Ventricular Arrhythmia in the Fontan Circulation:Prevalence,Risk Factors and Clinical Implications

Objective:Sudden cardiac death(SCD)and malignant ventricular arrhythmia(VA)are increasingly recognized as important issues for people living with a Fontan circulation,but data are lacking.We sought to characterize the cohort who had sudden cardiac death,most likely related to VA and/or documented VA in the Australia and New Zealand Fontan Registry including risk factors and clinical outcomes.Methods:A retrospective cohort study was performed.Inclusion criteria were documented non-sustained ventricular tachycardia,sustained ventricular tachycardia,ventricular fibrillation,resuscitated cardiac arrest or SCD>30 days post-Fontan completion.Results:Of 1611 patients,20(1.2%)had VA;14(1.0%)had VA without SCD and 6(<1%)had SCD(6%of all deaths recorded in Registry;5 of those had documented VA at the time of arrest and 1 was presumed to be VA-associated).The median age at first VA was 20.5(14–32)years,10(50%)were females,and the median age at Fontan operation was 8(4–17)years.On univariable analysis,hypoplastic left heart syndrome(p=0.03)and older age Fontan operation(p<0.001)were associated with VA.Earlier Fontan era(p<0.003),atriopulmonary Fontan(p<0.001),pre-Fontan atrioventricular valve repair(p=0.013)pre-or post-Fontan atrial arrhythmia(p=0.010)were associated with SCD.Patients with VA had a 3 times higher risk of death or heart transplant(HR 3.27(1.19,8.98),p=0.02).Conclusions:A proportion of people living with a Fontan circulation have malignant VA.Routine VA screening in this cohort is essential.More data are needed to aid risk stratification.

Preoperative Feeding in Single Ventricle Neonates is Predictive of Shorter Time to Goal Feed

Background:Patients with single ventricle anatomy are at increased risk of growth failure and malnutrition.Amongst cardiac centers,there is little standardization of feeding practices in this complex population.We hypothesized that initiation of our center’s preoperative feeding protocol would result in decreased gastrostomy tube(G-tube)use,decreased length of stay and would not result in increased Necrotizing Enterocolitis(NEC)rates.Methods:A single institution review of 52 patients who had undergone stage I single ventricle palliative repair was performed.Patient diagnoses were hypoplastic left heart syndrome(39%),atrioventricular canal(15%),and other(46%).Postoperative parameters such as time to goal feed and need for gastrostomy tube(G-tube)were compared among preoperatively fed and non-preoperatively fed groups.Time to goal feed was calculated as time from first postoperative enteral feed to goal volume of 100 mL/kg.Results:Of the 26 patients who met inclusion criteria for preoperative feeding,22 patients(85%)were fed prior to surgery.Cox proportional hazard ratio revealed that age at surgery(p=0.047)and being preoperatively fed(p=0.001)were associated with reaching goal feed sooner.Multivariable analysis revealed that being preoperatively fed made a patient twice as likely to reach goal feed sooner(p=0.047).Univariable logistic regression revealed that days on total parenteral nutrition(p=0.018),length of hospitalization(p=0.008),and time to 1st postoperative feed(p=0.020)were significantly associated with higher odds of needing a G-tube postoperatively.Multivariable logistic regression did not show any predictors of postoperative G-tube usage.However,there was a trend towards lower G-tube usage in the preoperatively fed group.Conclusions:Implementing a standardized preoperative feeding protocol in single ventricle neonates can result in significantly shorter time to goal feed in preoperatively fed patients.It is beneficial for institutions to begin implementing standard feeding protocols to improve nutrition and growth outcomes.

Associations between Bodyweight and Clinical Outcome in Patients Post-Fontan Procedure: A Systematic Review

Background: Patients born with a single ventricle circulation commonly experience growth failure in early life,which is associated with adverse outcomes in infancy. However, associations between bodyweight or weight trajectoryand clinical outcome post-Fontan procedure are yet to be determined. Methods: On the 1st of July 2021, asystematic review was performed in MEDLINE, EMBASE, the Cochrane Library, and Scopus of studies of patientswith clinical outcome data post-Fontan procedure and association with bodyweight. Quality of studies was evaluatedby Newcastle–Ottawa scale for cohort studies and Joanna Briggs Institute tool for cross-sectional studies.Results: Of 527 studies that underwent title and abstract screening, 15 were selected for final review. An increasedrisk of adverse post-Fontan outcomes was found for low weight patients, consistent with findings in infants.Whilst there is some evidence to suggest increased mortality in overweight adult patients, studies are conflictingas to whether overweight status is associated with increased heart failure. Increased BMI is associated with diminishedexercise capacity and deceased physiological functioning. Negative weight trajectory is associated withadverse outcomes in the peri-Fontan period, whereas a positive weight trajectory is associated with increased Fontanfailure in adulthood. Abnormal BMI (high or low) is associated with increased heart failure and poorer performancein quality-of-life scores. Conclusions: Bodyweight is a modifiable risk factor for poor clinical outcomein patients with a single ventricle circulation. Recognizing associations between bodyweight and Fontan pathophysiologymay help to define patient-centered exercise and diet interventions that minimize patient morbidityand mortality.