Optimal size of outflow patch in total correction of tetralogy of Fallot

Hemodynamic and angiocardiographic studies were performed in postoperative patients with tetralogy of Fallot. Pressure gradient between the right ventricle and pulmonary artery was correlated with the narrowest area in the pulmonary arterial pathway. Regurgitant fraction was also correlated with regurgitant area which was determined by preoperative area of the pulmonic annulus and width of the outflow patch. Follow-up study of postoperative patients with tetralogy indicated that those with pressure gradient less than 20 mmHg and regurgitant fraction less than 15% could be considered ideally corrected. A table was constructed for determining the most appropriate width of the outflow patch for the ideal correction.     

Sinus node dysfunction after complete correction of tetralogy of Fallot. Report of a case

Atrioventricular conduction defects after complete correction of tetralogy of Fallot are well known and their prevalence is decreasing with improved operative techniques. On the other hand, sinus node dysfunction has not been described after this type of surgery. The authors report the case of a 24 year old patient operated at the age of 2 for a favourable form of tetralogy of Fallot. In the long-term, this patient had a minimal anatomical sequel (mild pulmonary insufficiency) and first degree AVB with complete right bundle branch block with sinus bradycardia on the surface ECG. A recent aggravation of the patient's functional status led to rhythmological investigation which showed chronotropic atrial incompetence with nodal atrioventricular delay. The patient was implanted with a permanent DDD cardiac pacemaker programmed in the DDDR mode with a good outcome. Atrial chronotropic incompetence is one of the modes of expression of sinus node dysfunction. This has not been previously described in this context. This form of sinus node dysfunction should be systematically excluded after surgical cure of tetralogy of Fallot by exercise stress testing and 24 hour Holter ECG. Symptomatic patients are greatly improved by permanent cardiac pacing with hysteresis.     

The functional status of arrhythmia patients in the late period after the radical correction of tetralogy of Fallot

OBJECTIVE: To assess the cognitive performance of elderly patients referred to the memory clinic. DESIGN: The patients were interviewed using the computerised mental state programme, GMS-AGECAT, and assessed on the Cognitive Assessment Scale (CAS) which includes the Elderly Cognitive Assessment Questionnaire (ECAQ) and the Cambridge Memory Test (CMT), modified for Chinese elderly. SUBJECTS: There were 72 Chinese elderly subjects aged 65 years and above, referred to the NUH Memory Clinic in the first year. RESULTS: Only 45 (62.5%) of the 72 subjects were diagnosed to have dementia using DSM III R criteria. There were 25 cases of Alzheimer's Disease and 20 multi-infarct dementia. In the non-demented group, 15 (20.8%) had depression or anxiety disorders and 12 (16.7%), had no mental disorders but had physical illness which could affect memory. There was a highly significant difference in the ECAQ, CMT and CAS scores of demented and non-demented elderly. There was also a significant difference in the cognitive performance of elderly with mild dementia and those with no mental disorder. CONCLUSION: The memory clinic is a useful facility for the diagnosis and management of dementia. The Cognitive Assessment Scale provides a valid and reliable battery of tests for dementia.     

Study of tetralogy of Fallot by echocardiography

Twelve patients with a Fallot's tetralogy proved by a haemodynamic and angiographic examination were studied by echography, a non invasive technique. The diameters of the right and left ventricles, of the left atrium and of the aorta were measured. The movements of the interventricular septum and the position of the aorta in relation to it were analysed. Moreover, by scanning of the left ventricle an opening was looked for in the septum. The ventricular septal defect together with a dilatation of the right ventricle and a more or less intense dilatation of the root of the aorta were found in all cases. In 10 cases, an aorta overriding the septum was observed, and this was the more obvious the older the child. In the two post-operative cases studied, the septum was found to be in line with the aorta. There are therefore echocardiographic criteria making it possible to diagnose Fallot's tetralogy. These criteria are the more obvious the older the child.     

Radiofrequency catheter ablation of supraventricular tachycardia in an adult with corrected tetralogy of Fallot

An 18 year old female with Fallot's tetralogy had undergone complete repair at thirteen years of age. Two years later she first presented a wide complex right bundle branch block tachycardia at a rate of 220 beats/min which could not be controlled on intravenous verapamil. Electrical shock successfully converted tachycardia to sinus rhythm, which showed typical Wolff-Parkinson-White syndrome. On electrophysiological study, the ortodromic tachycardia was found to be due to left lateral atrioventricular accessory pathway, which was ablated by radiofrequency catheter ablation. One year later she was symptom-free without antiarrhythmic medication.     

Pyogenic myositis: caused by viridans streptococci in an adult with tetralogy of Fallot

A 34-year-old man came to this Emergency Room because of fever, swelling and pain in the right thigh. Tetralogy of Fallot with bicuspid pulmonary valve was diagnosed after serial examination, and computed tomography of the right thigh revealed pyogenic myositis. Surgical drainage of the right thigh abscess and a further pus culture yielded viridans streptococci. There has been no record in the medical literature of a pyogenic myositis caused by viridans streptococci in an adult tetralogy of Fallot. This is thus the first case reported.     

Long-term results following surgical operation of tetralogy of Fallot

(1) The ECGs of 84 patients who survived corrective surgery for tetralogy of Fallot were reviewed. The overall incidence of sudden death during at least 5 years period of follow-up was 4%, mortality being highest in those with CRBBB and LAH (40%). (2) The ratio of leftward to rightward QRS forces projected on the X axis (Rs/Sx) is significantly decreased in postoperative T/F patients. (3) Twenty-seven patients who had corrective surgery for tetralogy of Fallot underwent cardiac catheterization postoperatively. LVEF was mildly, but significantly diminished and LVEDV was increased significantly, while peak dp/dt, Vpm and Vmax were significantly depressed. These findings indicate that patients who had corrective surgery for tetralogy of Fallot have impaired left ventricular function.     

A case of an adult patient of tetralogy of Fallot having malignant hyperthermia during surgery

An episode of malignant hyperthermia occurring in a 42-year-old man undergoing hypothermic cardiopulmonary bypass is reported. Malignant hyperthermia is a syndrome initiated by a hypermetabolic state of skeletal muscle. A patient presented for correction of an acyanotic tetralogy of Fallot. The coincidental usage of hypothermic cardiopulmonary bypass obscured the classical presenting sings and symptoms of the malignant hyperthermia. And the disease of tetralogy of Fallot made the syndrome difficult to manage. Although the clinical diagnosis of malignant hyperthermia is difficult to be confirmed, when it is suspected, it is prudent for the case to be initially treated as malignant hyperthermia.     

Monocusp homograft VSD patch in atrioventricular canal with tetralogy of Fallot

A monocusp aortic homograft was used to compensate for deficient right atrioventricular valve tissue during repair of complete atrioventricular canal defect with tetralogy of Fallot. The homograft was used to produce a comma-shaped ventricular septal defect patch together with the septal leaflet of the right atrioventricular valve, thus committing native leaflet tissue to left atrioventricular valve reconstruction. One year postoperatively the child is in New York Heart Association class I with no tricuspid regurgitation.     

Response to exercise in patients after repair of tetralogy of Fallot

Cardiac catheterization and submaximal exercise testing was performed in 38 patients after repair of tetralogy of Fallot (TF), and compared to 6 control patients who had functional murmurs. Cardiac index, heart rate, and stroke volume index were significantly lower in the TF group than in the control group. Right and left ventricular end-diastolic pressure increased significantly during exercise, which was not found in the control group. Total pulmonary vascular resistance (TPVR), which decreased significantly with exercise in the control group, did not change remarkably during exercise. TPVR was significantly higher in the TF group than in the control group both at rest and during exercise. Several factors were compared between patients with good cardiac index (> 5.0 l/min/m2; Group 1) and poor cardiac index (< 5.0 l/min/m2; Group 2) during exercise. Stroke volume index, right ventricular ejection fraction at rest were significantly higher in Group 1 than Group 2. TPVR, right and left ventricular end-diastolic and end-systolic volume index were significantly lower in Group 1 than in Group 2. There was no significant difference in heart rate, left ventricular ejection fraction, residual pulmonary stenosis, right to left ventricular systolic pressure ratio, and severity of pulmonary regurgitation between two groups. These findings indicate that abnormalities of exercise tolerance in patients after repair of TF were related to poor response of heart rate, pulmonary vascular resistance, and systolic and diastolic ventricular function.     

Extracorporeal membrane oxygenation with heparin-coated systems in a 13-month-old infant with acute hypoxic respiratory failure after correction of tetralogy of Fallot

Hemorrhagic disorders due to systemic heparinization are frequent during extracorporeal lung support (veno-venous extracorporeal membrane oxygenation: vv-ECMO). The development of heparin-coated systems has reduced the need for high-dose heparinization. Whereas the use of these heparin-coated membrane lungs and tubings has been described in former studies in adults, only few reports exist in children. This case report describes the application of a heparin-coated extracorporeal system for long-term vv-ECMO in a 13-month-old infant suffering from acute hypoxic respiratory failure after correction of tetralogy of Fallot. Only moderately elevated levels of activated clotting time (ACT, 120-160 s) and activated partial thromboplastin time (aPTT, 40-60 s) were necessary to avoid thrombotic events in the extracorporeal system. Thoracotomies were performed twice without bleeding complications by discontinuation of the systemic heparinization. We conclude that the use of heparin-coated membrane lungs in infants may improve the safety of extracorporeal lung support and permits surgical intervention without major risk of bleeding.     

Balloon pulmonary valvuloplasty for infants with severe tetralogy of Fallot

Balloon pulmonary valvuloplasty was performed in 3 infants with severe tetralogy of Fallot at days 24, 54 and 86 because of progressive hypoxemia. In two patients, the balloon catheter (4 cm long, 5-8 mm diameter) could not pass through the pulmonary valve. This necessitated a smaller balloon and required a two-step procedure. Initially, a coronary artery balloon (2 cm long, 3.5 mm diameter) was used. Following balloon valvuloplasty, arterial oxygen saturation increased from 63 to 83% in case 1, from 69 to 85% in case 2 and 63 to 86% in case 3. Immediate postvalvuloplasty right ventricular cineangiography revealed that the maximal opening diameter of the pulmonary valve leaflets increased from 1-2 mm to 3-4 mm in cases 1 and 3, and from 2-3 mm to 4-5 mm in case 2. No significant complications occurred. Echocardiographic follow-up data showed that the diameter of the right ventricular outflow tract and pulmonary arteries increased with age. The present results show that the pulmonary valvuloplasty is an effective procedure for relief of pulmonary valve stenosis in tetralogy of Fallot and to improve oxygenation and growth of the pulmonary arteries and right ventricular outflow tract without the need of an immediate aortopulmonary shunt.     

Study of the cardiorespiratory response and chronotropic function after correction of tetralogy of Fallot. Important role of residual pulmonary regurgitation

The pathogenic O1 Amazonia variant of Vibrio cholerae has been shown previously to have a cytotoxin acting on cultured Vero and Y-1 cells, and to lack important virulence factors such as the cholera toxin (Coelho et al. 1995a). This study extends the molecular analysis of the Amazonia strains, detecting the presence of the toxR gene, with a very similar sequence to that of the E1 Tor and classical biotypes. The outer membrane proteins are analyzed, detecting a variation among the group of Amazonia strains, with three different patterns found. As a by-product of this work a polymerase chain reaction fragment was sequenced, reading part of the sequence of the Lon protease of the Amazonia strains. This gene was not previously described in V. cholerae, but its sequence is present in the TIGR database specific for this species.     

Anomalous coronary artery with tetralogy of Fallot and aortopulmonary window

Anomalous origin of the left main coronary artery from the pulmonary artery is rarely associated with other conditions. We report the case of an infant born with tetralogy of Fallot and aortopulmonary window who at the time of surgical repair was found to have an anomalous left main coronary artery originating from the right pulmonary artery.