Conduction Disturbances in Patients with Atrial Fibrillation

Background: The electrophysiological mechanisms underlying atrial fibrillation (AF) are incompletely understood. Experimental studies have shown that remodelling of the atrial myocardium is linked to the occurrence and perpetuation of AF. Interatrial conduction disturbances and also delayed conduction at the posteroparaseptal region have also been reported as potential arrhythmogenic substrates. However, there is insufficient clinical evidence. Pulmonary vein (PV) potentials are invariably recordable at the PV ostia in patients with AF, and delayed conduction around the PV ostia may play a role in the initiation and maintenance of AF. Objectives: 1) To find clinical evidence for the atrial remodelling in patients with chronic and paroxysmal AF; 2) to delineate the electrophysiological properties of transseptal conduction from the left to the right atrium in patients with paroxysmal AF; 3) to analyze the conduction velocities across the coronary sinus (CS) ostium (cross-CS ostium) and within the coronary sinus (intra-CS) in patients with and without paroxysmal AF; and 4) to investigate the presence and extent of PV potentials in patients without AF. Methods: Study I: To estimate the refractoriness of the atrium during AF, monophasic action potentials (MAPs) were recorded during AF from 1?3 sites in the right atrium in 7 patients with chronic AF (CAF) and in 11 patients with paroxysmal AF (PAF). The fibrillatory (FF) interval between two consecutive upstrokes of the MAP was measured. The mean, median, 15th, 10th, and 5th percentile and the shortest FF intervals were calculated in each patient and used as estimates of the local atrial effective refractory period (AERP) during AF. In 9 patients, AERP was also tested using the extra stimulus technique during sinus rhythm. Study II: To evaluate the left-to-right transseptal conduction, right atrial mapping using the CARTO electroanatomic mapping system was performed at 111 ? 16 sites during pacing from the distal CS in 16 patients with paroxysmal AF. Activation maps of the right atrium were obtained from all patients and the earliest breakthrough site was identified. The conduction times from the pacing site 1) to the earliest activation site of the septum, 2) to CS ostium, 3) to the presumed insertion of Bachmann's bundle, 4) the total septal activation time, and 5) the total right atrial activation time. Study III: To study the conduction delay across the CS ostium, the activation times and spatial distances of cross-CS ostium and intra-CS were measured between 5?11 paired sites, from which the activation velocities of cross-CS ostium and intra-CS were obtained in 13 patients with paroxysmal AF and 10 control patients with AV nodal re-entry tachycardia or ectopic atrial tachycardia, using the CARTO electroanatomic mapping system. Study IV: Circumferential catheter recordings at the PV ostia were obtained from 10 patients with paroxysmal AF and 9 with concealed WPW syndrome without any history of AF. Typical PV potential was defined as either rapid deflections that were separate from local atrial deflection with a time delay in between, or continuous, fractionated potentials that were not separate from the atrial deflection. The existence of PV potentials was verified during sinus rhythm and during atrial pacing at the distal CS for the left PVs or at the right atrial appendage for the right PVs. To quantify the extent to which the PV potentials were recordable, the number of PVs with typical PV potentials for each PV and for each patient was counted. The time interval from the onset to the end of the electrograms recordable at the PV ostium (A-PV interval) was measured, and the maximum and mean of these intervals were obtained. Results: Study I: Thirty-eight MAP recordings were obtained. The shortest FF interval during AF was significantly shorter in patients with chronic AF than in patients with paroxysmal AF (50±13 vs. 72±31 ms, p 0.05) during sinus rhythm and distal CS pacing. Study IV: Typical PV potentials were recorded in 31 of 34 PVs (91%) in patients with AF, but in 4 of 36 PVs (11.1%) in patients with concealed WPW syndrome. A simple, narrow potential was recorded in 3/34 PVs (9%) in patients with AF, but in 29/36 (81%) PVs in patients with concealed WPW syndrome. The maximal and mean A-PV intervals were significantly longer in patients with AF (71±24 and 49±13 ms, respectively) than in patients with concealed WPW syndrome (33±14 and 25±6 ms). Conclusions: Electrical remodelling of the atrial myocardium is more marked in patients with chronic AF than in patients with paroxysmal AF. The AERP was significantly shortened during AF as compared to that during sinus rhythm, and the AERP shortening was more marked in patients with chronic AF than in patients with paroxysmal AF. These clinical findings support the connection between the electrical remodelling and the occurrence and/or perpetuation of the AF. The preferential site of transseptal conduction during distal CS pacing is near the CS ostium in patients with paroxysmal AF. This has clinical implications when surgical dissection or catheter ablation is considered to eliminate interatrial connection in patients with AF. Interatrial conduction at the postero-paraseptal region across the CS ostium was significantly slower in patients with paroxysmal AF than in control patients, further supporting the link between interatrial conduction deterioration and paroxysmal AF. In patients with AF, typical PV potentials with marked conduction time delay were almost invariably recordable at the PV ostium; but in patients without any history of AF, merely simple, narrow potentials were found. These findings support the involvement of conduction delay and re-entrant activities around the PV ostia in the genesis and/or perpetuation of AF

The role of the nurse in enhancing quality of life in patients with an implantable cardioverter-defibrillator: the Swedish experience.

During the last 10-15 years, the implantable cardioverter-defibrillator (ICD) has become an important mode of treatment for patients suffering from grave ventricular arrhythmias, but ICD implantation involves psychosocial adjustments for both patients and relatives. The aim of this pilot study was to design a plan of education and to follow a selected group of patients with interviews, observations, and a questionnaire. The goals included seeing how well they accepted their situation after the operation when they had ongoing support of the nurse, in comparison to a control group who received conventional patient education by the physician. The patients were randomly allocated into two groups. Twenty patients were recruited, 10 in the study group and 10 in the control group, between February, 1997 and April, 1998. There were 16 men (average age, 63) and four women (average age, 57). The Nottingham Health Profile was used to measure health-related quality of life. Sleep disturbances were the greatest problem in both the study group and the control group before ICD implantation. In the study group, there was a significant improvement (p<0.05) after ICD implantation in four patients. The study also revealed a difference between men and women, with women having more sleep disturbances before ICD implantation than men (p<0.05). In both groups, there was a lack of energy and emotional reactions, both before and after ICD implantation. Few considered family life a problem before or after the study. In the control group, the patients missed the lack of contact with health care personnel more than in the study group. There was also a greater need for group meetings after the hospital stay. By means of the questionnaire, interviews, and observations, it became evident that there was a great need for information, and a plan of patient education in addition to follow-up by the nurse was felt to be very important. (c)2002 CHF, Inc

Novel Mutation in the KCNJ2 Gene Is Associated with a Malignant Arrhythmic Phenotype of Andersen-Tawil Syndrome.

Andersen-Tawil syndrome (ATS) is a rare inherited multisystem disorder associated with mutations in KCNJ2 and low prevalence of life-threatening ventricular arrhythmias. Our aim was to describe the clinical course of ATS in a family, in which the proband survived aborted cardiac arrest (ACA) and genetic screening revealed a previously unknown mutation (c.271_282del12[p.Ala91_Leu94del]) in the KCNJ2 gene

Evidence for electrical remodelling of the atrial myocardium in patients with atrial fibrillation. A study using the monophasic action potential recording technique.

Experimental studies have shown that remodelling of the atrial myocardium is linked to the occurrence and perpetuation of atrial fibrillation (AF). Clinical evidence, however, is insufficient. We recorded monophasic action potentials (MAP) during AF from one to three sites in the right atrium in seven patients with chronic AF (CAF) and in 11 patients with paroxysmal AF (PAF). The fibrillatory (FF) interval between two consecutive upstrokes of the MAP was measured using a computer-assisted manual method. The mean, median, 15th, 10th, 5th percentile and shortest FF intervals were calculated in each patient and used as estimates of the local atrial effective refractory period (AERP) during AF. In three patients burst pacing at 400 and 500 beats min(-1) was delivered during the MAP recording. In nine patients, the AERP was also tested using the extra stimulus technique during sinus rhythm. RESULTS: Thirty-eight recordings were obtained. The shortest FF interval was significantly shorter in patients with CAF as compared with that in patients with PAF (50+/-13 vs. 72+/-31 ms, P<005). Similar differences were seen in the mean, median, 15th, 10th, and 5th percentile FF interval. The AERP during sinusrhythm was significantly longer than the estimated AERPs (P<0 05 to P<0.01) in the nine patients. There was no significant difference in FF interval before and after the burst pacing in the three patients. CONCLUSION: The AERP was significantly shortened during AF, as compared with that during sinus rhythm, and the AERP shortening was more marked in patients with CAF than in patients with PAF. These clinical findings support the connection between the electrical remodelling and the occurrence and/ or perpetuation of the AF

Kateterablation - ny bot vid paroxysmalt förmaksflimmer. Fallbeskrivningar visar hur själva triggerfaktorn kan slås ut

Paroxysmalt förmaksflimmer initieras av extraslag som ofta uppstår i lungvenerna. Kateterablation av impulsledning från lungvenerna kan bota paroxysmalt förmaksflimmer. Även andra impulsursprung kan elimineras genom kateterablation, förutsatt att lokalisationen kartläggs elektroanatomiskt

Pulmonary vein potentials in patients with and without atrial fibrillation.

Background Pulmonary vein (PV) potentials are invariably recordable at the PV ostia in patients with atrial fibrillation (AF) and delayed conduction around the PV ostia may play a role in the initiation and maintenance of AF. Aims To investigate the presence and extent of PV potentials in patients with and without AF. Methods and results Circumferential catheter recordings at the PV ostia were obtained from 10 patients with paroxysmal AF and 9 with concealed Wolff-Parkinson-White (WPW) syndrome without history of AF. Typical PV potential was defined as either rapid deflections that separated from atrial deflection with a time delay in-between, or multiphasic, continuous or fractionated potentials. The presence of PV potentials was verified during sinus rhythm and during atrial pacing at the distal coronary sinus for the left PVs or at the right atrial appendage for the right PVs. To quantify the extent in which the PV potentials were recordable, the number of PVs with typical PV potentials recordable was counted. The time interval from the onset to the end of the electrograms recordable at the PV ostium (A-PV interval) was measured, and the maximal and mean of this interval were obtained. Typical PV potentials were recorded in 31 of 34 PVs (91%) in patients with AF, but in 4 of 36 PVs (11%) in patients with concealed WPW. A narrow, biphsic or triphasic, potential was recorded in 3 of 34 PVs (9%) in patients with AF, but in 29 of 36 (81%) PVs in patients with concealed WPW. The maximal and mean A-PV intervals were significantly longer in patients with AF (71 +/- 24 and 49 +/- 13 ms) than in patients with concealed WPW syndrome (33 +/- 14 and 25 +/- 6 ms). Conclusion In patients with AF, typical PV potentials with marked conduction time delay were almost invariably recordable at the PV ostium, but in patients without a history of AF, merely simple, narrow potentials were found. These findings support the involvement of conduction delay and re-entrant activities around the PV ostia in the genesis and/or perpetuation of AF

Regional heterogeneity of right atrial repolarization. Monophasic action potential mapping in swine.

Abstract Objectives. To establish a set of reference values for regional dispersion of repolarization of the right atrium in the in situ heart of pigs and to see if the global dispersion of repolarization could be estimated from regional mapping. Design. Monophasic action potential (MAP) were sequentially recorded from 28 ± 3 sites in seven different regional areas of the right atrium: lateral, anterior and posterior wall, septum, sinoatrial node (SAN), appendage, and near the tricuspid annulus (TA) in 10 healthy pigs using the CARTO mapping system. Results. The activation time (AT), MAP duration (MAPd) and end of repolarization time (EOR) of the whole right atrium were 68 ± 7, 239 ± 20 and 270 ± 23 ms, respectively. There were no significant differences on MAPd and EOR among the seven regional areas, nor between each of the regional and global values. The global dispersions of the MAPd and EOR were 75 ± 19 and 103 ± 13 ms, which were significantly greater than those obtained from any of the seven regional areas and those between two remote regions, SAN vs. TA and SAN vs. appendage regions. Conclusions. The data of regional and global dispersion of repolarization in healthy pigs can serve as reference values for evaluation of increased dispersion of repolarization. The global dispersions of MAPd and EOR in the right atrium were poorly estimated from regional mapping, suggesting the importance of global mapping in evaluating the dispersion of atrial repolarization