The electrophysiological effects of prostacyclin (PGI2) at increasing doses (2.5, 5 and 10 ng/kg/min) were assessed in 16 patients during classical investigations of sinus node function and ...atrioventricular conduction and during programmed atrial and right ventricular under basal conditions and during prostacyclin perfusion. Ten patients had normal sinus node function and atrioventricular conduction under basal conditions. Stastistically significant changes were observed during PGI2 perfusion: shortening of the sinus cycle length (p 0.01), decreased intraatrial conduction time (p less than 0.05), reduced atrial functional refractory period (p less than 0.01) and reduced effective and functional refractory periods of the AV node (p less than 0.05), increased anterograde (p less than 0.01) and retrograde (p less than 0.05) Wenckebach point. The changes were dose dependent. No significant changes were observed in sinus node recovery periods of the His Purkinje system. Similar changes were recorded on 4 other patients with various conduction defects. Paired atrial stimulation induced manifestations of hyperexcitability in 5 patients. In 2 patients with normal responses under basal conditions it was possible to induce non-sustained atrial tachycardia during PGI2 administration. In 3 patients with inducible atrial tachycardia under basal conditions, it was still possible to induce the tachycardia after PGI2 but this disappeared in all but one patient with the sick sinus syndrome after the addition of propranolol. The changes in ventricular excitability were studied by a specific protocol in 16 patients. Of the 13 patients without inducible ventricular tachycardia under basal conditions, 4 developed inducible non-sustained ventricular tachycardia after PGI2. Three patients had inducible VT under basal conditions.
Transesophageal stimulation is tending to replace endocavitary electrophysiological studies in the investigation and treatment of supraventricular tachyarrhythmias. The aim of this study was to ...determine the sensitivity of this technique in the evaluation of paroxysmal junctional tachycardia (PJT) and atrial tachycardia (AT). Fifty-eight patients with these arrhythmias (PJT, n = 23; AT, n = 35) were investigated under basal conditions and then during Isoproterenol infusions with a protocol using incremental atrial stimulation and programmed atrial stimulation delivering one and two extra-stimuli on two paced rhythms (400-600 ms). It was possible to induce the arrhythmia in the 23 patients with PJT either under basal conditions (n = 16) or during Isoproterenol (n = 7). A reentrant mechanism was suggested in 22 patients by the following findings: position of the auriculogramme with respect to the ventriculogramme, presence or absence of a delaying branch block, situation and morphology of the P wave in lead V1 compared with atrial activation recorded by the esophageal catheter. Atrial tachycardia was induced in 26 patients (74 per cent), 19 under basal conditions, 6 with Isoproterenol and once after carotid sinus massage. As a conclusion, we can say that the sensitivity of transesophageal stimulation is the same as for endocavitary stimulation.
Programmed ventricular stimulation (PVS) has been advocated as being capable of identifying patients with idiopathic non obstructive dilated cardiomyopathy (NOCM) and at high risk of sudden death. We ...have studied the results of that method in 56 patients aged from 29 to 69 years (mean 53 years) presenting with idiopathic NOCM. The patients were divided into two groups according to the presence or absence of ventricular tachycardia (VT). Group I (controls) comprised 23 patients without documented VT. Group II consisted of 33 patients with documented VT which was sustained in 5 cases. Finally, 7 patients from both groups experienced losses of consciousness. Ventricular stimulation was performed on 2 sites of the right ventricle, using 1 to 3 extrastimuli on 2 imposed cycles. It was repeated under isoprenaline on 25 occasions. PVS induced non sustained ventricular tachycardia (NSVT) in only 2 patients of group I; it reproduced the sustained ventricular tachycardia (SVT) observed in the 5 patients with spontaneous SVT. PVS was negative in 14 of the 28 patients with NSVT; it induced NSVT in 8/28 and SVT in 6/28 (including 4 with more than 280 beats/min). The isoprenaline test failed to induce SVT. 7 patients died suddenly: 3 presented with SVT and 4 had syncopes and NSVT; ventricular stimulation induced SVT in 3 of these 4 patients. It is concluded that induction of sustained VT is uncommon in NOCM, but a history of syncope should prompt a search for SVT. Patients with spontaneous symptomatic NSVT and inducible SVT must be considered at high risk of sudden death.
In order to determine the cause of syncopes or disorders of conduction, 584 programmed stimulations using 2 ventricular extrastimuli delivered during an imposed rhythm were performed, between 1981 ...and 1985, in patients without ventricular tachycardia (VT) proven by Holter recordings. Eighty-seven non-sustained VT (NSVT) (15%), 8 ventricular fibrillations (VF) (1%), 16 ventricular flutters (VF1) (3%) and 23 sustained VT (SVT) (4%) were induced. To appraise the significance of these responses the patients were followed up for a mean period of 2 +/- 1 years. Among the NSVT patients the first 47 were followed up until 1984 and the others, less numerous, until 1985. Patients who responded to stimulation with NSVT had (4.4%) or did not have an underlying cardiopathy; their mean left ventricular ejection fraction (LVEF) was 53.5 +/- 17% (n = 10); 17% died of heart disease, but the disease was related to VT in only one case; 36% of these patients had cardiac symptoms, but only one presented with episodes of NSVT. Patients who responded with VF had a normal (50%) or abnormal heart; their mean LVEF was 52 +/- 19%; one died of heart failure, the others were asymptomatic. All but one of the patients who responded with VF1 had an underlying cardiopathy and a mean LVEF of 38 +/- 19%; 3 died, 2 of heart failure and 1 of sudden death; 13 were asymptomatic. All patients who responded with SVT had an underlying cardiopathy and a mean LVEF of 37 +/- 13%; 7 (30%) died, including 2 sudden deaths; 2 had episodes of VT and 12 were asymptomatic. In summary, an underlying cardiopathy was present in one-half of the patients who responded with NSVT or VF and in all patients who responded with VF1 or SVT. The risk of VT was low (5%) in patients who responded with NSVT, VF or VF1 and was higher (17%) in those who responded with SVT.
Between 1974 and 1984, 207 patients with Wolff-Parkinson-White syndrome (WPW) were admitted to our hospital department; 195 of them were followed up for periods ranging from 1 to 12 years (6 years in ...children, 3 years and 9 months in adults on average); 160 had undergone electrophysiological exploration. Fifty-seven patients were less than 16 years old: 7 died, including 6 with associated congenital heart disease; an asymptomatic 12-year old girl died suddenly while taking part in a sporting event. The signs of WPW disappeared in 5 out of 10 children under 1 year of age. One hundred and thirty-eight patients were older than 15: 15 of them died, but only 3 deaths were related to WPW: one was consecutive to surgery for WPW and one to fulguration; the third patient died of WPW tachyarrhythmia; the refractory period of his Kent's bundle was short, but his compliance with treatment was irregular. We found no correlation between changes in functional symptoms and Kent's bundle refractory period values; paradoxically, the frequency of attacks and resistance to treatment was higher in cases with long refractory period. On the whole, this series confirms that WPW usually is a benign disease. However, the risk of sudden death, of which it offers an example, indicates that all patients with WPW should be evaluated with at least an exercise test and, depending on its results or on the socio-professional context, an electrophysiological exploration.
The prevalence of inducible ventricular arrhythmias is related to the underlying pathology. This study was undertaken to determine the prevalence of supraventricular tachyarrhythmias (SVT), atrial ...tachycardia, flutter or fibrillation, sustained for over 30 seconds. Programmed atrial stimulation was used to deliver 1 or 2 extrastimuli during sinus and paced rhythm in 230 subjects without obvious cardiac disease (149 without and 81 with spontaneous SVT) and 432 patients with documented cardiac pathology (407 without and 25 with spontaneous SVT). The incidence of inducible SVT with respect to that of spontaneous SVT and in relation to cardiac pathology was as follows: (table; see text) The prevalence of inducible SVT in patients without spontaneous SVT was related to the type of pathology: (table; see text) These results show that in patients with spontaneous SVT the induction of the arrhythmia was facilitated by the presence of underlying cardiac pathology (sensitivity increasing from 67% to 88%). In patients without spontaneous SVT, the nature of the underlying disease was related to the prevalence of inducible SVT, the risk being major in SA block, right ventricular dysplasia and mitral valve prolapse (60-80%) and moderate in dilated CMP and myocardial infarction (35 to 40%).
