[Sick sinus syndrome in children with a "healthy heart". Apropos of 2 cases with direct endocavitory tracing of the sino-atrial block]. / Maladie du sinus chez l'enfant à "coeur sain". A propos de deux cas avec enregistrement direct endocavitaire du bloc sino-auriculaire.

The sinus disease in children with "healthy hearts" is exceptional, and has never been documented by tracing of the sinus node. We are reporting two cases of two children, aged 4 and 14 years. An electrophysiological exploration with measurement of the direct activity of the sinus node, illustrates in one case the mechanism of sinus dysfunction. A review from the literature and our cases specifies some of the characteristics of this disease: 1) there are two forms: sporadic (case n. 1) 59 published cases, and familial (case n. 2) 28 published cases in 13 families; 2) the familial forms have a dominant autosomic transmission with variable penetration; 3) the disease may occur during the first days of life, suggesting a congenital origin (from the pathology findings, this disease may be one of the causes of the unexplained sudden death syndrome in infants; 4) association to atrio-ventricular conduction disorders and atrial and ventricular rhythm disorders; 5) frequent indication of stimulators, emphasizing the severity of this disease with a more severe course in sporadic forms (7 deaths in 59 cases).

Cigarette smoking during coronary angiography: diffuse or focal narrowing (spasm) of the coronary arteries in 13 patients with angina at rest and normal coronary angiograms.

To evaluate the acute effects of cigarette smoking on coronary arteries (CA), repeated coronary angiograms were performed in 13 patients with angina at rest and with normal coronary angiograms at basal state, during smoking, and then after methylergometrine (MEM) and after intracoronary nitroglycerin. Smoking induced anginal pain in three patients, triggered spasm (focal narrowing) in six, and/or an abnormal segmental diffuse narrowing (greater than 30%) in eight. The narrowing of the left CA was on average -21 +/- 13% (P less than 0.001), with more important narrowing of the mid-left anterior descending (-29 +/- 19%, P less than 0.001). The mean of the maximal segmental narrowing by patient was -34 +/- 13% (P less than 0.001). MEM produced similar effects and induced focal CA spasms in nearly the same patients at the same sites. Cigarette smoking may induce vasoconstrictive effects on CA in patients with rest angina and normal coronary angiograms. This action is not dose-dependent and may be initiated by less than one cigarette. These observations offer a new perspective for the understanding of the role of smoking in the precipitation of coronary events.

[Wolff-Parkinson-White syndrome and cardiopathies]. / Syndrome de Wolff-Parkinson-White et cardiopathies.

Forty-nine cases of Wolff-Parkinson-White syndrome (WPW) were diagnosed out of 10 750 patients with cardiac disease (0.45 p. 100), 24 cases out of 3 761 congenital malformations and 25 cases in the 6 989 patients with acquired heart disease. Right ventricular pre-excitation was recorded in 31 cases; 13 in the lateral zone, 12 in the posterior paraseptal zone and 6 in the anterior paraseptal zone. Left ventricular pre-excitation was recorded in 18 cases: 8 in the lateral zone, 5 in the anterior paraseptal and 5 in the posterior paraseptal zones. WPW and congenital heart disease: Out of 20 cases of Ebstein's anomaly, 5 cases of WPW were observed: 4 right posterior and 1 right lateral pre-excitations. Out of 218 cases of hypertrophic obstructive cardiomyopathy, 7 cases of WPW were observed, 4 of which were congenital. Three cases of WPW were recorded in 699 patients with ventricular septal defects. Out of 1 348 cases of atrial septal defect, 5 cases of pre-excitation were recorded, including 3 right posterior pre-excitations associated with an ostium primum defect. Pre-excitation was also observed in isolated cases of corrected transposition of the great arteries, supravalvular aortic stenosis, aortic incompetence and patent ductus arteriosus. Pre-excitation and acquired heart disease: Five cases of pre-excitation were recorded out of 305 cases of dilated cardiomyopathy (1.62 p. 100). Eleven cases of pre-excitation were recorded in a total of 3 471 cases of valvular heart disease (0.31 p. 100): 9 in rheumatic valve disease and 2 in mitral valve prolapse. Nine cases of pre-excitation were observed in 2 850 cases of coronary artery disease. Intermittent Wolff-Parkinson-White syndrome: Ventricular pre-excitation masks the ECG changes of complete right bundle branch block in Ebstein's anomaly, complete left bundle branch block in aortic incompetence and dilated cardiomyopathy, and the in-complete right bundle branch block often seen in mitral valve prolapse. The characteristic appearances of WPW depend on the zone of pre-excitation. Right ventricular hypertrophy observed in ventricular septal defect with pulmonary stenosis and mitral stenosis may be masked by right lateral pre-excitation. Changes of inferior wall myocardial infarction may be masked by left anterior wall pre-excitation. On the other hand, the effects of WPW on left ventricular hypertrophy are variable, high amplitudes of the resultant forces seeming to depend on late and isolated activation of one of the left ventricular walls.

[Coexistence of left branch block and ectopic rhythm simulating alternating block]. / Coexistence dans la branche gauche d'un bloc et d'un rythme ectopique simulant un bloc alternant.

During the acute phase of diaphragmatic myocardial infarction with septal extension, the ECG of a patient with a chronic left bundle branch block changed in a period of seconds from complete left bundle branch block to incomplete right bundle branch block then to narrow QRS complexes followed by incomplete and then complete left bundle branch block: the same QRS changes then occurred in reverse order; the atrial rhythm was absolutely stable during the recording. These appearances are explained by fusion of sinus and of an ectopic rhythm arising distal to the zone of block, the rate of which (sometimes faster and sometimes slower than the sinus rhythm) could have been influenced by an electrotonic effect after retrograde activation of the right bundle and concealed conduction in the left bundle. Appearances of bundle branch block may be recorded when the ventricle is partially activated from the point of breakthrough of the blocked branch.

[Time of occurrence of primary ventricular tachycardia in the acute phase of myocardial infarction]. / Horaire de survenue des tachycardies ventriculaires primaires de la phase aiguë de l'infarctus du myocarde.

The hour of day of primary ventricular tachycardia (VT) in the acute phase of myocardial infarction was studied in 63 consecutive patients without cardiac failure or antiarrhythmic therapy, admitted to hospital less than 6 hours after the onset of chest pain. There were 19 women and 44 men, with an average age of 63 years. The site of infarction was anterior in 23 cases, posterior in 34 cases and circumferential in 6 cases. The cardiac rhythm was analysed from the 6th hour following the onset of chest pain for 4 days, using a HP 98220 A computerised analyser CPK levels were measured daily. Ventricular tachycardia occurred in 73% of cases with no significant difference between daytime (18 patients) and night time (28 patients). The patients developing VT did not differ from the remainder with respect to age, sex, or site of ECG changes, but peak CPK levels were significantly higher than in patients without VT. The risk of VT decreased slowly as the interval from the onset of chest pain increased and fell practically to zero after the 40th hour. Diurnal and nocturnal VT were independent of age, sex or site of infarct. However, nocturnal VT correlated independently of the time of onset of chest pain to high values of CPK. There was no difference with respect to age, sex, location of infarct or incidence of ventricular tachycardia between infarcts with pain starting during the day, and infarcts with pain starting at night. However, when the pain started during the day, the peak CPK was significantly higher and there were significantly more attacks of nocturnal ventricular tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

[Sustained ventricular tachycardia 7 years after complete correction of tetralogy of Fallot]. / Tachycardie ventriculaire soutenue 7 ans après correction complète d'une tétralogie de Fallot.

The authors report a case of sustained ventricular tachycardia which occurred seven years after complete surgical correction of Fallot's tetralogy in a 13 year old girl. This arrhythmia was well tolerated haemodynamically, showed right-sided delay and was associated with mitral valve prolapse. After reviewing the literature, several physiopathological mechanisms are discussed: --the role of residual intraventricular conduction defects in sustaining the tachycardia; --the role of the ventriculotomy scar or of other associated lesions (mitral valve prolapse in this case) in the genesis of ventricular extrasystoles; --the postoperative haemodynamic status in the tolerance of the arrhythmias. This is a rare complication with an incidence of less than 2% of survivors followed-up over long periods. There is a risk of sudden death in 38% of these patients with ventricular arrhythmias which justifies Holter monitoring and ECG stress testing for their detection.

[Mexiletine therapy of ventricular extrasystoles in the acute phase of myocardial infarction]. / Traitement par la mexilétine des extrasystoles ventriculaires de la phase aiguë de l'infarctus du myocarde.

25 patients with recent myocardial infarction and ventricular extrasystole occurring either frequently or in bursts were treated by intravenous and then oral mexiletine. Side-effects occurred during the loading dose in 6 patients, then disappeared without sequel, even while treatment was continued in 2 of these patients, or after it was stopped in the remaining 4 (on account of the severity of the side-effects). Rhythm disorders disappeared under mexiletine in 14 patients as soon as the loading dose was administered; its effectiveness was maintained during intravenous perfusion and after the switch to oral administration. Failure occurred in cases of extensive infarction and/or cardiac insufficiency. Mortality, which was zero in those cases in which mexiletine was effective, reached 45% in the failure group. In cases in which mexiletine proved a failure, lidocaine was also ineffective. In one case in which mexiletine was effective, but was stopped because of side-effects, lidocaine proved ineffective. The efficacy of mexiletine is therefore at least equal to that of lidocaine and is maintained after the switch to oral administration.

[Significance of repetitive ventricular extrasystoles in the acute phase of myocardial infarction]. / Signification des extrasystoles ventriculaires répétitives de la phase aiguë de l'infarctus du myocarde.

Ventricular extrasystoles were analysed by a computerised monitor in 144 patients during the first three days of myocardial infarction. The patients had been hospitalised within 6 hours (77% of cases) and within 12 hours (92% of cases) of onset of symptoms. The patients were divided into 4 groups: Group A (46 cases) without repetitive ventricular extrasystoles; Group B (37 cases) with repetitive ventricular extrasystoles but without frequent isolated extrasystoles; Group C (25 patients) with repetitive ventricular extrasystoles and frequent isolated extrasystoles but without polymorphism or R on T phenomenon; and Group D (36 patients) with repetitive extrasystoles, frequent isolated polymorphic extrasystoles and/or R on T phenomenon. The size of infarction, as judged by peak CPK values, was smaller in Group A than in the other groups but was not significantly different in Groups B, C and D. The incidence of cardiac failure was comparable in Groups A and B and in Groups C and D, and was higher in the latter two groups than in A and B. The cardiothoracic ratio on admission was increased more often in Group D than in the other groups. Therefore, repetitive ventricular extrasystoles are the result of large infarcts. Their association with frequent isolated ventricular extrasystoles is a sign of insufficiency of the remaining myocardium. Patients with pre-existing poor myocardial function develop polymorphism and R on T phenomenon, signs which are associated with a particularly poor prognosis (hospital mortality: 42%). On the other hand, patients in Group B appeared to have satisfactory myocardial function despite the size of their infarcts, and the mortality, nil in this group, was less than in patients without arrhythmias.

[Lengthening of the direct sinoatrial conduction time: a criterion of sinus node dysfunction]. / L'allongement du temps de conduction sino-auriculaire direct: un critère de dysfonction sinusale.

In order to determine the significance of prolongation of the direct sinoatrial conduction time (DSACT), an attempt was made to record the sinus node potential in 110 patients which was successful in 84 cases. The DSACT was normal in 45 cases (Group A) and prolonged (over 130 ms) in 39 cases (Group B). The symptomatology, standard ECG and the results of investigation of sinus node function by atrial stimulation of the two groups were compared. The DSACT was prolonged in all 13 patients with paroxysmal sinoatrial block or the sick sinus syndrome, in 71% of 15 patients with permanent sinus bradycardia, in 88% of 22 patients with a corrected sinus node recovery time of over 525 ms, in 82% of 38 patients with a sinoatrial conduction time estimated by the extrastimulus method of over 130 ms or an abnormal zone II, in 80% of 39 patients with sinoatrial conduction times estimated by Narula's method of over 130 ms; therefore, 87% of the 35 patients with probable sinus node dysfunction had long DSACT. On the other hand only 2 out of 35 patients (6%) with apparently normal sinus node function had prolonged DSACT. These results indicate that prolongation of the DSACT is a sensitive and specific criterion of sinus node dysfunction. In cases of sinus node dysfunction dizziness and/or syncope without any known cause were common complaints in patients in Group B but absent in patients in Group A. A prolonged DSACT could be of prognostic significance in sinus node dysfunction.

Sinus node electrogram recording in 59 patients. Comparison with simultaneous estimation of sinoatrial conduction using premature atrial stimulation.

Directly measured sinoatrial conduction time was compared with sinoatrial conduction time assessed simultaneously by the single premature atrial stimulus technique in 59 patients: 20 with normal sinus function, 35 with sinus dysfunction, and four with sinus bradycardia but negative indirect methods. In patients with normal sinus function direct sinoatrial conduction time was 102.5 +/- 34 ms (mean +/- 2 SD) and was identical to indirect sinoatrial conduction time. Neither direct sinoatrial conduction time in the basal and return cycle, nor post-return and basal cycle lengths were different. Sinoatrial and atriosinus conduction durations were similar. In sinus dysfunction direct sinoatrial conduction time (average 160 +/- 47 ms) was longer than in normal sinus function. Prolonged direct sinoatrial conduction time may therefore be considered as a criterion of sinus dysfunction. In sinus dysfunction no significant correlation was observed between direct and indirect sinoatrial conduction times. Direct sinoatrial conduction time was equal to (17 patients), longer than (12 patients), or shorter than (six patients) indirect sinoatrial conduction time. These differences can be explained by delayed or incomplete premature depolarisation penetration into the sinus node rather than by the classical pacemaker shift.

[Comparison of various indirect methods for evaluation of sinus function]. / Comparaison de différentes méthodes indirectes d'évaluation de la fonction sinusale.

Sinus node function was evaluated by Mandel, Strauss and Narula's methods in 60 consecutive patients: 20 females, 40 males; average age 59 +/- 17 years. Three had second degree sinoatrial block, 2 had bradycardia-tachycardia syndromes and 10 had sinus bradycardia. The corrected sinus node recovery time was 414 +/- 417 ms. It exceeded 520 ms in 8 cases, 5 where the two other methods confirmed sinus node dysfunction, 1 where the two other methods showed no abnormality. In the last two patients pathological results with Narula's method coincided with normal values with Strauss' method but the basal sinus cycle and the post return cycle differed from one method to the other. The atriosinoatrial conduction time estimated by Narula's method was 274 +/- 117 ms. In the thirteen cases where it exceeded 300 ms abnormal results were also recorded with Strauss' (11 cases) and/or Mandel's method (7 cases). The atriosinoatrial conduction time assessed by Strauss' method was 239 +/- 106 ms. It exceeded 300 ms in 18 patients. In these patients the results of Narula and Mandel's methods were normal in 7 cases. This discordance cannot be explained either by variations in the catheter position, or by the duration of the basal sinus or the post return cycles. This raises the question of penetration of the sinus node by the last stimulus when Narula's technique is used. A significant linear correlation was observed between the atriosinoatrial conduction time assessed by Narula's method and the atriosinoatrial time assessed by Strauss' method (N = 60; r = 0,59) and with the corrected sinus node recovery time (N = 60; r = 0,43) and a double linear correlation was found with these two parameters (N = 60; r = 0,62). There was no significant linear correlation between the atriosinoatrial conduction time assessed by Strauss' method and the corrected sinus node recovery time (N = 60; r = 0,27). The atriosinoatrial conduction time evaluated by Narula's method seems to be intermediary between the two other parameters which seem to be independent of each other.

[Evaluation of the sinoauricular conduction time: comparison of the recording of the sinus potential and Narula's method]. / Evaluation du temps de conduction sinoauriculaire: comparaison de l'enregistrement du potentiel sinusal et de la méthode de Narula.

The sino-atrial conduction time, measured by Narula's method (SACTN) is compared to the direct sino-atrial conduction time measured by recording the sinus potential (SACTD) in 55 patients, 20 with normal sinus function and 35 with sinus dysfunction. In the absence of sinus dysfunction, SACTN and SACTD are not significantly different and a significant but mediocre correlation (r = 0.57) is observed between the two parameters. Major discordances between the two methods are seen in 4 patients. In cases with sinus dysfunction, there was no correlation between SACTD and SACTN; SACTN is close to SACTD in 12 patients, but much shorter in 11 patients and much longer in 10 patients. These discordances raise the problem of the penetration of the sinus node by the extrastimulus in Narula's method. This method does not seem capable of giving a reliable evaluation of the duration of sino-atrial conduction.