Conduction disturbances after surgical correction of ventricular septal defect by the atrial approach.

Conduction disturbances have been documented after correction of ventricular septal defects by the ventricular route. Recently, repair of the ventricular septal defect has been through the right atrium to overcome damage to the conduction system and a right ventriculotomy. Thirty-nine children with ventricular septal defects under the age of 5 years were operated upon by the atrial route (group 1). The incidence of conduction disturbances in this group was compared with that occurring in 19 children of comparable age with a ventricular septal defect repaired via a right ventriculotomy (group 2). Complete right bundle-branch block developed in 13 of 39 children (33.3%) in group 1, compared with 15 of 19 children (78.9%) in group 2. This was a statistically significant reduction in complete right bundle-branch block in group 1. The incidence of left axis deviation occurring with complete right bundle-branch block was similarly statistically reduced. Transient complete heart block and arrhythmias were not statistically different in the two groups. The atrial approach to the repair of the ventricular septal defect significantly reduced the incidence of complete right bundle-branch block alone and occurring with left axis deviation.     

Detection of late arrhythmia and conduction disturbance after correction of tetralogy of Fallot.

The electrocardiographic conduction disturbances were evaluated retrospectively, in relation to prognosis, in 196 patients who underwent correction of tetralogy of Fallot. The follow-up was one to 20 years (mean 10). After surgery complete right bundle-branch block occurred in 187 patients (95%), right bundle-branch block and left axis deviation in 17 patients (9%), and progressive conduction defects, either left axis deviation or right bundle-branch block, developed during follow-up in 21 patients (11%). Nine patients (4.6%) died suddenly and two patients developed complete heart block late after the operation. Though late sudden death or complete heart block occurred in 19 per cent of patients with progressive conduction defects as opposed to 4 per cent of the group with stable conduction defects, the difference was not significant. Twenty-four hour ambulatory electrocardiographic monitoring was performed in 74 patients; 41 per cent had significant (Lown grade 2, 3, or 4) ventricular arrhythmias. The incidence of ventricular arrhythmia in the group with progressive conduction defects (80%) was significantly higher than in the group with stable conduction defects (30%). As occult arrhythmia may be the cause of sudden death, it is important to identify these patients.     

Histologic observations of the cardiac conduction system in a patient with postoperative bilateral bundle branch block

It has been suggested that the postoperative development of a right bundle branch block pattern is due to injury of peripheral rather than proximal parts of the right bundle branch and does not affect the prognosis for the later development of complete heart block. However, the occurrence of complete heart block in a patient with postoperative right bundle branch block who later has left bundle branch block has not previously been documented. The entire specialized cardiac conduction system of a patient who had two operations for repair of double outlet right ventricle and multiple ventricular septal defects was serially sectioned. In the first operation, which resulted in a right branch block pattern, a subaortic ventricular septal defect was repaired through a right ventriculotomy. In the second operation complete heart block occurred after multiple muscular ventricular septal defects were repaired with a patch inserted through a left ventriculotomy. Examination of the conduction system showed that the right bundle branch was completely interrupted by the patch used to repair the subaortic ventricular septal defect and the left bundle branch was completely severed by the patch used to repair the muscular ventricular septal defects.     

Arrhythmia disorders after repair of ventricular septal defects. Comparison of atrial and ventricular approaches

Post-operative disorders of conduction and of ventricular and supraventricular excitability were studied in 50 patients operated upon for ventricular septal defect (VSD). The VSD was approached by right ventriculotomy in 29 patients aged 4.4 +/- 3.1 years at surgery and 15.1 +/- 6.5 years at evaluation. The VSD was closed by the atrial route in 21 patients aged 6.6 +/- 3.9 years at surgery and 12.1 +/- 6.8 years at evaluation. Complete right bundle branch block (CRBB) was significantly more frequent in patients who underwent ventriculotomy (62 p. 100 vs 33 p. 100, p less than 0.05), but 2 late complete atrioventricular blocks were observed in patients in whom the atrial route was used. 34 p. 100 of the patients with ventriculotomy and 26.5 p. 100 of those without ventriculotomy had significant ventricular arrhythmias on Holter recordings (greater than or equal to Lown's grade 2, p = NS). The occurrence of ventricular arrhythmias in the patient population as a whole increased significantly with age at surgery and age at evaluation (p less than 0.05); this increase was also noted in each group (p = 0.06). Pre-operative right ventricular systolic pressure, severity of intraventricular disorders of conduction or duration of extracorporeal circulation and aortic clamping had no influence on the occurrence of ventricular arrhythmias. Disorders of supraventricular excitability were found in 1 patient who had ventriculotomy and in 2 patients whose VSD was corrected by the atrial route. No sinus dysfunction was observed. It is concluded that the ventricular approach of VSD significantly increases the occurrence of post-operative CRBB.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgery in children with atrial septal defects without cardiac catheterization

We describe the results of surgical repair of atrial septal defects in 36 children who did not undergo pre-op cardiac catheterization. These cases were seen at the Hospital de Cardiologia y Neumología Dr. Luis Méndez del Centro Médico Nacional. There were 24 (67%) females and twelve (33%) males. The mean age was 6.4 +/- 2.4 years with a range from three to thirteen. All cases had auscultatory findings typical of atrial septal defect. Five patients with associated tricuspid murmur (chest film showed grade I cardiomegaly in 21 (58.3 per cent), grade II cardiomegaly in fifteen (41.7 percent). Pulmonary artery shadow was normal in 24 (66.6 percent) and increased in twelve (33.3%). Pulmonary blood flow was increased in all of them. Electrocardiogram showed sinus rhythm in 35 (97.2%). In one instance left atrial rhythm; all EKGs demonstrated right axis deviation, complete right bundle branch block and right ventricular hypertrophy with diastolic overload. Only three had right atrial hypertrophy. The M-mode echocardiogram showed right ventricular dilatation in all and paradoxically septal motion in 26 (72.2%). Two-dimensional echo with the subxiphoid view allowed direct visualization of the defect in all cases. We performed contrast echocardiogram in eight cases and Doppler echocardiogram in six of them. Cardiac surgery findings were ostium secundum atrial septal defect in 34 (94.4%). Two of them also had partial anomalous venous connection. All had uneventful recovery. We conclude that in typical atrial septal defects operative repair is feasible without prior cardiac catheterization.     

Ventricular arrhythmias after correction of ventricular septal defects: importance of surgical approach

To compare the prevalence of conduction disturbances and ventricular arrhythmias in cases of postoperative ventricular septal defect, 100 patients (50 with repair by right atriotomy, group 1; and 50 with repair by right ventriculotomy, group 2) underwent complete evaluation including an electrocardiogram (ECG) and 24 h ambulatory ECG monitoring. The two groups were comparable except for a shorter follow-up duration (7 +/- 3 versus 12.4 +/- 7 years) and a younger age at evaluation (12.4 +/- 5 versus 16.9 +/- 7 years) in group 1. Complete right bundle branch block was less frequent in group 1 than in group 2 (20% versus 50%, p less than 0.05) but three of the four patients with complete atrioventricular (AV) block detected on ambulatory monitoring were in group 1. Six patients had significant supraventricular arrhythmias, all well tolerated. Ambulatory monitoring revealed significant ventricular arrhythmias (modified Lown grade 2 or higher) in 39 patients, with a lower prevalence in group 1 (30% versus 48%, p = 0.05). No correlation was found between prevalence of ventricular arrhythmias and right ventricular systolic pressure, cardiopulmonary bypass duration, presence of a synthetic patch, previous pulmonary artery banding, presence of complete right bundle branch block and cardiomegaly on chest X-ray film. Prevalence of ventricular arrhythmias increased with follow-up duration, age at evaluation and age at surgery. These were always well tolerated and did not warrant treatment. Thus, right atriotomy reduces the prevalence of right bundle branch block but does not prevent late AV block. Ventricular arrhythmias are frequent after surgical closure of ventricular septal defect whatever the surgical approach and their prevalence is not statistically different from that in postoperative tetralogy of Fallot.(ABSTRACT TRUNCATED AT 250 WORDS)     

Correction of tetrad of fallot with reduced incidence of right bundle branch block

In 20 patients who underwent a modified surgical repair of tetrad of Fallot complete right bundle branch block developed in only 8 (40 percent). Standard and intraoperative conduction studies indicated that in these patients the right bundle branch block was due to injury of the right bundle branch near the ventricular septal defect (proximal right bundle branch block). The modified operative technique is aimed at minimizing the injury to the right ventricle and it includes a significantly shorter than usual ventriculotomy incision and avoidance of the septal (moderator) band during infundibulectomy. Intra- and postoperative hemodynamic studies of these patients revealed that relief of the right ventricular outflow obstruction was optimal.     

Conduction disorders after cardiac surgery with extracorporeal circulation

Two-hundred-fifty-eight patients who had cardiac surgery with extracorporeal circulation were studied to determine the frequency and significance of conduction disturbances. Fifty-eight (34%) developed new postoperative conduction defects. Seventeen patients developed new conduction alterations after coronary artery bypass graft. The most common disturbance was transient bifascicular block (right bundle branch block and anterior subdivision block of the left bundle branch of His) (p less than 0.01). After valvular surgery twenty-one patients developed conduction defects. Of those the most common disturbance was high degree AV block (57%). The authors found no relation between the AV block and the number of valves operated on or type of valvular surgery. After congenital heart surgery, twenty patients developed conduction defects. The most common defect was high degree AV block. The frequency of complete heart block was higher after the closure of atrial septal defects (P less than 0.01). None of the conduction defects were related to the amount of time the patient was exposed to extracorporeal circulation or to postoperative myocardial infarction. All conduction defects were transient except complete heart block in some patients with ventricular septal defect surgery. In this study there were no hemodynamic complications or mortality associated with the conduction disturbances.     

Conduction disturbances and operative results after closure of ventricular septal defects by three different surgical approaches

A total of 135 patients with ventricular septal defect (VSD) under 15 years of age, without associated cardiac lesions, underwent surgical repair by 3 different approaches of trans-pulmonary arteriotomy (PA), right atriotomy (RA) and right ventriculotomy (RA) between 1977 and 1981. Six hospital deaths (4.4%) occurred among the 135 patients. Of 41 children with PA, 53 with RA and 41 with RV, one child (2.4%), one child (1.9%) and 4 children (9.9%) died, respectively. In the trans-PA approach, 8 of 40 children (20.0%) developed complete right bundle branch block (CRBBB), but there was no occurrence of left axis deviation (LAD), transient complete heart block (CHB) and arrhythmias postoperatively. In the RA approach, 11 of 52 children (21.2%) developed CRBBB and 2 (3.8%) had a combination of LAD and CRBBB. Four of 52 children (7.7%) had a combination of LAD, CRBBB and CHB, but CHB has been treated successfully with medication. Three patients (5.8%) developed arrhythmias, such as junctional rhythm. In the trans-RV approach, 11 of 37 children (29.7%) developed CRBBB and 4 of the 37 (10.8%) had the combination of LAD and CRBBB. Two patients (5.4%) had arrhythmias which disappeared one month after surgery. All incidences of conduction disturbances and arrhythmias after closure of VSD were significantly less in the trans-PA than in the trans-RA or in the trans-RV (p less than 0.01). However, in the present study, the development of conduction disturbances and postoperative arrhythmias after closure of VSD was not significantly different between the trans-RA and the trans-RV approach.     

Conduction disturbance and tachyarrhythmia in postoperative ventricular septal defect and tetralogy of Fallot

The importance of conduction disturbances and tachyarrhythmias as the determining factors of the late results of postoperative patients with ventricular septal defect and tetralogy of Fallot was reconfirmed in this follow-up study. It was found, however, that the incidences of complete heart block, bilateral bundle-branch block, and ventricular tachyarrhythmia have decreased significantly since the establishment of cold cardioplegia. This has certainly contributed to the remarkable improvement in late follow-up results of postoperative patients with ventricular septal defect or tetralogy of Fallot.     

Vectorcardiographic study of aberrant conduction anterior displacement of QRS: another form of intraventricular block.

Aberrant ventricular conduction was induced in 44 subjects by introduction of atrial premature beats through a transvenous catheter-electrode. Multiple patterns of aberrant ventricular conduction were obtained in 32 patients and, in the whole group, 116 different configurations were recorded. Of these, 104 showed a classical pattern of mono- or biventricular conduction disturbance. The pattern frequencies were as follows: right bundle-branch block, 28; left anterior hemiblock combined with right bundle-branch block, 21; left anterior hemiblock, 17; left posterior hemiblock combined with right bundle-branch block, 12; left posterior hemiblock, 10; complete left bundle-branch block, 10; and incomplete left bundle-branch block, 6. The remaining 12 configurations could not be classified into the usual categories of intraventricular blocks. In 7 of them, the alterations only consisted of trivial modifications of the QRS contour. In the other 5 instances, aberrant conduction manifested itself by a conspicuous anterior displacement of the QRS loop, with increased duration of anterior forces. The latter observation is worthy of notice, as it indicates that, in the differential diagnosis of the vectorcardiographic pattern characterized by prominent anterior forces, conduction disturbances should be considered a possible aetiological factor in addition to right ventricular hypertrophy, and true posterior wall myocardial infarction.     

Right bundle-branch block and left axis deviation in acute myocardial infarction

Of 114 patients with acute myocardial infarction admitted consecutively to a coronary care unit, 10 had recent antero-septal myocardial infarction associated with right bundle-branch block and obvious left axis deviation, and I had recent antero-septal myocardial infarction with right bundle-branch block and right axis deviation. Attention is drawn to the high mortality (7 out of 11 patients), due mainly to cardiogenic shock. Frequent complications were sudden complete heart block (5 patients) and ventricular asystole (4 patients) without previous lengthening of the atrioventricular conduction time. An external on-demand pacemaker was inserted in 10 patients, and no patient died of complete heart block or ventricular asystole.     

Transatrial repair of ventricular septal defect subsequent to myocardial infarction

We describe successful transatrial repair of a ventricular septal defect occurring secondary to myocardial infarction. This approach avoids the need for ventriculotomy and may be technically simpler and safer than repair across the zone of infarction in a subset of patients with posterior defects and right ventricular dysfunction who survive the early period subsequent to their infarct.     

Right bundle-branch block and left axis deviation in acute myocardial infarction.

Of 114 patients with acute myocardial infarction admitted consecutively to a coronary care unit, 10 had recent antero-septal myocardial infarction associated with right bundle-branch block and obvious left axis deviation, and I had recent antero-septal myocardial infarction with right bundle-branch block and right axis deviation. Attention is drawn to the high mortality (7 out of 11 patients), due mainly to cardiogenic shock. Frequent complications were sudden complete heart block (5 patients) and ventricular asystole (4 patients) without previous lengthening of the atrioventricular conduction time. An external on-demand pacemaker was inserted in 10 patients, and no patient died of complete heart block or ventricular asystole.     

Herzrhythmusst?rungen bei Erwachsenen mit angeborenen Herzfehlern

The occurrence of arrhythmia represents the most important comorbidity in patients with congenital heart disease (CHD). Arrhythmia mechanisms vary according to the underlying anatomic defect and method of surgical repair. The incidence of arrhythmia is highest in patients with moderate and severe CHD. The most common arrhythmia mechanism in CHD patients involves a macroreentry circuit within the atria and is referred to as intra-atrial reentrant tachycardia (IART). Usually, IART, or sinus node dysfunction appear many years after an atriotomy or other surgical manipulation of the right atrium. Atrial fibrillation is not common in CHD. Patients at greatest risk for developing ventricular tachycardia appear to be those who have undergone ventriculotomy or patching of a ventricular septal defect, but it also occurs in patients with left ventricular hypertrophy or reduced ventricular function. Disorders of atrioventricular (AV) conduction can arise in patients with congenitally corrected transposition of the great arteries (ccTGA) or AV canal defects. Surgically induced heart block may occur after closure of ventricular septal defects, surgery for left-heart outflow obstruction, or AV valve replacement.     

Vectorcardiographic study on the right hypertrophy diagnosis in complete right bundle branch block]

Vectorocardiograms were led and interpreted by means of quantitative and qualititive criteria in 100 children with a complete block of the right bundle-branch occurring after correcting surgery of tetralogy of Fallot or isolated defect or the ventricular septum. The results are discussed after demonstrating the pathophysiological patterns of excitation associated with right ventricular hypertrophy and complete block of the right bundle-branch. After a survey of the literature a precise summary of the results is given in order to distinguish clearly by differential diagnosis necessary for postoperative observation of the vitiae cordis mentioned above, between complete block of the right bundle-branch and right ventricular hypertrophy. 4 vetorcardiograms were selected out of the total number of loops for demonstration of the defined criteria for right ventricular hypertrophy associated with complete block of the right bundle-branch.     

Complete atrioventricular septal defect with tetralogy of Fallot: diagnosis and management.

OBJECTIVE--To report recent experience of patients with complete atrioventricular septal defect and tetralogy of Fallot, with emphasis on anatomical features, diagnosis, and management. DESIGN--Case notes were reviewed and patients were assessed at follow up by clinical examination and cross sectional and Doppler echocardiography. SETTING--Tertiary cardiothoracic referral centre. PATIENTS--Between 1987 and 1992 13 patients with atrioventricular septal defect and tetralogy of Fallot (12 with concordant and one with double outlet ventriculoarterial connections) underwent surgery; 10 underwent complete intracardiac repair. 11 patients had Down's syndrome. The complete diagnosis was established preoperatively by cross sectional echocardiography in all but one patient. A tri-leaflet left atrioventricular valve as seen in parasternal short axis views was the diagnostic feature of atrioventricular septal defect, with tetralogy of Fallot diagnosed from the presence of anterocephalad deviation of the outlet septum producing subvalvar pulmonary stenosis as seen in subcostal right anterior oblique views. INTERVENTIONS--Total correction consisted of closure of the atrioventricular septal defect by a combined right atrial and ventricular approach, reconstruction of the atrioventricular valves, and relief of the obstruction within the right ventricular outflow tract. Separate patches were used to close the atrial and ventricular septal defects. Modified Blalock-Taussig shunts were performed in three patients, who await intracardiac repair. Surgical correction was carried out at mean (range) age of 5 (2 to 15) years. MAIN OUTCOME MEASURES--Diagnostic methods, surgical results, and functional state after complete correction. RESULTS--The presence of an atrioventricular septal defect was missed preoperatively in one patient with tetralogy of Fallot. The characteristic goose neck deformity on the left ventriculogram was not present and the tri-leaflet nature of the left atrioventricular valve was not sought on echocardiography. Of the 10 patients who underwent complete repair, nine are alive and one died 34 days after operation with adult respiratory distress syndrome. Examination at necropsy showed an excellent surgical correction. Mean (range) follow up was 23 (8 to 48) months. All nine patients are alive and well (New York Heart Association Class 1). CONCLUSION--Accurate diagnosis and staged management with improved surgical techniques have lowered mortality of this complex combination of cardiac defects. The current policy of this group is to recommend a systemic to pulmonary arterial shunt procedure for symptomatic children younger than 2 years and total correction in older children.     

Incidence and clinical features of asymptomatic atrial septal defect in school children diagnosed by heart disease screening.

The purpose of this study was to investigate the incidence and clinical features of atrial septal defect (ASD) in school children in Japan who were diagnosed by heart disease screening. From 1989 to 1998, a questionnaire, electrocardiography (ECG) and phonocardiogram were obtained from school children when they entered their first year of elementary school (n=86,142) or junior high school (n=80,632). In this program, 33 asymptomatic ASD patients were newly diagnosed (0.020%). The ECG findings showed incomplete right bundle-branch block (79%), right axis deviation (55%), and right ventricular hypertrophy (9%). An ejection systolic murmur was audible in 30 patients (94%) and mid-diastolic murmur in 10 patients (30%). Thirty patients (90%) showed fixed split of second heart sound. Using echocardiography or catheter observation, 31 patients (94%) were judged to require closure of the ASD. Although the medical care is widely available in Japan, undetected ASD patients were not rare and importantly, most of them required closure of the defect even if they were asymptomatic.     

Intermittent AV conduction disturbances in patients with AV nodal bypass tracts. Possible mechanisms of unusual variant of tachycardia-bradycardia syndrome.

His bundle recordings were performed in 2 patients in whom AV nodal bypass tracts coexisted with intermittent AV conduction disturbances occurring below the site from which the His bundle deflection was recorded. Case 1 had: (a) tachycardia dependent right bundle-branch block, (b) persistent HV prolongation, and (c) bradycardia dependent AV block. Case 2 showed: (a) intra-atrial conduction delay, (b) tachcardia dependent left bundle-branch block with HV prolongation, (c) bradycardia dependent HV conduction disturbance, (d) tachycardia-bradycardia syndrome of an unusual type; the latter presumably resulted, during atrial flutter, from the alternation of rapid AH conduction through the bypass tract with intermittent (complete) distal His bundle block or bilateral bundle-branch block.     

Changes in ventricular depolarization in patients in sinus rhythm following closure of ventricular septal defect associated with atrioventricular discordance

Closing the ventricular septal defect in patients with atrioventricular discordance with sutures placed through the defect onto the morphologically right septal surface should avoid production of complete heart block. To discover whether this procedure otherwise affects conduction, standard electrocardiogram (ECG) were compared preoperatively and postoperatively in 11 such patients. Operation had lengthened the PR interval in one and shortened it in another. The QRS interval remained unchanged in 5 patients thought 2 of these showed minor changes in QRS configuration. Four patients showed QRS prolongation (increase greater than 20 msec) with delayed conduction towards the right ventricle and the initial QRS vector preserved, i.e., morphologically right bundle branch block. Two patients showed QRS prolongation with initial QRS vector alteration and delayed conduction towards the left ventricle, i.e., morphologically left bundle branch block. Repair through the morphologically left ventricle invariably caused bundle branch block. Repair through a right atriotomy caused bundle branch block in only 3 of 8 patients. Therefore closure of a ventricular septal defect by this method, particularly transatrially, need not affect conduction. Morphologically left ventriculotomy rarely if ever causes morphologically left bundle branch block. When present, morphologically right bundle branch block presumably results from interruption of the proximal right bundle.