Clinical Significance of Thrombosis in an Intracardiac Blind Pouch After a Fontan Operation

The univentricular heart after the Fontan operation may have a blind pouch formed by the pulmonary stump or rudimentary ventricle according to the anatomy before surgery. Thrombosis in an intracardiac blind pouch of patients with a univentricular heart is a hazardous complication. Because only a few reports have described this complication, the authors evaluated the clinical significance of thrombosis in an intracardiac blind pouch of a univentricular heart. They performed a retrospective review of medical records from August 1986 to December 2007. Four patients were confirmed as having thrombosis in a pulmonary artery stump and one patient as having thrombosis in a rudimentary ventricle shown by cardiac computed tomography (CT). This represents 1.85% (5/271) of patients with ongoing regular follow-up evaluation after the Fontan operation. The median age at diagnosis was 14.2 years. Two of the five patients were taking aspirin and one patient was taking warfarin when they were identified for the development of thrombosis. None of the patients demonstrated thrombosis in the Fontan tract or venous side of the circulation. Brain magnetic resonance imaging (MRI) showed that three patients had cerebral infarction and one patient had suggestive old ischemia. Three patients with thrombus in the pulmonary stump underwent pulmonary artery stump thrombectomy and pulmonary valve obliteration. One patient with thrombus in the rudimentary ventricle underwent ventricular septal defect (VSD) closure with thrombectomy. Thrombus in a blind pouch could cause systemic thromboembolism despite little blood communication. Therefore, surgical modification of the pulmonary stump and VSD closure of the rudimentary ventricle are required to reduce the risk of later thrombus formation. Clinicians should not overlook the possibility of thrombus in a ligated pulmonary artery stump or a rudimentary ventricle after the Fontan operation, which may increase the risk of embolic stroke for patients with single-ventricle physiology.     

Effectiveness of Carvedilol for Congestive Heart Failure that Developed Long after Modified Fontan Operation

We report a case of a patient with severe heart failure after Fontan procedure in whom carvedilol was very effective. A 27-year-old man had intractable congestive heart failure due to severe ventricular dysfunction after Fontan operation. Central venous pressure was elevated to 29 mmHg. A right-to-left shunt was noted across a large collateral vessel between the innominate vein and the pulmonary vein. He was administered carvedilol (initial dose, 2 mg/day; maximum dose, 30 mg/day). Cardiac catheterization performed 1 year after carvedilol administration revealed a decrease in atrial pressure and improvement of ventricular function. He underwent a conversion operation to total cavopulmonary connection (TCPC) and ligation of a collateral vein communicating with the innominate and pulmonary veins. Carvedilol may be a legitimate treatment before TCPC conversion or heart transplantation for the high-risk group of patients with a failed Fontan circulation.     

心外管道全腔肺分流手术的临床应用

目的 探讨心外管道全腔肺分流手术在小儿复杂青紫型先天性心脏病中的应用价值.方法 1998年1月至2008年10月48例患儿接受了心外管道全腔肺分流手术,其中男37例,女11例;年龄3.1～14.5岁,平均(5.6±3.0)岁;体重13～56 kg,平均(21.1±10.3)kg;三尖瓣闭锁23例,单心室20例,右心室双出口(远离大动脉型)2例,室间隔完整的肺动脉闭锁2例,法乐四联症伴完全性房室间隔缺损1例;术前SPO270%～93%,平均(80.2±6.1)%.38例患儿在行心外管道全腔肺分流手术前接受多次手术,包括改良BT分流5例次,肺动脉环缩4例次,双向腔肺分流手术36例次.12例患儿在同一次手术中完成全腔肺分流手术.结果 术后早期死亡3例;乳糜胸7例,气胸2例,胸腔金葡菌感染1例,短暂的交界性心动过速2例,均治愈;术后胸腔引流放置3.5～48 d.随访1个月至12年,晚期死亡2例,其余35例心功能恢复至Ⅰ级,6例心功能Ⅱ级,2例心功能Ⅲ级,随访心电图均为窦性心律.统计分析Ⅰ期Fontan和分期Fontan在术后机械通气时间、监护时间、引流时间,病死率上无统计学差异.结论 心外管道全腔肺分流手术术后心律失常的发生率低,开窗术有助于围术期恢复,Ⅰ期Fontan在部分患儿中是可行的.     

Consensus on Timing of Intervention for Common Congenital Heart Diseases: Part II - Cyanotic Heart Defects

The purpose of this review/editorial is to discuss how and when to treat the most common cyanotic congenital heart defects (CHDs); the discussion of acyanotic heart defects was presented in a previous editorial. By and large, the indications and timing of intervention are decided by the severity of the lesion. While some patients with acyanotic CHD may not require surgical or transcatheter intervention because of spontaneous resolution of the defect or mildness of the defect, the majority of cyanotic CHD will require intervention, mostly surgical. Total surgical correction is the treatment of choice for tetralogy of Fallot patients although some patients may need to be palliated initially by performing a modified Blalock-Taussig shunt. For transposition of the great arteries, arterial switch (Jatene) procedure is the treatment of choice, although Rastelli procedure is required for patients who have associated ventricular septal defect (VSD) and pulmonary stenosis (PS). Some of these babies may require Prostaglandin E₁ infusion and/or balloon atrial septostomy prior to corrective surgery. In tricuspid atresia patients, most babies require palliation at presentation either with a modified Blalock-Taussig shunt or pulmonary artery banding followed later by staged Fontan (bidirectional Glenn followed later by extracardiac conduit Fontan conversion usually with fenestration). Truncus arteriosus babies are treated by closure of VSD along with right ventricle to pulmonary artery conduit; palliative banding of the pulmonary artery is no longer recommended. Total anomalous pulmonary venous connection babies require anastomosis of the common pulmonary vein with the left atrium at presentation. Other defects should also be addressed by staged correction or complete repair depending upon the anatomy/physiology. Feasibility, safety and effectiveness of treatment of cyanotic CHD with currently available medical, transcatheter and surgical methods are well established and should be performed at an appropriate age in order to prevent damage to cardiovascular structures.     

Radionuclide assessment of left ventricular performance on exercise after external conduit operation

Only limited information is available concerning left ventricular (LV) response to exercise after an external conduit operation for cyanotic congenital heart disease. Sixteen patients who had undergone external conduit repair (EC group) were studied with multi-gated cardiac pool imaging using a supine bicycle ergometer on 20 occasions. Six patients with a history of Kawasaki disease without coronary artery stenosis served as controls (control group). Myocardial imaging and cardiac catheterization were also performed in the EC group. There was no significant difference in left ventricular ejection fraction (LVEF) at rest between the groups. However, on exercise, LVEF of the EC group was significantly lower than that of the control group. Nine patients in the EC group showed a perfusion defect (PD) on 12 occasions. LVEF on exercise of the patients with PD was significantly lower than that of the patients without PD. Furthermore, only the patients with PD showed a LVEF decrease of 5% or more in response to exercise. In the EC group, a significant inverse relationship was demonstrated between right ventricular systolic pressure (RVP) and LVEF response to exercise. However, two out of four patients who underwent external conduit replacement improved their LVEF response to exercise with successful reduction of RVP. These findings indicate that an impaired left ventricular response to exercise was common in patients after external conduit operations. Myocardial damage and right ventricular outflow tract obstruction could be the causes of this left ventricular dysfunction.     

心外管道Fontan手术治疗复杂先天性心脏病

目的探讨心外管道Fontan手术方法治疗小儿复杂先天性心脏病的早期效果。方法9例复杂性先天性心脏病,男5例,女4例,年龄3~9岁。其中单心室5例,三尖瓣闭缩、右室双出口各2例。均在体外循环心脏不停跳下行心外管道Fontan手术。结果全组患儿无死亡,经皮血氧饱和度>95%,无心律失常,但均有明显胸腔积液表现。结论体外循环下心脏不停跳心外管道Fontan手术近期效果满意。     

Right Ventricle and Tricuspid Valve Function at Midterm After the Fontan Operation for Hypoplastic Left Heart Syndrome: Impact of Shunt Type

This study aimed to evaluate clinical outcomes including hemodynamics, right ventricle (RV) function, and tricuspid valve (TV) function in patients with hypoplastic left heart syndrome (HLHS) at midterm after completion of staged palliation based on the source of pulmonary blood flow provided at stage 1. The records of all patients with HLHS who completed Fontan palliation between 2001 and 2007 were retrospectively reviewed. The outcome variables were RV dysfunction, TV, and neo-atrioventricular (neo-AV) regurgitation (from latest echocardiogram), cardiac index (CI), pulmonary vascular resistance (PVR), pulmonary artery pressure (PAp), and right ventricular end-diastolic pressure (RVEDp) (from latest catheterization). Clinical status was obtained from medical records and by contact with the referring cardiologist if necessary. Of 118 patients undergoing a Fontan for HLHS, 116 had a fenestrated lateral tunnel and 2 had an extracardiac conduit. At the time of stage 1 palliation, 36 patients had a right ventricle-to-pulmonary artery (RV-PA) conduit, and 82 patients had a modified Blalock-Taussig shunt (mBTS). All the patients except one who died of sepsis on extracorporeal membrane oxygenation (ECMO) survived the Fontan operation and were discharged home. At a mean follow-up post-Fontan period of 28.4 months (range, 0.16-95.3 months), three patients had died (2 on the transplantation list and 1 from pulmonary vein stenosis), and one patient had the Fontan circulation taken down. No patient had a heart transplantation. A follow-up echocardiogram was performed for 115 patients (after a mean of 15.6 months for RV-PA and 32.1 months for BTS), and 66 patients underwent a post-Fontan catheterization (after a mean of 15.8 months for RV-PA and 29.3 months for BTS). The hemodynamic results for RV-PA conduit versus BTS were a CI of 3.4 ± 0.8 versus 3.4 ± 1.2, a PVR of 1.8 ± 0.7 versus 1.7 ± 0.8, a PAp of 14.3 ± 3.1 versus 14.2 ± 4.5, and an RVEDp of 7.1 ± 3.3 versus 8.9 ± 5.3. No statistically significant differences were found between shunt types regarding survival or degree of RV dysfunction or in terms of neo-AV regurgitation, CI, PVR, PAp, RVEDp, or rhythm problems. Patients in the BTS group required more tricuspid valvuloplasties and had more tricuspid regurgitation at follow-up evaluation. The patients in the RV-PA group had more PA interventions. In conclusion, the contemporary results after Fontan palliation for HLHS were excellent. At the midterm follow-up evaluation, outcomes and hemodynamic data were similar between shunt types. However, the patients in the BTS group exhibited more tricuspid regurgitation, and the patients in the RV-PA group had increased pulmonary artery interventions.     

Present status of surgery in congenital heart disease

A brief historical review of surgery for congenital heart disease is presented. Palliative procedures designed to improve a given physiologic abnormality, such as systemic artery (or venous) to pulmonary artery shunts of various types to increase the pulmonary blood flow, banding of the pulmonary artery to decrease the pulmonary blood flow and surgical or balloon atrial septostomy to augment intracardiac mixing have been performed with success. Most of the congenital heart defects can be corrected by open heart surgical techniques; those requiring prior pallition and those that can be operated without prior palliative surgery are listed. The mortality rates for several common congenital heart defects are tabulated. Recent surgical advances include early total surgical correction for tetralogy of Fallot, Mustard and Jatene operations for transposition of the great arteries, Fontan operation and its newer modifications for tricuspid atresia, intraventricular septation or modified Fontan for single ventricle, new operations for hypoplastic left heart syndrome and newer prosthetic valves, particularly left ventricular apex to descending aorta conduit. Prostaglandin E₁ for ductal dilation in patients with severe righ ventricular outflow tract obstruction, balloon and knife enlargement of atrial defects to enhance interatrial mixing and catheter closure techniques for nonsurgical repair of atrial septal defect and patent ductsus arteriosus are also reviewed briefly.     

Tricuspid atresia with imperforate valve: Angiographic findings and surgical implications in two cases with AV concordance and normally related great arteries

Summary The angiographic and intraoperative findings are described in two children with imperforate tricuspid valve with atrioventricular and ventriculoarterial concordance who underwent a successful Fontan operation. It is important from a surgical point of view to distinguish this rare variant of tricuspid atresia from the more classic form with absent atrioventricular connection. The characteristic feature of hearts with imperforate tricuspid valve is the presence of a normally formed right ventricle which, in the presence of ventriculo-arterial concordance, can be used to support the pulmonary circulation. When the imperforate valve is large, it may be possible to remove it, and restore atrioventricular continuity. Alternatively, an atrioventricular type of Fontan repair using a valved conduit should be considered as the treatment of choice in the presence of a suitable pulmonary arterial tree and pulmonary valve.     

Fenestration in Extracardiac Conduits in Children After Modified Fontan Operation by Implantation of Stent Grafts

Three patients (ages 3, 5, and 8 years) with various forms of functionally univentricular heart lesions received a total cavopulmonary connection with an extracardiac conduit as a final reconstructive procedure. Failure of the Fontan circulation occurred immediately after surgery because of spontaneous closure of surgical fenestrations in two children and absent fenestration in one. As an emergency procedure, in all patients the conduit was perforated by transcatheter intervention in order to create a connection to the anatomical right atrium. Following balloon dilatation of the perforated conduit, in all three patients covered stent grafts were placed in the newly created defect to attain a reliable communication. Patency of the fenestration was demonstrated by angiogram and any leakage was ruled out. Cardiac output improved and severe pleural effusion and ascites subsided. Right-to-left shunt could be demonstrated by echocardiography at follow-up after 7 months (median) in all three patients. Oxygen saturation remained stable between 85 and 90%. These preliminary results suggest that stent graft fenestration can serve as a valuable tool in failing Fontan circulation, particularly in patients with an extracardiac conduit. Covered stents have the potential to reduce the acute risk of bleeding and they help to prevent early spontaneous closure of the newly created fenestration.     

Left Innominate Vein–Pulmonary Artery Shunt with Glenn Anastomosis in a Fontan Candidate with Central Pulmonary Artery Stenosis

Heart failure developed 9 years after Fontan takedown with systemic–pulmonary artery shunt in a 12-year-old girl with pulmonary atresia, intact ventricular septum, and obstruction in the proximal pulmonary artery. Surgical scar after multiple operations complicated direct repair of the pulmonary artery, and thus she was not eligible for definitive palliation. Left innominate vein–to–left pulmonary artery shunt using an expanded polytetrafluoroethylene conduit in association with Glenn anastomosis functionally established an unobstructive superior cavopulmonary connection without direct repair of the central pulmonary artery, later facilitating one and a half ventricle repair. Use of an extraanatomical shunt may functionally relieve central pulmonary artery obstruction in candidates for Fontan-like circulation.     

Results of 100 Consecutive Extracardiac Conduit Fontan Operations

Throughout the years, the experience with Fontan's operation has increased and has opened the way to a much wider application of this principle. A number of major risk factors have been identified and managed by several modifications of the original Fontan procedure. In the past 15 years, operative and postoperative risks have been controlled to a major extent by the application of intermediate surgical procedures. Modifications to the original technique have been designed to simplify surgery and better protect the myocardium by avoiding, as much as possible, prolonged ischemic time. In 1988, we developed a new form of total extracardiac right heart bypass by means of associating an extracardiac conduit placed between the inferior vena cava (IVC) and the pulmonary artery with a bidirectional cavopulmonary anastomosis (BCPA)--the so-called total extracardiac cavopulmonary connection (TECC).Between November 1997 and October 2003, 100 patients with complex cardiac anomalies underwent a modified Fontan operation by TECC. In 88 patients, the repair was staged by preliminary BCPA that was bilateral in 15 patients and associated with a modified Damus-Kaye-Stansel procedure to bypass a subaortic obstruction in 24 patients. Early (in hospital) deaths occurred in 6% of patients and the extracardiac conduit was taken down in 2 additional patients for a total early failure rate of 8%. The cause of death was myocardial failure in 5 patients. Pulmonary artery distortion or hypoplasia appeared to be the cause of death in 1 patient and the cause of failure in 1 patient. Atrioventricular valve regurgitation was the cause of failure in 1 patient. Follow-up to December 2003 was available in all surviving patients. There were no late deaths. At follow-up, 87 patients (89%) were in New York Heart Association (NYHA) functional class I, 4 in class II, and 3 in class III due to moderate to severe atrioventricular valve regurgitation. Use of the following guidelines can result in the achievement of orthoterminal repair with complete separation of pulmonary and systemic circulation, with negligible early mortality and a long-term NYHA class I: (1) Not all patients with univentricular heart (UVH) should undergo the extracardiac Fontan procedure; (2) in UVH with favorable streaming, a Q (p)/Q (s) ratio of approximately 1 to 1, and mild cyanosis, natural history might be preferable to surgical history; (3) any form of fenestration is contradictory to orthodox application of Fontan's principle. Children in whom a planned fenestration seems necessary because of suboptimal conditions should instead undergo a combination of BCPA and associated forward pulmonary blood flow; and (4) negligible mortality should be considered mandatory in UVH, normal pulmonary arteries, and absent cardiomegaly after appropriated and correct staging.     

Dysplasia of AV valve in complete AV canal with tetralogy of Fallot: Surgical repair

Summary A five-year-old girl underwent surgery for tetralogy of Fallot and complete persistent atrioventricular (AV) canal. At operation, severe dysplasia of the right side of the common AV valve was found, with an accessory orifice and muscularization of a leaflet. Repair was carried out by closing the AV defect, through a combined right atrial and right ventricular approach, by a pericardial patch with a large anterior extension. Closure of the resulting mitral cleft, resection of anomalous muscle bundles and pulmonary valvotomy were also performed. Postoperatively the patient presented severe tricuspid regurgitation. Repair of the valve was deemed impossible and valve replacement was considered to have a very high risk due to the age of the patient, the small size of the right ventricle, and the previous repair of the AV defect. A modified Fontan operation was, therefore, considered preferable and successfully carried out. After the second operation, mediastinal infection developed and was successfully treated by local irrigation of diluted providone-iodine solution.     

Exercise Performance Following Repair of Hypoplastic Left Heart Syndrome: A Comparison with Other Types of Fontan Patients

Reports of exercise performance after Fontan surgery for hypoplastic left heart syndrome (HLHS) are lacking. We compared the exercise performance of total cavopulmonary connection type (TCPC) of Fontan subjects with HLHS (group 1, n= 7) to those not requiring a Norwood procedure having a systemic right ventricle (group 2, n= 6) or a systemic left ventricle (group 3, n= 8). The subjects underwent assessment of resting pulmonary mechanics followed by maximal exercise testing with a bicycle or treadmill protocol. ECG, oxygen consumption, and carbon dioxide production were measured continuously. There was not a significant difference seen between HLHS and the comparison groups for the following parameters: maximum heart rate, maximum oxygen consumption, respiratory exchange ratio, breathing reserve, and arterial oxygen saturation at rest or exercise. Exercise performance in the TCPC type of Fontan patients was comparable regardless of ventricular morphology or surgical approach.     

Plastic bronchitis. A case report and review of the literature

Plastic bronchitis is a rare complication in which bronchial casts of lymphatic origin develop in the tracheobronchial tree and cause airway obstruction. The main feature is expectoration of bronchial casts. This condition usually occurs in the postoperative period after the Fontan operation for congenital heart disease. Treatment modalities include mucolytics and chest physiotherapy, and in the most severe cases bronchoscopy to remove the casts and aerosolized urokinase or r-TPA. We describe a 12-year-old boy with pulmonary atresia with intact ventricular septum and severely hypoplastic right ventricle who underwent a modified Fontan operation at the age of 7 years. At the age of 12 years the patient started to present frequent episodes of coughing, dyspnea, and desaturation followed by difficult emission of white bronchial casts. An extracardiac Fontan conversion was performed to improve hemodynamics and symptoms. During the postoperative period frequent episodes of airway obstruction required bronchoscopy and finally improved with administration of aerosolized urokinase.     

Fontan Conversion Templates: Patient-Specific Hemodynamic Performance of the Lateral Tunnel Versus the Intraatrial Conduit With Fenestration

Intraatrial-conduit Fontan is considered a modification of both extracardiac and lateral-tunnel Fontan. In this study, the patient-specific hemodynamic performance of intraatrial-conduit and lateral-tunnel Fontan with fenestration, considered as conversion templates, was investigated based on the authors’ patient cohort. Pulsatile computational fluid dynamics simulations were performed using patient-specific models of intraatrial-conduit and lateral-tunnel Fontan patients. Real-time “simultaneous” inferior and superior vena cava, pulmonary artery, and fenestration flow waveforms were acquired from ultrasound. Multiple hemodynamic performance indices were investigated, with particular focus on evaluation of the pulsatile flow performance. Power loss inside the lateral-tunnel Fontan appeared to be significantly higher than with the intraatrial-conduit Fontan for patient-specific cardiac output and normalized connection size. Inclusion of the 4-mm fenestration at a 0.24 L/min mean flow resulted in a lower cavopulmonary pressure gradient and less time-averaged power loss for both Fontan connections. Flow structures within the intraatrial conduit were notability more uniform than within the lateral tunnel. Hepatic flow majorly favored the left lung in both surgical connections: conversion from lateral-tunnel to intraatrial-conduit Fontan resulted in better hemodynamics with less power loss, a lower pressure gradient, and fewer stagnant flow zones along the conduit. This patient-specific computational case study demonstrated superior hemodynamics of intraatrial-conduit Fontan over those of lateral-tunnel Fontan with or without fenestration and improved performance after conversion of the lateral tunnel to the intraatrial conduit. The geometry-specific effect of the nonuniform hepatic flow distribution may motivate new rationales for the surgical design.     

The Fontan Operation: The Pursuit of Associated Lesions and Cumulative Trauma

Our programmatic approach to the Fontan operation has evolved to include using an extracardiac conduit with aggressive presumptive treatment of associated lesions either in the catheterization laboratory or the operating room. Fenestration is used selectively based on hemodynamics, anatomy, and presence of associated lesions. We reviewed our experience to determine the effectiveness and outcome of this strategy and to assess the cumulative trauma to the patients. The records of 137 consecutive patients who underwent Fontan at Miami Children’s Hospital from 1995 to 2008 were reviewed. At mean follow up of 5.76 years, freedom from death or transplantation is 94.2% (129/137). Median age at operation was 4.6 years. Longer length of stay correlated with older operative age (P = 0.0056). Pacemakers were implanted in 11.7% (16/137). Additional (not pre-Glenn or pre-Fontan) interventional catheterizations were performed in 51.8% (71/137). Additional operations were done in 10.2% (14/137). No patient has required replacement or revision of the extracardiac conduit. Our current approach to the Fontan operation provides acceptable midterm results. The pursuit of residual lesions results in a significant number of additional interventional catheterizations and operative procedures but might have an important influence on long-term survival after the Fontan procedure.     

The Lateral Tunnel Fontan Procedure for Hypoplastic Left Heart Syndrome: Results of 100 Consecutive Patients

The Fontan procedure for hypoplastic left heart syndrome (HLHS) is well established. Multiple surgical techniques including extracardiac conduits and autologous tissue connections have been developed. We reviewed the results of 100 consecutive patients undergoing the lateral tunnel modification of the Fontan procedure at the University of Michigan. A cross-sectional retrospective study was performed for 100 consecutive patients identified in the University of Michigan Congenital Heart Surgery database with the diagnosis of HLHS. All patients had undergone a lateral tunnel Fontan procedure between June 2000 and August 2004. The medical record was reviewed to assess patient, procedural, and morphologic determinants of outcome. Hospital survival was 97% and intermediate-term survival was 96% with a median follow-up time of 34 months. Preoperative mean pulmonary artery pressure, right ventricular end diastolic pressure, aortic cross-clamp time, and tricuspid valve regurgitation were not associated with late right ventricular function or survival. Three patients required takedown of the lateral tunnel Fontan in the early postoperative period. A positive association was found between protein-losing enteropathy and prolonged (>2 weeks) postoperative pleural drainage (p = 0.035). No patient required cardiac transplantation or late intervention on the Fontan pathway. At the time of follow-up, 100% of patients were New York Heart Association class I or II and 90% were in normal sinus rhythm. The lateral tunnel Fontan procedure for HLHS can be performed with acceptable early and intermediate-term risk. There was a low prevalence of late rhythm disturbances and other complications. Protein-losing enteropathy and prolonged pleural drainage were associated.     

Myocardial Perfusion Abnormalities in Patients Occurring More Than 1 Year After Successful Univentricular (Fontan Surgery) and Biventricular Repair (Complete Repair of Tetralogy of Fallot)

The outcome of children born with cyanotic congenital heart disease has markedly improved over the years. Follow up is recommended for most post-operated cases as complications may occur over long term. One of the complications is the development of ventricular dysfunction, often seen after a successful Fontan surgery (or one of its modifications) for single ventricle. The aim of this study was to determine the prevalence of myocardial perfusion abnormalities in the ventricular myocardium of asymptomatic patients, older than 8 years of age, who had earlier undergone either a univentricular palliation (modified Fontan procedure) or a biventricular repair for tetralogy of Fallot, more than a year ago. All eligible patients underwent screening electrocardiogram (to rule out rhythm disturbance) and echocardiography. Patients with ventricular ejection fraction of more than 50 % by echocardiography were included. Enrolled patients were subjected to gated stress–rest myocardial perfusion imaging using Technitium-99m tetrofosmin single photon emission-computerized tomography (SPECT). Ventricular ejection fraction was also calculated from gated rest study. For the Fontan group, we also analyzed data to see if the morphology of the systemic ventricle would make a difference as far as myocardial perfusion was concerned. Twenty-six patients were enrolled (11 had undergone Fontan surgery and 15 had complete repair of tetralogy of Fallot). Seven of 11 patients in the Fontan group had myocardial perfusion defects (63.6 %) as against none in the repaired tetralogy of Fallot group (p < 0.001). The ejection fraction was within normal range in both the groups; it was statistically higher in the post tetralogy of Fallot repair group (p < 0.04). There were two subgroups in the post Fontan group depending on the morphology of systemic ventricle-left (4 patients) and non-left (7 patients). Higher number and larger size of perfusion defects were present in the non-left ventricular systemic ventricle morphology as compared with left ventricular morphology, but this difference did not reach statistical significance. Myocardial perfusion defects are common in patients who have undergone univentricular repair more than one year ago in contrast to patients who had a biventricular repair for tetralogy of Fallot. In the Fontan group, the morphology of the systemic ventricle was not predictive of prevalence of perfusion defect.