Risk of atrial fibrillation according to the initial presentation of a preexcitation syndrome.

BACKGROUND: Atrioventricular reentrant tachycardia (AVRT) is frequent in Wolff-Parkinson-White syndrome (WPW). Atrial fibrillation (AF) is rare. The purpose of the study was to determine the factors of spontaneous AF in WPW according to the initial presentation. METHODS AND RESULTS: Electrophysiological study (EPS) was performed among 709 patients with a preexcitation syndrome. First event was AF in 44 patients. Remaining patients were studied for AVRT (314), syncope (94), adverse presentation without AF (9) or systematically (248 asymptomatic patients). Patients with AF were older than other patients (44 ± 16 years vs 34.5 ± 17) (0.0003); maximal rate conducted over accessory pathway (AP) was higher in patients with AF than in other patients except in adverse presentation (0.0002); AVRT was induced more frequently in patients with AF than in asymptomatic patients (57% vs 14.5%) but less than in patients with AVRT (89%). AF was induced more frequently in patients with AF than in other patients except in adverse presentation (<0.0001). During follow-up AF occurred more frequently in patients with AF (5; 11%) than in patients with AVRT (7; 2%), with syncope (1%) and asymptomatic patients (4; 1.6%). Older age predicted recurrence (54 ± 16 vs 40 ± 17). CONCLUSIONS: AF was the first event in only 6% of patients with WPW and was a rare event in other patients. They are older but 10% are less than 18 years and have a more rapid conduction over AP than other patients.

Rapid and low-cost method to prove the nature of no documented tachycardia in children and teenagers without pre-excitation syndrome.

Aims Symptoms in children are often difficult to interpret. The purpose of this study was to report the results of transoesophageal electrophysiological study (EPS) performed in children complaining of sudden onset tachycardia with normal non-invasive studies. Methods and results Eighty-two children and teenagers (mean age 15 +/- 3 years) presented with suspected but no documented paroxysmal supraventricular tachycardia (SVT). ECG was normal. Non-invasive studies were negative; 23 children had syncope with tachycardias. They underwent transoesophageal EPS in our out-patient clinic. The mean duration of transoesophageal EPS was 11 +/- 5 min. Electrophysiological study was negative in 25 children. AV nodal re-entrant tachycardia could be induced in 37 children, 11 of them associated with syncope. Wolff-Parkinson-White syndrome (WPW) was diagnosed in five children in which atrioventricular re-entrant tachycardia was inducible. Atrioventricular re-entrant tachycardia due to a concealed AP was induced in 14 children. Verapamil-sensitive ventricular tachycardia was induced in one patient. Factors associated with tachycardia inducibility were an older age (15.5 +/- 2 vs. 14 +/- 4 years) (P < 0.05) and the absence of syncope (81 vs. 52%) (P < 0.05). During a mean follow-up of 3 +/- 1 year, no patient with negative EPS developed documented tachycardia. In 17 children with inducible SVT, radiofrequency ablation of the re-entrant circuit was subsequently performed. Conclusion Transoesophageal EPS is a fast method for proving the nature of paroxysmal tachycardia in children and teenagers presenting with normal ECG and for demonstrating WPW syndrome not visible on standard ECG. The negative predictive value of transoesophageal EPS for the diagnosis of SVT was 100%.

Are the results of electrophysiological study different in patients with a pre-excitation syndrome, with and without syncope?

AIMS: Syncope in Wolff-Parkinson-White (WPW) syndrome may reveal an arrhythmic event or is not WPW syndrome related. The aim of the study is to evaluate the results of electrophysiological study in WPW syndrome according to the presence or not of syncope and the possible causes of syncope. METHODS AND RESULTS: Among 518 consecutive patients with diagnosis of WPW syndrome, 71 patients, mean age 34.5 +/- 17, presented syncope. Transoesophageal electrophysiological study in control state and after isoproterenol infusion was performed in the out-patient clinic. Atrioventricular re-entrant tachycardia (AVRT) was more frequently induced than in asymptomatic patients (n = 38, 53.5%, P < 0.01), less frequently than in those with tachycardia; atrial fibrillation (AF) and/or antidromic tachycardia (ATD) was induced in 28 patients (39%) more frequently (P < 0.05) than in asymptomatic patients or those with tachycardia. The incidence of high-risk form [rapid conduction over accessory pathway (AP) and AF or ATD induction] was higher in syncope group (n = 18, 25%, P < 0.001) than in asymptomatic subjects (8%) or those with tachycardias (7.5%). Maximal rate conducted over AP was similar in patients with and without syncope, and higher in patients with spontaneous AF, but without syncope. Results were not age-related. CONCLUSION: Tachycardia inducibility was higher in patients with syncope than in the asymptomatic group. The incidence of malignant WPW syndrome was higher in patients with syncope than in asymptomatic or symptomatic population, but the maximal rate conducted over AP was not higher and another mechanism could be also implicated in the mechanism of syncope.

Increased sensitivity of electrophysiological study by isoproterenol infusion in unexplained syncope.

UNLABELLED: The purpose of the study was to evaluate the interests of electrophysiologic study (EPS) after infusion of isoproterenol in patients with syncope and negative EPS in control state. METHODS: 1350 patients were consecutively admitted for syncope and EPS. Patients were included if they had no history of tachycardia, a normal Holter monitoring, a negative EPS in control state. EPS was repeated after infusion of 2-4 mug/kg of isoproterenol. RESULTS: 256 patients, 35 with exercise-related syncope and 105 with heart disease (HD), were recruited. After isoproterenol, an arrhythmia was identified as the sign associated with syncope in 102 patients (40%): SVT in 32 patients, VT in 36 patients, infrahisian 2nd or 3rd degree AV block in three patients and vasovagal reaction in 31 patients. Arrhythmias were more frequent in patients with HD (50/105) than in those without HD (52/151) (p<0.05); SVT tended to be more frequent in patients without HD (n=23) than in those with HD (n=9) (p<0.1); VT was more frequent in patients with HD (n=26) than in those without HD (n=10) (p<0.001). There was no relationship between a positive isoproterenol testing and occurrence of syncope at exercise (19/35 vs 81/221) (p<0.1). CONCLUSION: isoproterenol infusion increased the sensitivity of EPS in patients with syncope, related or not to exercise, and with negative study in control state, but principally in those with HD. However, SVT was diagnosed in patients without HD and EPS associated with isoproterenol infusion remained an important and rapid tool to establish this diagnosis.

Paradoxical effect of isoprenaline infusion.

BACKGROUND: Isoprenaline (isoproterenol) is a beta-adrenergic drug, used to increase the heart rate and, during electrophysiological study, to facilitate the induction of supraventricular (SVT) and ventricular tachycardias (VT). Decrease in heart rate during isoprenaline infusion is a rare phenomenon. The purpose of the study was to evaluate the incidence, the possible mechanisms, and the significance of a paradoxical bradycardia induced by isoprenaline infusion. METHODS: Electrophysiological study was performed for the evaluation of tachycardias (n = 551) or dizziness/syncope (n = 214) in 765 patients aged from 15 to 85 years. The study was negative in the basal state, and was repeated after isoprenaline infusion (2-4 microg/min). RESULTS: In 714 patients, this perfusion increased the heart rate to 100-140 bpm. A bradycardia was noted in 51 patients (7%). Two bradyarrhythmias were noted: (1) sinus or junctional bradycardia (cycle length - 10%) occurred in 43 patients, aged 15-70 years, generally studied for unexplained syncope (n = 37); a young age (40+/-16 years), syncope (n = 37) and absence of heart disease (n = 27) were more frequent than that in patients without isoprenaline-induced sinus or junctional bradycardia; another arrhythmia (SVT or VT) was induced in seven patients with syncope, five with heart disease and two without; six young patients (<50 years) had no syncope and were studied for SVT or VT; (2) eight patients, aged 65+/-11 years, developed second-degree atrioventricular (AV) block which was supraHisian (n = 4) or infraHisian (n = 4); they were studied for exercise-related syncope; they had no signs of myocardial ischaemia and AV block was reproduced by ajmaline testing: isoprenaline revealed organic conduction disturbance. CONCLUSION: The occurrence of paradoxical bradycardia was a rare finding during isoprenaline infusion (7%); sinus or junctional bradycardia was a sign of hypervagotonia, but was without clinical significance in 35% of these patients. The development of second-degree AV block was always pathological and associated with AV conduction disturbances, which occurred spontaneously during exercise. Isoprenaline infusion appeared to be a simple means to detect organic AV conduction disturbance in patients complaining of exercise or stress-related dizziness/syncope and unable to perform exercise test.

Electrophysiologic characteristics of atria in patients without heart disease.

BACKGROUND: The significance of atrial fibrillation or tachycardia (AF) induction remains debatable. Some believe that the presence of heart disease (HD) increases the sensitivity and decreases the specificity of programmed atrial stimulation (PAS). There are few data in patients without HD. The purpose of the study was to evaluate the results of PAS in asymptomatic patients without HD and in those with documented spontaneous AF, but without HD, to know the diagnosis value of the technique. METHODS: A total of 4,900 PAS were consecutively performed. The control group (I, N=67) was defined by the absence of preexcitation syndrome, dizziness/syncope, hypertension, history of tachycardia, or other documented HD together with a normal 2D echocardiogram and 24-hour Holter monitoring. They were compared to a group (II) of 54 patients with documented paroxysmal AF and without HD. PAS used one and two extrastimuli, delivered during sinus rhythm and two drive rates (600, 400 ms). Atrial-effective refractory periods (ARP), their adaptation to cycle length, and conduction times were noted. AF induction was defined as the induction of AF lasting more than 1 minute. RESULTS: Group I patients (1.4% of 4,900) were younger than group II (51 +/- 17 vs 65 +/- 11 years, P < 0.001). A single extrastimulus never induced sustained AF in group I, but did so in 11 group II patients (20%); sustained AF was induced by two extrastimuli in 15 group I patients (22%) and in 31 group II patients (57%) (P < 0.001). There were no ARP and conduction time differences in group I patients with and without inducible AF, but there was a longer sinus cycle length in patients with inducible AF (977 +/- 164 vs 838 +/- 141 ms, P < 0.02). There were no electrophysiological differences in group II patients with and without inducible AF. No group I patient developed spontaneous AF (follow-up 4 +/- 2 years). The sensitivity of PAS with one extrastimulus was 20% and the specificity 100%; the sensitivity of PAS with two extrastimuli was 57% and the specificity 78%. CONCLUSION: Sustained AF was not induced by one extrastimulus in control patients without symptoms, nor heart disease, but sustained AF was induced by two extrastimuli in 22% of these patients. The induction of a sustained AF by two extrastimuli should be interpreted cautiously, particularly in patients with a relative sinus bradycardia. However, the sensitivity of PAS with one extrastimulus was very low and two extrastimuli were required in patients with spontaneous AF to induce the tachycardia. Other electrophysiological parameters were not useful to differentiate patients with and without inducible AF.

Significance of inducible ventricular flutter-fibrillation after myocardial infarction.

AIM: The purpose of this study was to determine the factors associated with the induction of ventricular flutter/fibrillation (VFl/VF)and its prognostic significance in post-myocardial infarction. METHODS: Programmed ventricular stimulation was performed after myocardial infarction (MI) for syncope (n = 232) or systematically (n = 755); 230 patients had an induced VFl/VF and were followed during 4 +/- 2 years. RESULTS: VFl/VF was induced in 49/232 patients (21%) with syncope versus 181/755 asymptomatic patients (24%) (NS) and 94/410 patients (23%) with left ventricular ejection fraction (LVEF) <40% versus 136/577 patients (22.5%) with LVEF >40% (NS). Cardiac mortality was 9%; LVEF was 33 +/- 15% in patients who died, 43 +/- 13% in alive patients (P < 0.004). In patients with LVEF <40%, induced VFl/VF, mortality rate was 31% in those with syncope, 10% in asymptomatic patients (P < 0.001), because of an increase of deaths by heart failure; patients with LVEF >40% with or without syncope had a low mortality (5% and 3%). After linear logistic regression, VFl/VF and LVEF were predictors of total cardiac mortality, but only LVEF <40% predicted sudden death. CONCLUSION: Syncope and the level of LVEF did not increase the incidence of VFl/VF induction after MI, but modified the cardiac mortality: induced VF increased total cardiac mortality in patients with syncope and LVEF <40%, but did not increase sudden death. In patients with LVEF >40%, induced VFl/VF has no significance neither in asymptomatic patients nor in those with syncope.

Utility of transesophageal atrial pacing in the diagnostic evaluation of patients with unexplained syncope associated or not with palpitations.

BACKGROUND: Noninvasive studies are often negative in patients with syncope, normal surface ECG and without heart disease. The purpose of the study was to determine the diagnostic impact of an esophageal electrophysiological study performed during a consultation. METHODS: A total of 154 patients aged from 16 to 87 years were consecutively recruited for unexplained syncope; they had a normal ECG in sinus rhythm, no documented arrhythmia and no patent heart disease. Half of them complained of palpitations. Electrophysiologic study was performed during a consultation by transesophageal route: rate of 2nd d AV block occurrence during atrial pacing and sinus node recovery time were determined; programmed atrial stimulation using one and two atrial extrastimuli were delivered in control state and then after infusion of 0.02-1 microg/min of isoproterenol; arterial blood pressure was monitored. RESULTS: (1) Electrophysiologic study was positive in 107 patients (69%); (2) sinus node dysfunction was noted in 9 patients (6%); (3) atrioventricular conduction disturbances were noted in 2 patients (1%); (4) vasovagal reaction which associated a junctional bradycardia and a fall of arterial blood pressure and which reproduced spontaneous symptoms was provoked by isoproterenol infusion in 21 patients (14%); (5) sustained atrial fibrillation was induced in 23 patients (15%); and (6) paroxysmal junctional tachycardia was induced in 52 patients (34%). Patients with negative study were younger (44+/-21.5 years) than those with sinus node dysfunction or atrial fibrillation (71+/-9 and 63+/-14 years, respectively). The treatment was guided by these data: patients with inducible atrial fibrillation were treated by antiarrhythmic drugs and those with inducible paroxysmal junctional tachycardia by the radiofrequency ablation of reentrant circuit. Syncope disappeared in all patients but 2. CONCLUSION: Esophageal electrophysiologic study performed during a consultation was a safe, rapid and economic means to detect an arrhythmia (sinus node dysfunction or supraventricular tachycardia) in patients with dizziness/syncope and palpitations in half cases. Supraventricular tachycardia was clearly an underestimated cause of syncope in this population.