scholarly journals Non-invasive Characterization of Human AV-Nodal Conduction Delay and Refractory Period During Atrial Fibrillation

2021 ◽  
Vol 12 ◽  
Author(s):  
Mattias Karlsson ◽  
Frida Sandberg ◽  
Sara R. Ulimoen ◽  
Mikael Wallman
Keyword(s):  
Atrial Fibrillation ◽  
Rate Control ◽  
Refractory Period ◽  
Conduction Delay ◽  
Parameter Estimates ◽  
Model Parameters ◽  
Av Node ◽  
Non Invasive ◽  
Fast Pathway

During atrial fibrillation (AF), the heart relies heavily on the atrio-ventricular (AV) node to regulate the heart rate. Thus, characterization of AV-nodal properties may provide valuable information for patient monitoring and prediction of rate control drug effects. In this work we present a network model consisting of the AV node, the bundle of His, and the Purkinje fibers, together with an associated workflow, for robust estimation of the model parameters from ECG. The model consists of two pathways, referred to as the slow and the fast pathway, interconnected at one end. Both pathways are composed of interacting nodes, with separate refractory periods and conduction delays determined by the stimulation history of each node. Together with this model, a fitness function based on the Poincaré plot accounting for dynamics in RR interval series and a problem specific genetic algorithm, are also presented. The robustness of the parameter estimates is evaluated using simulated data, based on clinical measurements from five AF patients. Results show that the proposed model and workflow could estimate the slow pathway parameters for the refractory period, RminSP and ΔRSP, with an error (mean ± std) of 10.3 ± 22 and −12.6 ± 26 ms, respectively, and the parameters for the conduction delay, Dmin,totSP and ΔDtotSP, with an error of 7 ± 35 and 4 ± 36 ms. Corresponding results for the fast pathway were 31.7 ± 65, −0.3 ± 77, 17 ± 29, and 43 ± 109 ms. These results suggest that both conduction delay and refractory period can be robustly estimated from non-invasive data with the proposed methodology. Furthermore, as an application example, the methodology was used to analyze ECG data from one patient at baseline and during treatment with Diltiazem, illustrating its potential to assess the effect of rate control drugs.

scholarly journals Characterization of Electrograms from Multipolar Diagnostic Catheters during Atrial Fibrillation

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Prasanth Ganesan ◽  
Elizabeth M. Cherry ◽  
Arkady M. Pertsov ◽  
Behnaz Ghoraani
Keyword(s):  
Atrial Fibrillation ◽  
Catheter Ablation ◽  
Simulation Study ◽  
Cycle Length ◽  
Human Subject ◽  
Conduction Delay ◽  
Ablation Procedure ◽  
Endocardial Surface ◽  
Diagnostic Catheter

Atrial fibrillation (AF) is the most common arrhythmia in USA with more than 2.3 million people affected annually. Catheter ablation procedure is a method for treatment of AF, which involves 3D electroanatomic mapping of the patient's left atrium (LA) by maneuvering a conventional multipolar diagnostic catheter (MPDC) along the LA endocardial surface after which pulmonary vein (PV) isolation is performed, thus eliminating the AF triggers originating from the PVs. However, it remains unclear how to effectively utilize the information provided by the MPDC to locate the AF-sustaining sites, known as sustained rotor-like activities (RotAs). In this study, we use computer modeling to investigate the variations in the characteristics of the MPDC electrograms, namely, total conduction delay (TCD) and average cycle length (CL), as the MPDC moves towards a RotA source. Subsequently, a study with a human subject was performed in order to verify the predictions of the simulation study. The conclusions from this study may be used to iteratively direct an MPDC towards RotA sources thus allowing the RotAs to be localized for customized and improved AF ablation.

Non-invasive assessment of the effect of beta blockers and calcium channel blockers on the AV node during permanent atrial fibrillation

2015 ◽  
Vol 48 (5) ◽  
pp. 861-866 ◽  
Author(s):  
Frida Sandberg ◽  
Valentina D.A. Corino ◽  
Luca T. Mainardi ◽  
Sara R. Ulimoen ◽  
Steve Enger ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Calcium Channel ◽  
Calcium Channel Blockers ◽  
Beta Blockers ◽  
Channel Blockers ◽  
Av Node ◽  
Non Invasive ◽  
Permanent Atrial Fibrillation

Diagnosis and management of arrhythmias associated with Wolff-Parkinson-White syndrome

1994 ◽  
Vol 14 (3) ◽  
pp. 30-39 ◽  
Author(s):  
MB Conover
Keyword(s):  
Atrial Fibrillation ◽  
Emergency Treatment ◽  
Accessory Pathway ◽  
P Wave ◽  
Av Node ◽  
Wpw Syndrome ◽  
Reentry Tachycardia ◽  
Fast Pathway ◽  
Wolff Parkinson White Syndrome

Because of the emergency nature of the arrhythmias associated with WPW syndrome, nurses are often called upon for diagnosis and intervention in critical settings. In such cases the nurse's understanding of mechanisms, ECG recognition, and emergency treatment guarantees the patient the best possible outcome, not only in the critical setting, but in the long term as well. The most common arrhythmias of WPW syndrome are PSVT and atrial fibrillation. In PSVT a differential diagnosis is made on the ECG between (1) CMT using the AV node anterogradely and an accessory pathway retrogradely and (2) AV nodal reentry tachycardia. Helpful clues are location of the P' wave, presence of QRS alternans, the initiating P'R interval, and presence of aberrancy. Atrial fibrillation with an accessory pathway has the morphology of VT but is differentiated because the rhythm is irregular and the rate is more than 200 beats per minute. Emergency treatment consists of blocking the accessory pathway with procainamide. Emergency treatment for both types of PSVT consists of breaking the reentry circuit at the AV node (eg, vagal maneuver, adenosine, or verapamil). Procainamide can also be used to block the retrograde fast pathway in the AV node and to terminate CMT by blocking the accessory pathway. Symptomatic patients with accessory pathways are referred for evaluation and possible radio-frequency ablation.

scholarly journals Functional mathematical model of dual pathway AV nodal conduction

2011 ◽  
Vol 300 (4) ◽  
pp. H1393-H1401 ◽  
Author(s):  
A. M. Climent ◽  
M. S. Guillem ◽  
Y. Zhang ◽  
J. Millet ◽  
T. N. Mazgalev
Keyword(s):  
Atrial Fibrillation ◽  
Mathematical Model ◽  
Refractory Period ◽  
Effective Refractory Period ◽  
Atrial Pacing ◽  
Wave Fronts ◽  
Av Node ◽  
Inferior Margin ◽  
His Bundle ◽  
Av Conduction

Dual atrioventricular (AV) nodal pathway physiology is described as two different wave fronts that propagate from the atria to the His bundle: one with a longer effective refractory period [fast pathway (FP)] and a second with a shorter effective refractory period [slow pathway (SP)]. By using His electrogram alternance, we have developed a mathematical model of AV conduction that incorporates dual AV nodal pathway physiology. Experiments were performed on five rabbit atrial-AV nodal preparations to develop and test the presented model. His electrogram alternances from the inferior margin of the His bundle were used to identify fast and slow wave front propagations. The ability to predict AV conduction time and the interaction between FP and SP wave fronts have been analyzed during regular and irregular atrial rhythms (e.g., atrial fibrillation). In addition, the role of dual AV nodal pathway wave fronts in the generation of Wenckebach periodicities has been illustrated. Finally, AV node ablative modifications have been evaluated. The model accurately reproduced interactions between FP and SP during regular and irregular atrial pacing protocols. In all experiments, specificity and sensitivity higher than 85% were obtained in the prediction of the pathway responsible for conduction. It has been shown that, during atrial fibrillation, the SP ablation significantly increased the mean HH interval (204 ± 39 vs. 274 ± 50 ms, P < 0.05), whereas FP ablation did not produce significant slowing of ventricular rate. The presented mathematical model can help in understanding some of the intriguing AV node mechanisms and should be considered as a step forward in the studies of AV nodal conduction.

scholarly journals Influence of Cheyne-Stokes respiration on ventricular response to atrial fibrillation in heart failure

2005 ◽  
Vol 99 (5) ◽  
pp. 1689-1696 ◽  
Author(s):  
Richard S. T. Leung ◽  
Michael E. Bowman ◽  
Tung M. Diep ◽  
Geraldo Lorenzi-Filho ◽  
John S. Floras ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Refractory Period ◽  
Low Frequency ◽  
Central Sleep Apnea ◽  
Power Spectral Analysis ◽  
Av Node ◽  
Respiratory Arrhythmia ◽  
High Frequencies ◽  
Power Spectral ◽  
Ventricular Response

In subjects with sinus rhythm, respiration has a profound effect on heart rate variability (HRV) at high frequencies (HF). Because this HF respiratory arrhythmia is lost in atrial fibrillation (AF), it has been assumed that respiration does not influence the ventricular response. However, previous investigations have not considered the possibility that respiration might influence HRV at lower frequencies. We hypothesized that Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) would entrain HRV at very low frequency (VLF) in AF by modulating atrioventricular (AV) nodal refractory period and concealed conduction. Power spectral analysis of R-wave-to-R-wave (R-R) intervals and respiration during sleep were performed in 13 subjects with AF and CSR-CSA. As anticipated, no modulation of HRV was detected at HF during regular breathing. In contrast, VLF HRV was entrained by CSR-CSA [coherence between respiration and HRV of 0.69 (SD 0.22) at VLF during CSR-CSA vs. 0.20 (SD 0.19) at HF during regular breathing, P < 0.001]. Comparison of R-R intervals during CSR-CSA demonstrated a shorter AV node refractory period during hyperpnea than apnea [minimum R-R of 684 (SD 126) vs. 735 ms (SD 147), P < 0.001] and a lesser degree of concealed conduction [scatter of 178 (SD 56) vs. 246 ms (SD 72), P = 0.001]. We conclude that CSR-CSA entrains the ventricular response to AF, even in the absence of HF respiratory arrhythmia, by inducing rhythmic oscillations in AV node refractoriness and the degree of concealed conduction that may be a function of autonomic modulation of the AV node.

scholarly journals Evaluation of the input site and characteristics of the antegrade fast pathway based on three-dimensional bi-atrial stimulus-ventricle mapping

2021 ◽  
Author(s):  
Kazuhisa Matsumoto ◽  
Takeshi Tobiume ◽  
Tomomi Matsuura ◽  
Takayuki Ise ◽  
Kenya Kusunose ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Three Dimensional ◽  
Right Atrial ◽  
Electroanatomical Mapping ◽  
Av Node ◽  
Mapping System ◽  
The Right ◽  
Electroanatomical Mapping System ◽  
Fast Pathway

Abstract Purpose Previous studies examined the right atrial (RA) input site of the antegrade fast pathway (AFp) (AFpI). However, the left atrial (LA) input to the atrioventricular (AV) node has not been extensively evaluated. In this study, we created three-dimensional (3-D) bi-atrial stimulus-ventricle (St-V) maps and analyzed the input site and characteristics of the AFp in both the RA and LA. Methods Forty-four patients diagnosed with atrial fibrillation or WPW syndrome were included in this study. Three-dimensional bi-atrial St-V mapping was performed using an electroanatomical mapping system. Sites exhibiting the minimal St-V interval (MinSt-V) were defined as AFpIs and were classified into seven segments, four in the RA (F, S, M, and I) and three in the LA (M1, M2, and M3). By combining the MinSt-V in the RA and LA, the AFpIs were classified into three types: RA, LA, and bi-atrial (BA) types. The clinical and electrophysiological characteristics were compared. Results AFpIs were most frequently observed at site S in the RA (34%) and M2 in the LA (50%), and the BA type was the most common (57%). AFpIs in the LA were recognized in 75% of the patients. There were no clinical or electrophysiological indicators for predicting AFpI sites. Conclusions Three-dimensional bi-atrial St-V maps could classify AFpIs in both the RA and LA. AFpIs in the LA were frequently recognized. There were no significant clinical or electrophysiological indicators for predicting AFpI sites, and 3-D bi-atrial St-V mapping was the only method to reveal the precise AFp input site.

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