[Predictive value of the ajmaline test in dysfunction of the sinus node. Prospective 4-year follow-up relative to 77 patients]. / Valore predittivo del test all'ajmalina nelle disfunzioni del nodo del seno. Follow-up prospettico di 4 anni relativo a 77 pazienti.

To establish the usefulness of Ajmaline test for the evaluation of sinus node function, 77 pts (47 M, 30 F, mean age +/- SD = 61 +/- 15 yrs) first underwent an electrophysiologic study and then were followed-up for a mean period of 46.3 months. The following parameters were determined before and after i.v. administration of Ajmaline (1 mg/kg in 1 minute): sinus cycle length (SCL), corrected sinus node recovery time (CSNRT) and sino-atrial conduction time (SACT). The pts were divided into 3 groups: Group A: 10 pts without clinical or electrocardiographic signs of sinus node dysfunction (SND) and with normal control CSNRT and SACT (less than or equal to 500 and less than or equal to 120 msec, respectively); Group B: 46 pts with clinical-electrocardiographic signs of suspected or apparently not severe SND (sinus bradycardia greater than or equal to 40 beats/min and/or syncopes with positive vagal manoeuvres) and/or slightly abnormal control CSNRT (greater than 500 less than or equal to 600 msec) and/or SACT (greater than 120 less than or equal to 150 msec); Group C: 21 pts with clinical-electrocardiographic signs of apparently severe SND (sinus bradycardia less than or equal to 39 beats/min, sino-atrial block, sinus arrest) and/or definitely prolonged control CSNRT and/or SACT (greater than 600 and greater than 150 msec, respectively). The Ajmaline test was considered negative for the presence of a severe SND if SCL was not prolonged after the administration of the drug more than 20% and CSNRT and SACT were not prolonged more than 50% compared to the control values. Otherwise the Ajmaline test was considered positive. Twenty-seven out of the 77 pts studied underwent permanent pacemaker implantation (23 immediately after the electrophysiologic study and 4 during the follow-up). The following results were obtained: the Ajmaline test was negative in 100% of group A, 87% of group B and 48% of group C pts and positive in 0% of group A, 13% of group B and 52% of group C pts; during the follow-up a negative test resulted predictive in 56 out of 60 pts (92%) and a positive test in 16 out of 17 pts (94%). The predictive accuracy of the test was, therefore, 93.5%. These results indicate that Ajmaline test is an useful provocative test for disclosing, during electrophysiologic studies, pts who have severe SND and for selecting those who need pacemaker implantation.

[Intrinsic function of the sinus node in patients with syncope and positive vagal maneuvers]. / La funzionalità intrinseca del nodo del seno nei pazienti con sincopie manovre vagali positive.

This study was undertaken to establish the nature (intrinsic or extrinsic) of sinus node dysfunction in patients presenting with syncope and abnormal response (sinus pause greater than 3'') to vagal manoeuvres (carotid sinus massage and/or eye-ball compression). To this purpose 29 patients (20 males, 9 females, aged 18-79 yrs, mean = 60) underwent an electrophysiologic study. In all we measured before and after autonomic blockade with Propranolol (0.2 mg/kg) and Atropine sulfate (0.04 mg/kg) the following parameters: sinus rate, corrected sinus node recovery time and sino-atrial conduction time. According to the presence or absence of electrocardiographic signs of sinus node dysfunction the patients were divided into three groups: Group A: 11 patients without electrocardiographic signs of sinus node dysfunction; Group B: 13 patients with borderline electrocardiographic signs of sinus node dysfunction (sinus bradycardia between 40 and 60 beats/min); Group C: 5 patients with definite electrocardiographic signs of sinus node dysfunction (sinus bradycardia less than or equal to 39 beats/min and/or sinoatrial block and/or sinus arrest). Fifteen patients (52%) had signs of organic heart disease. The main results obtained were: At least one electrophysiological test (sinus rate, corrected sinus node recovery time or sino-atrial conduction time) was abnormal in 10 patients (34,5%) before autonomic blockade and in 8 patients (27%) after autonomic blockade. Two of these 8 patients belonged to Group A (18%), 1 to Group B (8%) and 5 to Group C (100%). Six of these 8 patients were suffering from an organic heart disease and 2 were not.(ABSTRACT TRUNCATED AT 250 WORDS)

[Myocardial protection during repair of congenital heart disease in infants (author's transl)]. / La protection myocardique dans la chirurgie des cardiopathies congénitales de l'enfant.

The authors use the Bretschneider's cardioplegic solution at 4 degrees C as myocardial preservation in 45 open-heart cases in infants. Using moderate hypothermia at 28 degrees C, the mean myocardial temperature is 17.2 degrees C, using profound hypothermia at 18 degrees C, the mean myocardial temperature is 11.7 degrees C. The reinfusion criteria is myocardial temperature equal or up to perfusion temperature, that is about 40 to 50 minutes after the first infusion. The need of heart defibrillation has been 3 cases over 45 (6.5%). In the early post-operative course they notice 2 low cardiac output syndromes (5%) who responded well at catecholamines infusion. The hospital mortality is 2 deaths over 45 cases, unreliable with myocardial protection.