Béatrice Brembilla-Perrot

DIAGNOSTIC VALUE OF VENTRICULAR STIMULATION IN PATIENTS WITH IDIOPATHIC DILATED CARDIOMYOPATHY

To assess the response to programmed ventricular stimulation and the clinical outcome, we performed a prospective study in 103 patients with idiopathic dilated cardiomyopathy. The protocol used up to three extrastimuli delivered at two right ventricular sites during sinus rhythm and ventricular pacing at 100 and 150 beats/min and was repeated during infusion of 1 to 4 micrograms/min of isoproterenol. Sustained monomorphic ventricular tachycardia (VT) was induced in 8 of 11 patients with spontaneous sustained VT, in none of 35 patients without significant ventricular arrhythmias during Holter monitoring, and in 9 of 56 patients with salvos of ventricular premature beats. Isoproterenol infusion facilitated the induction of two episodes of sustained VT in patients with spontaneous sustained VT; however, in all but one of the remaining patients, induction of ventricular tachyarrhythmias was not impaired. During the follow-up period there were eight sudden deaths among patients who initially had syncope, inducible sustained VT, or both and three episodes of sustained VT in patients who initially had nonsustained VT but inducible sustained VT. Isoproterenol infusion can be used to safely facilitate induction of ventricular tachyarrhythmias in patients with dilated cardiomyopathy. The induction of sustained VT was associated with a poor prognosis.

Induction of sustained ventricular tachycardia after surgical repair of tetralogy of Fallot

Between 1980 and 1996, 89 unselected consecutive patients with repaired tetralogy of Fallot (TOF) underwent examination, including a prospective right ventricular programmed stimulation with the same protocol (S1 S2, S3, S4). Age at surgery was 4.2 +/- 3.5 years and age at electrophysiologic study was 10.9 +/- 6.5 years. Follow-up since surgery was 14.4 +/- 4.8 years and patient follow-up after programmed stimulation was 7.8 +/- 4.2 years. The aim of this study was to evaluate the main predictors of the inducibility of a sustained monomorphic ventricular tachycardia (VT) and its significance to identify a group of patients at risk of sudden death: 21 (group A) had and 68 (group B) had no induced sustained VT. The induction of VT was related to older age at programmed stimulation, prolonged QRS duration, presence of complex ventricular arrhythmia, symptoms, right ventricular overload, and increased right ventricular systolic pressure. Predictors of induced VT selected by multivariate analysis were age at electrophysiologic study (p <0.0001), previous palliative shunts (p <0.001), right ventricular systolic pressure (p <0.007), and symptoms (p <0.005). Among group A patients, 4 had previous sustained VT before stimulation, and 1 had sustained VT only during follow-up after stimulation. No patients of group B had clinical sustained VT. Late mortality was low but similar between both groups. A negative electrophysiologic study may be helpful for the management of patients after surgical repair of TOF, but because the arrhythmic event rate is low, the findings of even a positive electrophysiologic study should be interpreted with caution.

The Signal-Averaged Electrocardiogram Is of Limited Value in Patients With Bundle Branch Block and Dilated Cardiomyopathy in Predicting Inducible Ventricular Tachycardia or Death

An abnormal signal-averaged electrocardiogram (SAECG) has predictive value for arrhythmic events in patients with idiopathic dilated cardiomyopathy and a normal conduction. The purpose of this study was to investigate whether the presence of a complete bundle branch block (BBB) affects prognostic information of the SAECG. We prospectively obtained SAECGs in 128 patients with idiopathic dilated cardiomyopathy. Forty-three of them had BBB and 85 had a normal QRS duration. According to their clinical history and results of ventricular programmed stimulation, patients were divided into 4 groups: (1) group IA with BBB and ventricular tachycardia (VT) (n = 18); (2) group IB with BBB but without VT (n = 25); (3) group IIA without BBB but with VT (n = 40); (4) group IIB without BBB and without VT (n = 45). Patients were compared with 129 patients without heart disease and without VT. Fifty-seven of them had BBB (group III) and 72 had normal conduction (group IV). The filtered QRS duration was longer in group IB than in group III (175 +/- 21 vs 149 +/- 16 ms, p <0.001), and in group IIB than in group IV (111 +/- 19 vs 96 +/- 12 ms, p <0.05). QRS duration was similar in groups IA and IB (176 +/- 24 vs 175 +/- 21 ms) but longer in group IIA than in group IIB (131 +/- 24 vs 111 +/- 19 ms, p <0.001). The low-amplitude signal duration (LAS) and the root-mean-square voltage (RMS) of the last 40 ms of the filtered QRS did not differ between groups IB and III and IA and IB. LAS and RMS were, respectively, longer (44 +/- 20 vs 31 +/- 13 ms, p <0.01) and lower (21 +/- 20 vs 43 +/- 33 microV, p <0.001) in groups IIA and IIB. In groups IA and IB the combination of 2 of the 3 available criteria: QRS duration >170 ms, RMS <20 microV, LAS >45 ms lead up to the best overall statistical result, with a sensitivity and specificity of 78% and 56%, respectively. In groups IIA and IIB, using conventional late potential criteria, the sensitivity and specificity of the SAECG for VT detection were 65% and 73%, respectively. The risk of sudden death was not predicted by the SAECG, and total cardiac mortality was only dependent on left ventricular ejection fraction. In conclusion, QRS duration was prolonged in all of the patients with a dilated cardiomyopathy compared with those without heart disease. BBB did not change the sensitivity but decreased the specificity of the SAECG to predict any VT risk in dilated cardiomyopathy. The risk of sudden death and total cardiac mortality could not be predicted by the SAECG.

Value of esophageal pacing in evaluation of supraventricular tachycardia

Esophageal stimulation was performed in 40 patients who had spontaneous paroxysmal supraventricular tachycardias (SVTs). The purpose of this study was to look for the most sensitive stimulation protocol and criteria that would help to define the mechanism of reentry. In 20 patients (group I) atrial pacing up to second-degree atrioventricular block was performed under control conditions and isoproterenol, and SVT was induced in 14 patients (70%), 11 in the control state and 3 while receiving isoproterenol. In 20 patients (group II) atrial pacing and programmed atrial stimulation using 1 and 2 extrastimuli delivered at 2 cycle lengths (600 and 500 ms) was performed in the control state and while receiving isoproterenol. SVT was induced in all patients, in 13 patients in the control state and in 7 while receiving isoproterenol. Programmed stimulation always induced SVT and was the only method capable of tachycardia induction in 14 patients. The mechanism of SVT could be established in 91%. The measurement of the ventriculoatrial interval was the most useful sign to define the site of reentry. Occurrence of a bundle branch block helped to delineate the mechanism in 4 patients. When a positive P wave in V1 preceded the esophageal atrial electrocardiogram, it suggested that there was reentry through a left-sided accessory atrioventricular connection in 6 patients. SVT could always be induced by programmed atrial stimulation in the control state and under isoproterenol. The location of the P wave in V1 compared to the ventriculogram and the esophageal electrocardiogram helped to define the mechanism of tachycardia.

Influence of Age on the Potential Risk of Sudden Death in Asymptomatic Wolff‐Parkinson‐White Syndrome

BREMBILLA‐PERROT, B., et al.: Influence of Age on the Potential Risk of Sudden Death in Asymptomatic Wolff‐Parkinson‐White Syndrome. Sudden death might be the first event in patients with asymptomatic WPW. The purpose of the study was to know if the age of the patient modifies the electrophysiological characteristics of asymptomatic WPW. Transesophageal stimulation was performed on 92 asymptomatic WPW patients from the following age groups: 10–69 years (n =14), 20–29 years (n = 33), 30–39 years (n = 15), 40–49 years (n = 17), and 50–69 years (n = 13). The procedure consisted of atrial pacing up to the second AV block, programmed atrial stimulation using one and two extrastimuli delivered on two driven rhythms in the control state, and after infusion of isoproterenol. In the five age groups, paroxysmal junctional tachycardia occurred, respectively, in 1 (7%), 1 (3%), 2 (13%), 2 (12%) patients, and not at all in the oldest group. AF > 1 minute occurred, respectively, in 3 (21%), 9 (27%), 5 (33%), 3 (18%), and 4 (31%) patients. The dangerous form of WPW (rapid conduction in the Kent bundle > 240/min in the control state or > 300/min after isoproterenol + AF induction) occurred, respectively, in 3 (21%), 9 (27%), 4 (27%), 1 (6%), and 3 (23%) patients. In conclusion, electrophysiological data of asymptomatic WPW are not modified by age of the patient. Elderly patients remain at risk of a dangerous form of WPW; systematic evaluation of WPW is recommended in patients with an active life independent of age.

Organ dysfunction and muscular disability in myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder characterized by muscle weakness and multiple organ impairment, especially the eyes, lung, and heart. We conducted the current study to analyze the prevalence and intercorrelation among these disorders and their respective relationships with muscular disability. We assessed medical history, anthropometric data, lung volumes, arterial and venous blood samples, surface 12-lead electrocardiogram, echocardiography, ophthalmologic examination, and muscular impairment rating scale (MIRS) in 106 patients (48 male and 58 female) with DM1, aged 43.7 ± 12.8 years. Obesity, hypertriglyceridemia, and diabetes were found in respectively 25.6%, 47.6%, and 17.1% of patients. Disabling cataract was found in 43.4%, and was independently predicted by age and MIRS. Restrictive lung disease was noted in 34%, and was predicted by MIRS, CTG repeat expansion, and body mass index. Conduction disorders were found in 30.2% of patients and were predicted by left ventricular ejection fraction, MIRS, and CTG repeat expansion. We found significant relationships between cataract, restrictive lung disease, and conduction disorders: patients with cataract and those with conduction disorders exhibited more severe restrictive lung disease than the other patients. Conversely, the relative risk of restrictive lung disease was 2.42 (1% confidence interval [CI], 1.06-5.51) in patients with cataract and 2.54 (1% CI, 1.26-5.07) in patients with conduction disorders. Multivariate analysis revealed that MIRS was the only independent predictor for conduction disorders and restrictive lung disease. MIRS ≥3 and MIRS ≥4 were the best simple cutoff values to predict, respectively, lung and cardiac involvements. To conclude, muscular disability, ophthalmologic, and cardiac and pulmonary involvement are strongly correlated. Particular attention should be given to these entities in patients with distal or proximal muscular weakness. Abbreviations: BMI = body mass index, CI = confidence interval, DM1 = myotonic dystrophy type 1, ECG = surface 12-lead electrocardiogram, FEV1 = forced expiratory volume in 1 second, FSH = follicle-stimulating hormone, IgG = immunoglobulin G, LVEF = left ventricular ejection fraction, MIRS = muscular impairment rating scale, PaCO2 = arterial CO2 partial pressure, PaO2 = arterial O2 partial pressure, RNA = ribonucleic acid, RR = relative risk, RV = residual volume, TLC = total lung capacity, VC = vital capacity.

Incidence and Mechanism of Presyncope and/or Syncope Associated With Paroxysmal Junctional Tachycardia

The objectives of this study were to: (1) define the incidence of presyncope and/or syncope in patients with paroxysmal junctional tachycardias, (2) determine their causes, and (3) determine the outcome of symptoms. Syncope is a frequent problem and is often caused by paroxysmal tachycardia. The mechanism of hemodynamic instability is unknown. The population study consisted of 281 patients, consecutively recruited because they had paroxysmal tachycardia and a sinus rhythm on a normal electrocardiogram. Fifty-two patients (group I) had presyncope and/or syncope associated with tachycardia. The remaining patients (group II) had no loss of consciousness. Transesophageal programmed atrial stimulation used 1 and 2 atrial extrastimuli, delivered in a control state, and if necessary, after infusion of 20 to 30 microg of isoproterenol. Arterial blood pressure was monitored. Vagal maneuvers and echocardiogram were performed in all patients. Paroxysmal tachycardia was induced in 51 group I patients and 227 group II patients. Comparisons of groups I and II revealed that age (50 +/- 21 vs 49 +/- 17 years), presence of heart disease (10% vs 10%), mechanism of tachycardia with a predominance of atrioventricular nodal reentrant tachycardia (70.5% vs 76%), and rate of tachycardia (196 +/- 42 vs 189 +/- 37 beats/min) did not differ between the groups. However, there were differences in both groups with regard to significantly higher incidences of positive vasovagal maneuvers (35% vs 4%, p <0.01), isoproterenol infusion required to induce tachycardia (55% vs 17%, p <0.001), and vasovagal reaction at the end of tachycardia (41% vs 4%, p <0.05). Thirty-seven group I patients underwent radiofrequency ablation of the reentrant circuit, which suppressed presyncope and/or syncope in 36 of the 37 patients. Thus, presyncope and/or syncope frequently complicated the history of patients with paroxysmal junctional tachycardia (18.5%). Several mechanisms are implicated, but vasovagal reaction was the most frequent cause. Treatment of the tachycardia typically suppressed presyncope and/or syncope.

Influence of age on the electrophysiological mechanism of paroxysmal supraventricular tachycardias

The purpose of this study was to evaluate the influence of age on the mechanism of paroxysmal supraventricular tachycardia (PSVT). Previous studies have shown age and sex differences between certain arrhythmias and especially changes in electrophysiological characteristics of Wolff-Parkinson-White syndrome. Four hundred and eighty five patients aged 9-86 years, with PSVT and without Wolff-Parkinson-White syndrome in sinus rhythm, were studied. The esophageal or intracardiac electrophysiological study used a standardized atrial pacing protocol. Paroxysmal junctional tachycardia was induced in 475 patients. The mechanism of tachycardia was not influenced by age and atrioventricular nodal reentrant tachycardia (AVNRT) was found as the main cause of PSVT in all ranges of age. Atrioventricular reentrant tachycardia (AVRT) using a concealed accessory pathway (AP) had a similar incidence from youth to elderly. The ratio male/female (M/F) and the inducibility of other arrhythmias (atrial flutter/fibrillation) (AF/AFl) were also found to be similar in all ranges of age. The age of the patients did not influence the mechanism of the tachycardia. Most of PVST were related to a AV nodal reentrant tachycardia. Concealed accessory pathway was identified with a similar incidence in young and old patients.

Risk Factors of Adverse Presentation as the First Arrhythmia in Wolff‐Parkinson‐White Syndrome

Background:  The aim of the study was the evaluation of the predictors of adverse presentation as first arrhythmia in Wolff‐Parkinson‐White syndrome; they usually affect young patients with septal or multiple accessory pathways (AP).

Predictors of atrial flutter with 1:1 conduction in patients treated with class I antiarrhythmic drugs for atrial tachyarrhythmias.

OBJECTIVES The purpose of the study was to look for the predictor factors of atrial proarrhythmic effects of class I antiarrhythmic drugs. BACKGROUND Class I antiarrhythmic drugs may induce or exacerbate cardiac arrhythmias. The predictors of ventricular proarrhythmia are known. The predictors of atrial flutter with 1:1 conduction are unknown. METHODS Clinical history, EGG, signal-averaged EGG (SAECG) and electrophysiologic study were analysed in 24 cases of 1:1 atrial flutter with class I AA drugs and in 100 control patients without history of 1:1 atrial flutter with class I AA drugs. RESULTS The ages of patients varied from 46 to 78 years. Underlying heart disease was present in nine patients. The surface EGG revealed the presence of a short PR interval (PR<0.13 ms), visible in leads V5, V6 in eight (35%) patients with normal P wave duration; in other patients with prolonged P wave duration, PR seemed normaL On SAECG recording, there was a pseudofusion between P wave and QRS complex. The electrophysiologic study revealed some signs indicating a rapid AV nodal conduction (short AH interval or rate of 2nd degree AV block at atrial pacing >200 beats/mm) in 19 of the 23 studied patients. All patients, except one, had at least one sign indicating a rapid AV nodal conduction (short PR and/or P wave-QRS complex continuity on SAECG). In the control group, seven patients (7%) had a short PR interval (P<0.01) and 11 (11%) had a pseudofusion between P wave and QRS complex on SAECG (P<0.001). The P wave-QRS complex pseudofusion on SAECG had a sensitivity of 100% and a specificity of 89% for the prediction of an atrial proarrhythmic effect with class I antiarrhythmic drug. CONCLUSION We recommend avoiding class I AA drugs in patients with a short PR interval on surface EGG and to record SAECG in those with apparently normal PR interval to detect a continuity between P wave and QRS complex, which could indicate a rapid AV nodal conduction, predisposing to 1:1 atrial flutter with the drug.