Effect of Coupling Interval and Pacing Cycle Length on Morphology of Paced Ventricular Complexes

Circulation ◽  
1996 ◽  
Vol 94 (11) ◽  
pp. 2843-2849 ◽  
Author(s):  
Rajiva Goyal ◽  
Mark Harvey ◽  
Emile G. Daoud ◽  
Karin Brinkman ◽  
Bradley P. Knight ◽  
...  
Keyword(s):  
Cycle Length ◽  
Coupling Interval

Effects of infarction, procainamide, coupling interval, and cycle length on refractoriness of extrastimuli

1985 ◽  
Vol 248 (5) ◽  
pp. H606-H613
Author(s):  
F. E. Marchlinski ◽  
M. E. Cain ◽  
R. A. Falcone ◽  
R. F. Corky ◽  
J. F. Spear ◽  
...  
Keyword(s):  
Refractory Period ◽  
Cycle Length ◽  
Narrow Range ◽  
Left Ventricular ◽  
Effective Refractory Period ◽  
Stimulation Site ◽  
Refractory Periods ◽  
Coupling Interval ◽  
Cycle Lengths ◽  
Site Of Stimulation

The effects of prematurity, cycle length, site of stimulation, and procainamide on ventricular refractoriness following an extrastimulus (S2) were assessed in 10 dogs with and 10 dogs without infarction. Extrastimuli were introduced at preselected coupling intervals (S1-S2) from normal right and left ventricular sites and from left ventricular sites of infarction during drive cycle lengths (S1-S1) of 350 and 250 ms. At each S1-S2 interval, the effective refractory period of S2 was determined by introducing a second extrastimulus (S3). At all stimulation sites, cycle lengths, and before and during infusion of procainamide (mean concn 18.6 +/- 3.5 micrograms/ml), shortening (greater than 10 ms change) in refractoriness was most marked over a narrow range of closely coupled S1-S2 intervals. Regardless of stimulation site, the effective refractory period of S2 was less during a cycle length of 250 ms compared with a cycle length of 350 ms. In dogs without infarction, the effective refractory periods of S2 from left ventricular sites tended to be longer than from right ventricular sites, particularly during procainamide administration. The refractory period of S2 at sites of infarction did not differ consistently from those at normal sites. Finally, at all stimulation sites and cycle lengths, procainamide prolonged refractoriness of S2 at each S1-S2 interval and blunted the total shortening in refractoriness in response to S2.

Mechanism of atrioventricular nodal facilitation in rabbit heart: role of proximal AV node

1997 ◽  
Vol 273 (4) ◽  
pp. H1658-H1668 ◽  
Author(s):  
Todor Mazgalev ◽  
Kent Mowrey ◽  
Igor Efimov ◽  
Gerard J. Fahy ◽  
David Van Wagoner ◽  
...  
Keyword(s):  
Cellular Response ◽  
Cycle Length ◽  
Cellular Responses ◽  
Rabbit Heart ◽  
Black Box ◽  
Av Node ◽  
Functional Studies ◽  
Microelectrode Recordings ◽  
Coupling Interval

The phenomenon of atrioventricular (AV) nodal “facilitation,” described in traditional “black box”-functional studies, implies enhanced AV nodal dromotropic function. We investigated the role of atrial prematurities in the modulation of the nodal cellular responses in the mechanism of AV nodal facilitation. Atrial and His (H) bundle electrograms and microelectrode recordings from proximal AV nodal cells were analyzed in 15 superfused rabbit AV node preparations. The pacing protocol consisted of 30 basic beats (S1; coupling interval S1-S1= 300 ms) followed by a facilitating prematurity (S2; coupling intervals S1-S2of 300, 200, 150, and 130 ms) followed by the test beat (S3; coupling interval S2-S3scanned in 5-ms steps). Conduction curves (S2-H2vs. S1-S2, S3-H3vs. S2-S3, and S3-H3vs. H2-S3) were constructed. Facilitation (i.e., shortening of S3-H3when S1-S2was shortened) was demonstrated in all preparations using the H2-S3( P < 0.001) but not the S2-S3format. Microelectrode recordings revealed a causal relationship between the improved proximal AV nodal cellular responses in facilitation and the prolonged S2-S3interval. There was no evidence for enhanced nodal dromotropic function directly resulting from the introduction of the facilitating beats. Thus facilitation is based on inherent cycle-length-dependent properties of the AV node during application of a complex pacing protocol and primarily reflects the uncontrolled modulation of the proximal cellular response.

Abstract 2647: Analysis of the Anatomical and Electrophysiological Characteristics of Tachycardia Circuit in Atrioventricular Nodal Reentrant Tachycardia Accompanied by the Block in the Upper Common Pathway

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Kenji Morihisa ◽  
Hiroshige Yamabe ◽  
Yasuaki Tanaka ◽  
Takashi Uemura ◽  
Hisao Ogawa
Keyword(s):  
Cycle Length ◽  
Slow Pathway ◽  
Atrioventricular Nodal Reentrant Tachycardia ◽  
Reentrant Tachycardia ◽  
Common Pathway ◽  
Coronary Sinus Ostium ◽  
Coupling Interval ◽  
Atrial Electrogram ◽  
Sinus Ostium ◽  
Fast Pathway

We examined the anatomical and electrophysiological characteristic of the atrioventricular nodal reentrant tachycardia (AVNRT) accompanied by the ventriculo-atrial block during tachycardia, suggesting the presence of upper common pathway in 8 patients. Tachycardia was induced by the atrial burst and/or extrastimulation followed by the AH jump and the earliest atrial electrogram was observed at the His bundle (HB) site in all patients. The HA block was observed after gradual prolongation of the HA interval in 2 patient and abruptly in 6 patients. After administration of isoproterenol, 1:1 HA conduction was resumed in all patients. The tachycardia cycle length, AeHe interval and HeAe interval were 357±89, 275±55 and 80±44 msec, respectively. Single extrastimulus delivered from the HB site reset the tachycardia as soon as it was delivered during late diastole. However, single extrastimulus delivered from the inferior portion of the coronary sinus ostium (I-CSOS) was unable to reset the tachycardia without capturing the earliest atrial electrogram at the HB site, suggesting that atrium is not involved in the circuit. Thus, the longest coupling interval of single extrastimulus that reset the tachycardia at the HB site was significantly longer than that at I-CSOS (347±89 msec vs. 324±109 msec, p=0.012). The following return cycle after extrastimulation at the HB site did not differ from the tachycardia cycle length (357±89 msec, vs. 357±89 msec, p=NS), however, that at I-CSOS was significantly longer than the tachycardia cycle length (398±85 msec, vs. 357±89 msec, p=0.012). Catheter ablation was performed in a stepwise fashion starting at the inferior CSOS. Although the results of single extrastimulation showed that the atrial myocardium at I-CSOS was out of the reentry circuit, ablation near the I-CSOS, distant from HB site, selectively eliminated slow pathway conduction in all patients without impairment of fast pathway conduction. Conclusions: The AVNRT with upper common pathway has the characteristic of relatively long HA interval during tachycardia. Sub-atrial tissue, but not the atrium, extending from the HB site to I-CSOS forms the upper common pathway in AVNRT. It was shown that upper common pathway has an anatomical structure of a certain range.

scholarly journals A CORRELATIONAL STUDY BETWEEN COUPLING INTERVAL RATIO AND SYMPTOMS IN PATIENTS WITH IDIOPATHIC VENTRICULAR PREMATURE COMPLEXES IN 24 HRS HOLTER MONITORING

2020 ◽  
pp. 1-4
Author(s):  
G. Dharmaraj ◽  
G. Ravishankar*
Keyword(s):  
Transthoracic Echocardiography ◽  
Cycle Length ◽  
Holter Monitoring ◽  
Age Group ◽  
Coupling Interval ◽  
Ventricular Premature Complexes ◽  
Sinus Cycle Length ◽  
Group A ◽  
Group B ◽  
Interval Ratio

Background and objective:Ventricular premature complexes (VPCs) are the most common arrhythmia encountered in cardiology OPD. Patients with frequent VPCs are often symptomatic. Our study aims to identify the ECG predictors of symptoms in patients with idiopathic VPCs in 24 hours Holter monitoring. Subjects and methods: This study was conducted on 102 patients with VPCs during the period of February 2019 to December 2019 in cardiology OPD of our centre.All the patients were screened with transthoracic echocardiography.24 hours Holter monitoring was done, the measured parameters were QRS width (Both in sinus beat & VPC), coupling interval (CI),CI ratio (CL/sinus cycle length) and VPC burden (Number and percentage of VPCs per day). Results:Both group had similar categorical age group and gender.ORS width of both sinus beat (P = 0.389) and VPCs (P = 0.035), VPC CI (P=0.487) and VPC burden (P = 0.458) did not correlate with symptoms but VPC CI ratio were significantly higher in Group B(symptomatic) than in group A (P = 0.004) Conclusion:There is a relationship between VPC related symptoms and VPC CI ratio.

Cycle Length Dynamics and Spatial Stability at the Onset of Postinfarction Monomorphic Ventricular Tachycardias Induced in Patients and Canine Preparations

Circulation ◽  
1996 ◽  
Vol 93 (10) ◽  
pp. 1845-1859 ◽  
Author(s):  
Alain Vinet ◽  
René Cardinal ◽  
Pierre LeFranc ◽  
François Hélie ◽  
Pierre Rocque ◽  
...  
Keyword(s):  
Cycle Length ◽  
Spatial Stability ◽  
Ventricular Tachycardias

Estimating Pedestrian Impact on Coordination of Urban Corridors

2019 ◽  
Vol 2673 (7) ◽  
pp. 265-280 ◽  
Author(s):  
Sharmin-E-Shams Chowdhury ◽  
Aleksandar Stevanovic ◽  
Nikola Mitrovic
Keyword(s):  
Cycle Length ◽  
Network Performance ◽  
Traffic Signals ◽  
High Fidelity ◽  
Vehicular Traffic ◽  
Traffic Demand ◽  
Advantages And Disadvantages ◽  
Street Traffic ◽  
Pedestrian Impact ◽  
Signal Operations

Pedestrian walk timings at most U.S. traffic signals are run in concurrence with relevant signal phases for vehicular traffic. This usually means that signal operations coordinated for the major street can be interrupted by a pedestrian call. Such an interruption may in practice last for a few minutes, thus causing increased delays and stops for major traffic flows. An alternative to this design is to increase the cycle length and embed pedestrian timings within the ring-barrier structure of the prevailing coordination plan. Both approaches have advantages and disadvantages. A fresh approach offered by this study is a comprehensive experimental design and holistic performance evaluation perspectives. The study examines the two abovementioned treatments of pedestrian timings for a small corridor of five intersections in Utah. The experiments have been done in a high-fidelity microsimulation environment with the Software-in-the-Loop version of the field controller (Econolite ASC/3). Findings show that either approach works well for very low traffic demands. When the traffic demand increases findings cannot be generalized as they differ for major coordinated movements versus overall network performance. While major-street traffic prefers no interruption of the coordinated operations, the overall network performance is better in the other case. This can be explained by the fact that avoiding interruptions is usually achieved at the expense of longer cycle length, which increases delay for everyone in the network.

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