Bruno Cauchemez

Electrophysiological effects of catheter ablation of inferior vena cava-tricuspid annulus isthmus in common atrial flutter

BACKGROUNDnThe electrophysiological mechanisms for successful catheter ablation of atrial flutter (AFI) targeting the inferior vena cava-tricuspid annulus (IVC-TA) isthmus have not been determined.nnnMETHODS AND RESULTSnTwenty patients with common AFI were studied. All had inducible common AFI, and 8 of them had both common and reverse AFI. Right atrial (RA) activation sequences were investigated during pacing from sites proximal (low lateral RA) and distal (proximal coronary sinus) to the IVC-TA isthmus both during entrainment of common or reverse AFI and during pacing in sinus rhythm. This was repeated after ablation. During pacing in sinus rhythm from the low lateral RA, the septum was activated by caudocranial and craniocaudal wave fronts. Similarly, during pacing from the proximal coronary sinus, the lateral RA was activated by two wave fronts. Catheter ablation of the IVC-TA isthmus induced dramatic changes in mapping due to the loss of caudocranial wave front in all but 1 patient. The septum and the lateral RA were activated by a single craniocaudal front as during entrainment of reverse or common AFI, respectively. After a follow-up of 8 +/- 2 months, common or reverse AFI occurred in 4 patients. Two had no or only unidirectional changes in the isthmus conduction induced by ablation. The other 2 had a late recovery of conduction.nnnCONCLUSIONSnThe present study provides evidence that the mechanism of successful AFI ablation targeting the IVC-TA isthmus is local bidirectional conduction block. This change can be used as a new and complementary electrophysiological end point for the procedure. AFI recurrences are associated with failure to achieve a permanent block.

Failure in the rate adaptation of the atrial refractory period: its relationship to vulnerability.

We evaluated the relationship of rate-dependent changes in atrial refractoriness to atrial vulnerability in 39 patients. Vulnerability was considered present when sustained atrial tachyarrhythmias, lasting longer than 1 minute, could be provoked with one to three extra stimuli. Adaptation of atrial refractory period duration to rate was defined as: normal: steep rate reduction with a linear correlation slope value of 0.08 or more; non-adaptation: absence of rate reduction, the slope value being 0 to 0.01; poor adaptation: slight reduction with rate, the slope having values of 0.02 to 0.07. Increased vulnerability was demonstrable in 16 of 17 patients with non-adaptation of the effective refractory period (ERP), and in 10 of 10 with a similar defect of the functional refractory period (FRP); in the intermediate category (poor adaptation) the results for ERP and FRP were 7/11 and 5/6. By way of contrast when both measurements showed normal adaptation, vulnerability was elicited in 2/9 patients. The significance between these groups showed P less than 0.005. Of 17 patients with atrial arrhythmia by Holter, 14 showed poor or non-adaptation of the ERP. It is suggested that poor or absent rate adaptation of the atrial refractory period, and a propensity to atrial fibrillation or flutter, constitute a clinical entity not previously described.

Spontaneous sequences of onset of torsade de pointes in patients with acquired prolonged repolarization: quantitative analysis of Holter recordings.

OBJECTIVESnThis study investigated the cycle length changes preceding the spontaneous onset of torsade de pointes in patients with acquired prolonged ventricular repolarization.nnnBACKGROUNDnTorsade de pointes is a polymorphic ventricular tachycardia generally associated with prolonged ventricular repolarization. Because torsade de pointes is not inducible by programmed electrical stimulation, quantitative analysis of Holter recordings of spontaneous episodes may clarify the mechanisms favoring the onset of torsade de pointes in actual clinical conditions.nnnMETHODSnThe digitized Holter recordings of 12 patients were analyzed by a computerized Holter system (ATREC). All arrhythmias were grouped according to three classes: 1) isolated premature ventricular beats (n = 47,147, mean/patient [+/- SD] 3,929 +/- 11,571); 2) salvos of 2 to 4 consecutive beats (n = 2,003, mean/patient 167 +/- 359); 3) torsade de pointes > or = 5 beats (n = 105, mean/patient 9 +/- 11). For each patient and class of arrhythmias, six variables were computed from the 10 min and the 10 cycles preceding the event onset.nnnRESULTSnA significant heart rate increase in the last minute (p < 0.01) and typical oscillatory short-long-short cycle length sequences preceded the onset of arrhythmias, with greater oscillation preceding torsade de pointes than salvos and premature ventricular beats. The cycle lengths preceding the onset were highly correlated with the class of arrhythmias (r = 0.65, p < 0.005) and allowed the correct classification of 69% of events by discriminant analysis (p < 0.0001). A significant negative correlation was observed between the duration of torsade de pointes and the mean length of the initial cycles (r = -0.62, p < 0.001), indicating that longer torsade de pointes had a faster rate than that at onset.nnnCONCLUSIONSnIn patients with acquired prolonged repolarization, the spontaneous onset of ventricular arrhythmias was preceded by an increasing heart rate in the last minute and escalating oscillatory short-long-short cycle length patterns, with greater oscillations preceding torsade de pointes than salvos and isolated ventricular beats. These findings suggest that adrenergic- and pause-dependent mechanisms (possibly inducing afterdepolarizations and triggered activity) may have a synergetic role in the genesis of complex ventricular arrhythmias associated with delayed ventricular repolarization.

Determinants of the spontaneous ectopic activity in repetitive monomorphic idiopathic ventricular tachycardia

Twenty-four hour ambulatory electrocardiographic tape recordings of 30 patients (16 men and 14 women, mean age 42 +/- 17 years) with repetitive monomorphic idiopathic ventricular tachycardia were analyzed using a new computerized system designed to study 15 RR cycles and mean heart rate of the 3 minutes preceding any defined event. The mean (+/- SD) number of events analyzed per patient in 24 hours was 610 +/- 483 for single premature ventricular complexes, 622 +/- 490 for couplets, 260 +/- 411 for runs of 3 complexes, 186 +/- 476 for runs of 4, 108 +/- 173 for runs of 5, 82 +/- 129 for runs of 6 to 10 and 83 +/- 116 for runs of more than 10 complexes. The heart rate was faster before runs of ventricular tachycardia than before isolated extrasystoles (p less than 0.01) and a positive linear correlation was observed between the mean preceding heart rate and the type of extrasystolic activity, the length of the runs increasing with increasing preceding heart rate (r = 0.98, p less than 0.001). A long RR interval just before the occurrence of runs was present in 77% of the cases (23 of 30) with or without an oscillatory pattern of RR intervals due to bigeminy or trigeminy, and the length of the runs correlated positively with the duration of this long preceding diastole (r = 0.90, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Results of electrical fulguration in arrhythmogenic right ventricular disease

Eleven patients with sustained ventricular tachycardia (VT) refractory to antiarrhythmic drugs due to right ventricular disease shown by angiography underwent fulguration. Seven patients always had VT with the same morphology, and 4 had clinical VT with 2 or 3 different QRS waveforms. Five patients underwent a single fulguration and the other 6 underwent from 2 to 5 procedures; 2 to 14 shocks (mean 6) of 150 to 250 J were used. No serious complications occurred. At 31.5 +/- 9 months of follow-up, the arrhythmia was controlled in 8 patients, with continuation of previously ineffective antiarrhythmic drug therapy in 6 of 8. The number of VT episodes the year before and after fulguration was 0.5 +/- 0.7 vs 3.5 +/- 1.7 (p less than 0.001). There was no statistically significant difference between the success rate and the degree of prematurity of the onset of the local electrogram during VT: -36 +/- 31 ms for successes and -38 +/- 13 ms for failures. In 7 patients with monomorphic VT, there were 6 successes and 1 failure, and in 4 patients with several morphologies of VT, there were 2 successes and 2 failures (1 due to the appearance of a new VT). Thus, electrical fulguration of VT in patients with right ventricular disease is safe and most often effective, particularly in patients with monomorphic VT, when combined with antiarrhythmic drugs. In these patients, the usually recommended endocardial mapping criteria for the determination of the optimal fulguration site were not predictive of outcome. Further studies are necessary to better define the optimal site for fulguration.

Improved outcome following restoration of sinus rhythm prior to catheter ablation of persistent atrial fibrillation: A comparative multicenter study

BACKGROUNDnCatheter ablation of persistent atrial fibrillation (AF) is associated with longer procedure times and lower long-term success rates than that of paroxysmal AF.nnnOBJECTIVEnTo test the hypothesis that restoration/maintenance of sinus rhythm (SR) preablation would facilitate AF termination and improve outcomes in patients with persistent AF.nnnMETHODSnWe conducted a 2-group cohort study of consecutive patients with persistent AF and SR restored for at least 1 month prior to ablation (SR group; n = 40) and controls matched by age, sex, and AF duration (control group; n = 40). Radiofrequency stepwise catheter ablation was performed in AF for both groups (induced and spontaneous, respectively). Success was defined as freedom from atrial tachyarrhythmia without antiarrhythmic drugs beyond 1 year of follow-up.nnnRESULTSnDuring the index ablation procedure, AF cycle length was longer in the SR group than in the control group (183 ± 32 ms vs 166 ± 20 ms; P = .06), suggestive of reverse remodeling. In the SR group, AF more frequently terminated during ablation (95.0% vs 77.5%; P <.05) and required less extensive ablation of complex fractionated electrograms (40.0% vs 87.5%; P <.001) and linear lesions (42.5% vs 82.5%; P <.001). Mean procedural (199.8 ± 69.8 minutes vs 283.5 ± 72.3 minutes; P <.001), fluoroscopy (51.0 ± 24.9 minutes vs 96.3 ± 32.1 minutes; P <.001), and radiofrequency energy delivery (47.5 ± 18.9 minutes vs 97.0 ± 30.6 minutes; P <.001) times were shorter in the SR group. Clinical success rates were similar between groups for first (55.0% vs 45.0%; P = .28) and last (80.0% vs 70.0%; P = .28) procedures, during similar follow-up periods (21.1 ± 9.7 months).nnnCONCLUSIONSnRestoration of SR prior to catheter ablation for persistent AF whenever possible decreases the extent of ablation with the same high clinical efficacy.

Long-term follow-up after sustained monomorphic ventricular tachycardia: Causes, pump failure, and empiric antiarrhythmic therapy that modify survival

We analyzed the actuarial cardiac mortality rate of 295 consecutive patients with sustained monomorphic ventricular tachycardia who were referred to us between 1978 and 1988. Patients were divided into four groups: group I of 156 patients with coronary disease, group II of 55 patients with nonischemic left ventricular disease, group III of 65 patients with right ventricular disease, and group IV of 19 patients without detectable heart disease. Patients were treated empirically according to a prospective schema: (1) class I antiarrhythmic drugs, (2) in case of recurrence of ventricular tachycardia: amiodarone or beta-blockers, (3) in case of recurrence of ventricular tachycardia: drug combinations or surgery. The mean follow-up duration was 61 +/- 40 months after the first occurrence of ventricular tachycardia, and the clinical outcome was known in 67.5% of patients at 5 years. The actuarial mortality rates were considerably higher in groups I and II compared with those in groups III and IV (p less than 0.01). The mortality rate was slightly higher in group I than in group II (p less than 0.05). In groups I and II, actuarial mortality rate were much higher when left ventricular ejection fraction was less than 0.30 (p less than 0.01). Comparisons between treatments showed no difference in actuarial mortality rates in patients with ventricular tachycardia and left ventricular ejection fraction greater than 0.30.(ABSTRACT TRUNCATED AT 250 WORDS)

High take-off left inferior pulmonary vein as an obstacle in creating a conduction block at the lateral mitral isthmus.

AIMSnCreation of complete linear lesions in the lateral mitral isthmus (LMI) by catheter ablation for treating atrial fibrillation remains technically challenging. We aimed to clarify whether a high take-off left inferior pulmonary vein (LIPV) can hamper the creation of a complete block at the LMI.nnnMETHODS AND RESULTSnWe included 81 consecutive patients who underwent linear ablation at the LMI and cardiac computed tomography (CT) before ablation. We defined a high take-off LIPV when the level of the lower edge of the LIPV ostium was higher than that of the top of mitral annulus on CT. The clinical backgrounds, parameters, and long-term follow-up were then compared between the success (successful creation of a complete LMI block) and failure groups. A complete LMI block was obtained in 60/81 (76%) patients. In the failure group, a high take-off LIPV was noted more commonly and the LMI tended to be longer than the success group. Multivariate analysis revealed that a high take-off LIPV was an independent predictor of failure to achieve a complete LMI block. The sinus rhythm maintenance rate was not different between the success and failure groups.nnnCONCLUSIONnA high take-off LIPV hampered the creation of complete linear lesions in the LMI.

Correlation between atrial fibrillation driver locations and complex fractionated atrial electrograms in patients with persistent atrial fibrillation

The aim of this study was to evaluate a spatial correlation between active atrial fibrillation (AF) drivers measured by electrocardiographic imaging and complex fractionated atrial electrograms (CFAEs) in patients with persistent AF.

Catheter Ablation Versus Antiarrhythmic Drugs for Atrial FibrillationCLINICAL PERSPECTIVE: The A4 Study

Background— The mainstay of treatment for atrial fibrillation (AF) remains pharmacological; however, catheter ablation has increasingly been used over the last decade. The relative merits of each strategy have not been extensively studied. Methods and Results— We conducted a randomized multicenter comparison of these 2 treatment strategies in patients with paroxysmal AF resistant to at least 1 antiarrhythmic drug. The primary end point was absence of recurrent AF between months 3 and 12, absence of recurrent AF after up to 3 ablation procedures, or changes in antiarrhythmic drugs during the first 3 months. Ablation consisted of pulmonary vein isolation in all cases, whereas additional extrapulmonary vein lesions were at the discretion of the physician. Crossover was permitted at 3 months in case of failure. Echocardiographic data, symptom score, exercise capacity, quality of life, and AF burden were evaluated at 3, 6, and 12 months by the supervising committee. Of 149 eligible patients, 112 (18 women [16%]; age, 51.1±11.1 years) were enrolled and randomized to ablation (n=53) or “new” antiarrhythmic drugs alone or in combination (n=59). Crossover from the antiarrhythmic drugs and ablation groups occurred in 37 (63%) and 5 patients (9%), respectively (P=0.0001). At the 1-year follow-up, 13 of 55 patients (23%) and 46 of 52 patients (89%) had no recurrence of AF in the antiarrhythmic drug and ablation groups, respectively (P<0.0001). Symptom score, exercise capacity, and quality of life were significantly higher in the ablation group. Conclusion— This randomized multicenter study demonstrates the superiority of catheter ablation over antiarrhythmic drugs in patients with AF with regard to maintenance of sinus rhythm and improvement in symptoms, exercise capacity, and quality of life.