blood sampling and medical history was retrieved from medical records.

Results

Twenty-six (11%) patients died or had heart transplantation (HTx) after a mean (± SD) post-Fontan follow-up of 8.3 ± 5.7 years. Excluding perioperative deaths (n = 8), a linear probability of HTx-free survival was observed and estimated to 99.1% per year. Prevalence of clinically relevant arrhythmia and severe exercise intolerance increased significantly with age and was found in 32% and 85% of patients ≥ 20 years, respectively. Thus, from survival data and logistic regression models the future prevalence of patients, clinically relevant arrhythmia and severe exercise intolerance were estimated, revealing a considerable augmentation. Furthermore, resting and maximum cardiac index, resting stroke volume index and pulmonary diffusing capacity decreased significantly with age while diastolic and systolic ventricular function was unchanged.

Conclusions

The prevalence of clinically relevant arrhythmia and severe exercise intolerance increased significantly with age in Danish Fontan patients. The future Fontan burden was estimated showing an increase in the prevalence of older patients, clinically relevant arrhythmia, and severe exercise intolerance.

Introduction

Over the past four decades, the original Fontan operation and its many modifications have proved to be very successful procedures in patients with functionally univentricular hearts (UVH). The otherwise dismal natural history of UVH, with a survival rate of less than 50% at one year and 10% at ten years [1], has improved dramatically [2], [3] and surgical modifications have reduced the prevalence of Fontan-related complications markedly [4], [5]. Although not curative, these operations currently allow most young and middle-aged patients to enjoy almost normal daily activities, albeit frequently with a reduced effort tolerance [6]. Increasing long-term experience with these operations, however, has clearly confirmed their palliative nature with complications such as arrhythmias, exercise intolerance, heart failure, thromboembolism, protein-losing enteropathy frequently being recognized [7]. Consequently, evaluations concerning long-term complications are increasingly appreciated. Arrhythmias are frequently observed and associated with morbidity and mortality in Fontan patients [5], [8], [9]. Similarly, exercise capacity is an important determinant of health and provides numerous cardiovascular, psychological, and prognostic benefits [10] and exercise intolerance remains a powerful prognostic marker in patients with congenital heart disease [11].

Using a population-based design, we aimed to analyze the current burden of clinically relevant arrhythmia and severe exercise intolerance in Danish Fontan patients. Furthermore, we aimed to estimate the future Fontan burden from analysis of survival and the current clinical burden related to age.

Section snippets

Patients

The study included all surviving patients after the Fontan procedure in Denmark as per January 1st 2010. Fontan completions were performed from 1981 to 2009 (from 1981 to 1990 performed abroad) in the two tertiary pediatric cardiology centers; Rigshospitalet, Copenhagen and Aarhus University Hospital, Skejby, Aarhus. All surgical procedures were registered locally and all patients were followed up in either of the two operating centers or at Odense University Hospital, Odense.

The local ethics

Results

Baseline data of the study cohort and completion of examinations by age group are summarized in Table 1. Prevalence of morphological right ventricle as the systemic ventricle decreased significantly with increasing age group (p = 0.007) and age at Fontan completion increased significantly with increasing age group (p < 0.001).

Discussion

This population-based study assessed the survival, the current status of arrhythmias and exercise intolerance related to age, and estimated the future burden of Danish Fontan patients. The prevalence of arrhythmias and exercise intolerance increased significantly with age and the probability of HTx-free survival in perioperative survivors was 99.1% per year. From equations created from the current study, the future Fontan burden was estimated showing an increase in the prevalence of older

Conclusions

In conclusion, the prevalence of clinically relevant arrhythmias and severe exercise intolerance increased significantly with age in Danish Fontan patients. Furthermore, several parameters of the cardiopulmonary function decreased significantly with age. The probability of HTx-free survival in perioperative survivors was 99.1% per year. From equations created from results of the current study, the future Fontan burden was estimated showing an increase in the prevalence of older patients,

Disclosures

None.

Grant support

The Danish Register of Congenital Heart Disease was sponsored by The Danish Children's Heart Foundation, Aase and Ejnar Danielsen's Foundation, Wholesaler Sigurd Abrahamson and wife Addie Abrahamson's Foundation, The Beckett Foundation, The Danish Medical Research Council, and The Research Council of Department of Cardiology, Rigshospitalet.

Acknowledgment

The authors thank the nurses at the Section of Congenital Heart Disease at Aarhus University Hospital, Skejby, Aarhus and Rigshospitalet, Copenhagen for their assistance during patient visits in the outpatient department.

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