Marie S. Blackman

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.

Hemodynamic and electrophysiologic results of the Senning procedure for transposition of the great arteries

Of 24 patients, aged 6 days to 24 months, undergoing the Senning procedure for transposition of the great arteries, 2 patients died perioperatively (8% operative mortality): 1 patient, a neonate, from sepsis and 1 patient, born prematurely and with multiple anomalies, from congestive heart failure. One patient died late postoperatively from noncardiac causes. The 21 survivors are clinically well, and in 20 complete hemodynamic and electrophysiologic data were obtained by cardiac catheterization a mean of 13 months after repair. All patients have normal systemic arterial oxygen saturation. Left ventricular function and pulmonary artery pressures are normal in all. None had pulmonary venous obstruction. Narrowing at the junction of the superior vena cava and systemic venous atrium with mean pressure differences of 5 mm Hg or more was found in 4 of the 20 patients, but was clinically manifest in only 1 patient. No abnormality of atrioventricular conduction was seen in response to programmed electrical stimulation. Sinus node dysfunction was present in 6 patients, with abnormalities of both automaticity and sinoatrial conduction. Among these 6 patients were the 5 who were younger than 5 months at operation. The Senning procedure generally results in excellent hemodynamic and electrophysiologic status in patients who undergo operation after the newborn period. Identification of sinus node dysfunction, seen in patients in whom the procedure is performed in the first few months of life, is of concern and identifies a need for close follow-up of sinus node function in this cohort of patients.

Detection of dysrhythmia in pediatric patients with mitral valve prolapse.

The association of dysrhythmias with mitral valve prolapse in pediatric patients was investigated by graded treadmill exercise testing and 24-hour ambulatory ECG monitoring. Twenty-six unselected patients with a clinical diagnosis of mitral valve prolapse confirmed by echocardiography or angiocardiography or both were studied. On 24-hour ambulatory ECG monitoring, six patients (23%) had potentially serious ventricular dysrhythmias. Five of these patients also manifested ventricular dysrhythmias on treadmill exercise testing. Neither standard ECG abnormalities nor clinical symptoms correlated with detected dysrhythmias. This study shows that potentially serious ventricular arrhythmias are common in pediatric patients with mitral valve prolapse and that ambulatory ECG monitoring and treadmill exercise testing are useful for detecting dysrhythmias.

Atenolol therapy for exercise-induced hypertension after aortic coarctation repair

After successful repair of coarctation of the aorta in childhood, exercise-induced upper body systolic hypertension is well documented. Beta blockade has been shown to reduce the arm/leg gradient in untreated coarctation of the aorta; treatment before coarctation repair has decreased paradoxical hypertension after repair. Ten patients with successful surgical repair of coarctation, defined as a resting arm/leg gradient of less than or equal to 18 mm Hg, were evaluated by treadmill exercise before and after beta blockade with atenolol. Mean age was 5.5 years at repair and 18 at study. At baseline evaluation, systolic blood pressures at termination of exercise ranged from 201 to 270 mm Hg (mean 229 mm Hg). Arm/leg gradients at exercise termination ranged from 30 to 143 mm Hg (mean 84). Follow-up treadmill exercise studies were performed after beta blockade. Upper extremity systolic pressures at exercise termination were normalized in 9 of 10 patients. Maximal systolic blood pressure recorded at exercise termination ranged from 163 to 223 mm Hg (mean 196 mm Hg, p less than or equal to 0.005). Arm/leg gradient at termination of exercise also decreased significantly to a mean of 51 mm Hg (p less than 0.05). No patient had symptoms on atenolol and exercise endurance times were unchanged. The study results in this small series suggest that cardioselective beta blockade can be used to treat exercise-induced upper body hypertension effectively after surgical repair of coarctation. Because a high incidence of premature cardiovascular disease has been well documented after satisfactory surgical repair, the findings are of importance for this group of postoperative patients.

Subclavian—Pulmonary Artery Shunts with Polytetrafluoroethylene Interposition Grafts

Systemic-pulmonary artery shunts remain an important treatment in cyanotic patients. Central shunts continue to pose early and late problems when standard Blalock-Taussig shunts are not possible. Twenty patients underwent subclavian-pulmonary artery shunt procedures with polytetrafluoroethylene (PTFE) prostheses between October, 1980, and August, 1982. Their ages ranged from 1 day to 15 years; 11 patients were less than 14 days old. The arterial oxygen tension rose from 30.7 +/- 11.9 mm Hg to 51.3 +/- 9.1 mm Hg (standard deviation; p less than 0.001) and from 26.4 +/- 7.5 mm Hg to 50.5 +/- 9.3 mm Hg (p less than 0.001) among the 11 neonates. There were no hospital deaths and only 2 late deaths (not shunt related). All patients have patent shunts and excellent relief of cyanosis. The 18 survivors have been followed for an average of 19 months (range, 7 to 29 months). No patient has required reoperation for shunt inadequacy or thrombosis. Recatheterization in 11 patients has demonstrated normal pulmonary pressures and good pulmonary artery growth without vessel distortion. Subclavian-pulmonary shunts using PTFE provide long-term palliation in cyanotic patients. This type of shunt appears to offer important advantages over other shunt procedures, including the classic Blalock-Taussig operation, in newborns.

Results with the Two-Patch Technique for Repair of Complete Atrioventricular Septal Defect

From May, 1982, to September, 1983, 9 patients underwent repair of complete AV septal defect. They ranged in age from 11 months to 48 months and in weight from 5.3 kg to 16.5 kg. Seven patients were 24 months old or less. Previous operations included pulmonary artery banding in 1 patient and ligation of a patent ductus arteriosus with repair of coarctation in another. All patients had large left-to-right shunts (mean pulmonary to systemic flow ratio, 3.1), and the 7 young infants had marked pulmonary hypertension. Mitral regurgitation was absent in 2 patients, mild in 3, moderate in 2, and severe in 2. One patient had the right ventricular dominant form of complete AV septal defect. In all instances, repair was done using separate ventricular and atrial patches. Leaflet tissue was not divided, and a trileaflet mitral valve was left in each patient. Eight patients survived operation and are well 3 to 17 months after repair. The single operative death occurred in the patient with right ventricular dominance. Only 1 patient has mild residual heart failure 4 months after operation. Clinically, mitral regurgitation is absent in 4 patients and, at most, mild in the other 4. No patient has a conduction disturbance. Repair of complete AV septal defect is facilitated by using separate patches for the ventricular and atrial components of the defect. Less distortion is created, and a more accurate reconstruction of a competent trileaflet mitral valve can be done.

Sinus node shift after the Senning procedure compared with the mustard procedure for transposition of the great arteries

To investigate the nature of the dominant intrinsic cardiac pacemaker activity after the Senning procedure, endocardial mapping of the systemic venous atrium was accomplished a mean of 13 months after operation in 10 patients, aged 22 +/- 6 months. Multiple endocardial sites were measured to find the earliest atrial electrical activity timed back from the QRS complex. These data were compared with data from endocardial mapping performed in 6 patients late after the Mustard procedure. In 8 of 10 patients who had undergone the Senning procedure, the earliest activation time, corresponding by definition to the origin of the intrinsic pacemaker, was located in the inferior medial portion of the superior limb of the systemic venous atrium. In the other 2 patients who had undergone the Senning procedure, the earliest activity was in the high superior limb of the baffle at its junction with the superior vena cava. In contrast, the earliest activity in all patients who underwent the Mustard operation was at the junction of the superior vena cava and the superior limb of the systemic venous atrium. In response to programmed extrastimulation, the electrophysiologic behavior of the intrinsic pacemaker in the Senning group was abnormal compared with known normal sinus node (SN) data in only 3 of 10 patients, whereas all patients in the Mustard group had SN dysfunction. Abnormal SN function was noted in both patients in the Senning group, in whom a shift in the position of the earliest endocardial activation point was not seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriotomy for catheterization of the left side of the heart in children.

LESIONS of the left side of the heart, both congenital and acquired, demand precise physiologic and anatomic diagnosis for accurate surgical relief. This is especially true in infants and children....

Pulmonary hemodynamics and maintenance of palliation following polytetrafluoroethylene shunts for cyanotic congenital heart disease

Subclavian-to-pulmonary artery anastomoses with interposition polytetrafluoroethylene (PTFE) conduits provide excellent early palliation for many forms of cyanotic heart disease. It is important to assess whether patients with this condition maintain adequate arterial oxygenation without developing pulmonary artery distortion or hypertension. From October, 1980, to December, 1982, 29 PTFE shunts were performed. There were no hospital deaths or shunt failures. Catheterization was performed in 14 patients from 2 months to 2.5 years (mean 13.4 months) following operation. All shunts were patent. Arterial Po2 at the late study ranged from 33 to 96 torr (mean 57.1 +/- 17.3 torr) and was not significantly different from values obtained before hospital discharge at the time of the shunt procedure (mean 47.6 +/- 5.9 torr). Only one patient demonstrated moderate pulmonary hypertension (44/25 mm Hg), believed to be secondary to ventricular dysfunction. No patient demonstrated pulmonary artery distortion or kinking, and none required a second shunt because of inadequacy of the original procedure. The results in these patients, as well as the continued excellent clinical course of the patients not as yet recatheterized, have prompted us to use this shunt as our procedure of choice in neonates.

157 CARDIAC RHYTHM IN TRANSPOSITION OF THE GREAT ARTERIES PRIOR TO INTRA-ATRIAL SURGICAL CORRECTION

Atrial dysrhythmias and conduction abnormalities are well described after intra-atrial corrective procedures for transposition of the great arteries (TGA). To assess the incidence of such dysrhythmias in children with TGA prior to open heart surgery (OHS), 16 consecutive patients (pts) with this diagnosis underwent 24 hr. ECG monitoring (EM). All 16 pts underwent balloon atrial septostomy (BAS); 3 pts required subsequent surgical atrial septectomy. The initial EMs were performed at a median age of 7 days (Range: 2 days-18 mos.) following clinical stabilization. In 8 pts,EMs were performed both in the newborn period and just prior to OHS. All 24 EMs demonstrated exclusively sinus rhythm with no evidence of atrial dysrhythmias or conduction abnormalities; a single pt manifested occasional unifocal ventricular premature contractions on newborn EM. No change was demonstrated on the serial EMs obtained in the newborn period and prior to OHS. Four pts have undergone a Mustard procedure and 2 a Senning procedure. ECGs obtained 2 mos. to 1 yr. post-operatively now demonstrate low amplitude P waves in 3; a single pt with supra-ventricular tachycardia has frequent atrial premature contractions on EM. In this group of pts with TGA evaluated by EM after BAS and atrial septectomy, cardiac rhythm was normal; dysrhythmias seen after intra-atrial correction appear to be exclusively surgically acquired.