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At least 37 records · Page 2Linked to original sources
PubMed2003

The usefulness of surface 12-lead electrocardiogram to predict intra-atrial conduction block after successful atrial flutter ablation.

Intraatrial conduction block at the inferior vena cava-tricuspid annulus isthmus was shown to predict successful atrial flutter ablation. However, its demonstration requires the use of several electrode catheters. Thus, a simple approach using surface 12-lead ECG to prove the conduction block would be valuable. Twenty-two patients were prospectively studied during low septal and low lateral atrial pacing before and after successful atrial flutter ablation. Creation of the conduction block was confirmed by comparing the sequence of atrial activation using 3 multipolar catheters during atrial pacing before and after ablation. During low septal pacing, there was no significant difference before and after ablation in P-wave width, axis, or morphology. During low lateral atrial pacing, there was a significant P-wave axis rotation towards the right (from -67 +/- 27 degrees to +13 +/- 35 degrees, P <.001), and P-wave polarity in limb lead II changed from predominantly negative to predominantly positive in 21 of 22 patients. There was also an increase in P-wave width (from 136 +/- 32 to 169 +/- 36 ms, P <.001) and stimulus-to-QRS interval (from 268 +/- 61 ms to 343 +/- 95 ms, P <.001) during low lateral pacing that was not observed during low septal pacing. We conclude that creation of a conduction block in the inferior vena cava-tricuspid annulus isthmus modifies surface 12-lead ECG during low lateral atrial pacing only. We also suggest that P-wave polarity in limb lead II during low lateral pacing could be used as a noninvasive marker of unidirectional counter-clockwise conduction block during atrial flutter ablation.

Adult↗
PubMed2006

Rotigaptide (ZP123) improves atrial conduction slowing in chronic volume overload-induced dilated atria.

Chronic atrial dilation is associated with atrial conduction velocity slowing and an increased risk of developing atrial tachyarrhythmias. Rotigaptide (ZP123) is a selective gap junction modifier that increases cardiac gap junctional intercellular communication. We hypothesised that rotigaptide treatment would increase atrial conduction velocity and reduce the inducibility to atrial tachyarrhythmias in a model of chronic volume overload induced chronic atrial dilatation characterized by atrial conduction velocity slowing. Chronic volume overload was created in Japanese white rabbits by arterio-venous shunt formation. Atrial conduction velocity and atrial tachyarrhythmias inducibility were examined in Langendorff-perfused chronic volume overload hearts (n=12) using high-resolution optical mapping before and after treatment with rotigaptide. Moreover, expression levels of atrial gap junction proteins (connexin40 and connexin43) were examined in chronic volume overload hearts (n=6) and compared to sham-operated controls (n=6). Rotigaptide treatment significantly increased atrial conduction velocity in chronic volume overload hearts, however, rotigaptide did not decrease susceptibility to the induction of atrial tachyarrhythmias. Protein expressions of Cx40 and Cx43 were decreased by 32% and 72% (P<0.01), respectively, in chromic volume overload atria compared to control. To conclude, rotigaptide increased atrial conduction velocity in a rabbit model of chromic volume overload induced atrial conduction velocity slowing. The demonstrated effect of rotigaptide on atrial conduction velocity did not prevent atrial tachyarrhythmias inducibility. Whether rotigaptide may possess antiarrhythmic efficacy in other models of atrial fibrillation remains to be determined.

Animals↗
PubMed2004

Evaluation of atrial conduction time at various sites of right atrial pacing and influence on atrioventricular delay optimization by surface electrocardiography.

Cardiac function and electrical stability may be improved by programming of optimal AV delay in DDD pacing. This study tested the hypothesis if the global atrial conduction time at various pacing sites can be derived from the surface ECG to achieve an optimal electromechanical timing of the left heart. Data were obtained from 60 patients following dual chamber pacemaker implantation. Right atrial septal pacing was associated with significantly shorter atrial conduction time (P < 0.0005) and P wave duration (P < 0.005), compared to standard right atrial pacing sites at the right atrial appendage or at the right free wall. The last two pacing sites showed no significant difference. In a group of 31 patients with AV block, optimal AV delay was achieved by programming a delay of 100 ms from the end of the paced P wave to peak/nadir of the paced ventricular complex. Optimization of AV delay resulted in a relative increase of echocardiographic stroke volume (SV) (10.9 +/- 13.7%; 95% CI: 5.9-15.9%) when compared to nominal AV delay (170 ms). Optimized AV delay was highly variable (range 130-250 ms; mean 180 +/- 35 ms). The hemodynamic response was characterized by a weak significant relationship between SV increase and optimized AV delay (R2 = 0.196, R = 0.443, P = 0.047). The study validated that septal pacing is advantageous for atrial synchronization compared to conventional right atrial pacing. Tailoring the AV delay with respect to the surface ECG improved systolic function significantly and was superior to nominal AV delay settings in the majority of patients.

Aged↗
PubMed2001

Dissociation between coronary sinus and left atrial conduction in patients with atrial fibrillation and flutter.

INTRODUCTION: Coronary sinus (CS) recordings are routinely used during electrophysiologic studies for various supraventricular and ventricular arrhythmias with the understanding that they represent left atrial (LA) activity. However, the behavior of CS electrical activity during atrial arrhythmias has not drawn any special attention beyond standard considerations. METHODS AND RESULTS: The study population consisted of 9 patients (3 women; mean age 59 +/- 11 years) with atrial fibrillation (AF) and atrial flutter (AFL) who developed dissociation of conduction between the CS and posterior LA during spontaneous AF and AFL. In all patients, the LA and the CS were mapped using a 64-electrode basket catheter and a multipolar electrode catheter, respectively. The right atrium (RA) was mapped simultaneously using a 24-polar electrode catheter (7 patients) or a 64-electrode basket catheter (2 patients). Eight patients showed stable double potentials in CS recordings during AF (9 episodes) and AFL (3 episodes). During ongoing arrhythmias, the first row of potentials maintained a constant relationship with the RA activity, whereas the second row of potentials was discordant with the posterior wall of the LA in 7 patients and concordant in 2 patients. In 1 patient with counterclockwise AFL, CS activation was isolated from the posterior wall of the RA until it reached the distal portion of the CS, after which it entered the lateral region of the LA. In 1 patient, a macroreentrant LA tachycardia involving CS muscle was observed. Rapid atrial pacing from the proximal CS and extrastimuli produced longitudinal dissociation of CS activation in all patients. CONCLUSION: Conduction between the CS and posterior LA can be dissociated during spontaneous atrial arrhythmias and provocative proximal CS pacing.

Arrhythmias, Cardiac↗
PubMed1997

Atrial conduction abnormalities in patients with systemic progressive sclerosis.

BACKGROUND: Atrial abnormalities in patients with progressive systemic sclerosis have not been evaluated in terms of intra-atrial conduction. We hypothesized that a delay in atrial conduction in these patients might produce diastolic abnormalities as well as atrial arrhythmias. OBJECTIVE: To evaluate the atrial function of patients with progressive systemic sclerosis by using echocardiography to measure the intra-atrial electromechanical activation coupling interval. METHODS: Twenty patients with progressive systemic sclerosis were assessed by Doppler echocardiography. Twenty age-matched healthy controls were also evaluated. Two-dimensional guided M-modes of ventricular long axes were recorded using simultaneous phono- and electrocardiograms of the apical four chamber view at the right lateral, septal and left lateral sites of the atrioventricular rings. Transmitral and tricuspid pulsed Doppler flow velocities were also recorded. Filtered P wave duration was measured on the signal averaged ECG to determine the duration of atrial electrical activation. RESULTS: There was a delay in P on the electrocardiogram (P) at the onset of atrial contraction on long axis M-modes at all three atrioventricular ring sites in patients with progressive systemic sclerosis as compared with controls (P-right; 56 +/- 13 vs 47 +/- 10 ms, P-septal; 74 +/- 14 vs 55 +/- 10 ms, and P-lateral; 93 +/- 16 vs 72 +/- 11 ms, P < 0.01). Inter-atrial conduction time [(P-lateral)-(P-right)] was delayed in patients with progressive systemic sclerosis, compared with healthy controls (37 +/- 15 vs 25 +/- 6 ms, P < 0.01). Mitral A waves acceleration and deceleration times were also decreased in the patients. The interval was prolonged between P to the onset and the peak of the A wave in transmitral flow. Duration of the filtered P wave was significantly prolonged in progressive systemic sclerosis as compared with controls (124 +/- 12 ms vs 106 +/- 8 ms, P < 0.01). PQ intervals, E waves and acceleration and deceleration times did not differ significantly in progressive systemic sclerosis vs, controls. The A wave acceleration rate on transmitral flow (peak A wave velocity/acceleration time) showed a significant correlation with inter-atrial conduction delay (r = 0.55, P < 0.01). CONCLUSIONS: Intra-atrial electromechanical coupling intervals were delayed in patients with progressive systemic sclerosis. Thus, the mechanical late diastolic filling time due to atrial contraction in the total diastolic phase was severely limited, and this resulted in a restricted mitral A wave. We should therefore evaluate patients with progressive systemic sclerosis for significant atrial abnormalities.

Atrial Function↗
PubMed2005

Electroanatomical mapping and radiofrequency catheter ablation of atrial tachycardia originating from the recipient heart with recipient-to-donor atrio-atrial conduction after orthotopic heart transplantation.

Atrial tachycardias resulting from recipient-to-donor atrio-atrial conduction after orthotopic heart transplantation are difficult to treat. We present two patients in whom atrial tachycardia originating in the recipient heart were successfully treated by radiofrequency ablation guided by electroanatomical CARTO mapping system. These cases illustrate that such atrial tachycardia are curable by radiofrequency ablation. Electroanatomical CARTO mapping is useful in identifying the site of origin of the tachycardia and the atrio-atrial conduction sites.

Aged↗
PubMed2001

Effects of MgSO4 and glucose, insulin and potassium (GIK) on atrial conduction during the first 12 hours after DC-conversion of chronic atrial fibrillation.

OBJECTIVE: To investigate changes in atrial conduction induced by MgSO4 and glucose, insulin and potassium (GIK) during the first 12-h period of sinus rhythm after successful DC-conversion of chronic atrial fibrillation (CAF). METHODS: Signal-averaged P-wave duration, QRS-duration and PQ-time were recorded in 20 patients who were randomly assigned to control or intervention. Ten patients received no infusates (control group) and 10 patients received MgSO4 and GIK infusions (intervention group). P-wave duration was determined from the X-, Y- and Z-leads, which were further combined to obtain a spatial magnitude. P-wave morphology was studied by analysing global activation patterns and discrete components from the calculated spatial magnitude signal. RESULTS: No changes in the measured parameters were seen in the control group. The P-wave duration, QRS-duration and PQ-time increased from 139(13) [mean(SD)] to 149(15) (p < 0.01), 90(7) to 94(9) (p < 0.05) and 188(10) to 207(13) ms (p < 0.01). respectively, after bolus infusion of MgSO4. The time from the start of the P-wave to its 1st and 2nd max. locations increased by 6 ms (p < 0.01) in both cases after bolus infusion of MgSO4 and had reversed after 10 h of MgSO4 and GIK infusion. P-wave duration and PQ-time decreased after 10 h of MgSO4 and GIK infusion, from 149(34) (bolus) to 138(12) and from 207(13) to 195(27) ms (p < 0.05), respectively, in spite of an even higher serum Mg concentration at the end of this period. CONCLUSION: Bolus infusion of MgSO4 2 h after DC-conversion of CAF produced an intra-atrial conduction delay that could be reversed by adding a GIK infusion, in spite of a concomitant increase in serum Mg concentration. No recovery of the intra-atrial conduction delay, seen after DC-conversion of CAF, was observed in either of the two groups during the 12-h study period.

Aged↗
PubMed1975

[The effect of drugs on "sino-atrial conduction time" and on sinus-node automaticity in man].

The effect of atropine, propafenone, and disopyramide on sinus node automaticity and "sino-atrial conduction" was tested in normal patients and patients with the sick sinus-syndrome. "Sino-atrial conduction time" was estimated indirectly by the extrastimulus technique. Atropine (n = 11) caused a significant increase in heart rate in all patients. The sinus node recovery time was shortened in 10 patients. "Sino-atrial conduction time" decreased on an average 35% (P less than 0.01). Three patients with a sick sinus-syndrome demonstrated a change of the pattern of the postextrasystolic pauses indicating great improvement in sino-atrial conduction. Propafenone (n = 10) led to a significant prolongation of the sinus node recovery time by 17% and of the "sino-atrial conduction time" by 27%. Disopyramide (n = 8) had no significant influence on heart rate and "sino-atrial conduction time". Sinus node recovery time was not changed in 6 patients. However, in two patients with a sick sinus-syndrome a dangerous prolongation of the sinus node recovery time after application of disopyramide occurred. The results indicate that atropine enhances sinus node function and sino-atrial conduction. On the other hand, propafenone and disopyramide exert either a depressant influence on sinus node automaticity or on sino-atrial conduction.

Atropine↗
PubMed2002

Immediate recurrence of atrial fibrillation after internal cardioversion: importance of right atrial conduction variations.

This study investigates the importance of right atrial conduction features in predicting of immediate recurrence of atrial fibrillation (AF) after internal cardioversion (IC). Patients with chronic AF who were resistant to external cardioversion were studied. Twenty-four patients (16 female, 8 male mean age 58 +/- 7 years) who were successfully converted to sinus rhythm (SR) by IC, and experienced recurrence of AF within 1 minute of restoration of SR were enrolled in group A. Thirty-four patients, who were converted to SR by IC and in whom SR was maintained at least 1 minute after IC, were enrolled in group B (24 female, 10 male mean age 56 +/- 6 years) as control. There was no difference in age, left atrial diameter, use of antiarrhythmic drug, etiology and duration of AF between the groups. After successful IC, His bundle electrocardiograms via placed electrode catheters, and surface electrocardiograms were recorded for 1 minute. P-A interval duration, as a marker of right atrial conduction, was measured from the onset of the earliest registered surface P wave to the onset of the atrial deflection on His-bundle catheter recording. The difference between the recorded maximum P-A duration and minimum P-A duration obtained in 1 minute after IC was described as P-A interval absolute difference. There were no differences in the maximum P-A duration and minimum P-A duration between two groups. But, the P-A absolute difference was more pronounced in group A compared to group B (16.9 +/- 7.7 ms versus 10.3 +/- 6.4 ms, P < .001) and was significantly correlated with P wave dispersion derived from the surface electrocardiogram (r = .72, P < .001) In conclusion, variations in right atrial conduction might play an important role in predicting immediate recurrence of AF in patients converted to SR by IC.

Aged↗
PubMed2000

Failure of coronary sinus pacing in reducing local atrial conduction delay in patients with atrial fibrillation after successful internal cardioversion.

Recent studies suggested that distal coronary sinus (CS) pacing may prevent atrial fibrillation (AF) by reducing site dependent intraatrial conduction delay. The aim of this study was to investigate the effect of high right atrial (HRA) and distal CS pacing on local conduction delay in patients with AF. The study population consisted of 10 patients with persistent AF after transvenous atrial defibrillation and 10 control subjects. The local conduction delays along the anterolateral right atrium (RA), in the CS, and at the right atrial septum (RAS), and the incidence of AF in response to an atrial extrastimulus during HRA and distal CS pacing at a drive cycle length of 400, 500, and 600 ms were evaluated. In patients with AF, distal CS and HRA pacing are associated with more prominent and similar extent of conduction delay within the atria, without any significant difference in the dispersion of conduction delay and susceptibility to AF induction (70% vs 60%, P = 0.9). In normal controls, distal CS pacing reduces the conduction delay at the RAS and CS ostium and decreases the dispersion of conduction delay and the propensity for AF induction (0% vs 50%, P = 0.03) compared to HRA pacing. The pacing drive cycle length has no significant effect on conduction delay in patients with AF and normal controls (P > 0.05). Compared to normal controls, patients with AF have significantly longer conduction delay at the RAS and along the anterolateral RA during HRA and distal CS pacing. The result of this study demonstrates that the effect of HRA and distal CS pacing on the local atrial conduction delay in patients with and without AF differ significantly. These patients with AF may have more diffuse atrial anisotropy causing the changes in conduction, and pacing from distal CS in these patients dose not reduce the propensity for AF.

Atrial Fibrillation↗
PubMed1994

Incidence and electrophysiologic characteristics of supernormal atrial conduction in humans.

The incidence and electrophysiologic characteristics of supernormal atrial conduction (SNC) were examined by cardiac stimulation in 53 control subjects. Their ages ranged from 15 to 71 years (mean age, 50 +/- 21 years) (mean +/- SD). There were 27 women and 26 men in the study. Conduction of premature atrial responses from the sinus node to the atrioventricular node (intraatrial conduction time) was supernormal in 27 (51%) subjects and conduction to the left atrium (interatrial conduction time) was supernormal in 35 (66%) subjects (difference not significant). At coupling intervals ranging between 440 and 240 ms, the conduction time of the premature beats was as much as 25 ms shorter than that of the basic driven beats. The maximum decrease in interatrial conduction time during the period of SNC was 13 +/- 5 ms and the maximum decrease in intraatrial conduction time was 9 +/- 3 ms (P < .001). The supernormal interatrial conduction zone was 71 +/- 29 ms and the supernormal intraatrial conduction zone was 57 +/- 25 ms (P < .05). There was a significant positive correlation between the SNC zone and the maximum decrease in conduction time (r = .82; P < .001). Supernormal atrial conduction was stable, reproducible, and remained constant in individual patients. Supernormal atrial conduction was found to be a relatively frequent phenomenon. There was a significantly greater SNC zone and maximum decrease in conduction time in interartrial conduction than in intraatrial conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function↗
PubMed1985

Ventriculo-atrial conduction in patients with normal and impaired atrio-ventricular conduction.

Ventriculo-atrial (VA) conduction was studied in 133 patients with various kinds of arrhythmias using intracardiac electrograms and programmed stimulation. One-to-one VA conduction was observed during RV pacing at the rate just above the sinus rate in 6 of 31 patients (19.4%) with advanced AV block, in 7 of 26 patients (26.9%) with impaired AV nodal conduction, in 25 of 71 patients (35.2%) with normal AV nodal conduction and 3 of 5 patients (60%) with enhanced AV nodal conduction. However, the differences between these groups were not significant. There was no significant difference in either the AH block rate during RA pacing or the antegrade functional refractory period (FRP) of the AV node in patients with or without VA conduction, and the VA block rate during RV pacing was not significantly correlated with the AH block rate or the FRP of the AV node. VA conduction time (S-HRA) also showed no significant differences between these groups. The mean VA conduction time during RV pacing at rates of 60 to 80 bpm was 208 +/- 87 msec, ranging from 100 to 395 msec. In conclusion, AV conduction disturbances may influence VA conduction, but VA conduction cannot be predicted from antegrade conductivity.

Arrhythmias, Cardiac↗
PubMed2005

Inter-atrial conduction time shortens after blood pressure control in hypertensive patients with left ventricular hypertrophy.

UNLABELLED: Assuming that blood pressure control could induce a shortening of the inter-atrial conduction time and prevent atrial fibrillation occurrence, we studied the inter-atrial conduction time in hypertensive patients with left ventricular hypertrophy. METHODS: Sixty-eight (26 male) 58.34+/-8.08-year-old patient participated in the study. All were in sinus rhythm and had abnormal blood pressure (163+/-18/95+/-9 mm Hg). Their cardiac mass index was increased (151+/-43 g/m(2) SC) and their left atrial dimension was normal (3.67+/-0.54 cm). The inter-atrial conduction time was measured in the echocardiogram from the beginning of the electrocardiographic P wave to the beginning of the A wave in the mitral Doppler signal and was corrected for heart rate. Heart rhythm disturbances were monitored clinically and by means of a Holter. Most patients were treated with angiotensin antagonists. RESULTS: It was found that arterial blood pressure decreased significantly after treatment and that the P-A interval was significantly reduced (71.4+/-14.5 vs. 63.9+/-11.5 ms). During the follow-up, no patient complained of arrhythmia symptoms or exhibited atrial fibrillation in the Holter recording. CONCLUSION: In this selected group of patients with hypertensive heart disease (left ventricular hypertrophy), an effective blood pressure control was accompanied by a significant decrease in the inter-atrial conduction time. It is possible that these effects prevent atrial fibrillation.

Aged↗
PubMed1983

Localization of the accessory pathway in the Wolff-Parkinson-White syndrome from the ventriculo-atrial conduction time of right ventricular apical extrasystoles.

In 18 consecutive patients with the Wolff-Parkinson-White syndrome undergoing electrophysiologic study, the ventriculo-atrial conduction time of right ventricular apical extrasystoles which advanced atrial activation during circus movement tachycardia was studied in relation to accessory pathway location. Accessory pathway location was determined by delta wave morphology during maximal pre-excitation, mapping of atrial activation during circus movement tachycardia and ventricular pacing, the effect of bundle branch block on ventriculo-atrial conduction time during circus movement tachycardia, and the effect of pacing from different sites in the atria on the stimulus-to-delta wave interval. In 7 patients with septal accessory pathways, ventriculo-atrial conduction time was similar during circus movement tachycardia and following right ventricular apical extrasystoles (mean difference 0 +/- 6 ms, range -5 to +10 ms). In contrast, in 11 patients with a left free wall accessory pathway, ventriculo-atrial conduction time increased by 46 +/- 15 ms (range 15 to 65 ms) following right ventricular apical extrasystoles. Therefore, measurement of the ventriculo-atrial conduction time of right ventricular extrasystoles during circus movement tachycardia provides an easy way to distinguish between septal and left free wall accessory pathways. This finding may be of particular use in determining the location of concealed bypass tracts.

Adolescent↗
PubMed1985

Vagal effects on sinoatrial and atrial conduction studied with epicardial mapping in dogs: the influence of pacemaker shifts on the measurement of sinoatrial conduction time.

The influence of pacemaker shifts on sinoatrial conduction time (SACT) was studied by investigating the effects of vagal stimulation on SACT and atrial conduction in anesthetized open-chest dogs. Isochronal maps were drawn from unipolar electrograms simultaneously recorded at 60 epicardial sites on the right atrial free wall and the inferior and superior vena cava. Vagal stimulation caused atrial conduction velocity to increase from 0.99 +/- 0.10 m/s (mean +/- SD) to 1.23 +/- 0.23 m/s (p less than 0.01), and the pacemaker to shift to lower positions along the superior vena cava - right atrial junction. As a result of the changes, the distances and the atrial conduction times from the stimulating and recording electrodes to the pacemaker site varied, and hence, the SACT values obtained indirectly by premature atrial stimulation varied. The isochronal maps were used to measure the atrial conduction times from stimulating to recording electrodes (a), from stimulating electrode to pacemaker site (b), and from pacemaker site to recording electrode (c). Indirect SACT was lengthened by vagal stimulation from 43 +/- 16 to 64 +/- 22 ms (p less than 0.02). After correcting by subtracting the atrial conduction time (b + c - a), these values became 26 +/- 6 ms (control) and 40 +/- 11 ms (vagal stimulation) (p less than 0.01). SACT values measured directly from the electrograms were 27 +/- 7 ms (control) and 42 +/- 10 ms (vagal stimulation) (p less than 0.01). Corrected indirect SACTs were closer to direct SACTs than were the uncorrected indirect SACTs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗