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1.
Artigo em Inglês | MEDLINE | ID: mdl-32298038

RESUMO

INTRODUCTION: In patients with nonischemic cardiomyopathy (NICM) little is known about the clinical impact of catheter ablation (CA) of septal ventricular tachycardia (VT) resulting in the collateral injury of the conduction system (CICS). METHODS AND RESULTS: Ninety-five consecutive patients with NICM underwent CA of septal VT. Outcomes in patients with no baseline conduction abnormalities who developed CICS (group 1, n = 28 [29%]) were compared to patients with no CICS (group 2, n = 17 [18%]) and to patients with preexisting conduction abnormalities or biventricular pacing (group 3, n = 50 [53%]). Group-1 patients were younger, had a higher left ventricular ejection fraction and a lower prevalence of New York Heart Association III/IV class compared to group 3 while no significant differences were observed with group 2. After a median follow-up of 15 months, VT recurred in 14% of patients in group 1, 12% in group 2 (P = .94) and 32% in group 3 (P = .08) while death/transplant occurred in 14% of patients in group 1, 18% in group 2 (P = .69) and 28% in group 3 (P = .15). A worsening of left ventricular ejection fraction (LVEF) (median LVEF variation, -5%) was observed in group 1 compared to group 2 (median LVEF variation, 0%; P < .01) but not group-3 patients (median LVEF variation, -4%; P = .08) with a consequent higher need for new biventricular pacing in group 1 (43%) compared to group 2 (12%; P = .03) and group 3 (16%; P < .01). CONCLUSIONS: In patients with NICM and septal substrate, sparing the abnormal substrate harboring the conduction system provides acceptable VT control while preventing a worsening of the systolic function.

5.
Sci Rep ; 9(1): 9317, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31249352

RESUMO

Geometrical structure of the myocardium plays an important role in understanding the generation of arrhythmias. In particular, a heterogeneous tissue (HT) channel defined in cardiovascular magnetic resonance (CMR) has been suggested to correlate with conduction channels defined in electroanatomic mapping in ventricular tachycardia (VT). Despite the potential of CMR for characterization of the arrhythmogenic substrate, there is currently no standard approach to identify potential conduction channels. Therefore, we sought to develop a workflow to identify HT channel based on the structural 3D modeling of the viable myocardium within areas of dense scar. We focus on macro-level HT channel detection in this work. The proposed technique was tested in high-resolution ex-vivo CMR images in 20 post-infarct swine models who underwent an electrophysiology study for VT inducibility. HT channel was detected in 15 animals with inducible VT, whereas it was only detected in 1 out of 5 animal with non-inducible VT (P < 0.01, Fisher's exact test). The HT channel detected in the non-inducible animal was shorter than those detected in animals with inducible VTs (inducible-VT animals: 35 ± 14 mm vs. non-inducible VT animal: 9.94 mm). Electrophysiology study and histopathological analyses validated the detected HT channels. The proposed technique may provide new insights for understanding the macro-level VT mechanism.

6.
J Cardiovasc Electrophysiol ; 30(6): 865-876, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30834593

RESUMO

INTRODUCTION: Nonpulmonary vein (non-PV) triggers of atrial fibrillation (AF) are targets for ablation but their localization remains challenging. The aim of this study was to describe P-wave (PW) morphologic characteristics and intra-atrial activation patterns and timing from multipolar coronary sinus (CS) and crista terminalis (CT) catheters that localize non-PV triggers. METHODS AND RESULTS: Selective pacing from six right and nine left atrial common non-PV trigger sites was performed in 30 consecutive patients. We analyzed 12 lead ECG features based on PW duration, amplitude and morphology, and patterns and timing of multipolar activation for all 15 sites. Regionalization and then precise localization required criteria present in at least 70% of assessments at each pacing site. The algorithm was then prospectively evaluated by four blinded observers in a validation cohort of 18 consecutive patients undergoing the same pacing protocol and 60 consecutive patients who underwent successful non-PV trigger ablation. The algorithm for site regionalization included 1) negative PW in V1, ≥30 µV change in PW amplitude across the leads V1-V3, and PW duration ≤100 milliseconds in lead 2 and 2) unique intra-atrial activation patterns and timing noted in the multipolar catheters. Specific ECG and intra-atrial activation timing characteristics included in the algorithm allowed for more precise site localization after regionalization. In the prospective evaluation, the algorithm identified the site of origin for 72% of paced and 70% of spontaneous non-PV trigger sites. CONCLUSION: An algorithm based on PW morphology and intra-atrial multipolar activation pattern and timing can help identify non-PV trigger sites of origin.

7.
J Cardiovasc Electrophysiol ; 30(3): 427-437, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30614100

RESUMO

Epicardial ablation may be required to eliminate ventricular tachycardia (VT) in patients with underlying structural heart disease. The decision to gain epicardial access is frequently based on the suspicion of an epicardial origin for the VT and/or presence of an arrhythmogenic substrate. Epicardial pathology and VT is frequently present in patients with nonischemic right and/or left cardiomyopathies even in the setting of modest or no endocardial bipolar voltage substrate. In this setting, unipolar voltage mapping from the endocardium serves to help identify midmyocardial and/or epicardial VT substrate. The additional value of endocardial unipolar mapping includes its usefulness to predict the clinical outcome after VT ablation, to determine the irreversibility of myocardial disease, and to guide endomyocardial biopsy procedures to specific areas of intramural scarring. In this review, we aim to provide a guide to the use of endocardial unipolar mapping and its appropriate interpretation in a variety of clinical situations.

9.
PLoS One ; 13(10): e0205188, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30296291

RESUMO

Visualization of the complex 3D architecture of myocardial scar could improve guidance of radio-frequency ablation in the treatment of ventricular tachycardia (VT). In this study, we sought to develop a framework for 3D holographic visualization of myocardial scar, imaged using late gadolinium enhancement (LGE), on the augmented reality HoloLens. 3D holographic LGE model was built using the high-resolution 3D LGE image. Smooth endo/epicardial surface meshes were generated using Poisson surface reconstruction. For voxel-wise 3D scar model, every scarred voxel was rendered into a cube which carries the actual resolution of the LGE sequence. For surface scar model, scar information was projected on the endocardial surface mesh. Rendered layers were blended with different transparency and color, and visualized on HoloLens. A pilot animal study was performed where 3D holographic visualization of the scar was performed in 5 swines who underwent controlled infarction and electroanatomic mapping to identify VT substrate. 3D holographic visualization enabled assessment of the complex 3D scar architecture with touchless interaction in a sterile environment. Endoscopic view allowed visualization of scar from the ventricular chambers. Upon completion of the animal study, operator and mapping specialist independently completed the perceived usefulness questionnaire in the six-item usefulness scale. Operator and mapping specialist found it useful (usefulness rating: operator, 5.8; mapping specialist, 5.5; 1-7 scale) to have scar information during the intervention. HoloLens 3D LGE provides a true 3D perception of the complex scar architecture with immersive experience to visualize scar in an interactive and interpretable 3D approach, which may facilitate MR-guided VT ablation.


Assuntos
Ablação por Cateter/métodos , Cicatriz/diagnóstico por imagem , Holografia/métodos , Infarto do Miocárdio/complicações , Taquicardia Ventricular/cirurgia , Animais , Cicatriz/etiologia , Cicatriz/cirurgia , Meios de Contraste/administração & dosagem , Modelos Animais de Doenças , Endoscopia/métodos , Mapeamento Epicárdico , Estudos de Viabilidade , Gadolínio/administração & dosagem , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/patologia , Ventrículos do Coração/cirurgia , Humanos , Imagem por Ressonância Magnética/métodos , Projetos Piloto , Suínos , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/patologia
10.
JACC Clin Electrophysiol ; 4(4): 467-479, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-30067486

RESUMO

OBJECTIVES: This study sought to examine the biophysical properties of high-power and short-duration (HP-SD) radiofrequency ablation for pulmonary vein isolation. BACKGROUND: Pulmonary vein isolation is the cornerstone of atrial fibrillation ablation. However, pulmonary vein reconnection is frequent and is often the result of catheter instability, tissue edema, and a reversible nontransmural injury. We postulated that HP-SD ablation increases lesion-to-lesion uniformity and transmurality. METHODS: This study included 20 swine and a novel open-irrigated ablation catheter with a thermocouple system able to record temperature at the catheter-tissue interface (QDOT Micro Catheter). Step 1 compared 3 HP-SD ablation settings: 90 W/4 s, 90 W/6 s, and 70 W/8 s in a thigh muscle preparation. Ablation at 90 W/4 s was identified as the best compromise between lesion size and safety parameters, with no steam-pop or char. In step 2, a total of 174 single ablation applications were performed in the beating heart and resulted in 3 (1.7%) steam-pops, all occurring at catheter-tissue interface temperature ≥85°C. Additional 233 applications at 90 W/4 s and temperature limit of 65°C were applied without steam-pop. Step 3 compared the presence of gaps and lesion transmurality in atrial lines and pulmonary vein isolation between HP-SD (90 W/4 s, T ≤65°C) and standard (25 W/20 s) ablation. RESULTS: HP-SD ablation resulted in 100% contiguous lines with all transmural lesions, whereas standard ablation had linear gaps in 25% and partial thickness lesions in 29%. Ablation with HP-SD produced wider lesions (6.02 ± 0.2 mm vs. 4.43 ± 1.0 mm; p = 0.003) at similar depth (3.58 ± 0.3 mm vs. 3.53 ± 0.6 mm; p = 0.81) and improved lesion-to-lesion uniformity with comparable safety end points. CONCLUSIONS: In a preclinical model, HP-SD ablation (90 W/4 s, T ≤65°C) produced an improved lesion-to-lesion uniformity, linear contiguity, and transmurality at a similar safety profile of conventional ablation.


Assuntos
Ablação por Cateter/instrumentação , Ablação por Cateter/métodos , Veias Pulmonares/cirurgia , Animais , Desenho de Equipamento , Átrios do Coração/efeitos da radiação , Humanos , Segurança do Paciente , Suínos , Temperatura
11.
Nat Nanotechnol ; 13(11): 1048-1056, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30104619

RESUMO

Wearable and implantable devices require conductive, stretchable and biocompatible materials. However, obtaining composites that simultaneously fulfil these requirements is challenging due to a trade-off between conductivity and stretchability. Here, we report on Ag-Au nanocomposites composed of ultralong gold-coated silver nanowires in an elastomeric block-copolymer matrix. Owing to the high aspect ratio and percolation network of the Ag-Au nanowires, the nanocomposites exhibit an optimized conductivity of 41,850 S cm-1 (maximum of 72,600 S cm-1). Phase separation in the Ag-Au nanocomposite during the solvent-drying process generates a microstructure that yields an optimized stretchability of 266% (maximum of 840%). The thick gold sheath deposited on the silver nanowire surface prevents oxidation and silver ion leaching, making the composite biocompatible and highly conductive. Using the nanocomposite, we successfully fabricate wearable and implantable soft bioelectronic devices that can be conformally integrated with human skin and swine heart for continuous electrophysiological recording, and electrical and thermal stimulation.

12.
JACC Clin Electrophysiol ; 4(8): 1033-1048, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30139485

RESUMO

OBJECTIVES: In this study, the scientific objective was to characterize the electrophysiological substrate of the ventricular tachycardia (VT) isthmus during sinus rhythm. BACKGROUND: The authors have recently described the electrophysiological characteristics of the VT isthmus using a novel in vivo high-resolution mapping technology. METHODS: Sixteen swine with healed infarction were studied using high-resolution mapping technology (Rhythmia, Boston Scientific, Cambridge, Massachusetts) in a closed-chest model. The left ventricle was mapped during sinus rhythm and analyzed for activation, conduction velocity, electrogram shape, and amplitude. Twenty-four VTs allowed detailed mapping of the common-channel "isthmus," including the "critical zone." This was defined as the zone of maximal conduction velocity slowing in the circuit, often occurring at entrance and exit from the isthmus caused by rapid angular change in activation vectors. RESULTS: The VT isthmus corresponded to sites displaying steep activation gradient (SAG) during sinus rhythm with conduction velocity slowing of 58.5 ± 22.4% (positive predictive value [PPV] 60%). The VT critical zone displayed SAG with greater conduction velocity slowing of 68.6 ± 18.2% (PPV 70%). Critical-zone sites were consistently localized in areas with bipolar voltage ≤0.55 mV, whereas isthmus sites were localized in areas with variable voltage amplitude (1.05 ± 0.80 mV [0.03 to 2.88 mV]). Importantly, critical zones served as common-site "anchors" for multiple VT configurations and cycle lengths. Isthmus and critical-zone sites occupied only 18.0 ± 7.0% of the low-voltage area (≤1.50 mV). Isolated late potentials were present in both isthmus and nonisthmus sites, including dead-end pathways (PPV 36%; 95% confidence interval: 34.2% to 39.6%). CONCLUSIONS: The VT critical zone corresponds to a location characterized by SAG and very low voltage amplitude during sinus rhythm. Thus, it allows identification of a re-entry anchor with high sensitivity and specificity. By contrast, voltage and electrogram characteristics during sinus rhythm have limited specificity for identifying the VT isthmus.


Assuntos
Infarto do Miocárdio , Taquicardia Ventricular , Animais , Ablação por Cateter , Técnicas Eletrofisiológicas Cardíacas , Sistema de Condução Cardíaco/fisiopatologia , Masculino , Infarto do Miocárdio/complicações , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/fisiopatologia , Suínos , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/fisiopatologia
13.
Circ Arrhythm Electrophysiol ; 11(3): e005553, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29545358

RESUMO

BACKGROUND: Repolarization abnormalities in arrhythmogenic right ventricular (RV) cardiomyopathy and their relationship to ventricular tachycardia substrate are incompletely understood. METHODS AND RESULTS: In 40 patients (29 men, mean age 38 years) with arrhythmogenic RV cardiomyopathy, we compared the extent and location of abnormal T (NegT) waves ≥1 mm in depth (n=32) and downsloping elevated ST segment (n=13), in ≥2 adjacent leads, to area and location of endocardial bipolar (<1.5 mV) and unipolar (<5.5 mV) and epicardial bipolar (<1.0 mV) voltage abnormalities. Abnormal unipolar RV endocardial area of 33.4±19.3% was present in 8 patients without NegT waves. Patients with NegT waves extending beyond lead V3 (n=20) had larger low bipolar (31.4±18.9% versus 16.5±14.6%; P=0.008) and unipolar endocardial areas (66.0±19.6% versus 47.4±25.1%; P=0.013) and larger epicardial low bipolar area (56.0±19.3% versus 40.1±24.9%; P=0.030) compared with those with NegT waves limited to leads V1 through V3 (n=20). ECG location of NegT waves regionalized to location of substrate. Patients with downsloping elevated ST segment, all localized to leads V1 and V2, had more unipolar endocardial abnormalities (71.8±18.1% versus 49.4±23.5%; P=0.005) involving outflow and mid-RV, compared with patients without downsloping elevated ST segment. CONCLUSIONS: In arrhythmogenic RV cardiomyopathy, abnormal electroanatomic mapping areas are proportional to extent of T-wave inversion on 12-lead ECG. Marked voltage abnormalities can exist without repolarization change. Downsloping elevated ST-segment pattern in V1 and V2 occurs with more unipolar endocardial voltage abnormality, consistent with more advanced transmural disease.


Assuntos
Displasia Arritmogênica Ventricular Direita/fisiopatologia , Mapeamento Potencial de Superfície Corporal/métodos , Sistema de Condução Cardíaco/fisiopatologia , Ventrículos do Coração/fisiopatologia , Potenciais de Ação , Adulto , Displasia Arritmogênica Ventricular Direita/diagnóstico , Eletrocardiografia/métodos , Feminino , Seguimentos , Humanos , Masculino
14.
J Magn Reson Imaging ; 2018 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-29522262

RESUMO

BACKGROUND: Myocardial infarction (MI) survivors are at risk of complications including heart failure and malignant arrhythmias. PURPOSE: We undertook serial imaging of swine following MI with the aim of characterizing the longitudinal left ventricular (LV) remodeling in a translational model of ischemia-reperfusion-mediated MI. ANIMAL MODEL: Eight Yorkshire swine underwent mid left anterior descending coronary artery balloon occlusion to create an ischemia-reperfusion experimental model of MI. FIELD STRENGTH/SEQUENCES: 1.5T Philips Achieva scanner. Serial cardiac MRI was performed at 16, 33, and 62 days post-MI, including cine imaging, native and postcontrast T1 , T2 and dark-blood late gadolinium enhanced (DB-LGE) scar imaging. ASSESSMENT: Regions of interest were selected on the parametric maps to assess native T1 and T2 in the infarct and in remote tissue. Volume of enhanced tissue, nonenhanced tissue, and gray zone were assessed from DB-LGE imaging. Volumes, cardiac function, and strain were calculated from cine imaging. STATISTICAL TESTS: Parameters estimated at more than two timepoints were compared with a one-way repeated measures analysis of variance. Parametric mapping data were analyzed using a generalized linear mixed model corrected for multiple observations. A result was considered statistically significant at P < 0.05. RESULTS: All animals developed anteroseptal akinesia and hyperenhancement on DB-LGE with a central core of nonenhancing tissue. Mean hyperenhancement volume did not change during the observation period, while the central core contracted from 2.2 ± 1.8 ml at 16 days to 0.08 ± 0.19 ml at 62 days (P = 0.008). Native T1 of ischemic myocardium increased from 1173 ± 93 msec at 16 days to 1309 ± 97 msec at 62 days (P < 0.001). Mean radial and circumferential strain rate magnitude in remote myocardium increased with time from the infarct (P < 0.05). DATE CONCLUSION: In this swine model of MI, serial quantitative cardiac MR exams allow characterization of LV remodeling and scar formation. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

15.
Magn Reson Med ; 79(1): 351-360, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28382726

RESUMO

PURPOSE: To develop a dark blood-late gadolinium enhancement (DB-LGE) sequence that improves scar-blood contrast and delineation of scar region. METHODS: The DB-LGE sequence uses an inversion pulse followed by T2 magnetization preparation to suppress blood and normal myocardium. Time delays inserted after preparation pulses and T2 -magnetization-prep duration are used to adjust tissue contrast. Selection of these parameters was optimized using numerical simulations and phantom experiments. We evaluated DB-LGE in 9 swine and 42 patients (56 ± 14 years, 33 male). Improvement in scar-blood contrast and overall image quality was subjectively evaluated by two independent readers (1 = poor, 4 = excellent). The signal ratios among scar, blood, and myocardium were compared. RESULTS: Simulations and phantom studies demonstrated that simultaneous nulling of myocardium and blood can be achieved by selecting appropriate timing parameters. The scar-blood contrast score was significantly higher for DB-LGE (P < 0.001) with no significant difference in overall image quality (P > 0.05). Scar-blood signal ratios for DB-LGE versus LGE were 5.0 ± 2.8 versus 1.5 ± 0.5 (P < 0.001) for patients, and 2.2 ± 0.7 versus 1.0 ± 0.4 (P = 0.0023) for animals. Scar-myocardium signal ratios were 5.7 ± 2.9 versus 6.3 ± 2.6 (P = 0.35) for patients, and 3.7 ± 1.1 versus 4.1 ± 2.0 (P = 0.60) for swine. CONCLUSIONS: The DB-LGE sequence simultaneously reduces normal myocardium and blood signal intensity, thereby enhancing scar-blood contrast while preserving scar-myocardium contrast. Magn Reson Med 79:351-360, 2018. © 2017 International Society for Magnetic Resonance in Medicine.


Assuntos
Sangue/diagnóstico por imagem , Meios de Contraste/química , Gadolínio/química , Coração/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Infarto do Miocárdio/diagnóstico por imagem , Adulto , Idoso , Animais , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Miocárdio/patologia , Imagens de Fantasmas , Reprodutibilidade dos Testes , Suínos
16.
Artigo em Inglês | MEDLINE | ID: mdl-29133380

RESUMO

BACKGROUND: Obstructive sleep apnea (OSA) is associated with atrial remodeling, atrial fibrillation (AF), and increased incidence of arrhythmia recurrence after pulmonary vein (PV) isolation. We aimed to characterize the atrial substrate, including AF triggers in patients with paroxysmal AF and OSA. METHODS AND RESULTS: In 86 patients with paroxysmal AF (43 with ≥moderate OSA [apnea-hypopnea index ≥15] and 43 without OSA [apnea-hypopnea index <5]), right atrial and left atrial voltage distribution, conduction velocities, and electrogram characteristics were analyzed during atrial pacing. AF triggers were examined before and after PV isolation and targeted for ablation. Patients with OSA had lower atrial voltage amplitude (right atrial, P=0.0005; left atrial, P=0.0001), slower conduction velocities (right atrial, P=0.02; left atrial, P=0.0002), and higher prevalence of electrogram fractionation (P=0.0001). The areas of atrial abnormality were consistent among patients, most commonly involving the left atrial septum (32/43; 74.4%). At baseline, the PVs were the most frequent triggers for AF in both groups; however, after PV isolation patients with OSA had increased incidence of additional extra-PV triggers (41.8% versus 11.6%; P=0.003). The 1-year arrhythmia-free survival was similar between patients with and without OSA (83.7% and 81.4%, respectively; P=0.59). In comparison, control patients with paroxysmal AF and OSA who underwent PV isolation alone without ablation on extra-PV triggers had increased risk of arrhythmia recurrence (83.7% versus 64.0%; P=0.003). CONCLUSIONS: OSA is associated with structural and functional atrial remodeling and increased incidence of extra-PV triggers. Elimination of these triggers resulted in improved arrhythmia-free survival.


Assuntos
Fibrilação Atrial/etiologia , Veias Pulmonares/fisiopatologia , Apneia Obstrutiva do Sono/complicações , Potenciais de Ação , Adulto , Idoso , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/fisiopatologia , Fibrilação Atrial/cirurgia , Remodelamento Atrial , Ablação por Cateter , Intervalo Livre de Doença , Técnicas Eletrofisiológicas Cardíacas , Feminino , Frequência Cardíaca , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Veias Pulmonares/cirurgia , Recidiva , Fatores de Risco , Índice de Gravidade de Doença , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/fisiopatologia , Fatores de Tempo , Resultado do Tratamento , Estados Unidos
18.
Heart Rhythm ; 14(8): 1234-1240, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28455271

RESUMO

BACKGROUND: An in vivo animal thigh model is the standard technique for evaluation of ablation catheter technologies, including efficacy and safety of ablation. However, the biophysics of ablation in a thigh model may not be similar to a beating heart. OBJECTIVE: The purpose of this study was to compare efficacy and safety of ablation between a thigh preparation model and a beating heart. METHODS: In 7 swine, radiofrequency ablation using a 3.5-mm open irrigated catheter (ThermoCool Smart Touch) was performed sequentially in a thigh muscle and in vivo beating ventricles. Ablation was performed at low (30 W for 40 s) and high (40 W for 60 s) energy settings and at similar contact force. Ablation lesions were scanned in high resolution and measured using electronic calipers. RESULTS: A total of 152 radiofrequency ablation lesions were measured (86 thigh and 66 heart). At low energy, lesion width was greater in the thigh model (12.19 ± 1.8 mm vs 8.99 ± 2.1 mm; P <.001), whereas lesion depth was similar between the thigh and heart (5.71 ± 0.8 mm vs 5.95 ± 1.3 mm, respectively; P = .18). The planar cross-sectional lesion area was greater in the thigh model (thigh 54.8 ± 10.8 mm2 vs heart 43.1 ± 16.1 mm2; P <.001). At the high-energy setting, lesion depth, width, and area were all greater in the thigh model (thigh 91.5 ± 16.8 mm2 vs heart 56.0 ± 15.5 mm2; P <.001). The incidence of steam pop and char formation was similar between the models. CONCLUSION: The thigh preparation model is a reasonable technique for evaluation of ablation catheter technology; however it often results in overestimation of lesion size, especially at higher energy settings.


Assuntos
Arritmias Cardíacas/cirurgia , Cateteres Cardíacos , Ablação por Cateter/métodos , Ventrículos do Coração/fisiopatologia , Músculo Esquelético/fisiopatologia , Animais , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/fisiopatologia , Estudos Transversais , Modelos Animais de Doenças , Impedância Elétrica , Desenho de Equipamento , Ventrículos do Coração/patologia , Teste de Materiais , Suínos , Irrigação Terapêutica/métodos
19.
JACC Clin Electrophysiol ; 3(3): 220-231, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-29759516

RESUMO

OBJECTIVES: This study sought to evaluate an investigational catheter that incorporates 3 microelectrodes embedded along the circumference of a standard 3.5-mm open-irrigated catheter. BACKGROUND: Mapping resolution is influenced by both electrode size and interelectrode spacing. Multielectrode mapping catheters enhance mapping resolution within scar compared with standard ablation catheters; however, this requires the use of 2 separate catheters for mapping and ablation. METHODS: Six swine with healed infarction and 2 healthy controls underwent mapping of the left ventricle using a THERMOCOOL SMARTTOUCH SF catheter with 3 additional microelectrodes (0.167 mm2) along its circumference (Qdot, Biosense Webster, Diamond Bar, California). Mapping resolution in healthy and scarred tissue was compared between the standard electrodes and microelectrodes using electrogram characteristics, cardiac magnetic resonance, and histology. RESULTS: In healthy myocardium, bipolar voltage amplitude was similar between the standard electrodes and microelectrodes, with a fifth percentile of 1.19 and 1.30 mV, respectively. In healed infarction, the area of low bipolar voltage (defined as <1.5 mV) was smaller with microelectrodes (16.8 cm2 vs. 25.3 cm2; p = 0.033). Specifically, the microelectrodes detected zones of increased bipolar voltage amplitude, with normal electrogram characteristics occurring at the end of or after the QRS, consistent with channels of preserved subendocardium. Identification of surviving subendocardium by the microelectrodes was consistent with cardiac magnetic resonance and histology. The microelectrodes also improved distinction between near-field and far-field electrograms, with more precise identification of scar border zones. CONCLUSIONS: This novel catheter combines high-resolution mapping and radiofrequency ablation with an open-irrigated, tissue contact-sensing technology. It improves scar mapping resolution while limiting the need for and cost associated with the use of a separate mapping catheter.


Assuntos
Mapeamento Potencial de Superfície Corporal/instrumentação , Ablação por Cateter/instrumentação , Cicatriz/fisiopatologia , Técnicas Eletrofisiológicas Cardíacas/instrumentação , Ventrículos do Coração/fisiopatologia , Microeletrodos/efeitos adversos , Animais , Cicatriz/patologia , Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas/métodos , Endocárdio/patologia , Endocárdio/fisiopatologia , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/patologia , Espectroscopia de Ressonância Magnética/métodos , Masculino , Microeletrodos/normas , Infarto do Miocárdio/fisiopatologia , Miocárdio/patologia , Estudos Prospectivos , Suínos , Taquicardia Ventricular/fisiopatologia
20.
JACC Clin Electrophysiol ; 3(7): 654-665, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-29759533

RESUMO

OBJECTIVES: The purpose of this study was to evaluate the relationship between electrocardiogram (ECG) QRS fragmentation (fQRS) and right ventricular (RV) endocardial (ENDO) and epicardial (EPI) electroanatomic substrate abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). BACKGROUND: fQRS is frequently observed in patients with ARVC and reflects delayed conduction due to RV fibrosis. METHODS: A total of 30 consecutive patients met the task force criteria for ARVC (19 men, mean age 41.1 ± 14.3 years) presenting for ventricular tachycardia ablation with detailed RV ENDO and EPI electroanatomic maps were included. Of these, 25 patients had depolarization abnormalities (fragmentation during and/or immediately after the QRS complex [fQRS]) in ≥2 contiguous ECG leads. Inferior (II, III, aVF) fQRS was identified in 23 patients, anterior (V1 to V3) in 15 patients, and basal superior (I/aVR) in 11 patients. The surface area and anatomic distribution of ENDO and EPI bipolar low-voltage regions (ENDO ≤1.5 mV, <0.5 mV "dense scar"/EPI ≤1.0 mV) and degree of isolated late potential activity consistent with a marked substrate abnormality were compared to the location of region-specific fQRS. RESULTS: In fQRS patients, ENDO very low bipolar voltage area (27.4 ± 24.9 cm2 [median 19 cm2] vs. 5.8 ± 5.4 cm2 [median 5 cm2]; p = 0.02) and EPI late potential percentage (22.6 ± 9.6% [median 24%] vs. 6.8 ± 3.9% [median 8%]; p = 0.002) were significantly larger than in patients without fQRS. Overall, ENDO and EPI bipolar low voltage area and late potential density increased as the number of fQRS ECG regions (0 to 3) increased. Inferior fQRS most frequently identified EPI inferior substrate (82% sensitivity, 100% specificity), anterior fQRS identified RV EPI mid-free wall substrate (55% sensitivity, 100% specificity), and basal superior fQRS identified ENDO (45.8% sensitivity, 100% specificity) and EPI (52% sensitivity, 100% specificity) RV outflow tract substrate abnormalities. CONCLUSIONS: The extent and distribution of RV voltage substrate abnormalities can be predicted by region-specific ECG depolarization changes in patients with ARVC and ventricular tachycardia.


Assuntos
Displasia Arritmogênica Ventricular Direita/diagnóstico , Eletrocardiografia/métodos , Ventrículos do Coração/fisiopatologia , Adulto , Displasia Arritmogênica Ventricular Direita/fisiopatologia , Eletrocardiografia/instrumentação , Mapeamento Epicárdico , Humanos , Masculino , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/fisiopatologia
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