Sinus node dysfunction after Fontan modifications--influence of surgical method.

BACKGROUND: Sinus node dysfunction (SND) is reported to be a troublesome complication following various types of Fontan operations. The correlation of post-Fontan SND with surgical methods was evaluated in this study. METHODS: By reviewing the medical records, surface ECGs, and Holter monitoring, the range of heart rate (HR) and the risk of SND at intermediate term after Fontan type operation (follow up: 41.3+/-13.1 months) were analyzed between two age matched groups of patients, consisting of the extracardiac conduit group (EC, n=33) and the lateral tunneling group (LT, n=35). RESULTS: Junctional rhythm was observed in nine out of 35 patients in LT and five out of 33 patients in EC during the follow-up period. Resting HR was faster in EC than that in LT (108+/-15 vs. 82+/-21, P<0.001). Average and maximal HR in Holter monitoring were also faster in EC than those in LT. SND was found in 13 cases (10 in LT, three in EC) during follow-up and one required pacemaker implantation. In the case of situs solitus heart, SND was less frequent in EC than in LT (0/16 vs. 8/26, P=0.01). In the case of heterotaxy syndrome, SND occurred in similar number of cases (3/17 vs. 2/9). The staged approach to Fontan completion did not influence SND. LT repair was the only factor causing sinus node dysfunction according to multivariate logistic regression (P=0.03, OR 5.96). CONCLUSIONS: Lateral tunnel type surgical repair was more likely to lead to the development of sinus node dysfunction than extracardiac conduit operation. In the case of heterotaxy syndrome, surgical method had no significant influence.

Envolvimento do nódulo sinusal na doença de Chagas / Simus node involvement in Chagas' disease

Foi encontrada acentuada fibrose, acompanhada de atrofia e fragmentaçäo das fibras específicas, no nódulo sinusal em todos os 11 casos em que esta estrutura foi investigada através de cortes seriados em portadores de miocardiopatia crônica chagásica. A lesäo sinusal tinha aspecto cicatricial, em contraste com o ativo processo inflamatório crônico encontrado no miocárdio de todos os casos. Apenas em um destes casos, a disfunçäo sinusal se apresentava clinicamente bem evidente. Estes achados sugerem que o envolvimento do nódulo sinusal se faz freqüentemente e intensamente nos chagásicos crônicos e que a sua exteriorizaçäo clínica pode passar despercebida se testes apropriados näo forem utilizados. Em complementaçäo a este estudo, foi feita investigaçäo experimental em que 7 cäes jovens, com miocardite chagásica aguda, foram submetidos a duplo bloqueio autonômico com atropina (0,4 mg/kg) e propranolol (2,25 mg/kg) para obtençäo da freqüência sinusal intríseca. Esta foi de 169 ñ 5,4 antes da infecçäo. Aos 18 dias após a inoculaçäo, 60% dos cäes exibiam diminuiçäo da FSI (> 10%) , sendo considerados portadores de disfunçäo intrínseca do nódulo sinusal. Ao exame histológico constatou-se acentuado processo de miocardite, a qual se estendia e destruia parcialmente o nódulo sinusal. Este nódulo parece assim vulnerável às alteraçöes da miocardite chagásica e seu envolvimento morfológico-funcional ocorre diretamente e näo apenas após destruiçäo do sistema nervoso autonômico

Anatomopathology of the normal and abnormal AV conduction system.

The specialized conduction system of the heart is responsible for both congenital and acquired disorders of cardiac rhythm. Sinoatrial disorders may result from disruption of nodal cells and takeover by subsidiary pacemaker cells. AV block may occur congenitally or result from the ravages of ischemic heart disease. Clinically overt or concealed accessory pathway conduction via various types of bypass tracts are responsible for the genesis of many supraventricular arrhythmias. Anatomohistologic correlations provide the analytic basis for many disturbances of rhythm.

[Adult familial idiopathic binodal block]. / Le bloc binodal idiopathique et familial de l'adulte.

Four brothers with a maximum age difference of 20 years, the eldest of whom has been re-examined after a 10 year interval, have sinoatrial block, a supra-hisian atrioventricular block and paroxysmal atrial arrhythmias which have led to partial atrial standstill in the eldest: left anterior hemiblock is also present in the two youngest brothers. The condition is very well tolerated. This family is compared to the other 12 reported cases of familial idiopathic binodal block in the adult, an autosomal dominant condition with variable penetration. The diagnosis is reserved and justifies endocavitary investigation of the sinus node function and atrioventricular conduction in the four brothers and the most exposed members of their family. The mechanism of the condition is unknown. It seems to arise from variable degrees of nonspecific of the nodal and atrial tissues.

Histopathological correlates of sinoatrial disease.

Six hearts from patients suffering from rhythm disorders consistent with the diagnosis of sinoatrial disease were histologically examined. Four of the patients had shown a tachycardia-bradycardia syndrome, and the remaining two patients episodes of sinus arrest or sinoatrial block with a slow junctional escape rhythm. The rhythm disorders had occurred in the setting of chronic sinoatrial disease (3 cases), acute myocardial infarction (2 cases), and diphtheritic myocarditis (1 case). The abnormalities which were more consistently observed consisted of (1) total or subtotal destruction of the sinus node (6 cases); (2) total or subtotal destruction of the areas of nodal atrial continuity (5 cases); (3) inflammatory or degenerative changes of the nerves and ganglia surrounding the node (6 cases); (4) pathological changes in the atrial wall (5 cases). Chronic or acute lesions involving the AV node, the bundle of His, and its branches or their distal subdivisions were also found in all 6 hearts. The relationship between the observed pathological changes and the physiological disorders are discussed.

Pathology of sinoatrial node. Correlations with electrocardiographic findings in 111 patients.

Histological study of the sinoatrial node (SAN) was performed in 111 patients in order to estabilsh correlations between the ECG findings and the anatomical lesions. This series includes both patients with sinus rhythm and patients with atrial arrhythmias. The results are as fololows: (a) the amount of nodal cells in the SAN was found to be inversely proportional to the age of the patients (p less than 0.001); (b) normal sinus rhythm was present in some cases with severe fibrosis of the SAN; (c) the present study does not support lesions of the SAN as responsible for atrial fibrillation; (d) chronic sinoatrial block was associated with extensive lesions of the approaches of the AV node or the AV node itself; (e) the auricular tachycardia-bradycardia syndrome was associated in most cases with both lesions of the main feature of the SAN lesion. The pathogenesis of these fibrotic lesions are discussed.

A clinicopathological study on the sick sinus syndrome.

A total of 6 cases of sick sinus syndrome were presented, including 2 cases of sinoatrial (SA) block and 4 cases of bradycardia-tachycardia syndrome. There were 2 men and 4 women, and their ages ranged from 69 to 91 years. Electrophysiological studies were performed in 3 cases, showing positive overdrive suppression in 1 and normal atrioventricular (AV) conduction in 3. Syncopal attacks were found in 4 cases, and 2 cases died suddenly. Histological examination of the SA node and AV conduction system disclosed (1) marked reduction of the SA nodal muscle fibers by 70 t0 80%, (2) moderate to marked proliferation of connective tissues in the SA node, and (3) moderate fibrosis in part of the left bundle branch. The SA node artery was patent.

[Postmortal coronarography by means of a roentgen double contrast method]. / Postmortale Koronarangiographie mit einem Röntgendoppelkontrast-Verfahren

In the conventional postmortem coronary angiogram and vessels are illustrated by a "compact" filling with contrast medium. In the case of the double contrast technique, a thin film of contrast medium is brought about the inner surface of the arteries. Gas injected under controlled pressures into the vessels acts as a further control against the surrounding media. The method is suitable for a more precise illustration of the subepicardial and large intramural coronary arteries. Of particular advantage is the high transparency of the x-ray pictures and the possibility to make the coronary ostia visible. The evaluation of x-ray pictures produced at different controlled pressures permits conclusions about pressure-volume relations of defined vessel sections, which then can be analysed histologically.