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Introduction: The safety of hyperbaric oxygen treatment (HBO2) in patients with cardiovascular implanted electronic devices (CIED) remains unclear. Methods: We conducted a retrospective analysis of seven CIED patients (median age 79 [73-83] years, five males [71.4%]), including five with pacemakers and two with implantable cardioverter defibrillators (ICD), who underwent HBO2 between June 2013 and April 2023. During the initial session, electrocardiogram monitoring was conducted, and CIED checks were performed before and after the treatment. In addition, the medical records were scrutinized to identify any abnormal CIED operations. Results: All seven CIED patients underwent HBO2 within the safety pressure range specified by the CIED manufacturers or general pressure test by the International Organization for Standardization (2.5 [2.5-2.5] atmosphere absolute × 18 [5-20] sessions). When comparing the CIED parameters before and after HBO2, no significant changes were observed in the waveform amplitudes, pacing thresholds, lead impedance of the atrial and ventricular leads, or battery levels. All seven patients, including two with the rate response function activated, exhibited no significant changes in the pacing rate or pacing failure. Two ICD patients did not deactivate the therapy, including the defibrillation; however, they did not experience any arrhythmia or inappropriate ICD therapy during the HBO2. Conclusion: CIED patients who underwent HBO2 within the safety pressure range exhibited no significant changes in the parameters immediately after the HBO2 and had no observable abnormal CIED operations during the treatment. The safety of defibrillation by an ICD during HBO2 should be clarified.
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Various ablation technologies with different energy sources are currently being either used or being investigated for atrial fibrillation (AF) ablation. Potential complications continue to occur due to the indiscriminate thermal effects on non-targeted tissues adjacent to the myocardium that are common to all thermal ablation modalities. Pulsed field ablation (PFA) has recently gained significant attention and interest as an approach to AF ablation. PFA uniquely has the ability to circumvent certain complications related to thermal energy. PFA is a non-thermal ablation modality with the potential for unique-tissue selectivity that can minimize damage to collateral cardiac structures. Several PFA systems for AF ablation are currently being investigated. Some PFA systems have been designed to serve as single-shot approaches to achieve pulmonary vein isolation (PVI), and others have focal designs enabling flexible PVI lesion sets as well as linear/focal ablations. Favorable acute success rates and low incidence of complications with short procedure times have been reported with several PFA systems regardless of catheter design (single-shot or focal catheter). Clinical PFA studies in which chronic remapping was conducted, demonstrated pulmonary vein (PV) durability improved with evolutional modifications of pulsed field waveforms/dosing, achieving over 90% PV durability with optimized waveforms. Rare adverse events related to PFA may surface with its increasing use worldwide and as sicker patients get exposed to PFA. We believe that both excitement and vigilance are in order as we embark on yet another new chapter of AF ablation.
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Background: We explore an optimized approach for increasing lesion size using a novel ablation catheter with a surface thermocouple and efficient irrigation in a temperature-control setting. Methods: We conducted radiofrequency applications at various power levels (35 W, 40 W, and 45 W), contact forces (CFs, 10 g/20 g), and durations (60 s/120 s/180 s) in perpendicular/parallel catheter orientations, with normal saline irrigation (NS-irrigation) and Half NS-irrigation (HNS-irrigation) in an ex-vivo model (Step 1). In addition, we performed applications (35 W/40 W/45 W for 60 s/120 s/180 s in NS-irrigation and 35 W/40 W for 60 s/120 s/180 s in HNS-irrigation) in four swine (Step 2), evaluating lesion characteristics and the occurrence of steam pops. Results: In Step 1, out of 288 lesions, we observed 47 (16.3%) steam pops, with 13 in NS-irrigation and 34 in HNS-irrigation (p = .001). Although steam pops were mostly observed with the most aggressive setting (45 W/180 s, 54%) with NS-irrigation, they happened in less aggressive settings with HNS irrigation. Lesion size significantly increased with longer-duration ablation but not with HNS-irrigation. The optimal %impedance-drop cutoff to predict steam pops was 20% with a negative-predictive-value (NPV) = 95.1% including NS- and HNS-irrigation groups, and 22% with an NPV = 96.1% in NS-irrigation group. In Step 2, similar to the ex-vivo model, lesion size significantly increased with longer-duration ablation but not with HNS-irrigation. Steam pops were absent with NS-irrigation (0/35) even with the largest %impedance-drop reaching 31% at 45 W/180 s. All steam pops were observed with HNS-irrigation (6/21, 29%). The optimal %impedance-drop cutoff predicting steam pops was 24% with an NPV = 96.3% including both NS- and HNS-irrigation groups. Conclusions: Rather than using HNS-irrigation, very long-duration of radiofrequency applications up to 45 W/180 s may be recommended to safely and effectively increase lesion dimensions using this catheter with NS-irrigation.
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Background: Pulmonary vein isolation (PVI) with cryoballoon technology is a well-established therapy for treatment of atrial fibrillation (AF). Recently, a size-adjustable cryoballoon (POLARxTM FIT) that enables delivery in a standard 28-mm or an expanded 31-mm size was introduced. Objective: The purpose of this study was to perform a randomized clinical trial to evaluate the safety and efficacy of this novel cryoballoon compared to the conventional cryoballoon. Methods: The CONTRAST-CRYO II trial is a multicenter, prospective, open-label, randomized controlled trial in which 214 patients with paroxysmal AF will be randomized 1:1 to cryoballoon ablation with either a conventional cryoballoon (Arctic Front AdvanceTM Pro) or a size-adjustable cryoballoon (POLARx FIT). The study was approved by the Institutional Review Boards at all investigational sites and has been registered in the UMIN Clinical Trials Registry (UMIN000052500). Results: The primary endpoint of this study will be the incidence of phrenic nerve injury. Secondary endpoints include procedural success, chronic success through 12 months, procedure-related adverse events, biophysiological parameters during applications for each pulmonary vein (PV), total procedural and fluoroscopy times, level of PVI and isolation area, and probability of non-PV foci initiating AF. Conclusion: The CONTRAST-CRYO II trial is a multicenter, prospective, randomized controlled trial designed to assess the safety and efficacy of the POLARx FIT vs the Arctic Front Advance Pro. The findings from this trial will provide additional utility data on the efficacy of the size-adjustable cryoballoon for isolating PVs in patients with paroxysmal AF.
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BACKGROUND: Unlike conventional microsecond pulsed electrical fields that primarily target the cell membranes, nanosecond pulses are thought to primarily electroporate intracellular organelles. We conducted a comprehensive preclinical assessment of catheter-based endocardial nanosecond pulsed field ablation in swine. METHODS: A novel endocardial nanosecond pulsed field ablation system was evaluated in a total of 25 swine. Using either a low-dose (5-second duration) or high-dose (15-second duration) strategy, thoracic veins and discrete atrial and ventricular sites were ablated. Predetermined survival periods were <1 (n=1), ≈2 (n=7), ≈7 (n=6), 14 (n=2), or ≈28 (n=9) days, and venous isolation was assessed before euthanasia. Safety assessments included evaluation of esophageal effects, phrenic nerve function, and changes in venous caliber. All tissues were subject to careful gross pathological and histopathologic examination. RESULTS: All (100%) veins (13 low-dose, 34 high-dose) were acutely isolated, and all reassessed veins (6 low-dose, 15 high-dose) were durably isolated. All examined vein lesions (10 low-dose, 22 high-dose) were transmural. Vein diameters (n=15) were not significantly changed. Of the animals assessed for phrenic palsy (n=9), 3 (33%) demonstrated only transient palsy. There were no differences between dosing strategies. Thirteen mitral isthmus lesions were analyzed, and all 13 (100%) were transmural (depth, 6.4±0.4 mm). Ventricular lesions were 14.7±4.5 mm wide and 7.1±1.3 mm deep, with high-dose lesions deeper than low-dose (7.9±1.2 versus 6.2±0.8 mm; P=0.007). The esophagus revealed nontransmural adventitial surface lesions in 5 of 5 (100%) animals euthanized early (2 days) post-ablation. In the 10 animals euthanized later (14-28 days), all animals demonstrated significant esophageal healing-8 with complete resolution, and 2 with only trace fibrosis. CONCLUSIONS: A novel, endocardial nanosecond pulsed field ablation system provides acute and durable venous isolation and linear lesions. Transient phrenic injury and nontransmural esophageal lesions can occur with worst-case assessments suggesting limits to pulsed field ablation tissue selectivity and the need for dedicated assessments during clinical studies.
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Estudios de Factibilidad , Nervio Frénico , Animales , Porcinos , Factores de Tiempo , Miocardio/patología , Ablación por Catéter/métodos , Ablación por Catéter/efectos adversos , Venas/fisiopatología , Modelos Animales , Ventrículos Cardíacos/fisiopatología , Ventrículos Cardíacos/patología , Esófago , Atrios Cardíacos/fisiopatología , Atrios Cardíacos/patologíaRESUMEN
BACKGROUND: Endocardial catheter-based pulsed field ablation (PFA) of the ventricular myocardium is promising. However, little is known about PFA's ability to target intracavitary structures, epicardium, and ways to achieve transmural lesions across thick ventricular tissue. METHODS: A lattice-tip catheter was used to deliver biphasic monopolar PFA to swine ventricles under general anesthesia, with electroanatomical mapping, fluoroscopy and intracardiac echocardiography guidance. We conducted experiments to assess the feasibility and safety of repetitive monopolar PFA applications to ablate (1) intracavitary papillary muscles and moderator bands, (2) epicardial targets, and (3) bipolar PFA for midmyocardial targets in the interventricular septum and left ventricular free wall. RESULTS: (1) Papillary muscles (n=13) were successfully ablated and then evaluated at 2, 7, and 21 days. Nine lesions with stable contact measured 18.3±2.4 mm long, 15.3±1.5 mm wide, and 5.8±1.0 mm deep at 2 days. Chronic lesions demonstrated preserved chordae without mitral regurgitation. Two targeted moderator bands were transmurally ablated without structural disruption. (2) Transatrial saline/carbon dioxide assisted epicardial access was obtained successfully and epicardial monopolar lesions had a mean length, width, and depth of 30.4±4.2, 23.5±4.1, and 9.1±1.9 mm, respectively. (3) Bipolar PFA lesions were delivered across the septum (n=11) and the left ventricular free wall (n=7). Twelve completed bipolar lesions had a mean length, width, and depth of 29.6±5.5, 21.0±7.3, and 14.3±4.7 mm, respectively. Chronically, these lesions demonstrated uniform fibrotic changes without tissue disruption. Bipolar lesions were significantly deeper than the monopolar epicardial lesions. CONCLUSIONS: This in vivo evaluation demonstrates that PFA can successfully ablate intracavitary structures and create deep epicardial lesions and transmural left ventricular lesions.
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Ablación por Catéter , Ventrículos Cardíacos , Tabique Interventricular , Animales , Tabique Interventricular/fisiopatología , Tabique Interventricular/diagnóstico por imagen , Tabique Interventricular/cirugía , Ablación por Catéter/métodos , Ablación por Catéter/instrumentación , Porcinos , Ventrículos Cardíacos/fisiopatología , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/cirugía , Estudios de Factibilidad , Músculos Papilares/fisiopatología , Músculos Papilares/cirugía , Músculos Papilares/diagnóstico por imagen , Factores de Tiempo , Pericardio/cirugía , Pericardio/fisiopatología , Catéteres Cardíacos , Ultrasonografía Intervencional , Técnicas Electrofisiológicas Cardíacas , Diseño de Equipo , FemeninoRESUMEN
BACKGROUND: Risk stratification for patients with non-ischemic cardiomyopathy (NICM) remains challenging as previous studies predicting life-threatening ventricular arrhythmia (LTVA) events were conducted before the establishment of the current standard treatment. We investigated the prognostic value of non-sustained ventricular tachycardia (NSVT) in NICM patients among recent studies. METHODS: MEDLINE, Embase were searched from January 2000 to October 2023. The risk of NSVT on LTVA and mortality was assessed using a random-effects model for patients with NICM. A meta-regression analysis was employed to identify sources of heterogeneity. The systematic review and meta-analysis were carried out according to the PRISMA guidelines. RESULTS: A total of 18 studies were identified, including 5238 pooled participants. Meta-analysis demonstrated that the presence of NSVT was considered a significant prognostic indicator for LTVA events [hazard ratio (HR): 2.90; 95â¯% CI; 2.31-3.64] with low heterogeneity (I2: 19â¯%) and for mortality (HR; 2.28; 95%CI; 1.26-4.13) with high heterogeneity (I2: 69â¯%). The prognostic value of NSVT for LTVA was not affected by either ejection fraction or medications at baseline. CONCLUSION: NSVT remained an important predictor of LTVA events even in patients receiving healthcare in contemporary eras. Detection of NSVT helps us to identify the high-risk patients with NICM.
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Cardiomiopatías , Taquicardia Ventricular , Humanos , Taquicardia Ventricular/etiología , Taquicardia Ventricular/mortalidad , Cardiomiopatías/complicaciones , Cardiomiopatías/etiología , Cardiomiopatías/mortalidad , Pronóstico , Medición de RiesgoRESUMEN
Background: Lesion size is reported to become larger as contact force (CF) increases. However, this has not been systematically evaluated in temperature-guided very high-power short-duration (vHPSD) ablation, which was therefore the purpose of this study. Methods: Radiofrequency applications (90 W/4 s, temperature-control mode) were performed in excised porcine myocardium with four different CFs of 5, 15, 25, and 35 g using QDOT-MICRO™ catheter. Ten lesions for each combination of settings were created, and lesion metrics and steam-pops were compared. Results: A total of 320 lesions were analyzed. Lesion depth, surface area, and volume were smallest for CF of 5 g than for 15, 25, and 35 g (depth: 2.7 mm vs. 2.9 mm, 3.0 mm, 3.15 mm, p < .01; surface area: 38.4 mm2 vs. 41.8 mm2, 43.3 mm2, 41.5 mm2, p < .05; volume: 98.2 mm3 vs. 133.3 mm3, 129.4 mm3, 126.8 mm3, p < .01 for all pairs of groups compared to CF = 5 g). However, no significant differences were observed between CFs of 15-35 g. Average power was highest for CF of 5 g, followed by 15, 25, and 35 g (83.2 W vs. 82.1 W vs. 77.1 W vs. 66.1 W, p < .01 for all pairs), reflecting the higher incidence of temperature-guided power titration with greater CFs (5 g:8.8% vs. 15 g:52.5% vs. 25 g:77.5% vs. 35 g:91.2%, p < .01 for all pairs except for 25 g vs. 35 g). The incidence of steam-pops did not significantly differ between four groups (5 g:3.8% vs. 15 g:10% vs. 25 g:6.2% vs. 35 g:2.5%, not significant for all pairs). Conclusions: For vHPSD ablation, lesion size does not become large once the CF reaches 15 g, and the risk of steam-pops may be mitigated through power titration even in high CFs.
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BACKGROUND: Unipolar electrograms (uni-EGMs) are an essential part of intracardiac mapping. Although Wilson central terminal (WCT) is conventionally used as a reference for signals, avoidance of contamination by far-field and nonphysiologic signals is challenging. OBJECTIVE: The aim of the study was to explore the impact of an intracardiac indifferent reference electrode close to the recording electrodes, in lieu of WCT, on electrograms. METHODS: Sinus node activation was mapped in patients undergoing catheter ablation by a multielectrode array with a close indifferent electrode (CIE) embedded in the distal end of the catheter shaft. An equal number of points was sequentially acquired at each site with use of CIE as a reference first and subsequently with WCT. Uni-EGMs, bipolar EGMs, and the earliest activation area (defined as the area activated in the first 10 ms of the beat) were compared between CIE- and WCT-based activation maps. RESULTS: Seventeen patients (61 ± 18 years; 76% male) were studied. Uni-EGM voltages acquired with CIE were significantly larger than (n = 11) or comparable to (n = 4) those acquired with WCT. When points from the entire cohort were analyzed altogether, unipolar voltages and their maximum negative dV/dT and bipolar voltages recorded with CIE were significantly larger than those recorded with WCT (2.36 [1.42-3.79] mV vs 1.96 [1.25-3.03] mV, P < .0001; 0.40 [0.18-0.77] mV/s vs 0.35 [0.15-0.71] mV/s, P < .0001; and 1.46 [0.66-2.81] mV vs 1.33 [0.54-2.64] mV, P < .0001, respectively). The earliest activation area was significantly smaller in CIE-based activation maps than in WCT-based ones (0.3 [0.7-1.4] cm2 vs 0.6 [1.0-1.8] cm2, P = .01). CONCLUSION: CIE-based maps were associated with an approximately 20% increase in unipolar voltage and may highlight the origin of a focal activation more clearly than WCT-based ones.
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Ablación por Catéter , Electrodos , Técnicas Electrofisiológicas Cardíacas , Humanos , Masculino , Femenino , Persona de Mediana Edad , Técnicas Electrofisiológicas Cardíacas/métodos , Ablación por Catéter/métodos , Sistema de Conducción Cardíaco/fisiopatología , Diseño de Equipo , ElectrocardiografíaRESUMEN
Pulsed field ablation (PFA) is a novel energy form for the catheter ablation of cardiac arrhythmias, which uses electrical fields to mediate myocardial death via irreversible electroporation and other modalities. It is believed to offer relative tissue specificity, lowering - or even eliminating - the risk of complications associated with thermal energy, such as atrio-oesophageal fistulas. The proposed superior safety profile compared to thermal ablation has contributed to the enthusiastic implementation of PFA into clinical practice and is supported by early preclinical and clinical data. However, data about the effects of PFA on the oesophagus remain limited. This organ's susceptibility to PFA has important clinical ramifications and there are two highly relevant questions. First, is the oesophagus absolutely spared by PFA or is there susceptibility to injury at higher field strengths? Second, if oesophageal injury can occur, can atrio-oesophageal fistulas ensue? The aim of this article is to provide a literature review on the effects of PFA on the oesophagus and to address these questions based on the data described.
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BACKGROUND: Strokes after left atrial appendage closure (LAAC) prophylaxis are generally less severe than those after warfarin prophylaxis-thought to be secondary to more hemorrhagic strokes with warfarin. Hemorrhagic strokes are similarly infrequent with direct oral anticoagulant (DOAC) prophylaxis, so the primary subtype after either LAAC or DOAC prophylaxis is ischemic stroke (IS). OBJECTIVES: The purpose of this study was to compare the severity of IS using the modified Rankin Scale in atrial fibrillation patients receiving prophylaxis with DOACs vs LAAC. METHODS: A retrospective analysis was performed of consecutive patients undergoing LAAC at 8 centers who developed an IS (ISLAAC) compared with contemporaneous consecutive patients who developed IS during treatment with DOACs (ISDOAC). The primary outcome was disabling/fatal stroke (modified Rankin Scale 3-5) at discharge and 3 months later. RESULTS: Compared with ISDOAC patients (n = 322), ISLAAC patients (n = 125) were older (age 77.2 ± 13.4 years vs 73.1 ± 11.9 years; P = 0.002), with higher HAS-BLED scores (3.0 vs 2.0; P = 0.004) and more frequent prior bleeding events (54.4% vs 23.6%; P < 0.001), but similar CHA2DS2-VASc scores (5.0 vs 5.0; P = 0.28). Strokes were less frequently disabling/fatal with ISLAAC than ISDOAC at both hospital discharge (38.3% vs 70.3%; P < 0.001) and 3 months later (33.3% vs 56.2%; P < 0.001). Differences in stroke severity persisted after propensity score matching. By multivariate regression analysis, ISLAAC was independently associated with fewer disabling/fatal strokes at discharge (OR: 0.22; 95% CI: 0.13-0.39; P < 0.001) and 3 months (OR: 0.25; 95% CI: 0.12-0.50; P < 0.001), and fewer deaths at 3 months (OR: 0.28; 95% CI: 0.12-0.64; P < 0.001). CONCLUSIONS: Ischemic strokes in patients with atrial fibrillation are less often disabling or fatal with LAAC than DOAC prophylaxis.
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Fibrilación Atrial , Accidente Cerebrovascular Hemorrágico , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Warfarina/efectos adversos , Fibrilación Atrial/complicaciones , Fibrilación Atrial/tratamiento farmacológico , Fibrilación Atrial/cirugía , Accidente Cerebrovascular Isquémico/inducido químicamente , Accidente Cerebrovascular Isquémico/complicaciones , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Accidente Cerebrovascular Hemorrágico/inducido químicamente , Accidente Cerebrovascular Hemorrágico/complicaciones , Accidente Cerebrovascular Hemorrágico/tratamiento farmacológico , Estudios Retrospectivos , Cierre del Apéndice Auricular Izquierdo , Resultado del Tratamiento , Anticoagulantes/efectos adversos , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/etiología , Accidente Cerebrovascular/prevención & control , Hemorragia/inducido químicamenteRESUMEN
BACKGROUND: Ultrastructural findings immediately after pulsed field ablation (PFA) of the myocardium have not been described. OBJECTIVES: The purpose of this study was to elucidate ultrastructural characteristics and differences between microsecond PFA at the 1- and 4-hour timepoints after pulse delivery and to compare them to irrigated radiofrequency ablation (RFA) lesions. METHODS: Healthy swine underwent endocardial PFA or RFA followed by necropsy. Discrete microsecond PFA and irrigated RFA lesions were created in the ventricles with a lattice tip ablation catheter. Lesions were delivered in a manner so as to allow sampling to occur 1 and 4 hours after ablation. All lesions were located at necropsy, and samples were carefully obtained from within the lesion core, lesion periphery, and adjacent healthy myocardium. Transmission electron microscopic assessment was performed after fixation using paraformaldehyde and glutaraldehyde. RESULTS: One hour after microsecond PFA delivery, myocytes were noted to be significantly and uniformly disrupted. Clustered, misaligned, swollen mitochondria coupled with degenerating nuclei and condensed chromatin were visualized. These findings progressed over the subsequent few hours with worsening edema. Similar changes were seen with RFA but reduced in severity. However, there was prominent extravasation of red blood cells with occlusion of capillaries that was not seen in PFA. At the lesion periphery, an abrupt change in the degree of myocyte damage was observed with PFA but not RFA. CONCLUSION: Transmission electron microscopy demonstrates evidence of widespread destruction of myocytes as early as an hour after PFA and corroborates known histologic features such as sparing of vessels and sharp lesion margins.
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Fibrilación Atrial , Ablación por Catéter , Ablación por Radiofrecuencia , Porcinos , Animales , Ablación por Catéter/efectos adversos , Miocardio , Ventrículos Cardíacos/cirugía , Frecuencia Cardíaca , Fibrilación Atrial/cirugíaRESUMEN
AIMS: The usefulness of coronary venous system mapping has been reported for assessing intramural and epicardial substrates in patients with scar-related ventricular tachycardia (VT). However, there has been little data on mapping from coronary arteries. We investigated the safety and utility of mapping from coronary arteries with a novel over-the-wire multielectrode catheter in scar-related VT patients. METHODS AND RESULTS: Ten consecutive scar-related VT patients with non-ischaemic cardiomyopathy who underwent mapping from a coronary artery were analysed. Six patients underwent simultaneous coronary venous mapping. High-density maps were created by combining the left ventricular endocardium and coronary vessels. Substrate maps were created during the baseline rhythm with 2438 points (IQR 2136-3490 points), including 329 (IQR 59-508 points) in coronary arteries. Abnormal bipolar electrograms were successfully recorded within coronary arteries close to the endocardial substrate in seven patients. During VT, isthmus components were recorded within the coronary vessels in three patients with no discernible isthmus components on endocardial mapping. The ablation terminated the VT from an endocardial site opposite the earliest site in the coronary arteries in five patients. CONCLUSION: The transcoronary mapping with an over-the-wire multielectrode catheter can safely record abnormal bipolar electrograms within coronary arteries. Additional mapping data from the coronary vessels have the potential to assess three-dimensional ventricular substrates and circuit structures in scar-related VT patients.
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Ablación por Catéter , Taquicardia Ventricular , Humanos , Cicatriz/complicaciones , Cicatriz/diagnóstico por imagen , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/etiología , Taquicardia Ventricular/cirugía , Arritmias Cardíacas , Ventrículos Cardíacos , Endocardio , Ablación por Catéter/efectos adversos , Ablación por Catéter/métodosRESUMEN
PURPOSE: Radiofrequency (RF) ablation with half-normal saline (HNS) irrigation is reported to potentially enlarge local lesion compared to normal saline (NS) in power-controlled ablation (PC-Abl). However, the effect of HNS-irrigation in temperature-flow-controlled ablation (TFC-Abl) on lesion characteristics is unknown. We compared this between TFC-Abl with QDOT-Micro™ catheter and PC-Abl with Thermocool SmartTouch SF™ catheter (STSF). METHODS: RF-application with NS (n = 480) and HNS (n = 480) irrigation were performed on swine myocardium placed in a circulating saline bath. Lesion characteristics without steam-pops under various conditions (target AI, 400/550; ablation power, 30/50 W; contact force, 10/20/30 g; catheter orientation, perpendicular/parallel) were assessed and compared between two irrigants. RESULTS: After matching, 343 lesions without steam-pops in each group were evaluated. In PC-Abl, lesion size did not differ between two groups (NS, 188 ± 97 vs. HNS, 200 ± 95 mm3, p = 0.28 in volume; 33.9 ± 7.3 vs. 34.8 ± 9.5 mm2, p = 0.34 in surface area; and 4.0 ± 1.0 vs. 4.0 ± 1.0 mm, p = 0.81 in depth), but steam-pops were more frequently observed with HNS-irrigation (23.8% vs. 37.9%, p = 0.001). Contrary, in TFC-Abl, HNS-irrigation produced significantly larger (214 ± 106 vs. 243 ± 128 mm3, p = 0.017) and deeper (4.0 ± 1.0 vs. 4.3 ± 1.1 mm, p = 0.002) lesions without increasing the risk of steam-pops (15.0% vs 15.0%, p = 0.99). Automatic temperature-guided titration was more frequently observed in HNS-irrigation (54.8% vs. 78.5%, p < 0.001). CONCLUSIONS: TFC-Abl with QDOT-Micro™ catheter utilizing HNS-irrigation might increase volume and depth of local lesion without increasing the risk of stem-pops compared to NS-irrigation. Power-controlled ablation with HNS-irrigation showed similar focal lesion with higher incidence of steam-pops (SPs) compared to normal saline (NS) irrigation. Contrary, temperature-flow-controlled ablation with HNS-irrigation provided larger and deeper lesion than NS-irrigation with similar incidence of SPs. ns, p > 0.05; *, 0.01 < p ≤ 0.05; **, 0.005 < p ≤ 0.01. HNS, half-normal saline; NS, normal saline.
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BACKGROUND: For lesion size prediction, each input parameter, including ablation energy (AE), and output parameter, such as impedance, is individually used. We hypothesize that using both parameters simultaneously may be more optimal.MethodsâandâResults: Radiofrequency applications at a range of power (30-50 W), contact force (10 g and 20 g), duration (10-60 s), and catheter orientation with normal saline (NS)- or half-normal saline (HNS)-irrigation were performed in excised porcine hearts. The correlations, with lesion size of AE, absolute impedance drop (∆Imp-drop), relative impedance drop (%Imp-drop), and AE*%Imp-drop were examined. Lesion size was analyzed in 283 of 288 lesions (NS-irrigation, n=142; HNS-irrigation, n=141) without steam pops. AE*%Imp-drop consistently showed the strongest correlations with lesion maximum depth (NS-irrigation, ρ=0.91; HNS-irrigation, ρ=0.94), surface area (NS-irrigation, ρ=0.87; HNS-irrigation, ρ=0.86), and volume (NS-irrigation, ρ=0.94; HNS-irrigation, ρ=0.94) compared with the other parameters. Moreover, compared with AE alone, AE*%Imp-drop significantly improved the strength of correlation with lesion maximum depth (AE vs. AE*%Imp-drop, ρ=0.83 vs. 0.91, P<0.01), surface area (ρ=0.73 vs. 0.87, P<0.01), and volume (ρ=0.84 vs. 0.94, P<0.01) with NS-irrigation. This tendency was also observed with HNS-irrigation. Parallel catheter orientation showed a better correlation with lesion depth and volume using ∆Imp-drop, %Imp-drop, and AE*%Imp-drop than perpendicular orientation. CONCLUSIONS: The combination of input and output parameters is more optimal than each single parameter for lesion prediction.
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Ablación por Catéter , Solución Salina , Animales , Porcinos , Ventrículos Cardíacos/patología , Corazón , Catéteres , Ablación por Catéter/métodos , Diseño de Equipo , Impedancia EléctricaRESUMEN
BACKGROUND: During electrophysiological mapping of tachycardias, putative target sites are often only truly confirmed to be vital after observing the effect of ablation. This lack of mapping specificity potentiates inadvertent ablation of innocent cardiac tissue not relevant to the arrhythmia. But if myocardial excitability could be transiently suppressed at critical regions, their suitability as targets could be conclusively determined before delivering tissue-destructive ablation lesions. We studied whether reversible pulsed electric fields (PFREV) could transiently suppress electrical conduction, thereby providing a means to dissect tachycardia circuits in vivo. METHODS: PFREV energy was delivered from a 9-mm lattice-tip catheter to the atria of 12 swine and 9 patients, followed by serial electrogram assessments. The effects on electrical conduction were explored in 5 additional animals by applying PFREV to the atrioventricular node: 17 low-dose (PFREV-LOW) and 10 high-dose (PFREV-HIGH) applications. Finally, in 3 patients manifesting spontaneous tachycardias, PFREV was applied at putative critical sites. RESULTS: In animals, the immediate post-PFREV electrogram amplitudes diminished by 74%, followed by 78% recovery by 5 minutes. Similarly, in patients, a 69.9% amplitude reduction was followed by 84% recovery by 3 minutes. Histology revealed only minimal to no focal, superficial fibrosis. PFREV-LOW at the atrioventricular node resulted in transient PR prolongation and transient AV block in 59% and 6%, while PFREV-HIGH caused transient PR prolongation and transient AV block in 30% and 50%, respectively. The 3 tachycardia patients had atypical atrial flutters (n=2) and atrioventricular nodal reentrant tachycardia. PFREV at putative critical sites reproducibly terminated the tachycardias; ablation rendered the tachycardias noninducible and without recurrence during 1-year follow-up. CONCLUSIONS: Reversible electroporation pulses can be applied to myocardial tissue to transiently block electrical conduction. This technique of pulsed field mapping may represent a novel electrophysiological tool to help identify the critical isthmus of tachycardia circuits.
Asunto(s)
Bloqueo Atrioventricular , Ablación por Catéter , Taquicardia por Reentrada en el Nodo Atrioventricular , Humanos , Animales , Porcinos , Técnicas Electrofisiológicas Cardíacas , Electrocardiografía , Nodo Atrioventricular , Ablación por Catéter/efectos adversos , Ablación por Catéter/métodosRESUMEN
BACKGROUND: Left bundle branch block (LBBB) pattern on the electrocardiogram includes patients with both complete conduction block in the His-Purkinje system as well as nonspecific left ventricular conduction delay without discrete block. OBJECTIVE: The purpose of this study was to characterize electrocardiographic morphological features of LBBB patterns in patients with (1) LBBB after transcatheter aortic valve replacement (TAVR) and (2) LBBB correctable by conduction system pacing (CSP). METHODS: Consecutive patients with post-TAVR (n = 123) or CSP-correctable LBBB (n = 58) from 2 centers were included in this retrospective evaluation. QRS durations as well as detailed morphological features, including notching and slurring, of QRS complexes in leads I, aVL, V1, V2, V5, and V6 and in all 3 inferior leads were recorded. RESULTS: The mean age of the entire cohort was 78.3 ± 10.1 years, with 48% of the cohort being male (87/181). In the CSP-correctable group (n = 58), 14 (24.1%) underwent His-bundle pacing and 44 (75.9%) left bundle branch area pacing. A total of 17 of 181 (9.4%) of the combined cohort failed to completely meet the Strauss criteria. QRS morphology in lead V1/V2 was always either rS or QS, and there were no q/Q waves noted in lead V5/V6. Although dominant R waves were seen in leads I and aVL of 176 of 181 (97.2%), q/Q waves were present in only 21 of 181 (11.6%). Importantly, notched or slurred QRS complexes were identified in at least 1 lead of 4 leads I, aVL, V5, and V6 in 181 of 181 (100%). CONCLUSION: Strauss criteria and QRS notching are highly prevalent in LBBB after TAVR and in LBBB correctable by CSP.