Abstract 2200: Variability in Post-pacing Intervals Predicts Global Atrial Activation Pattern During Tachycardia

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Ilyas K Colombowala ◽  
Ali G Massumi ◽  
Abdi Rasekh ◽  
Mohammad Saeed ◽  
Jie Cheng ◽  
...  
Keyword(s):  
Cycle Length ◽  
Atrial Arrhythmia ◽  
Atrial Pacing ◽  
Activation Pattern ◽  
Activation Patterns ◽  
Cycle Lengths ◽  
Overdrive Pacing ◽  
Atrial Activation ◽  
The Difference ◽  
High Degree

Background: Knowledge of the global atrial activation pattern is critical to ablation of an atrial arrhythmia. We hypothesized that the variability in post-pacing intervals (PPI) with pacing at different cycle lengths (CL) from the same pacing site, regardless of distance to the circuit, can be used to identify atrial activation patterns during tachycardia. Methods and Results: Patients referred for ablation of SVT were included (n=28, 31 total tachycardias). During tachycardia, overdrive atrial pacing was performed. The variability in PPIs (PPIV) was calculated by comparing the difference in PPIs after overdrive pacing at trains 10, 20, and 30 ms shorter than the tachycardia cycle length (TCL). The global activation pattern was defined as circuitous (grossly visible circuit) or centrifugal (focal origin with centrifugal radiation) by electroanatomic mapping. Except for one case, all pacing was performed from the proximal CS bipole. Circuitous tachycardias exhibited minimal variability with pacing at 10 ms and 30 ms shorter than TCL (6.0±2.5 ms), whereas centrifugal tachycardias displayed a high degree of variability (56.5±20.6 ms, 8 of 14 were micro-reentrant). Rank sum analysis of PPIV suggests that the two groups are indeed distinct (P<0.001). Using PPIV cutoffs of ≤10 ms and ≥30 ms, circuitous and centrifugal activation patterns were classified with a high degree of sensitivity (94% circuitous, 92.8% centrifugal) and 100% specificity. Conclusion: Our data supports the use of PPIV to rapidly and accurately predict global activation pattern during atrial arrhythmia.

Effects of hypoxia on atrioventricular node of adult and neonatal rabbit hearts

1989 ◽  
Vol 256 (5) ◽  
pp. H1337-H1343 ◽  
Author(s):  
M. L. Young ◽  
R. C. Tan ◽  
B. M. Ramza ◽  
R. W. Joyner
Keyword(s):  
Cycle Length ◽  
Atrioventricular Node ◽  
The Other ◽  
Adult Rabbit ◽  
Atrial Pacing ◽  
Isolated Perfused Heart ◽  
Heart Model ◽  
Perfused Heart ◽  
Av Node ◽  
The Difference

We used an isolated perfused heart model to assess the effects of graded hypoxia (95, 45, 20, 10, or 0% O2, exposure for 5 min) on the adult and neonatal (0-3 days) rabbit atrioventricular (AV) node. The AV nodal function was assessed by measuring the A-H interval at a constant atrial pacing cycle length, the longest pacing cycle length resulting in Wenckebach periodicity [Wenckebach cycle length (WCL)] and the AV nodal effective refractory period (AVNERP). The A-H intervals remained stable in neonatal hearts until O2 saturation was decreased to 10%. On the other hand, the A-H intervals began to increase in adult rabbit hearts at 20% O2. In 95% O2, the AV nodal WCL was longer in adult hearts than in the neonatal hearts (165 +/- 8 ms vs. 142 +/- 7 ms). The effect of hypoxia on the AV nodal WCL was significantly greater in adult hearts than in neonatal hearts when the O2 saturation was decreased to 20% (a 54% increase in adults vs. a 14% increase in neonates, P = 0.02). The difference was greater at lower levels of O2. In 95% O2 at comparable basis driving cycle length (240 ms), the A-H intervals were equal in neonatal and adult hearts (43 +/- 3 vs. 43 +/- 7 ms), but the AVNERP of the neonates was significantly longer than that of the adults (133 +/- 21 vs. 97 +/- 19 ms, P = 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Superior-Type Fast-Slow Atrioventricular Nodal Reentrant Tachycardia Phenotype Mimicking the Slow-Fast Type

2020 ◽  
Vol 13 (11) ◽  
Author(s):  
Yoshiaki Kaneko ◽  
Tadashi Nakajima ◽  
Shuntaro Tamura ◽  
Hiroshi Hasegawa ◽  
Takashi Kobari ◽  
...  
Keyword(s):  
Cycle Length ◽  
Slow Pathway ◽  
Atrioventricular Nodal Reentrant Tachycardia ◽  
Reentrant Tachycardia ◽  
Common Pathway ◽  
His Bundle ◽  
Overdrive Pacing ◽  
Atrial Activation ◽  
The Right ◽  
Superior Type

Background: Superior-type fast-slow (sup-F/S-) atrioventricular nodal reentrant tachycardia (AVNRT) is a rare AVNRT variant using a superior slow pathway (SP) as the retrograde limb. Its intracardiac appearance, characterized by a short atrio-His (AH) interval and the earliest site of atrial activation in the His-bundle, is an initial indicator for making a diagnosis. Methods: Among 22 consecutive patients with sup-F/S-AVNRT, 3 (age, 68–81 years) patients had an apparent slow-fast (S/F-) AVNRT characterized by a long AH interval and the earliest site of atrial activation in or superior to the His-bundle region (tachy-long-AH). Results: The diagnosis of sup-F/S-AVNRT was based on the standard criteria in 2 patients and on the occurrence of Wenckebach-type atrioventricular block during tachycardia, which was attributable to a block at the lower common pathway (LCP) below the circuit of the AVNRT, detected owing to the lower common pathway potentials, in one patient. As with the typical S/F-AVNRT, tachy-long-AH was induced after a jump in the AH interval. In contrast to typical S/F-AVNRT, fluctuation in the ventriculoatrial interval was observed during the tachy-long-AH. Ventricular overdrive pacing was unable to entrain or terminate the tachy-long-AH. Moreover, the tachy-long-AH reciprocally transited to/from sup-F/S-AVNRT spontaneously or was triggered by ventricular contractions while the atrial cycle length and earliest site of atrial activation remained unchanged. Both tachycardias were cured by ablation at a single site in the right-side para-Hisian region of 2 patients and the noncoronary aortic cusp of one patient. Collectively, the essential circuit of both tachycardias was identical, and the tachy-long-AH was diagnosed as another phenotype of sup-F/S-AVNRT accompanied by sustained antegrade conduction via another bystander slow pathway breaking through the His-bundle owing to the repetitive antegrade block at the lower common pathway, thus representing a long AH interval during the ongoing sup-F/S-AVNRT. Conclusions: An unknown sup-F/S-AVNRT phenotype exists that apparently mimics the typical S/F-AVNRT and is also an unknown subtype of apparent S/F-AVNRT.

scholarly journals Conduction left-to-right and right-to-left across the crista terminalis

2001 ◽  
Vol 280 (4) ◽  
pp. H1683-H1691 ◽  
Author(s):  
Kunihiro Matsuo ◽  
Kikuya Uno ◽  
Celeen M. Khrestian ◽  
Albert L. Waldo
Keyword(s):  
Atrial Fibrillation ◽  
Inferior Vena ◽  
Conduction Block ◽  
Vena Cava ◽  
Atrial Pacing ◽  
Crista Terminalis ◽  
Cycle Lengths ◽  
Bachmann’S Bundle ◽  
Atrial Activation ◽  
The Right

A line of block between the vena cava and the crista terminalis (CT) region is important for atrial flutter (AFL), but whether it is fixed or functional is controversial. To test the hypothesis that conduction across the CT normally occurs, but when block occurs in this region it is functional, we analyzed atrial activation during right and left atrial pacing (cycle lengths of 500–130 ms), AFL, and atrial fibrillation in 15 dogs with sterile pericarditis and 7 normal dogs. Electrograms from 396 right, left, and septal atrial sites were simultaneously recorded. Activation across the CT occurred during atrial pacing, AFL, and atrial fibrillation. Activation wave fronts from the right to the left atrium and vice versa traveled over several routes, including Bachmann's bundle and inferior to the inferior vena cava, as well as across the CT. In these models, there is no fixed conduction block across the CT, and when block in the CT region occurs, as during AFL, it is functional.

Influence of cardiac denervation on subsidiary atrial pacemaker stabilization

1984 ◽  
Vol 247 (4) ◽  
pp. H523-H530
Author(s):  
J. A. Sterba ◽  
L. E. Rinkema ◽  
W. C. Randall ◽  
S. B. Jones ◽  
G. Brynjolfsson
Keyword(s):  
Heart Rate ◽  
Cycle Length ◽  
Atrial Pacing ◽  
Adrenergic Blockade ◽  
P Waves ◽  
Conscious Animal ◽  
Before And After ◽  
Cycle Lengths ◽  
Time Required ◽  
Short Time

Overdrive suppression was determined by measuring cardiac cycle lengths after rapid atrial pacing in nine alert conscious dogs sustaining total intrapericardial denervation. Rapid atrial pacing was performed at 125-400% of spontaneous heart rate for 30 s and at 200% spontaneous rate for 30, 60, 120, and 180 s, with and without cholinergic (atropine 0.2 mg/kg iv) or adrenergic blockade (propranolol 0.5 mg/kg iv). Corrected recovery time (CRT) was defined as the first recovery cycle length minus average control cycle length. To compare responses of the intact sinoatrial node (SAN) and subsidiary atrial pacemakers, CRT was measured in the conscious animal before and after SAN excision. Immediately after SAN excision, a junctional rhythm was frequently observed, but within a short time (min-h), subsidiary atrial pacemaker dominance was established with well-formed P waves and P-R interval averaging 85.3 +/- 3.4 ms. CRT before SAN excision ranged from 100 to 300 ms. Following pacing at 125-400% of spontaneous heart rate soon after SAN excision, CRT was markedly prolonged, ranging up to 6,000 ms. Atropine and propranolol did not influence CRT in the denervated preparation. CRT of subsidiary atrial pacemakers in the normally innervated dog heart returned to control pre-SAN excision values in 1-2 wk. In the denervated heart complete autonomic denervation exaggerated time required for return to control CRT values to 5-8 wk.

The Influence of Cycle Length on the Radionuclide Left Ventricular Volume Curve Acquired with a Scintillation Camera and ECG-Triggered Data Processor

1983 ◽  
Vol 22 (03) ◽  
pp. 145-148
Author(s):  
A. L. van Gelder ◽  
Irene Dormehl
Keyword(s):  
Cycle Length ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Scintillation Camera ◽  
Atrial Pacing ◽  
Ventricular Ejection Fraction ◽  
Volume Curve ◽  
Cycle Lengths ◽  
Data Processor

This study was designed to evaluate the effect of cycle length on the parameters of left ventricular function such as left ventricular ejection fraction (LVEF), ejection rates and ejection times. Radionuclide (in vivo 99mTc-labelled red blood cells) volume curves were obtained from ten chacma baboons. Transoesophageal atrial pacing of the baboon hearts was controlled by a microcomputer. A sequence of four beats was generated during arrhythmic pacing, consisting of two beats of equal cycle lengths, followed by a beat 15% shorter and a subsequent beat after a compensatory pause. Triggering impulses were sent to the data processor coincident with one of these beats until sufficient counts were obtained, before advancing to the next beat. Global LVEFs were found to be influenced by the preceding cycle length, increasing on a previous long cycle and decreasing on a previous short cycle and were even found to be influenced one normal beat on from the unrepresentative cycle. Similar trends were found for ejection times and rates. Discarding specific unrepresentative cycle lengths in order to correct for arrhythmia without attention to the previous cycle and even to the following cycle is therefore inappropriate.

Overdrive pacing of early ischemic ventricular tachycardia: evidence for both reentry and triggered activity

2005 ◽  
Vol 288 (3) ◽  
pp. H1124-H1130 ◽  
Author(s):  
David O. Arnar ◽  
Dezhi Xing ◽  
James B. Martins
Keyword(s):  
Ventricular Tachycardia ◽  
Cycle Length ◽  
Three Dimensional ◽  
Coronary Artery Occlusion ◽  
Canine Model ◽  
Artery Occlusion ◽  
Triggered Activity ◽  
Three Dimensional Mapping ◽  
Cycle Lengths ◽  
Overdrive Pacing

Entrainment can be a useful method to identify reentry as a mechanism of ventricular tachycardia (VT). In this study, we evaluated the effect of gradually decreasing cycle lengths of overdrive pacing for stable VT induced in a canine model 1–3 h after coronary occlusion. Intact dogs underwent anterior descending coronary artery occlusion after instrumentation of the risk zone with 21 multipolar plunge needles, each recording 6 bipolar electrograms. Overdrive pacing was attempted if the animals had sustained hemodynamically stable VT, looking for evidence of entrainment. Subsequent three-dimensional mapping determined the mechanism of VT. Fifteen of the 21 dogs studied demonstrated entrainment with overdrive pacing by progressive QRS fusion alone ( 1 ), the first nonpaced QRS entrained to the paced cycle length only ( 7 ), or both ( 7 ). Five of these 15 dogs also had postpacing acceleration of the VT at a subsequent faster pacing cycle length. The mechanism of acceleration in four was a change to a VT with a focal origin. The prepacing mechanism in all 15 dogs was subsequently mapped to reentry. Regarding the six VTs, which demonstrated no evidence for entrainment, the site of earliest activity was mapped to a focal origin in all. These data showing entrainment of inducible reentrant VTs and lack of such for focal VTs support that the focal VTs seen in this study are unlikely the result of microreentry but possibly a mechanism as triggered activity.

Atrial Overdrive Pacing for Conversion of Atrial Flutter in Children

PEDIATRICS ◽  
1985 ◽  
Vol 75 (4) ◽  
pp. 730-736
Author(s):  
Robert M. Campbell ◽  
Macdonald Dick ◽  
Janice M. Jenkins ◽  
Robert L. Spicer ◽  
Dennis C. Crowley ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Heart Rate ◽  
Atrial Flutter ◽  
Direct Current ◽  
Cycle Length ◽  
Right Atrial ◽  
Atrial Pacing ◽  
Direct Current Cardioversion ◽  
Overdrive Pacing ◽  
Mean Heart Rate

Twenty-three successive patients with 27 different episodes of sustained atrial flutter were treated with atrial pacing for conversion of the tachyarrhythmia; 15 patients with 16 episodes of atrial flutter underwent intracardiac right atrial pacing and eight patients with 11 episodes of atrial flutter were treated with transesophageal atrial pacing. Ten of sixteen episodes (63%) and eight of 11 episodes (73%) were successfully converted using intracardiac and transesophageal techniques, respectively. Mean flutter cycle length for all 27 episodes was 219 ms (mean heart rate 274 beats per minute); successful pacing conversion cycle length (n = 15) was 72% of the flutter cycle length. Hemodynamic, electrophysiologic, and roentgenographic data were not predictive of conversion by either technique. Induction of localized atrial fibrillation or failure to meet critical pacing criteria may explain pacing failures. Based on this experience, a trial of transesophageal atrial pacing for acute conversion of any episode of atrial flutter in children prior to direct current cardioversion is recommended.

scholarly journals The Neural Basis of Vivid Memory Is Patterned on Perception

2012 ◽  
Vol 24 (9) ◽  
pp. 1867-1883 ◽  
Author(s):  
Bradley R. Buchsbaum ◽  
Sabrina Lemire-Rodger ◽  
Candice Fang ◽  
Hervé Abdi
Keyword(s):  
Brain Activity ◽  
Sensory Perception ◽  
Direct Perception ◽  
Neural Basis ◽  
Activation Patterns ◽  
Short Video ◽  
Initial Perception ◽  
Experiential Quality ◽  
High Degree

When we have a rich and vivid memory for a past experience, it often feels like we are transported back in time to witness once again this event. Indeed, a perfect memory would exactly mimic the experiential quality of direct sensory perception. We used fMRI and multivoxel pattern analysis to map and quantify the similarity between patterns of activation evoked by direct perception of a diverse set of short video clips and the vivid remembering, with closed eyes, of these clips. We found that the patterns of distributed brain activation during vivid memory mimicked the patterns evoked during sensory perception. Using whole-brain patterns of activation evoked by perception of the videos, we were able to accurately classify brain patterns that were elicited when participants tried to vividly recall those same videos. A discriminant analysis of the activation patterns associated with each video revealed a high degree (explaining over 80% of the variance) of shared representational similarity between perception and memory. These results show that complex, multifeatured memory involves a partial reinstatement of the whole pattern of brain activity that is evoked during initial perception of the stimulus.

Impact of Turning Lane Storage Length and Turning Proportions on Throughput at Oversaturated Signalized Intersections

2021 ◽  
pp. 036119812110171
Author(s):  
A. M. Tahsin Emtenan ◽  
Christopher M. Day
Keyword(s):  
Flow Rate ◽  
Cycle Length ◽  
Signal Timing ◽  
Real World Data ◽  
Left Turn ◽  
Common Response ◽  
Cycle Lengths ◽  
Saturation Flow Rate ◽  
Saturation Flow ◽  
Timing Strategies

During oversaturated conditions, common objectives of signal timing are to maximize vehicle throughput and manage queues. A common response to increases in vehicle volumes is to increase the cycle length. Because the clearance intervals are displayed less frequently with longer cycle lengths and fewer cycles, more of the total time is used for green indications, which implies that the signal timing is more efficient. However, previous studies have shown that throughput reaches a peak at a moderate cycle length and extending the cycle length beyond this actually decreases the total throughput. Part of the reason for this is that spillback caused by the turning traffic may cause starvation of the through lanes resulting in a reduction of the saturation flow rate within each lane. Gaps created by the turning traffic after a lane change may also reduce the saturation flow rate. There is a relationship between the proportions of turning traffic, the storage length of turning lanes, and the total throughput that can be achieved on an approach for a given cycle length and green time. This study seeks to explore this relationship to yield better signal timing strategies for oversaturated operations. A microsimulation model of an oversaturated left-turn movement with varying storage lengths and turning proportions is used to determine these relationships and establish a mathematical model of throughput as a function of the duration of green, storage length, and turning proportion. The model outcomes are compared against real-world data.

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