Effect of Atrial Stimulation Site on the Electrophysiological Properties of the Atrioventricular Node in Man

Batsford, William P.; Akhtar, Masood; Caracta, Anthony R.; Josephson, Mark E.; Seides, Stuart F.; Damato, Anthony N.

doi:10.1161/01.cir.50.2.283

Cited by 82 publications

(25 citation statements)

References 22 publications

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“…The right atrial appendage was used in all cases to minimize the effect of atrial stimulation site on AV conduction. 25 After the above control measurements were completed, a drug was infused intravenously and the experimental protocol was repeated. Diltiazem and verapamil were dissolved in 0.9% saline.…”

Section: Methodsmentioning

confidence: 99%

Frequency-dependent effects of calcium antagonists on atrioventricular conduction and refractoriness: demonstration and characterization in anesthetized dogs.

Talajic¹,

Nattel²

1986

Circulation

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Calcium-channel blockers are known to affect slow inward current in a frequencydependent fashion. The purpose of these experiments was to study use-dependent effects of verapamil, diltiazem, and nifedipine on atrioventricular conduction in vivo. Loading and maintenance infusion techniques were developed to study each drug at a series of stable plasma concentrations in autonomically blocked dogs anesthetized with morphine and a-chloralose. All 1156 also shown frequency-dependent effects of fast-channel blockers in vivo. [7][8][9] Calcium-channel blockers have also been shown to have frequency-dependent properties. Verapamil was initially found to produce a greater increase in rabbit atrioventricular (AV) nodal conduction time at faster atrial pacing rates than at slower rates, although the mechanism of this observation was unclear.'`Subsequently, it was observed that verapamil and its methoxy derivative, D600, had a more depressant effect on contractility as driving rate was increased."l 12 Frequency-dependent decreases in slow inward current have been demonstrated for both verapamil'3 14 and diltiazem. 15-17 Although nifedipine was initially reported to have a pure tonic effect on slow inward current without significant frequency dependency,'9 more recent work with faster pacing rates has indicated that some use-dependent block occurs with nifedipine.19 To date, the bulk of data on interval-dependent actions of

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Section: Methodsmentioning

confidence: 99%

Frequency-dependent effects of calcium antagonists on atrioventricular conduction and refractoriness: demonstration and characterization in anesthetized dogs.

Talajic¹,

Nattel²

1986

Circulation

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“…However, the obtained outcomes cannot be reliably referred to AVNRT patients because of their marginal participation in those studies. Moreover, different right (high, mid, or low) and left atrial pacing sites (via different CS sites, a persistent foramen ovale or a transseptal puncture) and EPS protocols seem to be the possible reason for conflicting results [1][2][3][4][5][6][7][8]. In all mentioned studies LA stimulation resulted in shorter AH intervals than did RA stimulation.…”

Section: Anterograde Avn Transmission During Pacingmentioning

confidence: 99%

“…Previous reports have documented that the site of atrial stimulation can affect AVN function and the ability to initiate dual AVN pathways and AVNRT [1][2][3][4][5][6][7][8].…”

Section: Electrophysiological Properties Of the Av Junction And Inducmentioning

confidence: 99%

“…Clinical studies in humans have shown the site of atrial stimulation to influence atrioventricular (AV) conduction times and refractory periods, the demonstration of dual atrioventricular nodal (AVN) pathways, and induction of AVN reentry [1][2][3][4][5][6][7][8]. These studies often found conflicting results that could be explained by different atrial pacing sites and the electrophysiological study (EPS) protocol applied.…”

Section: Introductionmentioning

confidence: 99%

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The effect of atrial pacing site on electrophysiological properties of the atrioventricular junction and induction of atrioventricular nodal reentry in patients with typical atrioventricular nodal reentrant tachycardia

Kiedrowicz

Kaźmierczak²,

Wielusiński³

2017

Kardiol Pol

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A b s t r a c tBackground: Clinical studies in humans have shown the site of atrial stimulation to influence atrioventricular (AV) conduction times and refractory periods, the demonstration of dual AV nodal (AVN) pathways, and induction of AVN reentry. These studies often found conflicting results. Moreover, among enrolled patients a minority of them were found to have AVN reentrant tachycardia (AVNRT). Aim:The purpose of this study was to investigate the effect of right and left atrial pacing on the electrophysiological properties of the AV junction in the typical AVNRT population.Methods: Ninety-two consecutive patients with typical AVNRT were included. Atrial pacing was performed from the high right atrium (HRA) and the left atrium via the proximal coronary sinus (CS). Results:Stimulation from either the HRA or the CS could result in dual AVN physiology and AVNRT. No site-dependent differences in the ease of induction of dual AVN pathways with variability of initiation from either site were found. However, AVNRT was easier to induce from the HRA. With CS pacing the leftward but not the rightward AVN approaches were the entry point to the AV node because of significantly shorter AH conduction times compared to HRA pacing. Conduction over the leftward AVN extensions could initiate the tachycardia with significantly shorter critical AH interval compared to conduction over the rightward AVN extensions; however, the AH interval during AVNRT and its cycle length were not significantly different. Conclusions:Rightward and leftward AVN extensions are regular features of the AV node. Their different electrophysiological properties lead to variation in the demonstration of discontinuous AVN conduction and AVNRT during right and left atrial pacing. Despite the observation that the left AVN extensions could compose the entry point to the reentrant circuit, there is no evidence that they constitute the critical component of sustained typical AVNRT.

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“…It should also be remembered that changing the atrial stimulation site can alter the functional properties of the AV node (Batsford, Akhtar, Caracta, Josephson, Seides & Damato, 1974), and that the antegrade and retrograde properties of the AV node and accessory pathways may differ (Akhtar, Damato, Batsford, Rusken & Ogunkelu, 1975).…”

Section: Intracardiac Recordings and Stimulationmentioning

confidence: 99%

The Electrocardiogram in the Assessment of the Effect of Drugs on Cardiac Arrhythmias

Reid¹

1980

Cardiovascular System

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upon Tyne NE7 7DNThe search for the ideal antiarrhythmic drug continues since none of the available agents offers optimum antiarrhythmic therapy. The continuing search coupled with the interest in the mechanisms of cardiac arrhythmias has led to the development of new techniques for the study of arrhythmias and antiarrhythmic drugs. In this article it is proposed to discuss the electrocardiographic methods used in the assessment of antiarrhythmic drugs. Firstly, to discuss the electrocardiogram in the assessment of the clinical electrophysiological properties of a drug and secondly, the electrocardiogram in the assessment of the value of the drug in the management of cardiac arrhythmias in man. Assessment of the electrophysiological effects of drugs Standard ECG intervalsThe standard electrocardiogram can give some information on the effects of a drug on automaticity and conduction velocity within the heart by analysis of the standard ECG intervals-P-P (or R-R), PR and QRS intervals (Table 1).The P-P interval reflects intrinsic sinus node function and the autonomic influences on the sinus node. Thus, any change in the P-P interval following drug administration can be a direct effect of that drug on sinus node function, or by its effect on the autonomic nervous system either directly or through reflex mechanisms. Thus, antiarrhythmic drugs such as quinidine and disopyramide can influence the P-P interval by their direct depressant effect on the sinus node, by their anticholinergic effects or by reflex autonomic changes as a result of a fall in systemic pressure.The P-R interval represents conduction through the atria, AV node and His purkinje tissue and changes in the PR interval following drug administration could reflect changes in any of these. However, because there is a difference in conduction velocity in the AV node and His purkinje system (it takes 100-120 ms for the impulse to cross the AV node and approximately 40 ms to traverse the His purkinje system), major changes in conduction in the His purkinje system have to occur before they are detected on the standard ECG run at conventional paper speeds of 25-50 mm/s. For example, a 10% change in AV nodal conduction may result in a change of 10-12 ms in PR interval, but a 10% change in His purkinje conduction will only be in the region of 4 ms. Thus, significant changes in His purkinje conduction can occur without being detected on the standard electrocardiogram.QRS duration reflects conduction through the ventricular myocardium and any change reflects changes in ventricular muscle conduction-e.g. procainamide prolongs QRS duration.Since the QT interval represents ventricular repolarization, analysis of the QT interval gives some information on the effect of the drug on ventricular repolarization time. Since repolarization time is dependent on heart rate it can be corrected for rate by formulas of Bazett (1920) or in children by that of Fraser, Froggatt & James (1964). Drugs that prolong ventricular repolarization such as amiodarone or quinidine will prolong...

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Effect of Atrial Stimulation Site on the Electrophysiological Properties of the Atrioventricular Node in Man

Cited by 82 publications

References 22 publications

Frequency-dependent effects of calcium antagonists on atrioventricular conduction and refractoriness: demonstration and characterization in anesthetized dogs.

Frequency-dependent effects of calcium antagonists on atrioventricular conduction and refractoriness: demonstration and characterization in anesthetized dogs.

The effect of atrial pacing site on electrophysiological properties of the atrioventricular junction and induction of atrioventricular nodal reentry in patients with typical atrioventricular nodal reentrant tachycardia

The Electrocardiogram in the Assessment of the Effect of Drugs on Cardiac Arrhythmias

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