Hemodynamics and intracardiac conduction after operative repair of tetralogy of Fallot

Electrophysiologic studies were performed in 47 children aged 3 to 18 years, 15 of whom had cardiac arrhythmias 1 to 15 years after repair of tetralogy of Fallot. Six exhibited sinus or atrioventricular nodal dysfunction, 8 had ventricular extrasystoles, and 1 had supraventricular tachycardia. Hemodynamic and electrophysiologic data were obtained at postoperative catheterization. Although electrophysiologic responses were abnormal in a proportion of both the children with and those without arrhythmia, hemodynamic values were similar. Three of 6 children with impaired sinus impulse generation or atrioventricular nodal conduction had a prolonged A-H interval, and in 3 Wenckebach heart block developed at low pacing rates. Ventricular ectopic rhythm was not associated with any particular abnormality of basic intracardiac conduction intervals. Thus, arrhythmias and conduction abnormalities are not consistently related to residual right ventricular hypertension. Abnormalities in electrophysiologic function are common after repair of tetralogy of Fallot in patients with sinus rhythm and may have prognostic implications for these patients.     

Ventilatory response to exercise after intracardiac repair of tetralogy of Fallot

Previous radionuclide studies have shown residual maldistribution of lung perfusion after intracardiac repair of Tetralogy of Fallot (TF). Maldistribution of perfusion may also be detectable by measurements of gas exchange during exercise. Thus, we used exercise to test for maldistribution of perfusion in 13 children (8 to 18 yr of age) who were clinically well (New York Heart Association Class 1) 7 to 14 yr after repair of TF. Sixteen children, matched to the study group by age, size, and sex, served as control subjects. Peak oxygen consumption during progressive exercise on a cycle ergometer was 28.7 +/- 6.6 (SD) ml/kg/min for the study group compared with 35.7 +/- 6.9 for the control subjects (p less than 0.05). During steady-state exercise at a VCO2 of 0.6 L/min, ventilation (VE) and the ventilatory equivalents for oxygen (VE/VO2) and carbon dioxide (VE/VCO2) were high (VE/VCO2 = 35.9 +/- 4.4 versus 32.0 +/- 3.5, p less than 0.05), whereas mixed expired and end-tidal CO2 concentrations were low (PETCO2 = 34.0 +/- 2.4 versus 39.2 +/- 3.0 mm Hg, p less than 0.001). Indices of pulmonary function were normal; FVC values were 96 +/- 17% and FEV, values were 96 +/- 16% of predicted values. Therefore, children who are clinically well may exhibit gas exchange abnormalities compatible with mild maldistribution of lung perfusion 7 to 14 yr after repair of TF.     

Alternative approach for angioplasty of stenosed left pulmonary artery following intracardiac repair of tetralogy of Fallot

A 5-year-old boy with stenosed left pulmonary artery following total correction of tetralogy of Fallot underwent surgical pulmonary arterioplasty through a left anterolateral thoracotomy on a normothermic perfused heart under cardiopulmonary bypass. We found this to be a convenient approach, and recommend it for correction of this lesion in the absence of gross pulmonary regurgitation and right ventricular outflow tract dilatation.     

Hemodynamic evaluation of 221 patients after intracardiac repair of tetralogy of Fallot

Cardiac catheterization and angiocardiographic studies were performed in 221 patients an average of 2 years (range 2 weeks to 10 years) after intracardiac repair of tetralogy of Fallot. The group represented 32.5 percent of the postoperative survivors. The postoperative result was classified as “excellent” (43 percent), “good” (35 percent), “satisfactory” (7 percent) or “unsatisfactory” (14 percent) on the basis of right ventricular peak systolic pressure, right ventricle to pulmonary artery peak systolic gradient and presence of a persistent large or small left to right shunt at the ventricular level. Unsatisfactory results were associated with obstructive pulmonary vascular disease (four patients), severe malformations with obstruction of the right ventricular outflow tract and/or a left to right shunt with a Qp:Qs ratio of greater than 1.5:1 or with currently uncorrectable obstructive anomalies of the right ventricular outflow tract or pulmonary arteries.The postoperative result depended upon the amount of reconstruction of the right ventricular outflow tract and the caliber of the pulmonary arteries. Patients who required a systemic to pulmonary artery anastomosis before total correction and those who required a prosthetic patch for the right ventricular outflow tract fared worse than younger patients who had minimal resection of the right ventricular outflow tract. Pulmonary insufficiency was detected in 94 percent of patients with a right ventricular outflow tract prosthesis and in 10 percent of those who had infundibulectomy alone. The insufficiency was well tolerated clinically and hemodynamically unless there was distal obstruction of the pulmonary artery or its branches.Postoperative catheterization is necessary to assess the immediate and long-term operative results in patients with tetralogy of Fallot. Total correction of tetralogy of Fallot as a primary procedure provides acceptable hemodynamic results even in children less than 4 years of age, providing that the right ventricular outflow tract obstruction can be relieved and that pulmonary insufficiency is not aggravated by increased main pulmonary arterial pressure.     

Lung function in children and adolescents with tetralogy of Fallot after intracardiac repair

We studied lung function in 41 patients, aged 6–27 years, 1–5 years after intracardiac surgical repair (ICR) of tetralogy of Fallot (TOF) and about 5 years after the establishment of the Pediatric Cardiac Center in Prague. The measurements included vital capacity (VC). total lung capacity (TLC), functional residual capacity (FRC), residual volume (RV), forced expiratory flows (FEF), specific airway conductance (SGaw), lung recoil pressure (Pst), and specific static lung compliance (S_1st). Single or mutiple abnormal lung function parameters were found in 83% of patients. Lung function was not related to shunting operations prior to ICR, hemoglobin concentration, and hematocrit, and had no specific pattern. Pst at 100% TLC and 90% TLC declined with increasing age at ICR and at lung function testing, while SC, rose, as did the ratio FRC/TLC. Fifteen patients were studied before and after surgery. Single or multiple lung function tests were abnormal in 93% before and in 84% after ICR. After ICR the ratios FRC/TLC and also RV/TLC, FEF at 25% VC, and FEF at 60% TLC were less frequently abnormal, while Pst at 100% TLC and at 90% TLC, as well as SGaw and TLC, were more frequently abnormal after ICR. The results indicated a regression of smaller airway obstruction and lung hyperinflation after ICR. The evolution of abnormally compliant (emphysematous) lungs with growth of the patients might be a sign of permanent sequelae of early lung damage from abnormal pulmonary hemodynamics. Pediatr Pulmonol. 1993; 16:23–30. © 1993 Wiley-Liss, Inc.     

Fatal esophageal-arterial fistula 17 years following tetralogy of Fallot repair.

Blalock-Taussig shunts (subclavian to pulmonary anastomoses) have remained the most effective palliation in cyanotic heart disease. Late complications are rare but can be devastating. The case of a 26-year-old female with tetralogy and an original Blalock shunt constructed at age four years is reported. Despite subsequent primary repair of the tetralogy and presumed ligation of the Blalock shunt, the patient succumbed to a fatal hemorrhage due to esophageal-arterial fistula involving the Blalock shunt. The circumstances leading to this dramatic outcome are outlined and discussed. It is important for cardiologists caring for congenital heart disease patients to be aware of the late complications of congenital heart surgery, and carry out the proper follow-up investigations.     

Comparison of late clinical status between patients with different hemodynamic findings after repair of tetralogy of Fallot

Long-term results and postoperative hemodynamic findings were reviewed in 144 cases of tetralogy of Fallot. A correlation was found between the late clinical status of patients and the postoperative hemodynamic findings. The mortality in our series of patients followed for 10 years was 6.25%. Each of the deaths occurred in the group with unsatisfactory postoperative hemodynamic findings. An ideal late clinical result can be anticipated in most patients with excellent or satisfactory postoperative hemodynamic findings. The greater the deviation from normal hemodynamic findings, the worse the prognosis. From the excellent group to the unsatisfactory group, the incidence of late ideal result decreased from 95% to 61.1%, while the incidence of poor result increased from 0% to 27.8%. Among various factors in patients in the unsatisfactory hemodynamic group, right ventricular outflow tract obstruction seems to have the worst late result. A large right ventricular-pulmonary artery pressure gradient was noted in three of four who died suddenly. The late result of patients with a small shunt (pulmonary blood flow/systemic blood flow less than 2) seems acceptable; the decision to reoperate in these patients should be made very cautiously.     

Reduced heart rate variability following repair of tetralogy of Fallot

OBJECTIVE: To examine autonomic function as assessed by heart rate variability in patients 10 or more years after repair of tetralogy of Fallot, and to relate this to cardiac structure, function, and electrocardiographic indices. METHODS: Heart rate variability was measured by standard time domain techniques on a 24 hour Holter ECG in 28 patients, aged 12 to 34 years (mean 19.5), who had undergone repair of tetralogy of Fallot at least 10 years previously. Echocardiography was performed to assess left ventricular size and function, right ventricular size and pressure, and any proximal pulmonary arterial stenosis. Right ventricular function was evaluated by radionuclide scan. QRS duration, QT interval, and QT dispersion were measured on a standard 12 lead ECG. Measurements of heart rate variability were compared with values from 28 age matched healthy controls (mean age 19.9 years). Interrelations between variables were assessed using Pearson correlation coefficients and stepwise regression analysis. RESULTS: Heart rate variability was reduced, compared with values for age matched normal controls, in 12 of the 28 patients. Reduced heart rate variability was associated with increased age, increased right ventricular size and pressure, and widening of the QRS complex. CONCLUSIONS: Reduced heart rate variability is a feature following repair of tetralogy of Fallot. It is associated with increasing age, impaired right ventricular haemodynamics, and widening of the QRS complex. Under these circumstances, reduced heart rate variability may be a marker for deteriorating right ventricular function. Increased QRS duration has been identified as a risk factor for sudden death following repair of tetralogy of Fallot, and impaired cardiac autonomic control may be one of the mechanisms involved.     

Utility of Sonoclot analysis and tranexamic acid in tetralogy of Fallot patients undergoing intracardiac repair

Sonoclot analysis is a point of care test to monitor the coagulation process, presenting a comprehensive evaluation of the clot formation and retraction as well as platelet function. This randomized double-blinded study was designed to investigate the utility of Sonoclot analysis in monitoring the coagulation profile as also the antifibrinolytic effects of tranexamic acid administered in patients with tetralogy of Fallot undergoing intracardiac repair. Eighty of a total 94 patients were randomly divided into two groups of 40 each. In the study group, TA was administered thrice at a dosage of 10 mg/kg, i.e. before CPB, on CPB and after CPB, whereas in the control group, placebo was administered at the same time intervals. Sonoclot analysis and D-dimer measurement were performed at baseline and following heparin neutralisation. An additional variable, DR?? (diminishing rate of clot strength at 15 min postmaximal clot strength), was calculated from the Sonoclot graph and was compared with d-dimer levels as a measure of fibrinolysis. The three Sonoclot variables, i.e. activated clotting time, clot rate and platelet function, were deranged at baseline in all the patients. Post-CPB, the change in these variables was not significant. ACT, clot rate and platelet function showed no significant (P > 0.05) difference in both the groups at both the time intervals. DR?? and d-dimer values were comparable at baseline in both the groups. However, a significant (P < 0.05) difference was seen in these variables in the control group as compared with the TA group following heparin neutralisation. To conclude, Sonoclot analysis is a useful, point of care method for the monitoring of coagulation and fibrinolysis in patients with tetralogy of Fallot undergoing intracardiac repair.     

His bundle electrogram after intracardiac repair of tetralogy of Fallot. Analysis of data in 59 patients

His bundle electrograms were recorded in 59 patients after intracardiac repair of tetralogy of Fallot and were correlated with the postoperative electrocardiogram. Except for five patients with first degree atrioventricular block postoperatively all patients in Group A (those with either a normal electrocardiogram or solitary right bundle branch block) had a normal A-H interval (77.7 +/- 21.6 msec) (mean +/- standard deviation); all had a normal H-V interval (39.5 +/- 7.2 msec). Patients in Group B (bifascicular block) tended to have a normal A-H interval (97.2 +/- 26.2 msec) with a prolonged H-V interval (48.8 +/- 10.7 msec). Patients in Group C (trifascicular block) had prolongation of both the A-H (160.0 +/- 32.4 msec) and the H-V interval (58.8 +/- 10.6 msec) by comparison with control values. Patients in Group D (transient complete heart block) had a normal A-H interval (79.5 +/- 28.2 msec) but a prolonged H-V interval (57.8 +/- 16.4 msec), similar to that in Group C. A good hemodynamic result was associated with a normal H-V interval; a prolonged interval accompanied a poor result.     

Prognosis of right bundle branch block and left anterior hemiblock after intracardiac repair of tetralogy of Fallot.

One hundred and forty-one survivors of intracardiac repair of tetralogy of Fallot (TOF), operated on between 1958 and 1972, were studied in order to document the incidence of right bundle branch block and left anterior hemiblock (RBBB and LAH) and to definite the late prognosis. RBBB and LAH occurred in 31 patients (22 per cent), all of whom have had complete follow-up. Transient complete heart block (CHB) occurred postoperatively in 2 patients; there were no other significant arrhythmias. Two late deaths have occurred, neither from arrhythmia (one from progressive congestive heart failure, and the other from attempted reclosure of a ventricular septal defect). The remainder of the patients are well an average of 76 months postoperatively (range, 144 to 12 months). The absence of late-onset CHB or sudden death in this series contrasts with the relatively high incidence of these events in some studies of RBBB and LAH after intracardiac repair of TOF. However, in those reports a history of transient postoperative CHB (indicative of trifascicular disease in this setting) can be found in 75 per cent of those who developed late-onset CHB or died suddenly. We conclude that the occurrence of RBBB and LAH after intracardiac repair of TOF does not of itself carry a bad late prognosis. The critical factor in a bad late prognosis in patients with ECG evidence of RBBB and LAH may be with ECG evidence of RBBB and LAH may be the history of transient postoperative CHB.     

Left ventricular function following attempted surgical repair of tetralogy of Fallot

Left ventricular function was assessed by angiographic methods in 40 patients (ages 3-27), 1-12 years following repair of tetralogy of Fallot. Twenty of the 40 patients (group A) had a satisfactory repair with a pulmonary-systemic flow ratio (Qp/Qs) less then or equal to 1.5 and a right ventricular systolic pressure of less than or equal to 60% of the left ventricular value. The other 20 patients (group B) had a Qp/Qs greater than 1.5 and/or a right ventricular systolic pressure greater than 60% of the left ventricular value. Group A patients had a normal left ventricular end-diastolic volume (LVEDV), end-diastolic pressure (LVEDP), ejection fraction (LVEF), and mass (LVM), while the group B patients had significantly elevated LVEDV, LVEDP, LVM, and a significantly depressed LVEF. These findings indicate that patients with a satisfactory hemodynamic repair of tetralogy of Fallot have normal left ventricular function while patients with postoperative unsatisfactory hemodynamics have significantly impaired left ventricular function.     

Results of the intracardiac repair of tetralogy of Fallot and interventricular communication before the age of 2 years

The post-operative review of 81 patients operated for a large interventricular communication before the age of two years reveals excellent results: the mean age at operation was 7 months, extracorporeal circulation was performed in 25 patients for a mean duration of 77 minutes and profound hypothermia to 18 degrees C was induced in 56 patients. The atrial approach was used in 30% of cases. The mean follow-up period is 26 months. There was one case of complete bundle branch block, which was subsequently fitted with a pacemaker, 7 cases of bifascicular branch block and a right bundle branch block in the majority of cases. The pulmonary vascular resistance was virtually normal (a mean of 3.2 U.m-2 prior to the operation and a mean of 1.9 U.m-2 after the operation). The left ventricular volume, which was markedly increased in all patients preoperatively, returned to normal with maintenance of a normal ejection fraction. The neuro-psychomotor behaviour was abnormal in 13 of the 63 patients tested. These abnormalities are not related to the correction procedure, but to pre-existing pathology (small birth weight). 52 patients from a series of 63 cases operated for tetralogy of Fallot before the age of 2 years (median age 12 months) were also reviewed. Extracorporeal circulation lasting a mean of 115 minutes was performed in 31 patients, cardiac arrest under profound hypothermia was induced in the other cases, for a mean duration of 61 minutes. The mean follow-up period was 29 months.(ABSTRACT TRUNCATED AT 250 WORDS)     

Routine primary repair vs two-stage repair of tetralogy of Fallot.

Fifteen of 194 patients (7.7%) with tetralogy of Fallot operated upon since January 1, 1972 under a protocol of routine primary repair despite young age died in-hospital. Most deaths were from low cardiac output. Young age and smallness of size increased the risk of operation. No deaths occurred among patients older than 4 years. High hematocrit was also a risk factor. Transannular patching has an independent effect in increasing risk. The post-repair ratio of peak pressure in the right ventricle to that in the left did not exert an independent effect. To project current risks of a two-stage approach, we determined that five of 158 patients (3.2%) died in-hospital after secondary intracardiac repair after a previous Blalock-Taussig or Waterston anastomosis between 1967--1978. Using these data and those we have published on the risk of shunting, we project that except in very small babies, the risks of hospital death of a two-stage approach are not less than those of primary repair done without a transannular patch, except when body surface area is less than about 0.35 m2. When a transannular patch is used in the primary repair, the two-stage approach is projected to be safer when the child has a body surface area of about 0.48 m2 or smaller.