Electrophysiologic study of patients with ventricular dysrhythmias during long-term follow-up after repair of tetralogy of Fallot

We performed an electrophysiologic study (EPS) in 8 patients who had received corrective surgery for tetralogy of Fallot. The mean age was 30 years. An average of 15 years had elapsed after corrective surgery. Two patients had episodes of syncope. ECG showed normal sinus rhythm in 7 patients and atrial fibrillation in 1, and all had complete right bundle branch block. All patients had ventricular premature beats of grade 3 or higher of Lown's classification. Overdrive suppression test was performed in 6 patients. Corrected sinus node recovery time (CSNRT) ranged from 230 msec to 510 msec. Wenckebach block of atrioventricular nodal conduction occurred at rates of 130 to 170 bpm during atrial pacing. The H-V interval was prolonged to 60 msec in 1 patient, but was below 55 msec in the others. Programmed stimulation induced ventricular tachycardia (VT) in 3 patients, nonsustained VT in 2 and sustained VT in 1. In 2 of 3 patients, delayed potential or fragmentations were recorded in the outflow tract of the right ventricle. During the follow-up period of 20 months, 2 patients died suddenly. Their CSNRTs and H-V intervals were normal. Ventricular tachyarrhythmia seems to be important as a cause of late sudden death after repair of tetralogy of Fallot.     

Ventricular late potentials and induced ventricular arrhythmias after surgical repair of tetralogy of Fallot.

Ventricular tachycardia (VT) and sudden death are rare but recognized complications after surgical repair of tetralogy of Fallot. We prospectively studied 31 patients (19 boys and 12 girls, mean age +/- standard deviation 7 +/- 4 years) with postoperative tetralogy of Fallot, by means of right-sided cardiac catheterization, 24-hour Holter monitoring, body-surface and intracavitary signal-averaging (gain 10(5) to 10(6), filters of 100 and 300 Hz) and programmed ventricular stimulation (1 and 2 extrastimuli, 3 basic cycle lengths, right ventricular apex and outflow tract). All patients were asymptomatic and none had documented or suspected ventricular arrhythmias. Ventricular late potentials were detected in 10 of 31 patients (32%) and spontaneous ventricular arrhythmias in 12 of 31 patients (39%). No sustained VT was induced by programmed ventricular stimulation but nonsustained VT was induced in 3 patients (10%). Patients with inducible VT more often had late potentials (3 of 3 vs 7 of 28, p less than 0.01), and spontaneous ventricular premature complexes (VPCs) during Holter monitoring (3 of 3 vs 9 of 28, p less than 0.05). To predict VT inducibility, late potentials had a sensitivity of 100%, a specificity of 75%, a positive predictive value of 30% and a negative predictive value of 100%. For spontaneous VPCs, the figures were 100, 68, 25 and 100%, respectively. It is concluded that shortly after repair of tetralogy of Fallot, the presence of both spontaneous VPCs and ventricular late potentials are associated with an increased incidence of inducible VT. Conversely, the absence of VPCs and ventricular late potentials may identify patients at low risk of subsequent ventricular arrhythmias.     

Prevention of sudden death after repair of tetralogy of Fallot: treatment of ventricular arrhythmias

The majority of sudden deaths after repair of tetralogy of Fallot have been presumed to be due to ventricular arrhythmia; however, it remains to be demonstrated that antiarrhythmic medication reduces the incidence of sudden death. Since 1978, ventricular arrhythmias have been treated aggressively; these include any ventricular arrhythmia on routine electrocardiogram and more than 10 uniform premature ventricular complexes per hour on 24 hour electrocardiogram. A review was undertaken of 488 patients followed up for more than 1 month after repair of tetralogy of Fallot (mean follow-up time 6.1 years); 13.5% had ventricular arrhythmia on routine electrocardiogram. Ventricular arrhythmia appeared from 2 months to 21 years postoperatively (mean 7.3 years). Ventricular arrhythmias were significantly (p less than 0.01) related to: longer follow-up duration, older age at follow-up, older age at operation and higher postoperative right ventricular systolic and end-diastolic pressures. Ventricular arrhythmia on routine electrocardiogram occurred in 100% of those who later died suddenly compared with 12% of those who did not die (p less than 0.01). Treatment for ventricular arrhythmia was given to 46 patients and considered "successful" if there were fewer than 10 uniform premature ventricular complexes per hour on 24 hour electrocardiogram. A successful drug was found in 44 of the 46: 30 of 34 given phenytoin, 6 of 9 given propranolol, 1 of 7 given quinidine, 1 of 2 given disopyramide, 8 of 9 given mexiletine and 4 of 5 given amiodarone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ventricular arrhythmias and biventricular dysfunction after repair of tetralogy of Fallot

To test the hypothesis that subclinical levels of ventricular dysfunction contribute to the development of ventricular arrhythmias after repair of tetralogy of Fallot, 38 postoperative patients were studied by radionuclide ventriculography and M-mode echocardiography. Eighteen patients (group I) had Lown grade 2 or greater ventricular arrhythmias on ambulatory electrocardiography or treadmill exercise, or both; 20 patients (group II) had no documented ventricular arrhythmias. Radionuclide ventriculograms were performed using technetium -99m-labeled red cells; ejection fractions were derived by computer from multigated images, with normal values being 45% for the right ventricle and 55% for the left ventricle. From M-mode echocardiography, right and left ventricular end-diastolic dimensions were expressed as a ratio, the highest normal value being 0.45. By radionuclide ventriculography, right ventricular ejection fraction was lower for group I (28 +/- 3%) than for group II (31 +/- 2%), but the difference was not significant (p less than 0.10). Left ventricular ejection fraction was significantly lower for group I than for group II (45 +/- 5% versus 55 +/- 3%, p less than 0.05). The echocardiographic right and left ventricular diastolic dimension ratio was elevated in all patients except two in group II; it was significantly greater in group I than in group II (0.84 +/- 0.06 versus 0.63 +/- 0.04, p less than 0.005). This study provides evidence for right ventricular dilation by M-mode echocardiography and for biventricular dysfunction by radionuclide ventriculography in patients who have undergone repair of tetralogy of Fallot.(ABSTRACT TRUNCATED AT 250 WORDS)     

Induction of sustained ventricular tachycardia after surgical repair of tetralogy of Fallot

Between 1980 and 1996, 89 unselected consecutive patients with repaired tetralogy of Fallot (TOF) underwent examination, including a prospective right ventricular programmed stimulation with the same protocol (S1 S2, S3, S4). Age at surgery was 4.2 +/- 3.5 years and age at electrophysiologic study was 10.9 +/- 6.5 years. Follow-up since surgery was 14.4 +/- 4.8 years and patient follow-up after programmed stimulation was 7.8 +/- 4.2 years. The aim of this study was to evaluate the main predictors of the inducibility of a sustained monomorphic ventricular tachycardia (VT) and its significance to identify a group of patients at risk of sudden death: 21 (group A) had and 68 (group B) had no induced sustained VT. The induction of VT was related to older age at programmed stimulation, prolonged QRS duration, presence of complex ventricular arrhythmia, symptoms, right ventricular overload, and increased right ventricular systolic pressure. Predictors of induced VT selected by multivariate analysis were age at electrophysiologic study (p <0.0001), previous palliative shunts (p <0.001), right ventricular systolic pressure (p <0.007), and symptoms (p <0.005). Among group A patients, 4 had previous sustained VT before stimulation, and 1 had sustained VT only during follow-up after stimulation. No patients of group B had clinical sustained VT. Late mortality was low but similar between both groups. A negative electrophysiologic study may be helpful for the management of patients after surgical repair of TOF, but because the arrhythmic event rate is low, the findings of even a positive electrophysiologic study should be interpreted with caution.     

Calcified right ventricular outflow tract aneurysm after repair of tetralogy of Fallot

Right ventricular outflow tract obstruction in tetralogy of Fallot often includes the pulmonic valve, its anulus, the main and branch pulmonary arteries in addition to the expected infundibular narrowing. Widening of this multiple area of obstructions frequently necessitates patch augmentation. Both synthetic (Ivalon^®, Dacron^®, Teflon^®, Gore-Tex^®, Impra^®) and natural (dura mater and parietal pericardium) materials are used for this purpose. Debate has arisen as to which materials are preferable.¹     

Angiography of right ventricular volume after surgical repair of tetralogy of Fallot

Right ventricular volume and ejection fraction were measured in children who had undergone surgical repair for tetralogy of Fallot with excellent results. Fourteen children who had been operated upon at the age of 3 +/- 2.6 years had cardiac catheterization and cineangiography of the right ventricle at the age of 4.6 +/- 2.7 years. Right ventricular volumes were determined from single-plane cineangiography in right anterior oblique projection (Ferlinz method). Eleven children with a normal right ventricle served as controls. Dual projection cineangiography of the pulmonary artery enabled the pulmonary insufficiency to be divided into 4 grades. Echocardiography with colour-coded doppler velocimetry was also performed, showing the absence of residual shunt and of tricuspid, mitral and aortic valve abnormalities. The extension of pulmonary regurgitation flow to the right ventricle was analysed and divided into 4 grades. Pulmonary insufficiency was present in all patients; it was graded 1 or 2 by the two methods in 8 cases (group A) and 3 or 4 by one or the other of the two methods in 6 cases (group B). In 7 patients of group A the operation had included the insertion of a small patch to widen the pulmonary channels (infundibulum alone in 3 cases, transvalvular in 4 cases); in 5 patients of group B a large infundibulo-pulmonary transvalvular patch had been installed. The right ventricular systolic pressure was always below 50 mmHg (mean: 40.9 +/- 6.7 mmHg) and the systolic gradient between right ventricle and pulmonary artery never exceeded 30 mmHg (mean: 14.9 +/- 6.2 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Late ventricular arrhythmia is rare after early repair of tetralogy of Fallot

Objectives. This study was conducted to describe the incidence of ventricular arrhythmia during prospective long-term follow-up in a group of patients who had repair of tetralogy of Fallot during early childhood.Background. Ventricular arrhythmia has been a common finding in patients who have undergone repair of tetralogy of Fallot in late childhood or as adults. Whether earlier repair lowers the incidence of late ventricular arrhythmia or late sudden death is unknown.Methods. Twenty-nine asymptomatic patients who underwent repair at age 1.2 to 7.7 years (mean [±SD] age 4 ± 1.4 years) between 1979 and 1984 were studied. Twenty-one patients had simple repair (Group A), and eight had complex or multiple operations (Group B). All had ambulatory electrocardiographic monitoring preoperatively, postoperatively, at early follow-up (after 4.2 ± 1.3 years) and again at late follow-up (after 11.8 ± 1.3 years). At late follow-up, 28 subjects also underwent echocardiography, and 26 had an exercise test.Results. No patient had significant ventricular arrhythmia (≥modified Lown grade 2) before or immediately after repair. There was no significant increase in the incidence of arrhythmia at early and late follow-up (14% to 28%), but at each of these periods the incidence of ventricular arrhythmia was higher in Group B patients (3 [43%] of 7 vs. 1 [5%] of 22 with early repair, p = 0.03; 6 [75%] of 8 vs. 2 (10%) of 21 with late repair, p = 0.001). No patient had symptoms of arrhythmia, and there were no sudden deaths. Late ventricular arrhythmia did not correlate with estimated right ventricular systolic pressure, outflow tract gradient or degree of pulmonary incompetence or right ventricular dilation. On exercise, 5 (19%) of 26 patients had ventricular premature complexes at low levels of exercise that were suppressed at maximal exercise in all patients.Conclusions. Late ventricular arrhythmia is rare in patients with successful early correction of tetralogy of Fallot, unless complex or multiple operations are performed.     

Electrophysiologic characteristics of sustained ventricular tachycardia occurring after repair of tetralogy of fallot

The electrophysiologic characteristics of sustained ventricular tachycardia occurring after total repair of tetralogy of Fallot are reported. Four patients, 8 to 31 years of age, who had spontaneous episodes of sustained ventricular tachycardia underwent electrophysiologic study to determine the mechanism and site of origin of the tachycardia. In each patient, the tachycardia could be reproducibly initiated and terminated by programmed electrical stimulation. In two patients, initiation and maintenance of the tachycardia depended on the development and perpetuation of continuous electrical activity in the right ventricular outflow tract. These observations suggested a reentrant mechanism. In each patient, catheter endocardial mapping demonstrated the site of origin to be the right ventricular outflow tract. In two patients intraoperative mapping showed the reentrant circuit originating at the site of healed right ventriculotomy site. We conclude that sustained ventricular tachycardia after repair of tetralogy of Fallot in our patients was caused by reentry at the site of the previous operation in the right ventricular outflow tract.     

Incidence and severity of chronic ventricular dysrhythmias after repair of tetralogy of Fallot

A group of 72 patients who had undergone surgical correction of tetralogy of Fallot (TF) more than 5 years previously were evaluated for the presence and severity of ventricular dysrhythmias by treadmill exercise testing (TE) and 24-hour ambulatory ECG monitoring (AM). The results of rhythm evaluation were correlated with surgical and clinical data to determine characteristics which identified patients at risk for sudden death. Of the 72 patients, 30 (42%) manifested serious ventricular dysrhythmias on TE and/or AM. Four patients with documented ventricular dysrhythmias had subsequent cardiac arrest; an additional patient was admitted in ventricular tachycardia. Patients with ventricular dysrhythmias (group II) were found to be significantly older than patients without dysrhythmias (group I), both at the time of surgery and at the time of evaluation. The incidence of residual elevation of right ventricular systolic or diastolic pressure on postoperative catheterization did not differ between the two groups of patients. Ventricular extrasystoles on standard ECG were significantly more frequent in patients with documented ventricular dysrhythmias. Chronic serious ventricular dysrhythmias are very common in patients after TF repair. TE and AM should be an integral part of the long-term postoperative assessment in these patients.     

Right and left ventricular systolic function late after repair of tetralogy of Fallot

Right ventricular (RV) dysfunction has adverse effects on long-term outcome in patients with repaired tetralogy of Fallot (TOF). We employed serial radionuclide angiography (RNA) to examine RV and left ventricular (LV) systolic function in adults late after TOF repair and its relation to clinical outcome. We reviewed 10-year records of 95 patients (53 men) with TOF followed in our clinic (mean age at repair 12.6 ± 10.5 years, mean age at last follow-up 37.7 ± 9.8 years) who underwent at least 2 RNAs between 1987 and 1997. Most patients were well by the end of the study (80% were New York Heart Association class I, 17% were class II, and 3% were in class III). Sixteen patients experienced sustained tachyarrhythmias (8 had atrial; 8 patients had ventricular). One patient died suddenly. Fifteen patients underwent RV outflow reoperations (15 underwent pulmonary valve replacement; 7 had relief of RV outflow obstruction); RV systolic function during exercise in these 15 patients was significantly impaired before and returned to similar levels after surgery, compared with the rest of the patients. Overall, RV and LV function remained stable in the whole group at a mean interval of 5.7 ± 2.2 years between first and last RNA. This group of closely followed adults with TOF remained well over 10 years with a low incidence of sudden death and stable RV and LV systolic function, despite a relatively large number of RV outflow reoperations. Aggressive intervention for right-sided hemodynamic abnormalities may have contributed to this outcome. Preserved ventricular function may herald a favorable long-term outlook in this group.     

Incidence and factors favouring ventricular arrhythmia after surgical repair of tetralogy of Fallot

The prevalence and factors favorising postoperative ventricular arrhythmias in 62 patients undergoing surgical repair of tetralogy of Fallot between 1971 and 1982 were analysed. Nineteen patients (31 %) had significant ventricular arrhythmias (Lown greater than or equal to 2) on Holter monitoring or exercise stress testing. The arrhythmia could only be recorded after stress testing in 5 patients. The patient's age at operation, the duration of follow-up and age at evaluation were significantly greater in the group with ventricular arrhythmias. However, age at operation was closely related to the other two parameters and a discriminating analysis showed that the age at operation was not a favorising factor for the occurrence of ventricular arrhythmias (p = 0.23), in contrast to the duration of follow-up (p = 0.0015) and age at evaluation (p = 0.0007). No relationship was found between ventricular arrhythmias and the following factors: previous anastomosis, outflow patch, necessity of a ventriculotomy or reoperation, presence of residual ventricular septal defect, postoperative systolic right ventricular pressure, severity of intraventricular conduction defects, and effort tolerance. These results suggest that after surgical repair of tetralogy of Fallot, the incidence of ventricular arrhythmias increases with time. The main problem is to identify patients with a high risk of sudden death, i.e. those with high degree ventricular arrhythmias and poor haemodynamic results of repair.     

Sustained ventricular tachycardia after repair of tetralogy of Fallot: New electrophysiologic findings

Ventricular arrhythmia originating from the outflow tract of the right ventricle is a presumed cause of late sudden death in patients after repair of tetralogy of Fallot. Exercise testing has been shown to enhance detection, and phenytoin has been shown to control ventricular arrhythmias in these patients. This study reports new findings in 3 patients who underwent electrophysiologic studies at postoperative cardiac catheterization; in each, sustained ventricular tachycardia was induced and found to originate from the inflow-septal area of the right ventricle. Using serial studies, the same sustained ventricular tachycardia was induced during therapeutic serum concentrations of phenytoin but not after propranolol. No patient had ventricular arrhythmia during a 24-hour electrocardiogram or during exercise. Although no patient had normal hemodynamic function, only 1 patient had right ventricular pressure greater than two-thirds systemic pressure. Each patient had undergone initial intracardiac repair at a relatively late age (3, 9, and 9 years).     

Incidence and severity of ventricular arrhythmia in patients after repair of tetralogy of Fallot

To evaluate the incidence and severity of ventricular arrhythmias (VA) in a large group of patients who underwent corrective surgery for tetralogy of Fallot (TF) more than 4 years previously (mean age at surgery: 6 years 5 months), cardiac catheterization and cineangiography as well as 24 hour ambulatory Holter electrocardiography (HE) were performed in 45 patients. Fifteen (33%) of the 45 patients had VA of Lown grade 2 or greater. Patients with VA (group I) were found to be significantly older at surgery than patients without VA (group II) (p less than 0.05). There were no significant differences in the ratio of postoperative right and left ventricular systolic pressures (RVSP/LVSP), and also right ventricular ejection fraction (RVEF) between the 2 groups. As far as we know, none of our patients has suffered a sudden late death after repair of TF. Still, the overall incidence of VA was significantly high.     

Ventricular late potentials and spontaneous ventricular arrhythmias after surgical repair of tetralogy of Fallot: do they have prognostic value?

OBJECTIVE--To determine the prognostic significance of ventricular late potentials and spontaneous ventricular arrhythmias detected early after surgical repair of tetralogy of Fallot. DESIGN--Prospective observational. SETTING--Cardiology department of a teaching hospital. METHODS--Between June 1984 and June 1991, 104 children (63 boys, 41 girls) were studied by signal averaging and 24 hour ambulatory monitoring after surgical repair of tetralogy of Fallot. Mean (SD) age at operation was 6 (3) years, mean interval between operation and evaluation was 8 (25) months, and the follow up after evaluation was one to 88 (mean 30) months. RESULTS--Ventricular late potentials were detected in 24/104 patients (23%) and spontaneous ventricular arrhythmias in 39/96 patients (38%); usually (in 81%) these were unifocal and rare. Patients with ventricular late potentials were older at operation than patients without late potentials (9 (3) v 6 (3) years, P = 0.002). No correlation was found between the presence of ventricular late potentials and the presence or complexity of spontaneous ventricular arrhythmias early after operation. During the mean follow up of 2.5 years no case of sudden death or sustained ventricular tachycardia was found. CONCLUSION--Short-term prognosis after surgical repair of tetralogy of Fallot is good; ventricular late potentials and spontaneous ventricular arrhythmias are often detected shortly after operation, but in the medium term follow up they do not predict sudden death or serious ventricular arrhythmias.     

Management after childhood repair of tetralogy of Fallot

Opinion statement The four characteristic findings in tetralogy of Fallot (TOF) include the following: 1) a malaligned ventricular septal defect; 2) right ventricular outflow and/or pulmonary valve/artery stenosis or atresia; 3) a dextraposed overriding aorta; and 4) right ventricular hypertrophy. This article focuses solely on the outcomes and treatment of surgically corrected patients born with TOF. In the modern era, early surgical repair consisting of ventricular septal defect closure and alleviation of right ventricular outflow obstruction have gained favor over early palliation with an aortopulmonary shunt followed by intracardiac repair. Surgical outcomes are excellent and dramatically improve prognosis. However, these patients are not "cured" and are at significant risk of developing subsequent electrical and hemodynamic problems. An operated patient with TOF should be evaluated at regular intervals by a cardiologist trained in congenital heart disease; any symptoms suggestive of hemodynamic or electrical compromise should spur further investigation. Advances in imaging, medical therapy, electrophysiology, device/resynchronization therapy, and percutaneous intervention provide the clinician with a number of therapeutic options. Surgical techniques have changed significantly since the early intracardiac repairs of the 1960s and 1970s. The deleterious hemodynamic and electrical effects of pulmonary regurgitation and ventriculotomy scars have spurred efforts to ensure pulmonary valvular competence and minimize the extent of ventricular incisions. Since Blalock and Taussig’s first palliative shunt in 1945, the survival and quality of life for patients with TOF has improved dramatically; this is one of the great accomplishments for cardiovascular medicine in the 20th century. The 21st century promises further success with the advent of a myriad of technologic advancements.