People who have undergone the Fontan procedure have been known to be prone to developing arrhythmias, but few studies have evaluated their prognosis, so researchers from Australia and New Zealand analyzed results of more than 1,000 patients with Fontan circulation and found that two-thirds did not have any arrhythmia at 20 years, and that, among those who did have arrhythmias, almost three-quarters survived 10 years.

“After the first onset of an arrhythmia, close surveillance of ventricular function is required,” Thomas A. Carins, MD, and his colleagues reported ( J Thorac Cardiovasc Surg. 2016;152:1355-63 ). They analyzed data from 1,034 patients who had Fontan procedures from 1975 to 2014 in the Australia and New Zealand Fontan Registry. “The development of an arrhythmia is associated with a heightened risk of subsequent failure of the Fontan circulation,” they wrote.

The study aimed to determine the type of arrhythmias Fontan patients had and what impact that had on long-term outcomes. The most common Fontan approach used in study patients was the extracardiac conduit (555), followed by the lateral tunnel approach (269) and atriopulmonary (210). Those who had the extracardiac Fontan were least likely to develop an arrhythmia, with a hazard ratio of 0.23 (P less than .001), which Dr. Carins and his coauthors noted was in line with previous reports of arrhythmias occurring in patients who had undergone the atriopulmonary connection ( Circulation. 2004;109:2319-25 ; J Thorac Cardiovasc Surg. 1998;115:499-505 ).

Overall, 195 patients in the study developed arrhythmia, with 162 having tachyarrhythmia, 74 having bradyarrhythmia and 41 having both. “At 20 years, freedom from any arrhythmia, tachyarrhythmia, and bradyarrhythmia was 66%, 69%, and 85%, respectively,” the researchers said.

The following outcomes occurred after the first onset of arrhythmia – tachyarrhythmia in 153 patients and bradyarrhythmia in 42: Thirty-three died; 12 had heart transplants, 30 had a Fontan correction to an extracardiac conduit, three had a Fontan takedown, 12 developed enteropathy, and 25 developed New York Heart Association class III or IV symptoms. Eighty-four patients reached the composite endpoint of Fontan failure.

After they developed arrhythmias, most patients in all three Fontan procedure groups remained free from Fontan failure at 10 years: 67% in the extracardiac conduit group; 54% in the lateral tunnel group; and 51% in the atriopulmonary group.

Medical management of up to four medications was the preferred initial treatment for those with tachyarrhythmias (86%); 101 patients had a single episode of tachyarrhythmia at follow-up intervals of four to 13 years (7.6 year median). “Those who experienced a single versus multiple episodes of tachyarrhythmia showed comparable freedom from Fontan failure at 15 years,” noted Dr. Carins and his coauthors – with rates of 34% and 33%, respectively. Of the 74 patients with bradyarrhythmias, 66 received pacemakers.

“Survival after the onset of an arrhythmia was surprisingly good with 67% and 84% of patients alive at 10 years after the onset of a tachyarrhythmia and bradyarrhythmia, respectively,” the study authors said. “There was no association between occurrence of arrhythmia and survival.”

About 40% of the patients with a tachyarrhythmia or bradyarrhythmia in the study had reduced ventricular function at 10 years after onset, the researchers wrote. “Although the assessment of ventricular function in this study was clearly subjective, we nonetheless believe that these findings suggest that the onset of an arrhythmia is associated with a progressive deterioration in cardiac function,”they noted.

Coauthor Andrew Bullock, MBBS, disclosed receiving consulting fees from Actelion. Dr. Cairns and other coauthors had no financial relationships to disclose.


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