The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
Melvin M Scheinman - One of the best experts on this subject based on the ideXlab platform.
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site specificity of transverse crista terminalis conduction in patients with atrial flutter
Pacing and Clinical Electrophysiology, 2005Co-Authors: Yanfei Yang, George M Wahba, Taylor Liu, Iqwal Mangat, Edmund C Keung, Philip C Ursell, Melvin M ScheinmanAbstract:Introduction: The causes of transcristal conduction (TC) in patients with atrial flutter (AFL) are unknown. Methods and Results: In two groups of patients referred for AFL ablation, 36 had cavotricuspid isthmus (CTI) dependent flutter (Group I) and 24 had lower (n = 21) or upper loop reentry (n = 5) (Group II). After ablation, isthmus block was evaluated by pacing from the coronary sinus (CS) and low lateral right atrium and by alternative techniques, including mapping with electrodes spanning the CTI or electroanatomic mapping. After bidirectional CTI block was verified, 21/36 (58%) in Group I showed TC with CS pacing, including low TC in 16 (including 11 showing “pseudo” CTI conduction), higher TC in 6 and multiple breaks in 3. However, 8 with low TC during CS pacing showed unidirectional block by pacing outside of the CS os. Twelve (50%) in Group II had TC during CS pacing after bidirectional CTI block, with low TC in 5 (2 mimicking residual CTI conduction) and higher breaks in 9. There was no significant difference in the incidence of TC during CS pacing after CTI block between groups. In seven autopsied hearts, the muscle orientation between the proximal CS musculature and Eustachian Ridge were examined. Muscular connections between the CS and Eustachian Ridge coursing toward the orifice of inferior vena cava were found in one of the hearts. Conclusions: It is concluded that in patients with bidirectional CTI block, pacing from the CS may be associated with TC mimicking a conduction leak through the isthmus. Pacing just outside the CS os helps distinguish pseudo from true isthmus block.
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electrophysiological response of the right atrium to ibutilide during typical atrial flutter
Circulation, 2002Co-Authors: Jie Cheng, Kathryn Glatter, Yanfei Yang, Shulong Zhang, Randall Lee, Melvin M ScheinmanAbstract:Background— The efficacy of ibutilide in conversion of atrial fibrillation and flutter (AFL) has been demonstrated. However, its electrophysiological effects on human atria have not been fully studied. Methods and Results— Twelve patients with typical AFL were studied. Electrograms were recorded from the anterolateral right atrium, His bundle position, and coronary sinus. During AFL, we measured the conduction time, CTi, through the isthmus between the tricuspid annulus and Eustachian Ridge and the conduction time, CTni, through the remainder of the right atrium. Resetting response curves and atrial effective refractory periods were determined with single extrastimuli delivered in the tricuspid annulus–Eustachian Ridge isthmus. After infusion of ibutilide (2 mg over 15 minutes), AFL cycle length (CL) increased from 260±30 to 295±39 ms (P<0.0003) because of an increase in either CTi, CTni, or both. Effective refractory periods increased from 149±16 to 208±26 ms (P<0.001). AFL CL variability increased, with...
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right atrial flutter due to lower loop reentry mechanism and anatomic substrates
Circulation, 1999Co-Authors: Jie Cheng, William R Cabeen, Melvin M ScheinmanAbstract:Background—The mechanisms of an atrial flutter (AFL) that is more rapid and at times more irregular than typical AFL are unknown. Methods and Results—Twenty-nine patients with AFL were studied. Atrial electrograms were recorded from a 20-pole catheter placed against the tricuspid annulus (TA), with its distal electrodes lateral to the isthmus between the TA and the Eustachian Ridge (ER), and from the His bundle and coronary sinus catheters. Atrial extrastimuli were delivered in the TA-ER isthmus during typical AFL. Episodes of a right atrial flutter rhythm that was different from typical AFL were induced in 3 patients and occurred spontaneously in 3 patients. This sustained AFL, designated as lower-loop reentry (LLR), involved the lower right atrium (RA), as manifested by early breakthrough in the lower RA, wave-front collision in the high lateral RA or septum, and conduction through the TA-ER isthmus. Linear ablation resulting in bidirectional conduction block in the TA-ER isthmus terminated spontaneous ...
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acceleration of typical atrial flutter due to double wave reentry induced by programmed electrical stimulation
Circulation, 1998Co-Authors: Jie Cheng, Melvin M ScheinmanAbstract:Background—Acceleration of reentrant tachycardia induced by programmed electrical stimulation is a well-documented phenomenon, but the mechanisms remain poorly understood. Methods and Results—Twelve patients with typical atrial flutter were studied. Activation sequence of the underlying reentrant circuit was recorded by multiple multipolar electrodes placed in the right atrium. In five patients, 27 episodes of atrial flutter acceleration were induced by single extrastimuli delivered in the isthmus between the tricuspid annulus and Eustachian Ridge (TA-ER isthmus) and one by rapid overdrive atrial pacing. Analyses of the activation sequences, intracardiac electrograms, and 12-lead surface ECG P-wave morphology indicated that the acceleration was caused by two successive activation wave fronts circulating in the same direction along the same reentrant circuit (double-wave reentry, DWR). DWR was induced only within a narrow range of coupling interval, from 2 to 45 ms beyond the effective refractory period, a...
Joel A Garcia - One of the best experts on this subject based on the ideXlab platform.
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on line multi slice computed tomography interactive overlay with conventional x ray a new and advanced imaging fusion concept
International Journal of Cardiology, 2009Co-Authors: Joel A Garcia, Shyam Bhakta, Joseph Kay, Kakchen Chan, Onno Wink, Daniel Ruijters, John D CarrollAbstract:Abstract Background Computed tomography (CT) has revolutionized noninvasive cardiovascular evaluations. Complicated percutaneous procedures require precise imaging guidance that conventional X-ray is often unable to provide. By combining X-ray imaging with real-time, interactive, CT-based landmarks, interventional procedures could be facilitated. We describe two cases using the first CT/Live X-ray overlay in which this technology shows its potential. Case reports A 31-year-old male with an anatomically complicated atrial septal defect (ASD) was referred for percutaneous closure. Transesophageal echocardiography (TEE) revealed an inferior location of the ASD complicated by it's proximity to a prominent Eustachian Ridge. The CT was used to create a patient-specific physical model in preparation for the procedure and an in-lab real-time CT overlay allowing successful closure. A second case of a 41-year-old male with coronary artery disease status-post coronary artery bypass, aortic valve replacement (AVR), and aortic root replacement with an abnormal coronary computed tomography angiogram (CTA). In a prior procedure years ago the saphenous vein graft (SVG) to the left anterior descending artery (LAD) could not be cannulated during invasive angiography, given the patient's complicated and unusual anatomy. Using CT overlay, the superiorly and anteriorly located SVG was cannulated successfully. Discussion CT/Live X-ray overlay provided an adequate anatomical intra-procedural ASD evaluation, defect sizing, and guidance in one case and localization of an anatomically challenging graft ostium in the other case. Adding the CT landmarks as an overlay to traditional X-ray techniques provides a revolutionary and advanced imaging fusion concept that should improve procedural success.
Michael D Lesh - One of the best experts on this subject based on the ideXlab platform.
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classification of atrial flutter and regular atrial tachycardia according to electrophysiologic mechanism and anatomic bases a statement from a joint expert group from the working group of arrhythmias of the european society of cardiology and the north american society of pacing and electrophysiology
Journal of Cardiovascular Electrophysiology, 2001Co-Authors: M Nadir D Saoudi, Michael D Lesh, M Francisco D Cosio, M Albert D Waldo, M Shihann D Chen, M Yoshito D Iesaka, M Sanjeev D Saksena, M Jorge D Salerno, M Wolfgang D SchoelsAbstract:Regular atrial tachycardias classically are classified into flutter or tachycardia, depending on the rate and presence of a stable baseline on the ECG. However, current understanding of electrophysiology atrial tachycardias makes this classification obsolete, because it does not correlate with mechanisms. The proposed classification is based on electrophysiologic mechanisms, defined by mapping and entrainment. Radiofrequency ablation of a critical focus or isthmus can afford proof. Focal tachycardias are characterized by radial spread of activation and endocardial activation not covering the whole cycle. Ablation of the focus of origin interrupts the tachycardia. The mechanism of focal firing is difficult to ascertain by clinical methods. Macroreentrant tachycardias are characterized by circular patterns of activation that cover the whole cycle. Fusion can be shown during entrainment on the ECG or by multiple endocardial recordings. Ablation of a critical isthmus interrupts the tachycardia. Macroreentry can occur around normal structures (terminal crest, Eustachian Ridge) or around atrial lesions. The anatomic bases of these tachycardias must be defined, to guide appropriate treatment. Atrial flutter is a mere description of continuous undulation on the ECG, and only some strictly defined typical flutter patterns correlate with right atrial macroreentry bounded by the tricuspid valve, terminal crest, and caval vein orifices. This classification should be considered open, as some classically described tachycardias, such as reentrant sinus tachycardia, inappropriate sinus tachycardia, and type II atrial flutter, cannot be classified accurately. Furthermore, the possibility of fibrillatory conduction makes the limits with atrial fibrillation still ill defined.
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classification of atrial flutter and regular atrial tachycardia according to electrophysiologic mechanism and anatomic bases a statement from a joint expert group from the working group of arrhythmias of the european society of cardiology and the north american society of pacing and electrophysiology
Journal of Cardiovascular Electrophysiology, 2001Co-Authors: M Nadir D Saoudi, Michael D Lesh, M Francisco D Cosio, M Albert D Waldo, M Shihann D Chen, M Yoshito D Iesaka, M Sanjeev D Saksena, M Jorge D Salerno, M Wolfgang D SchoelsAbstract:New Classification of Atrial Tachycardia. Regular atrial tachycardias classically are classified into flutter or tachycardia, depending on the rate and presence of a stable baseline on the ECG. However, current understanding of electrophysiology atrial tachycardias makes this classification obsolete, because it does not correlate with mechanisms. The proposed classification is based on electrophysiologic mechanisms, defined by mapping and entrainment. Radiofrequency ablation of a critical focus or isthmus can afford proof. Focal tachycardias are characterized by radial spread of activation and endocardial activation not covering the whole cycle. Ablation of the focus of origin interrupts the tachycardia. The mechanism of focal firing is difficult to ascertain by clinical methods. Macroreentrant tachycardias are characterized by circular patterns of activation that cover the whole cycle. Fusion can be shown during entrainment on the ECG or by multiple endocardial recordings. Ablation of a critical isthmus interrupts the tachycardia. Macroreentry can occur around normal structures (terminal crest, Eustachian Ridge) or around atrial lesions. The anatomic bases of these tachycardias must be defined, to guide appropriate treatment. Atrial flutter is a mere description of continuous undulation on the ECG, and only some strictly defined typical flutter patterns correlate with right atrial macroreentry bounded by the tricuspid valve, terminal crest, and caval vein orifices. This classification should be considered open, as some classically described tachycardias, such as reentrant sinus tachycardia, inappropriate sinus tachycardia, and type II atrial flutter, cannot be classified accurately. Furthermore, the possibility of fibrillatory conduction makes the limits with atrial fibrillation still ill defined.
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atypical right atrial flutter patterns
Circulation, 2001Co-Authors: Yanfei Yang, Leslie A Saxon, Michael D Lesh, Jie Cheng, Andy Bochoeyer, Mohamed H Hamdan, Robert C Kowal, Richard L Page, Paul R Steiner, Gunnard ModinAbstract:Background—The purpose of our study was to define the incidence and mechanisms of atypical right atrial flutter. Methods and Results—A total of 28 (8%) of 372 consecutive patients with atrial flutter (AFL) had 36 episodes of sustained atypical right AFL. Among 24 (67%) of 36 episodes of lower loop reentry (LLR), 13 (54%) of 24 episodes had early breakthrough at the lower lateral tricuspid annulus, whereas 11 (46%) of 24 episodes had early breakthrough at the high lateral tricuspid annulus, and 9 (38%) of 24 episodes showed multiple annular breaks. Bidirectional isthmus block resulted in elimination of LLR. A pattern of posterior breakthrough from the Eustachian Ridge to the septum was observed in 4 (14%) of 28 patients. Upper loop reentry was observed in 8 (22%) of 36 episodes and was defined as showing a clockwise orientation with early annular break and wave-front collision over the isthmus. Two patients had atypical right AFL around low voltage areas (“scars”) in the posterolateral right atrium. Conclu...
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activation and entrainment mapping defines the tricuspid annulus as the anterior barrier in typical atrial flutter
Circulation, 1996Co-Authors: Jonathan M Kalman, Jeffrey E Olgin, Leslie A Saxon, Westby G Fisher, Michael D LeshAbstract:Background The importance of anatomic barriers in the atrial flutter reentry circuit has been well demonstrated in canine models. It has been shown previously that the crista terminalis and its continuation as the Eustachian Ridge form a posterior barrier. In this study we tested the hypothesis that the tricuspid annulus forms the continuous anterior barrier to the flutter circuit. Methods and Results Thirteen patients with typical atrial flutter were studied. A 20-pole halo catheter was situated around the tricuspid annulus. A mapping catheter was used for activation and entrainment mapping from seven sequential sites around the tricuspid annulus and from three additional sites including the tip of the right atrial appendage, at the fossa ovalis, and in the distal coronary sinus. Sites were considered to be within the circuit when the postpacing interval minus the flutter cycle length and the stimulus time minus the activation time were ≤10 ms; sites were considered to be outside the circuit when these i...
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role of right atrial endocardial structures as barriers to conduction during human type i atrial flutter activation and entrainment mapping guided by intracardiac echocardiography
Circulation, 1995Co-Authors: Jeffrey E Olgin, Jonathan M Kalman, Adam P Fitzpatrick, Michael D LeshAbstract:Background The importance of barriers in atrial flutter has been demonstrated in animals. We used activation and entrainment mapping, guided by intracardiac echocardiography (ICE), to determine whether the crista terminalis (CT) and Eustachian Ridge (ER) are barriers to conduction during typical atrial flutter in humans. Methods and Results In eight patients, ICE was used to guide the placement of 20-pole and octapolar catheters along the CT and interatrial septum and a roving catheter to nine sites: just posterior (1) and anterior (2) to the CT along the lateral right atrium, at the fossa ovalis (3), and just posterior and anterior to the ER at the low posterolateral (4 and 5), low posterior (6 and 7), and low posteromedial (8 and 9) right atrium. Entrainment was performed, and each site was considered within the flutter circuit if the postpacing interval–flutter cycle length (PPI−FCL) and the stimulus time–activation time (stim time−act time) were <10 msec. Split potentials were recorded along the CT wi...
John D Carroll - One of the best experts on this subject based on the ideXlab platform.
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on line multi slice computed tomography interactive overlay with conventional x ray a new and advanced imaging fusion concept
International Journal of Cardiology, 2009Co-Authors: Joel A Garcia, Shyam Bhakta, Joseph Kay, Kakchen Chan, Onno Wink, Daniel Ruijters, John D CarrollAbstract:Abstract Background Computed tomography (CT) has revolutionized noninvasive cardiovascular evaluations. Complicated percutaneous procedures require precise imaging guidance that conventional X-ray is often unable to provide. By combining X-ray imaging with real-time, interactive, CT-based landmarks, interventional procedures could be facilitated. We describe two cases using the first CT/Live X-ray overlay in which this technology shows its potential. Case reports A 31-year-old male with an anatomically complicated atrial septal defect (ASD) was referred for percutaneous closure. Transesophageal echocardiography (TEE) revealed an inferior location of the ASD complicated by it's proximity to a prominent Eustachian Ridge. The CT was used to create a patient-specific physical model in preparation for the procedure and an in-lab real-time CT overlay allowing successful closure. A second case of a 41-year-old male with coronary artery disease status-post coronary artery bypass, aortic valve replacement (AVR), and aortic root replacement with an abnormal coronary computed tomography angiogram (CTA). In a prior procedure years ago the saphenous vein graft (SVG) to the left anterior descending artery (LAD) could not be cannulated during invasive angiography, given the patient's complicated and unusual anatomy. Using CT overlay, the superiorly and anteriorly located SVG was cannulated successfully. Discussion CT/Live X-ray overlay provided an adequate anatomical intra-procedural ASD evaluation, defect sizing, and guidance in one case and localization of an anatomically challenging graft ostium in the other case. Adding the CT landmarks as an overlay to traditional X-ray techniques provides a revolutionary and advanced imaging fusion concept that should improve procedural success.
Jie Cheng - One of the best experts on this subject based on the ideXlab platform.
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electrophysiological response of the right atrium to ibutilide during typical atrial flutter
Circulation, 2002Co-Authors: Jie Cheng, Kathryn Glatter, Yanfei Yang, Shulong Zhang, Randall Lee, Melvin M ScheinmanAbstract:Background— The efficacy of ibutilide in conversion of atrial fibrillation and flutter (AFL) has been demonstrated. However, its electrophysiological effects on human atria have not been fully studied. Methods and Results— Twelve patients with typical AFL were studied. Electrograms were recorded from the anterolateral right atrium, His bundle position, and coronary sinus. During AFL, we measured the conduction time, CTi, through the isthmus between the tricuspid annulus and Eustachian Ridge and the conduction time, CTni, through the remainder of the right atrium. Resetting response curves and atrial effective refractory periods were determined with single extrastimuli delivered in the tricuspid annulus–Eustachian Ridge isthmus. After infusion of ibutilide (2 mg over 15 minutes), AFL cycle length (CL) increased from 260±30 to 295±39 ms (P<0.0003) because of an increase in either CTi, CTni, or both. Effective refractory periods increased from 149±16 to 208±26 ms (P<0.001). AFL CL variability increased, with...
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atypical right atrial flutter patterns
Circulation, 2001Co-Authors: Yanfei Yang, Leslie A Saxon, Michael D Lesh, Jie Cheng, Andy Bochoeyer, Mohamed H Hamdan, Robert C Kowal, Richard L Page, Paul R Steiner, Gunnard ModinAbstract:Background—The purpose of our study was to define the incidence and mechanisms of atypical right atrial flutter. Methods and Results—A total of 28 (8%) of 372 consecutive patients with atrial flutter (AFL) had 36 episodes of sustained atypical right AFL. Among 24 (67%) of 36 episodes of lower loop reentry (LLR), 13 (54%) of 24 episodes had early breakthrough at the lower lateral tricuspid annulus, whereas 11 (46%) of 24 episodes had early breakthrough at the high lateral tricuspid annulus, and 9 (38%) of 24 episodes showed multiple annular breaks. Bidirectional isthmus block resulted in elimination of LLR. A pattern of posterior breakthrough from the Eustachian Ridge to the septum was observed in 4 (14%) of 28 patients. Upper loop reentry was observed in 8 (22%) of 36 episodes and was defined as showing a clockwise orientation with early annular break and wave-front collision over the isthmus. Two patients had atypical right AFL around low voltage areas (“scars”) in the posterolateral right atrium. Conclu...
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right atrial flutter due to lower loop reentry mechanism and anatomic substrates
Circulation, 1999Co-Authors: Jie Cheng, William R Cabeen, Melvin M ScheinmanAbstract:Background—The mechanisms of an atrial flutter (AFL) that is more rapid and at times more irregular than typical AFL are unknown. Methods and Results—Twenty-nine patients with AFL were studied. Atrial electrograms were recorded from a 20-pole catheter placed against the tricuspid annulus (TA), with its distal electrodes lateral to the isthmus between the TA and the Eustachian Ridge (ER), and from the His bundle and coronary sinus catheters. Atrial extrastimuli were delivered in the TA-ER isthmus during typical AFL. Episodes of a right atrial flutter rhythm that was different from typical AFL were induced in 3 patients and occurred spontaneously in 3 patients. This sustained AFL, designated as lower-loop reentry (LLR), involved the lower right atrium (RA), as manifested by early breakthrough in the lower RA, wave-front collision in the high lateral RA or septum, and conduction through the TA-ER isthmus. Linear ablation resulting in bidirectional conduction block in the TA-ER isthmus terminated spontaneous ...
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acceleration of typical atrial flutter due to double wave reentry induced by programmed electrical stimulation
Circulation, 1998Co-Authors: Jie Cheng, Melvin M ScheinmanAbstract:Background—Acceleration of reentrant tachycardia induced by programmed electrical stimulation is a well-documented phenomenon, but the mechanisms remain poorly understood. Methods and Results—Twelve patients with typical atrial flutter were studied. Activation sequence of the underlying reentrant circuit was recorded by multiple multipolar electrodes placed in the right atrium. In five patients, 27 episodes of atrial flutter acceleration were induced by single extrastimuli delivered in the isthmus between the tricuspid annulus and Eustachian Ridge (TA-ER isthmus) and one by rapid overdrive atrial pacing. Analyses of the activation sequences, intracardiac electrograms, and 12-lead surface ECG P-wave morphology indicated that the acceleration was caused by two successive activation wave fronts circulating in the same direction along the same reentrant circuit (double-wave reentry, DWR). DWR was induced only within a narrow range of coupling interval, from 2 to 45 ms beyond the effective refractory period, a...
