Surgical and Hybrid Ablation of Atrial Fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia in humans and is known to be associated with an increased risk of stroke, dementia, heart failure and mortality. Non-pharmacological therapy with ablation using either surgical or percutaneous techniques is recommended in drug refractory AF. Early attempts to devise procedures to ablate AF and restore sinus rhythm culminated with the Cox-Maze procedure, the first truly successful procedure. Since then, ablation surgery has been conducted predominately as a concomitant procedure. The Cox Maze procedure is complex and technically demanding and has, therefore, been extensively modified with new techniques for creating the linear ablation lines, new lesion sets, minimally invasive surgical techniques and most recently hybrid surgical-catheter ablation techniques. Surgical ablation techniques result in a marked reduction in atrial fibrillation when compared to conventional therapy with only a small increase in procedural risk. However, further research is required to more accurately quantify those benefits and to determine the optimal lesion sets, specific to the underlying arrhythmia mechanism and the optimal energy sources for ablation.

Right ventricular outflow tract enlargement prior to pulmonary valve replacement is associated with poorer structural and functional outcomes, in adults with repaired Tetralogy of Fallot.

BACKGROUND: Pulmonary valve replacement (PVR) is commonly performed late after Tetralogy of Fallot (TOF) repair. We examined the effects of PVR on cardiac structure, function and exercise capacity in adults with repaired TOF. METHODS: Eighteen adult patients with repaired TOF and severe pulmonary regurgitation (PR) with right ventricular (RV) dilatation requiring PVR for clinical reasons (age; 25±8 years) were recruited to undergo cardiac MRI (1.5T) and cardiopulmonary exercise testing before and 14±3 months after PVR. RESULTS: Reduced indexed RV end-diastolic volume (RVEDVi; 186±32mL/m(2) pre-op vs 114±20mL/m(2) post-op, p<0.001) was observed after PVR. "Normalisation" of RVEDVi (≤108mL/m(2)) was achieved in only seven of 18 patients. Pre-PVR RVEDVi correlated with post-operative change in RVEDVi (change=-72.1±20.4mL/m(2), r=-0.815, p<0.001). Exercise capacity remained high-normal post-PVR (% predicted maximal workload: 93±16% vs 91±12%, p=0.5). Regional RV volumes were assessed; RV outflow tract (RVOT) volumes were compared to the RV muscular corpus. Large pre-PVR RVOT volumes correlated negatively with post-surgical RV ejection fraction, peak VO2 and delta VO2 at anaerobic threshold (p<0.05 for all). CONCLUSIONS: Normalisation of RV volume is unlikely to be achieved above a pre-PVR RVEDVi of 165mL/m(2) or more. In particular, an enlarged RVOT prior to PVR predicts suboptimal structural and functional outcomes.

A Simplified Approach to Predicting Reintervention in the Arterial Switch Operation.

We investigated patients with transposition anatomy suitable for the arterial switch operation (ASO) to evaluate a simplified approach to prediction of reintervention. A retrospective review was performed of 180 consecutive patients who underwent ASO from 2009 to 2018. Patients were classified as Category I (n = 122) d-transposition of great arteries (dTGA) + intact ventricular septum, Category II (n = 28) dTGA + ventricular septal defect (VSD) and Category III (n = 30) dTGA + Aortic arch obstruction (AAO) +/- VSD or Taussig-Bing Anomaly (TBA) +/- AAO. Outcomes included reintervention-free survival (using Kaplan-Meier estimates) and predictors of reintervention. Median follow up was 3.3 (interquartile range 1.7-5.8) years with no difference between categories(P = 0.082). There were 3 mortalities- 2 early (one each in Category I and II) and one late (in Category I). Reintervention-free survival for the whole group at 1, 3, 5 and 8 years was 94%, 91%, 90% and 86% respectively. Conventional criteria predicting reintervention included the presence of TBA(P = 0.0054) and AAO(P = 0.027). Low birth weight did not predict reintervention(P = 0.2). When analyzed by category, multivariable analysis showed that patients in Category III carried a high risk of reintervention [Hazard risk (HR) = 7.43, 95% confidence interval (CI)=(2.39, 23.11), P < 0.001], but so did those in Category II [HR=6.90, 95% CI = (2.19, 21.75, P < 0.001] when compared to Category I. Conventional risk factors for technical difficulty may not be the best predictors of reintervention. A simplified approach highlights Category II patients (dTGA + VSD) as being at substantial risk of re-intervention, and not part of a low risk cohort.

The Ross/Ross-Konno procedure in infancy is a safe and durable solution for aortic stenosis.

OBJECTIVE: The objective of this study was to characterize early and midterm outcomes after the Ross/Ross-Konno procedure performed in infancy for severe aortic valve disease. METHODS: Between January 1995 and December 2018, 35 infants younger than 1 year (13 neonates) underwent a Ross/Ross-Konno procedure. Patients were followed up to a median of 4.1 years (interquartile range [IQR], 2.6-9.5). Primary outcome measures were survival, early morbidity, freedom from reintervention and long-term functional and echocardiographic status. RESULTS: Median age at operation was 49 days (IQR, 17-135) and weight was 4 kg (IQR, 3.4-5.2). Thirty-one (89%) had undergone a previous procedure, including balloon valvuloplasty in 26 (74%). Thirty (86%) required annular enlargement (Konno incision). Five required concomitant aortic arch surgery (2 neonates, 3 infants). There were no early deaths, and 1 late death at 18 months. Freedom from reoperation was 85% (95% confidence interval [CI], 68%-93%) at 1 year, 76% (95% CI, 54%-88%) at 5 years, and 62% (95% CI, 36%-79%) at 10 years. One modified Konno was performed at 5 years after a Ross in infancy. Ten right ventricle to pulmonary artery conduits have required reintervention (2 percutaneous pulmonary valve implantations). One child required a permanent pacemaker for complete heart block. At latest follow-up, 32 (94%) of 34 survivors were asymptomatic. There was no significant change in neoaortic Z-scores between 6 weeks and latest follow-up. CONCLUSIONS: The neonatal and infant Ross/Ross-Konno procedure can be performed with low mortality and achieves a stable left ventricular outflow tract. Significant early morbidity reflects the preoperative condition of the patients but definitive surgery of this type can be considered as a primary approach.

Five-year analysis of operative mortality and neonatal outcomes in congenital heart disease.

BACKGROUND: We sought to compare overall mortality with neonatal outcomes over a five year period to define risk factors for mortality and service development priorities. METHODS: A retrospective cohort study of surgical outcomes following repair or palliation of structural congenital heart defects January 2005-2010. We defined mortality according to contemporary international guidelines and classified surgical procedures using the Risk Adjustment in Congenital Heart Surgery (RACHS-1) score. The effect of age and weight at operation on mortality and annual variation in case-complexity and surgeon case-mix were assessed. Subgroup analysis was performed in patients who were ≤30 days at operation (neonates). RESULTS: Overall mortality within 30 days of operation or prior to hospital discharge was 1.3 and 1.9%, respectively. Mortality was higher in neonates (6.8%) and low birth weight infants (≤2.5kg) (12.1%). Mortality was similar in bypass versus non-bypass procedures (odds ratio 0.74, p=0.425). Annual mortality rates were consistent despite a marked increase in case-complexity. Neonates overall required longer periods of intensive care support and were more likely to suffer serious complications compared to older children. Age, weight and RACHS-1 score were independent risk factors for mortality on multivariate analysis. In neonates undergoing bypass procedures, only RACHS-1 score was a significant risk factor. CONCLUSIONS: This study provides an accurate and contemporary audit of mortality risk associated with congenital heart surgery. Outcomes compare favourably to international benchmarks but highlight the risks of morbidity and mortality associated with neonatal cardiac surgery.

Modified pulmonary artery banding: A novel strategy for balancing pulmonary blood flow with transposed great arteries.

OBJECTIVE: To study the outcomes of a novel modified pulmonary artery banding (mPAB) technique used for staged repair of a subset of patients with complex transposition physiology. METHODS: A total of 13 patients who underwent mPAB during their staged repair (biventricular repair [BVR], n = 6) or palliation (1-1/2 repair, n = 1; univentricular repair [UVR], n = 6) from 2004 to 2020 were studied retrospectively. A restrictive interposition graft was used to reconstruct the main PA between the pulmonary root and the distal pulmonary confluence, functioning as a mPAB. Twelve of the 13 patients (92.3%) underwent a concurrent arterial switch operation (ASO), of which 6 were palliative ASOs for 1-1/2 repair (n = 1) or UVR (n = 5). Patient weight and cardiac anatomy determined the size of interposition graft. RESULTS: The disease spectrum included dextro transposition of the great arteries (d-TGA) with multiple ventricular septal defects (VSDs) (n = 4), Taussig-Bing anomaly (n = 3), d-TGA with VSD and hypoplastic right ventricle (RV) (n = 3), double-inlet left ventricle with l-TGA (n = 2), and congenitally corrected TGA with double-outlet RV (n = 1). The Lecompte procedure was performed in 10 patients. Predischarge echocardiography revealed a band gradient of 61 mm Hg (interquartile range [IQR], 40-90 mm Hg) for BVR/1-1/2 ventricular repair (n = 7) and 49 mm Hg (IQR, 37-61 mm Hg) for UVR (n = 6). Survival was 100% at a median follow-up of 3.7 years (IQR, 2.6-4.0 years). CONCLUSIONS: The mPAB technique is effective and reproducible for staged BVR or UVR for patients with TGA. It effectively regulates pulmonary blood flow, may reduce neopulmonary root distortion, and eliminates complications associated with band migration in standard PAB.

Congenitally corrected transposition: complex anatomic repair or Fontan pathway?

Background Successful anatomic repair of congenitally corrected transposition of the great arteries achieves excellent outcomes. Several centers report excellent long-term survival with the Fontan pathway as well. We have selectively applied both approaches depending on individual patient morphology, with anatomic repair preferred but utilizing the Fontan pathway when high technical complexity or operative risk is anticipated. Methods Hospital records over an 18-year period (1998-2016) were reviewed to identify patients with congenitally corrected transposition of the great arteries who underwent surgical management. Physiological repairs and hypoplastic ventricles were excluded. Patient- and procedure-related variables were reviewed. Results We identified 19 patients. Group 1 consisted of 12 anatomic repairs, of which 10 (83.3%) required prior interim staging procedures. Mean age at anatomic repair was 2.6 ± 1.3 years, mean follow-up was 8.7 ± 5.3 years. Nine (75%) patients experienced important complications and 4 (33.3%) required reintervention during follow-up. There were no deaths; one patient required heart transplantation. Group 2 (7 patients) underwent Fontan palliation. Mean age at Fontan completion was 7.2 ± 3.8 years, mean follow-up was 6.3 ± 4 years. There was no reintervention, death, or transplant. Conclusion Patients with congenitally corrected transposition of the great arteries and two adequate-sized ventricles do well with both anatomic repair and the Fontan pathway in the medium term. Excellent outcomes with reduced early complication and reintervention rates can be achieved for this cohort of patients when a strategy of avoiding complex anatomic repair in favor of the Fontan pathway is used.

Early outcomes from a new regional programme for the surgical management of hypoplastic left heart syndrome.

BACKGROUND: Early survival and quality of outcome after surgery for hypoplastic left heart syndrome (HLHS) are influenced by patient-specific factors, the quality of surgery and perioperative care. Some skills are common to the care of other complex neonatal presentations but integrating this expertise is a key challenge for new programmes. We began offering surgery for HLHS from 2006 and provided a regional service from January 2009 and report early outcomes. METHODS: Prospectively collected data for neonates with HLHS undergoing surgical palliation from January 2006 until June 2011 were analysed. Standard definitions of high-risk and standard-risk presentations were utilized. RESULTS: Thirty neonates underwent surgical palliation of HLHS with a modified Norwood procedure with an overall survival to stage II palliation of 80%. A total of 46.7% of our patients were categorized as high-risk, mostly on the basis of low birth weight. Survival to stage II palliation was 100% in standard-risk patients and 57.1% in the high-risk group. CONCLUSION: Outcomes for this new programme are comparable to reported outcomes demonstrating the feasibility of integrating a new complex procedure within an existing multidisciplinary unit handling large volumes of other complex neonatal work. Excellent outcomes can be achieved in standard-risk patients. Outcomes in the high-risk group may be improved by alternative approaches and rigorous case selection.

Circulatory arrest for repair of postcoarctation site aneurysm.

BACKGROUND: Aneurysm at previous coarctation repair may be seen more frequently as children operated for this condition survive into adulthood. We use deep hypothermic circulatory arrest to repair these aneurysms. METHODS: A case series was conducted using 12-year, single-institution, retrospective chart review. RESULTS: Twenty-one patients underwent left thoracotomy and repair of aneurysm at the site of previous coarctation repair. Three cases presented emergently as aortobronchial fistulas. The age range was 16 to 73 years (median, 26 years). The median circulatory arrest time was 33 minutes (range, 22 to 55 minutes). Repair involved interposition graft replacement. Six patients required additional tube graft replacement of the left subclavian artery. There was 1 operative mortality in a patient having a hypoxic brain injury secondary to an anaphylactic reaction to a plasma expander. There were no embolic strokes or paraplegia. One patient had a recurrent laryngeal nerve paresis. There was 1 case of Horner's syndrome after subclavian artery replacement. CONCLUSIONS: Circulatory arrest allows for the accurate repair of this difficult pathologic process and avoids the risk of clamp-related injuries. Follow-up out to 16 years demonstrates this technique of repair to be durable, with no late deaths or reoperations for recurrent aneurysm.

Comparison of epicardial and endocardial linear ablation using handheld probes.

BACKGROUND: The optimal technique for producing linear radiofrequency thermal lesions in myocardial tissue is unclear. We compared epicardial ablation on the beating heart with endocardial ablation after cardioplegia. METHODS: Radiofrequency lesions were produced using a multielectrode malleable handheld probe in ovine myocardium with three wall thicknesses. Detailed analysis of lesion dimensions was used to assess the effects of site of ablation, muscle thickness, and duration of ablation. RESULTS: After epicardial atrial ablation, myocardial lesions were detected in all sections without macroscopically visible epicardial fat (n = 10), but only 43% (6/14) of sections with epicardial fat. Three of 24 atrial epicardial sections (13%) and 92% (23/25) of endocardial atrial lesion sections were clearly transmural. In thicker tissues lesion depth was independent of endocardial (right ventricle: 3.9 +/- 1.1 mm, left ventricle: 3.8 +/- 0.7 mm) or epicardial (right ventricle: 3.4 +/- 0.6 mm, left ventricle: 4.3 +/- 0.9 mm) ablation site. Epicardial lesions are less deep in thinner areas of myocardium (p = 0.003). Lesions were all wider than they were deep. There was no significant increase in lesion depth with the increase in ablation duration from 1 to 2 minutes. CONCLUSIONS: Lesions were unlikely to be transmural with either technique when the wall thickness was greater than about 4 mm. Epicardial fat has an important negative effect on epicardial lesion formation. Where epicardial fat is absent epicardially produced lesions penetrate less deeply when the wall thickness is small, possibly due to endocardial cooling by circulating blood. Prolongation of the duration of ablation from 1 to 2 minutes does not significantly increase lesion depth.

Tailored strategies for staged management of complex congenital cardiac lesions.

Although many complex congenital cardiac lesions can be primarily repaired, there remain circumstances where a staged approach may carry lower risk than a primary repair. We present 4 clinical cases where stable intermediate stages allowed somatic growth and facilitated successful biventricular repair or univentricular palliation.

Outcomes for surgical treatment of atrial fibrillation using cryoablation during concomitant cardiac procedures.

BACKGROUND: Surgical treatment of atrial fibrillation (AF) with heat-based therapies has been associated with a high rate of arrhythmia recurrence. We studied the short-term to medium-term outcomes with a unique biatrial linear ablation procedure for AF treatment using an argon-based cryoablation device during concomitant cardiac operations. METHODS: Between March 2005 and July 2008, 57 patients (47% men) with problematic AF underwent a linear endocardial ablation procedure (Star pattern) using the flexible argon-based cryoablation probe during concomitant cardiac operations. Procedures were performed with valve or coronary operations, including mitral valve replacement (25%), mitral valve repair (16%), coronary artery bypass grafts (21%), and congenital heart surgery (8%). Atrial fibrillation was persistent or long-standing persistent in 50.9% of patients. RESULTS: Kaplan-Meier survival curves (with the standard error) demonstrated 91% (3.9%) of patients were still free of their first recurrence at 6 months, 81% (5.6%) at 12 months, and 70% (6.8%) at 24 months. Time to first recurrence was not significantly associated with age (p = 0.47), gender (p = 0.52), or type of AF (p = 0.69). There were no complications attributed to the cryoablation procedure. There was one in-hospital death and one death after discharge. Twelve patients (21%) required permanent pacemaker implantation postoperatively. There were no early or late thromboembolic events. CONCLUSIONS: This study demonstrated the medium-term efficacy of cryoablation with a unique biatrial pattern of linear lesions for the treatment of AF during a concomitant cardiac operation. Short-term to medium-term outcomes were at least equivalent to those reported for other energy modalities.

Outcomes following surgery for congenital heart disease in low-birthweight infants.

AIM: To describe cardiac surgery, survival and outcomes for low-birthweight (< or = 2500 g) infants undergoing surgery for congenital heart disease. METHODS: Using data from a prospectively collected population-based database of admissions to neonatal intensive care units in New South Wales and the Australian Capital Territory, we identified all low-birthweight infants undergoing cardiac surgery between 1992 and 2001. Infants with only a persistent ductus arteriosus were excluded. Two-year cardiac and neurodevelopmental outcome data were sought from hospital medical records. RESULTS: A total of 121 low-birthweight infants underwent cardiac surgery, of whom 34% had a congenital syndrome or non-cardiac birth defect. Most (81%) underwent a palliative surgical procedure in the neonatal period. There were 19 early (15.7%) and 19 late deaths giving a 2-year mortality of 31%. Factors associated with mortality included birthweight below 1500 g (P = 0.006), low weight at surgery (P = 0.028) and Apgar score at 1 min (P = 0.019). No single factor predicted 30-day mortality. By 2 years of age, 27 (33% of survivors) were known to have neurodevelopmental delay. Although 22 children are known to be developing normally, the neurodevelopmental status of 34 children was not known. CONCLUSIONS: These surgical data were comparable to previous single-institution studies. This group had a high risk of disability due to prematurity, low birthweight and associated conditions. There is a need to prospectively assess and manage neurodevelopmental outcomes in this group.

Levosimendan for low cardiac output: a pediatric experience.

This was a retrospective observational study in a pediatric intensive care unit, in which 19 patients received levosimendan. There were no adverse events attributable to levosimendan and no instances where the clinical condition worsened after administration. Arterial lactate levels decreased significantly following levosimendan administration during cardiopulmonary bypass for anticipated low cardiac output. In those with established low cardiac output, trends toward improved hemodynamics were seen, with heart rate reduction, an increase in mean blood pressure, a reduction in arterial lactate, and reduced conventional inotrope use. Levosimendan was safely used in a small number of pediatric patients with established low cardiac output state who demonstrated improved hemodynamics and tissue perfusion, with a tendency to reduced conventional inotrope usage, and this warrants its evaluation as an inotrope in the pediatric population.

Thoracic epidural anesthesia for cardiac surgery: the effects on tracheal intubation time and length of hospital stay.

UNLABELLED: Improvements in analgesia after major surgery may allow a more rapid recovery and shorter hospital stay. We performed a prospective randomized trial to study the effects of epidural analgesia on the length of hospital stay after coronary artery surgery. The anesthetic technique and postoperative mobilization were altered to facilitate early intensive care discharge and hospital discharge. Fifty patients received high (T1 to T4) thoracic epidural anesthesia (TEA) with ropivacaine 1% (4-mL bolus, 3-5 mL/h infusion), with fentanyl (100-microg bolus, 15-25 microg/h infusion) and a propofol infusion (6 mg x kg(-1) x h(-1)). Another 50 patients (the General Anesthesia group) received fentanyl 15 microg/kg and propofol (5 mg x kg(-1) x h(-1)), followed by IV morphine patient-controlled analgesia. The TEA group had lower visual analog scores with coughing postextubation (median, 0 vs 26 mm; P < 0.0001) and were extubated earlier (median hours [interquartile range], 3.2 [2.1-4.6] vs 6.7 [3.3-13.2]; P < 0.0001). More than half of all patients were discharged home on Postoperative Day 4 (24%) or 5 (33%), but there was no difference in the length of stay between the TEA group (median [interquartile range], Day 5 [5-6]) and the General Anesthesia group (median [interquartile range], Day 5 [4-7]). There were no differences in postoperative spirometry or chest radiograph changes or in markers for postoperative myocardial ischemia or infarction. No significant TEA-related complications occurred. In summary, TEA provided better analgesia and allowed earlier tracheal extubation but did not reduce the length of hospital stay after coronary artery surgery. IMPLICATIONS: We found that epidural analgesia was more effective than IV morphine for cardiac surgery. Epidural anesthesia also allowed earlier weaning from mechanical ventilation, but it did not affect hospital discharge time.

Mid-term results for double inlet left ventricle and similar morphologies: timing of Damus-Kaye-Stansel.

BACKGROUND: Patients with double inlet left ventricle/l-transposition and similar morphologies have their systemic outflow traverse a bulboventricular foramen (BVF), which has a propensity to narrow over time. A Norwood procedure may be performed as the initial palliation. We prefer aortic arch repair and pulmonary artery banding, delaying Damus-Kaye-Stansel (DKS) or BVF resection until the second palliation. The aims of this study were to compare our results with those reported for Norwood strategy and examine the development of systemic outflow obstruction. METHODS: Retrospective study of patients with double inlet left ventricle, L-TGA or similar morphology presenting between 1990 and 2000. Follow-up with clinical assessment, echocardiography and catheter studies. RESULTS: Twenty-five patients had initial palliation with pulmonary artery banding with repair of any associated arch obstruction. Twelve patients had DKS performed as part of their second stage procedure, and 3 had DKS performed later for recurrent stenosis after prior enlargement of BVF. Six patients had BVF resection without later restenosis and 4 patients did not develop BVF stenosis. There was one early death (4%) and two late (8%). Fontan completion was achieved in 20 of the 22 survivors. There were no cases of DKS obstruction, no pulmonary valve had more than mild regurgitation. CONCLUSIONS: Our approach achieves low operative mortality and morbidity and compares favorably with reported results for Norwood palliation. The significant rate of systemic outflow obstruction in those who did not undergo DKS at the second stage confirms the utility of early DKS in children with this morphology.