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1.
Heart Rhythm ; 2024 May 31.
Article in English | MEDLINE | ID: mdl-38823665

ABSTRACT

BACKGROUND: The potential risk of embolic events during ablation in the left ventricle (LV) with a heated saline-enhanced radiofrequency (SERF) needle-tip ablation catheter has not been characterized. OBJECTIVE: This study aimed to investigate the formation of microemboli or other untoward events during SERF ablation. METHODS: Ninety-three radiofrequency (RF) ablation procedures were performed in the LV of 14 pigs by using a SERF catheter (35 W, 70 seconds, and 60°C; normal or degassed saline [NS or DS] irrigation with a flow rate of 10 mL/min) vs a standard irrigated-tip radiofrequency (S-RF) catheter (30 or 50 W, 30 seconds, and 17 mL/min). Microbubble formation was graded on the basis of intracardiac echocardiography. Microbubbles, microembolic signals, and microparticles were monitored using our established model. RESULTS: There was no significant difference in microbubble volume among SERF-NS, SERF-DS, and S-RF 30 W with "grade 1" intracardiac echocardiography microbubbles (median and 25th-75th percentiles 0.201 [0.011-3.13], 0.455 [0.06-2.66], and 0.004 µL [0.00-0.16 µL], respectively). There was no significant difference in microembolic signals among SERF-NS, SERF-DS, and S-RF 30 W with grade 1 bubbles (n = 8.0 ± 5.8, n = 7.6 ± 4.2, and n = 6.1 ± 6.1, respectively). Both SERF-NS and SERF-DS created larger lesions than did both S-RF 30 W and S-RF 50 W deliveries (mean 1241.5 ± 658.6, 1497.7 ± 893.4, 75.0 ± 24.8, and 184.0 ± 93.8 mm3; P < .001). There was no significant difference in microparticle incidence among groups (P = .675). No evidence of embolic events was found in the brain and other organs at the histology assessment. CONCLUSION: In the setting of SERF ablation, significantly large LV lesions can be created without any increment in embolic microbubble or particle events. Grade 1 microbubble is related to the efficacy and safety.

2.
JACC Clin Electrophysiol ; 8(1): 26-37, 2022 01.
Article in English | MEDLINE | ID: mdl-34454888

ABSTRACT

OBJECTIVES: This study aimed to compare the efficacy and safety of ablation with high and low power settings using either a flexible tip or straight SF tip irrigated catheter in the left ventricle (LV) using a peripheral microemboli monitoring system. BACKGROUND: The microemboli risk of flexible and straight SF tip irrigated catheters in creating ablative lesions in the LV at variable power settings has not been adequately assessed. METHODS: Six pigs underwent catheter ablation in the LV using a flexible tip or straight SF tip catheter with 2 energy settings (30 or 50 W, 30 seconds, irrigation saline 17 mL/min). RESULTS: A total of 79 radiofrequency (RF) applications were assessed. High power settings via a flexible tip formed a significantly higher arterial microbubble volume in the extracorporeal circulation (P = 0.005). Notably, RF applications with a steam pop induced an exponential increase of microbubble volume with both catheters. A higher power setting induced a significantly higher number of microembolic signals on carotid artery Doppler ultrasound with a flexible tip irrigated catheter (P < 0.001). Similarly, the straight SF tip irrigated catheter tended to increase the number of microembolic signals with 50 W (P = 0.091). CONCLUSIONS: RF ablation at high power settings in the LV carries a risk of microembolic events compared with lower power settings. When high power settings are used for creating ablative lesions for deep intramural foci in the LV, the risk of microembolic events induced by RF ablation should be carefully monitored.


Subject(s)
Catheter Ablation , Animals , Catheter Ablation/adverse effects , Catheters , Electrocardiography , Equipment Design , Heart Ventricles/diagnostic imaging , Heart Ventricles/surgery , Swine
3.
Europace ; 23(11): 1826-1836, 2021 11 08.
Article in English | MEDLINE | ID: mdl-33993234

ABSTRACT

AIMS: With the implementation of saline-enhanced radiofrequency (SERF) needle-tip ablation, real-time validation of lesion formation is needed for the controllable creation of transmural lesions. The aim of the study was to analyse the ability of two-dimensional intracardiac echocardiography (2D-ICE) to guide and validate SERF ablation in real-time. METHODS AND RESULTS: Fifty-six SERF energy deliveries at left ventricular sites of 11 dogs guided by 2D-ICE were analysed (power: 15-50 W; time: 25-120 s; irrigation saline: 60°C with 10 mL/min flow rate). Catheter tip/tissue orientation and lesion formation could be well detected by 2D-ICE in 49 (87.5%) energy deliveries. Gross pathology analysis confirmed excellent 2D-ICE lesion localization, the ability to detect transmural lesions (70% sensitivity, 47% specificity) and positive correlation between 2D-ICE and the corresponding gross pathology measurements of 'maximal lesion depth'; (repeated measures correlation: rrm = 0.43, P = 0.012) and 'depth at maximal lesion width' (D@MW; rrm = 0.51, P = 0.003). The median angle between SERF catheter tip and endocardium was 76° [interquartile range (IQR) 58-83°]. The more perpendicular the catheter tip/tissue orientation was the deeper D@MW (rrm = 0.32, P = 0.045). Grade 3 microbubbles on 2D-ICE during ablation, indicating inadequate catheter tip/tissue contact, was associated with smaller lesion volumes than with Grade 1 microbubbles (284.8 mm3 [IQR 151.3-343.1] vs. 2114.1 mm3 [IQR 1437.0-3026.3], P < 0.001). CONCLUSION: With excellent lesion localization and a 70% detection rate of transmural lesions, 2D-ICE is well suited to validate SERF ablation lesion formation in real-time. The catheter tip/tissue angle impacts the lesion formation and through perpendicular catheter positioning, deeper intramural areas of the myocardium can be reached.


Subject(s)
Catheter Ablation , Animals , Catheter Ablation/methods , Dogs , Echocardiography/methods , Humans , Myocardium/pathology , Needles , Pericardium
4.
Heart Rhythm ; 18(3): 443-452, 2021 03.
Article in English | MEDLINE | ID: mdl-33212248

ABSTRACT

BACKGROUND: Irrigated needle catheter ablation is efficacious for creation of transmural lesions in the left ventricle (LV). However, interdependence of needle orientation and myocardial fiber orientation and the resulting influence on lesion creation remain unclear. OBJECTIVE: The purpose of this study was to investigate the impact of myocardial fiber orientation on reproducibility and controllability of lesion creation in LV myocardium using a heated saline-enhanced radiofrequency (SERF) needle-tip catheter system. METHODS: Eleven dogs underwent catheter ablation using this novel catheter. Ablative lesions were created using different power and ablation times (15-50 W; application 25-120 seconds; 60°C irrigation saline at 10 mL/min). Hearts were explanted, and lesions were evaluated using 3-T cardiac magnetic resonance (CMR), gross pathologic, and histologic investigations. RESULTS: Forty-three of 57 lesions (75.4%) were transmural, and lesion depth reached approximately 90% of LV wall thickness. Lesion volume in both gross pathology and ex vivo CMR showed a positive linear correlation with power × radiofrequency (RF) time index (r = 0.637, P <.001; and r = 0.786, P <.001, respectively). Maximum width (circumferential direction of LV) and maximum length (long-axis direction) of all lesions were distributed in the middle layer of LV where myocardium runs circumferentially. Paired-sample t-test showed maximum lesion width was significantly greater than maximum lesion length by both CMR and gross pathologic evaluation (26.1 ± 9.6 mm vs 17.2 ± 6.7 mm, P <.001; and 22.5 ± 7.7 mm vs 18.6 ± 5.9 mm, P <.001, respectively). CONCLUSION: This catheter showed feasibility in creating transmural LV lesions. Power × RF time index was strongly correlated with lesion volume and predicted lesion size. More importantly, SERF lesions extended along the myocardial fiber orientation.


Subject(s)
Catheter Ablation/instrumentation , Magnetic Resonance Imaging, Cine/methods , Myocardium/pathology , Tachycardia, Ventricular/surgery , Animals , Disease Models, Animal , Dogs , Equipment Design , Feasibility Studies , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/physiopathology
5.
Circ Arrhythm Electrophysiol ; 13(12): e009090, 2020 12.
Article in English | MEDLINE | ID: mdl-33198498

ABSTRACT

BACKGROUND: Inability to eliminate intramural arrhythmogenic substrate may lead to recurrent ventricular tachycardia after catheter ablation. The aim of the present study was to evaluate intramural and full thickness lesion formation using a heated saline-enhanced radiofrequency (SERF) needle-tip catheter, compared with a conventional ablation catheter in normal and infarcted myocardium. METHODS: Twenty-two adult mongrel dogs (30-40 kg, 15 normal and 7 myocardial infarct group) were studied. Lesions were created using the SERF catheter (40 W/50 °C) or a standard contact force (CF) catheter in both groups. RESULTS: Comparing SERF to CF ablation, the SERF catheter produced larger lesion volumes than the standard CF catheter-even with >20 g of CF-in both normal (983.1±905.8 versus 461.9±178.3 mm3; P=0.023) and infarcted left ventricular myocardium (1052.3±543.0 versus 340.3±160.5 mm3; P=0.001). SERF catheter lesions were more often transmural than standard CF lesions with >20 g of CF in both groups (59.1% versus 7.7%; P<0.001 and 60.0% versus 12.5%; P=0.017, respectively). Using the SERF catheter, mean depth of ablated lesions reached 90% of the left ventricular wall in both normal and infarcted myocardium. CONCLUSIONS: The SERF catheter created more transmural and larger ablative lesions in both normal and infarcted canine myocardium. SERF ablation is a promising new approach for endocardial intramural and full thickness ablation of ventricular tachycardia substrate that is not accessible with current techniques.


Subject(s)
Cardiac Catheters , Catheter Ablation/instrumentation , Myocardial Infarction/pathology , Myocardium/pathology , Saline Solution/administration & dosage , Tachycardia, Ventricular/surgery , Therapeutic Irrigation/instrumentation , Animals , Disease Models, Animal , Dogs , Needles , Tachycardia, Ventricular/pathology , Tachycardia, Ventricular/physiopathology
6.
Circ Arrhythm Electrophysiol ; 13(10): e008838, 2020 10.
Article in English | MEDLINE | ID: mdl-32921132

ABSTRACT

BACKGROUND: Proton beam therapy offers radiophysical properties that are appealing for noninvasive arrhythmia elimination. This study was conducted to use scanned proton beams for ablation of cardiac tissue, investigate electrophysiological outcomes, and characterize the process of lesion formation in a porcine model using particle therapy. METHODS: Twenty-five animals received scanned proton beam irradiation. ECG-gated computed tomography scans were acquired at end-expiration breath hold. Structures (atrioventricular junction or left ventricular myocardium) and organs at risk were contoured. Doses of 30, 40, and 55 Gy were delivered during expiration to the atrioventricular junction (n=5) and left ventricular myocardium (n=20) of intact animals. RESULTS: In this study, procedural success was tracked by pacemaker interrogation in the atrioventricular junction group, time-course magnetic resonance imaging in the left ventricular group, and correlation of lesion outcomes displayed in gross and microscopic pathology. Protein extraction (active caspase-3) was performed to investigate tissue apoptosis. Doses of 40 and 55 Gy caused slowing and interruption of cardiac impulse propagation at the atrioventricular junction. In 40 left ventricular irradiated targets, all lesions were identified on magnetic resonance after 12 weeks, being consistent with outcomes from gross pathology. In the majority of cases, lesion size plateaued between 12 and 16 weeks. Active caspase-3 was seen in lesions 12 and 16 weeks after irradiation but not after 20 weeks. CONCLUSIONS: Scanned proton beams can be used as a tool for catheter-free ablation, and time-course of tissue apoptosis was consistent with lesion maturation.


Subject(s)
Ablation Techniques , Atrioventricular Node/radiation effects , Heart Ventricles/radiation effects , Proton Therapy , Ablation Techniques/adverse effects , Animals , Apoptosis , Atrioventricular Node/diagnostic imaging , Atrioventricular Node/pathology , Female , Heart Ventricles/diagnostic imaging , Heart Ventricles/pathology , Magnetic Resonance Imaging, Cine , Male , Models, Animal , Necrosis , Proton Therapy/adverse effects , Radiation Dosage , Sus scrofa , Time Factors , Tomography, X-Ray Computed
7.
Heart Rhythm ; 17(12): 2190-2199, 2020 12.
Article in English | MEDLINE | ID: mdl-32673796

ABSTRACT

BACKGROUND: Scar-related ventricular arrhythmias are common after myocardial infarction. Catheter ablation can improve prognosis, but the procedure is invasive and results are not always satisfactory. Noninvasive, catheter-free ablation using ionizing radiation has recently gained interest among electrophysiologists, but the tissue effects and physiological outcome have not been fully characterized. OBJECTIVE: The purpose of this study was to investigate the structural effects of cardiac scanned pencil beam proton therapy on infarct scar, the time course of imaging biomarkers, arrhythmias, and cardiac function in a porcine model. METHODS: Fourteen infarcted swine underwent proton beam treatment of the scar (40 or 30 Gy) and were followed for up to 30 weeks. Magnetic resonance imaging was performed every 4 weeks. RESULTS: Treated scar areas showed a significantly lower fraction of surviving myocytes at 30 weeks compared to untreated scar (30.1% ± 18.5% and 59.9% ± 10.1% in treated and untreated infarct, respectively), indicating scar homogenization. Four animals died suddenly during follow-up, all from documented monomorphic ventricular tachycardia. Cardiac function remained stable over the course of the study. Distinct imaging morphologies corresponded to certain tissue dose ranges and time points. CONCLUSION: Radioablation of cardiac infarct scar leads to significant homogenization of the scar, replicating the histologic effects of radiofrequency ablation. These changes correspond to distinct imaging morphologies on delayed contrast-enhanced cardiac magnetic resonance imaging, enabling noninvasive confirmation of tissue ablation effects The present study is the first to thoroughly investigate the structural effects of cardiac proton beam therapy in infarcted myocardium.


Subject(s)
Ablation Techniques/methods , Myocardial Infarction/complications , Myocardium/pathology , Proton Therapy/methods , Tachycardia, Ventricular/radiotherapy , Animals , Disease Models, Animal , Dose-Response Relationship, Radiation , Magnetic Resonance Imaging, Cine , Myocardial Infarction/diagnosis , Swine , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/etiology , Treatment Outcome
8.
Heart Rhythm ; 17(11): 1967-1975, 2020 11.
Article in English | MEDLINE | ID: mdl-32470624

ABSTRACT

BACKGROUND: The cryoballoon (CB) catheter is an established tool for pulmonary vein isolation (PVI), but its use is limited for that purpose. OBJECTIVE: The purpose of this study was to investigate the biophysical properties of a newly developed linear cryoablation catheter for creation of linear ablation lesions in an in vivo model. METHODS: Twenty-nine dogs (14 acutely ablated, 15 chronically followed) underwent cryoablation using the linear cryoablation catheter. Regions of interest included the cavotricuspid isthmus (CTI), mitral isthmus (MI), left atrial (LA) roof, and LA posterior wall in an acute study. Cryoablations for CTI and MI were performed in 14 atrial fibrillation animals after PVI and followed over 1 month in the chronic study. Tissue temperature during cryoablation was monitored using implanted thermocouples in the regions of interest. Gross and microscopic pathologic characteristics of the lesions were assessed. RESULTS: In acute animals, lesion length (transmurality) was CTI 34 ± 4 mm (89% ± 11%); MI 29 ± 4 mm (90% ± 13%); LA roof 19 ± 3 mm (90% ± 8%); and LA posterior wall 19 ± 2 mm (81% ± 13%), with 1 or 2 freezes. Chronic bidirectional block was achieved in 13 of 14 CTI (93%) and 10 of 14 MI (71%) ablations after 1-month follow-up and was consistent with lesion continuity and transmurality upon pathology. The lowest tissue temperature correlated well with the closest distance to the linear cryocatheter (r = 0.688; P <.001). CONCLUSION: This linear cryocatheter created continuous and transmural linear lesions with "single-shot" cryoenergy application and has the potential for clinical use in the setting of various arrhythmias.


Subject(s)
Ablation Techniques/methods , Cryosurgery/methods , Electrocardiography , Heart Conduction System/physiopathology , Pulmonary Veins/surgery , Tachycardia, Ectopic Atrial/surgery , Animals , Disease Models, Animal , Dogs , Tachycardia, Ectopic Atrial/physiopathology
9.
Circ Arrhythm Electrophysiol ; 12(11): e007570, 2019 11.
Article in English | MEDLINE | ID: mdl-31707808

ABSTRACT

BACKGROUND: Noninvasive electrocardiographic imaging (ECGi) is used clinically to map arrhythmias before ablation. Despite its clinical use, validation data regarding the accuracy of the system for the identification of arrhythmia foci is limited. METHODS: Nine pigs underwent closed-chest placement of endocardial fiducial markers, computed tomography, and pacing in all cardiac chambers with ECGi acquisition. Pacing location was reconstructed from biplane fluoroscopy and registered to the computed tomography using the fiducials. A blinded investigator predicted the pacing location from the ECGi data, and the distance to the true pacing catheter tip location was calculated. RESULTS: A total of 109 endocardial and 9 epicardial locations were paced in 9 pigs. ECGi predicted the correct chamber of origin in 85% of atrial and 92% of ventricular sites. Lateral locations were predicted in the correct chamber more often than septal locations (97% versus 79%, P=0.01). Absolute distances in space between the true and predicted pacing locations were 20.7 (13.8-25.6) mm (median and [first-third] quartile). Distances were not significantly different across cardiac chambers. CONCLUSIONS: The ECGi system is able to correctly identify the chamber of origin for focal activation in the vast majority of cases. Determination of the true site of origin is possible with sufficient accuracy with consideration of these error estimates.


Subject(s)
Electrocardiography/instrumentation , Heart Conduction System/physiopathology , Imaging, Three-Dimensional , Tachycardia, Ventricular/diagnosis , Animals , Cardiac Pacing, Artificial/methods , Catheter Ablation/methods , Disease Models, Animal , Endocardium/physiopathology , Equipment Design , Female , Male , Preoperative Period , Reproducibility of Results , Swine , Tachycardia, Ventricular/physiopathology , Tachycardia, Ventricular/therapy , Tomography, X-Ray Computed
10.
Heart Rhythm ; 16(11): 1710-1719, 2019 11.
Article in English | MEDLINE | ID: mdl-31004779

ABSTRACT

BACKGROUND: Noninvasive cardiac ablation of ventricular tachycardia (VT) using radiotherapy has recently gained interest among electrophysiologists. The effects of left ventricular (LV) ablative radiation treatment on global LV function and volumes are unknown. OBJECTIVE: The purpose of this study was to investigate the effects of noninvasive ablation on LV function over time. METHODS: Twenty domestic swine underwent proton beam treatment of LV sites in a dose-finding design and were followed for up to 40 weeks by cardiac magnetic resonance imaging at 4-week intervals. Doses investigated were either 40 Gy at 1 site (n = 8) or 30 Gy at 2 sites (n = 4) in the low-dose group and 40 Gy at 3 sites (n = 8) in the high-dose group. RESULTS: LV mean dose (13.2 ± 1.8 Gy vs 4.6 ± 1.8 Gy) and the volume receiving at least 20 Gy (V20Gy) (24.7% ± 4.8% vs 6.4% ± 3.0%) differed significantly between groups. Dose-dependent effects on left ventricular ejection fraction (LVEF) and LV end-diastolic volume became manifest about 3 months after treatment. LVEF decline was correlated to mean dose (correlation coefficient ρ = -0.69; P = .008) and V20Gy (ρ = -0.66; P = .01), as was LV dilation (ρ = 0.72; P = .005; and ρ = 0.75, P = .003 respectively). CONCLUSION: Possible adverse effects on LV function, seen about 3 months after treatment, are dose dependent. Therefore, precise target definition and focused energy delivery are paramount in catheter-free ablation.


Subject(s)
Proton Therapy/methods , Tachycardia, Ventricular/radiotherapy , Ventricular Function, Left/radiation effects , Animals , Disease Models, Animal , Dose-Response Relationship, Radiation , Magnetic Resonance Imaging , Radiotherapy Dosage , Stroke Volume , Swine , Tomography, X-Ray Computed
11.
Article in English | MEDLINE | ID: mdl-28408649

ABSTRACT

BACKGROUND: This study sought to investigate external photon beam radiation for catheter-free ablation of the atrioventricular junction in intact pigs. METHODS AND RESULTS: Ten pigs were randomized to either sham irradiation or irradiation of the atrioventricular junction (55, 50, 40, and 25 Gy). Animals underwent baseline electrophysiological evaluation, cardiac gated multi-row computed tomographic imaging for beam delivery planning, and intensity-modulated radiation therapy. Doses to the coronary arteries were optimized. Invasive follow-up was conducted ≤4 months after the irradiation. A mean volume of 2.5±0.5 mL was irradiated with target dose. The mean follow-up length after irradiation was 124.8±30.8 days. Out of 7 irradiated animals, complete atrioventricular block was achieved in 6 animals of all 4 dose groups (86%). Using the same targeting margins, ablation lesion size notably increased with the delivered dose because of volumetric effects of isodose lines around the target volume. The mean macroscopically calculated atrial lesion volume for all 4 dose groups was 3.8±1.1 mL, lesions extended anteriorly into the interventricular septum. No short-term side effects were observed. No damage was observed in the tissues of the esophagus, phrenic nerves, or trachea. However, histology revealed in-field beam effects outside of the target volume. CONCLUSIONS: Single-fraction doses as low as 25 Gy caused a lesion with interruption of cardiac impulse propagation using this respective target volume. With doses of ≤55 Gy, maximal point-doses to coronary arteries could be kept <7Gy, but target conformity of lesions was not fully achieved using this approach.


Subject(s)
Ablation Techniques , Atrioventricular Node/surgery , Photons , Radiotherapy, Intensity-Modulated , Ablation Techniques/adverse effects , Action Potentials , Animals , Atrioventricular Node/diagnostic imaging , Atrioventricular Node/pathology , Atrioventricular Node/physiopathology , Cardiac-Gated Imaging Techniques , Electrocardiography , Electrophysiologic Techniques, Cardiac , Female , Heart Rate , Male , Models, Animal , Multidetector Computed Tomography , Photons/adverse effects , Radiation Dosage , Radiotherapy Planning, Computer-Assisted , Radiotherapy, Intensity-Modulated/adverse effects , Sus scrofa , Time Factors
12.
Sci Rep ; 6: 38895, 2016 12 20.
Article in English | MEDLINE | ID: mdl-27996023

ABSTRACT

High-energy ion beams are successfully used in cancer therapy and precisely deliver high doses of ionizing radiation to small deep-seated target volumes. A similar noninvasive treatment modality for cardiac arrhythmias was tested here. This study used high-energy carbon ions for ablation of cardiac tissue in pigs. Doses of 25, 40, and 55 Gy were applied in forced-breath-hold to the atrioventricular junction, left atrial pulmonary vein junction, and freewall left ventricle of intact animals. Procedural success was tracked by (1.) in-beam positron-emission tomography (PET) imaging; (2.) intracardiac voltage mapping with visible lesion on ultrasound; (3.) lesion outcomes in pathohistolgy. High doses (40-55 Gy) caused slowing and interruption of cardiac impulse propagation. Target fibrosis was the main mediator of the ablation effect. In irradiated tissue, apoptosis was present after 3, but not 6 months. Our study shows feasibility to use high-energy ion beams for creation of cardiac lesions that chronically interrupt cardiac conduction.


Subject(s)
Arrhythmias, Cardiac/radiotherapy , Radiotherapy, High-Energy/methods , Animals , Apoptosis/radiation effects , Arrhythmias, Cardiac/diagnostic imaging , Arrhythmias, Cardiac/metabolism , Arrhythmias, Cardiac/pathology , Dose-Response Relationship, Radiation , Female , Male , Myocardium/metabolism , Myocardium/pathology , Positron-Emission Tomography , Sus scrofa
13.
Circ Arrhythm Electrophysiol ; 9(1): e003226, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26763224

ABSTRACT

BACKGROUND: Formation of microemboli during catheter ablation has been suggested as a cause for asymptomatic cerebral emboli. However, it is unknown which part of the process and ablation setting/strategy is most strongly related to this occurrence. METHODS AND RESULTS: A total of 27 pigs were used. Catheter/sheath manipulations in left atrium were performed in 25 of 27 pigs outfitted with microemboli monitoring systems. Ablations using open-irrigated radiofrequency catheters were performed in 18 of 25 pigs. Two of 27 pigs did not undergo left atrial procedures and were injected with microembolic materials in the carotid artery to serve as positive controls. In total, 334 sheath/catheter manipulations (transseptal puncture, sheath flushing, catheter insertion, pulmonary vein venography, and sheath exchange) and 333 radiofrequency applications (power setting, 30/50 W; point-by-point/drag ablations) were analyzed. High microbubble volume in the extracorporeal circulation loop and a high number of microembolic signals in carotid artery were observed during sheath/catheter manipulations especially in saline/contrast injections at fast speed and ablations with steam pop. Fast sheath flushing produced significantly higher microbubble volume than slow sheath flushing (median, 12 200 versus 121 nL; P<0.0001). A total of 44 of 126 (35%) blood filters in the circulation loop showed microparticles (thrombus/coagulum and tissue). Most of them were seen after radiofrequency application especially in 50-W ablations, drag ablations, and steam pop. Brain magnetic resonance imaging showed positive-embolic lesions in control pigs. CONCLUSIONS: Formation of microbubbles was the greatest during fast saline/contrast injections and steam pops, whereas high-power radiofrequency applications, drag ablations, and steam pops produced most of the microparticles.


Subject(s)
Atrial Fibrillation/surgery , Catheter Ablation/adverse effects , Heart Atria/surgery , Intracranial Embolism/etiology , Microbubbles/adverse effects , Animals , Atrial Fibrillation/physiopathology , Catheter Ablation/methods , Disease Models, Animal , Electrocardiography , Equipment Design , Risk Factors , Swine , Therapeutic Irrigation
14.
Circ Arrhythm Electrophysiol ; 8(4): 836-45, 2015 Aug.
Article in English | MEDLINE | ID: mdl-26082516

ABSTRACT

BACKGROUND: The differences in ablation characteristics of freezing time and balloon size using second generation cryoballoon are still unknown. METHODS AND RESULTS: Twenty-six dogs underwent pulmonary vein (PV) isolation. Balloon and tissue temperatures (left atrial-PV junction, phrenic nerve, and internal esophagus) were monitored. The ablation duration was randomized to either 3 or 4 minutes, which did not show significant differences in temperature profiles, PV isolation success rate, complications, or histological changes. Twenty dogs underwent cryoablation using 28-mm cryoballoon, 6 dogs were done using the 23-mm cryoballoon. Positioning of the 23-mm cryoballoon was more distal in the PV, which resulted in better PV occlusion. Temperature profiles showed lower temperatures in the 23-mm cryoballoon than in the 28-mm cryoballoon (inner balloon, median [range]: -51.5 [-66.0 to -31.0] versus -43.0 [-64.0 to -26.0]°C, P<0.001; balloon surface: -43.0 [-60.0 to -15.8] versus -6.5 [-46.2 to 28.9]°C, P<0.001; left atrial-PV junction: -6.7 [-20.0 to 21.4] versus 15.8 [-14.4 to 35.1]°C, P<0.001), and trended toward a higher PV isolation success rate in the 23-mm cryoballoon. Histologically, deeper extensions of ablative lesions into the PV were seen with 23-mm cryoballoon, and larger ablative lesions were seen in the left atrial antrum using 28-mm cryoballoon. CONCLUSIONS: The efficacy of 3-minute ablation was not significantly different from 4-minute ablation in dogs. The 23-mm cryoballoon had a greater cooling effect than the 28-mm cryoballoon for small PVs, but showed narrower ablative lesions in the left atrial antrum.


Subject(s)
Atrial Fibrillation/surgery , Body Temperature/physiology , Cryosurgery/instrumentation , Freezing , Heart Atria/surgery , Heart Conduction System/surgery , Pulmonary Veins/surgery , Animals , Atrial Fibrillation/physiopathology , Catheters , Dogs , Equipment Design , Heart Atria/physiopathology , Heart Conduction System/physiopathology , Time Factors , Treatment Outcome
15.
Circ Arrhythm Electrophysiol ; 8(1): 186-92, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25532529

ABSTRACT

BACKGROUND: Thermodynamics in the left atrium-pulmonary vein (PV) junction, phrenic nerve, and esophagus during PV isolation (PVI) using the second-generation cryoballoon are not known. METHODS AND RESULTS: Twenty dogs underwent PVI using second-generation cryoballoon. Ablations were performed for ≤2 deliveries based on PVI without a bonus freeze. Inner balloon, balloon surface, and tissue temperatures were monitored during cryoablation. The tissue thermocouples were placed on the epicardial surface of the left atrium-PV junction, as well as on the phrenic nerve and within the esophagus. A total of 259 cryoballoon and 229 tissue tissue thermocouples profiles during 53 cryoablations of 40 PVs were analyzed. Acutely, PVI was achieved in 36 of 40 PVs (90%). Conductive tissue cooling spread radially from the balloon-left atrium-PV contact point. The lowest tissue temperatures were dependent on the distance of the tissue thermocouples to the balloon surface (r=0.85; P<0.001). In addition, blood flow leaks around the balloon had a warming effect on the balloon and tissue temperature profiles. Chronic isolation (mean, 48±16 days) was achieved in 27 of 36 PVs (75%). In 8 of 9 acutely isolated but with chronic reconnection PVs, the blood flow leak location was concordant with chronic reconnection gap. Although only 1 esophageal ulcerated lesion was observed, neither phrenic nerve palsy nor severe PV stenosis was seen in any dogs. CONCLUSIONS: Variance in tissue thermodynamics during cryothermal ablation depends on the distance from balloon and peri-balloon blood flow leaks. This information may be useful for successful PVI without severe complications.


Subject(s)
Cardiac Catheters , Cryosurgery/instrumentation , Pulmonary Veins/surgery , Animals , Blood Flow Velocity , Cryosurgery/adverse effects , Dogs , Equipment Design , Models, Animal , Pulmonary Circulation , Pulmonary Veins/pathology , Pulmonary Veins/physiopathology , Regional Blood Flow , Temperature , Time Factors
16.
Am J Prev Med ; 43(6 Suppl 5): S435-42, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23157762

ABSTRACT

BACKGROUND: Hurricanes Katrina and Rita struck the Gulf Coast forcing unprecedented mass evacuation and devastation. Texas 2-1-1 is a disaster communication hub between callers with unmet needs and community services at disaster sites and evacuation destinations. PURPOSE: To describe the location and timing of unmet disaster needs collected in real-time through Katrina-Rita disaster phases. METHODS: In 2008-2010, a total of 25 data sets of Texas 2-1-1 calls from August-December 2005 were recoded and merged. In 2011-2012, analysis was performed of unmet need types, with comparisons over time and location; mapping was adjusted by population size. RESULTS: Of 635,983 total 2-1-1 calls during the study period, 65% included primary disaster unmet needs: housing/shelter (28%); health/safety (18%); food/water (15%); transportation/fuel (4%). Caller demand spiked on Mondays, decreasing to a precipitous drop on weekends and holidays. Unmet needs surged during evacuation and immediate disaster response, remaining at higher threshold through recovery. Unmet need volume was concentrated in metropolitan areas. After adjusting for population size, "hot-spots" showed in smaller evacuation destinations and along evacuation routes. CONCLUSIONS: New disaster management strategies and policies are needed for evacuation destinations to support extended evacuation and temporary or permanent relocation. Planning and monitoring disaster resources for unmet needs over time and location could be targeted effectively using real-time 2-1-1 call patterns. Smaller evacuation communities were more vulnerable, exhausting their limited resources more quickly. Emergency managers should devise systems to more quickly authorize vouchers and reimbursements. As 2-1-1s expand and coordinate disaster roles nationwide, opportunities exist for analysis of unmet disaster needs to improve disaster management and enhance community resiliency.


Subject(s)
Disaster Planning/organization & administration , Disasters , Health Services Needs and Demand , Information Services/organization & administration , Benzocaine , Communication , Emergency Shelter/statistics & numerical data , Humans , Information Services/statistics & numerical data , Telephone , Texas , Time Factors
17.
Aust N Z J Psychiatry ; 39(10): 899-906, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16168017

ABSTRACT

OBJECTIVE: As deliberate self-harm (DSH) is a common concomitant of depressive disorders, we undertook a study examining the relevance of possible determinants and correlates of DSH. METHOD: Three separate samples of depressed outpatients were studied to determine consistency of identified factors across samples, with principal analyses involving gender, age and diagnosis-matched DSH and non-DSH subjects. RESULTS: Across the samples, some 20% of subjects admitted to episodes of DSH. Women reported higher rates and there was a consistent trend for higher rates in bipolar patients. Univariate analyses examined the relevance of several sociodemographic variables, illicit drug and alcohol use, past deprivational and abusive experiences, past suicidal attempts and disordered personality functioning. Multivariate analyses consistently identified previous suicide attempts and high 'acting out' behaviours across the three samples, suggesting the relevance of an externalizing response to stress and poor impulse control. CONCLUSIONS: Results assist the identification and management of depressed patients who are at greater risk of DSH behaviours.


Subject(s)
Depressive Disorder/psychology , Self-Injurious Behavior/psychology , Adult , Alcoholism/psychology , Anxiety Disorders/epidemiology , Anxiety Disorders/psychology , Child , Child Abuse/psychology , Child Abuse, Sexual/psychology , Female , Humans , Male , Odds Ratio , Parents/psychology , Personality Disorders/psychology , Socioeconomic Factors , Stress, Psychological/psychology , Substance-Related Disorders/psychology
18.
Am J Psychiatry ; 162(4): 796-8, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15800157

ABSTRACT

OBJECTIVE: The authors' goal was to determine if prescription of antidepressant medication plus olanzapine initiates a more rapid response than prescription of antidepressant alone. METHOD: Twenty patients with major depression were studied. For 2 weeks the patients were blindly assigned to receive antidepressant plus olanzapine or antidepressant plus placebo. After 2 weeks, olanzapine augmentation was initiated for patients who did not improve with placebo augmentation. Response to medication was measured primarily by Hamilton Depression Rating Scale score. Other measures were the CORE, Clinical Global Impression, Beck Depression Inventory, and Daily Rating Schedule. RESULTS: Hamilton depression scores improved nonsignificantly in response to olanzapine combination therapy, but that trend was not evident on any secondary measure. Four patients who did not improve while receiving antidepressant and placebo showed rapid remission following late olanzapine augmentation. CONCLUSIONS: Failure to demonstrate any benefit from initial combination therapy may reflect an underpowered rather than a negative study. The distinct impact of late olanzapine augmentation suggests that pretreatment with an antidepressant may be required to facilitate a rapid antidepressant response to combined treatment.


Subject(s)
Antidepressive Agents/therapeutic use , Antipsychotic Agents/therapeutic use , Benzodiazepines/therapeutic use , Depressive Disorder, Major/drug therapy , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/psychology , Drug Therapy, Combination , Female , Humans , Male , Middle Aged , Olanzapine , Personality Inventory , Pilot Projects , Placebos , Psychiatric Status Rating Scales/statistics & numerical data , Severity of Illness Index , Time Factors , Treatment Outcome
19.
Curr Opin Psychiatry ; 18(1): 1-5, 2005 Jan.
Article in English | MEDLINE | ID: mdl-16639176

ABSTRACT

PURPOSE OF REVIEW: A 2004 review of 'atypical depression' in Current Opinion in Psychiatry could be read as more reifying the Columbian and DSM-IV concept rather than considering an alternative model that has been supported by independent studies undertaken in Australia and North America. Additional analyses of the Australian data set are reported to examine inter-study agreement further and to consider the implications. RECENT FINDINGS: Both studies recruited patients meeting criteria for a major depressive episode, and then contrasted patients meeting or not meeting DSM-IV criteria for definite atypical depression. In both studies, those with atypical depression were comparable in terms of female preponderance, age, age at first episode and depression severity, but developed earlier and more persistent episodes, showed a slight female preponderance, and were more likely to meet criteria for panic disorder, social phobia and hypochondriasis, and of avoidant and dependent personality styles. In both, there was a lack of evidence suggesting that atypical depression differs in severity, in being clearly less likely to have certain 'endogeneity' symptoms, or in being more likely to be associated with bipolar disorder, while neither the centrality of mood reactivity nor interdependence of symptoms could be demonstrated. SUMMARY: Findings from both studies challenge the view that atypical depression is an entity and the current model of its constituent features. Both found support for primacy of personality style (rather than mood reactivity) and for certain expressions of anxiety. Both effectively argue for and assist shaping of a revisionist model for conceptualizing atypical depression as a syndrome or spectrum disorder.

20.
Int J Geriatr Psychiatry ; 18(12): 1102-9, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14677142

ABSTRACT

OBJECTIVE: To determine if we could find support for a three-class depression sub-typing model (and identify differentiating constituent clinical features) in a sample of elderly depressed patients. BACKGROUND: Depression is currently modelled dimensionally, with little concession to descriptive psychopathology and distinction of meaningful clinical depressive sub-types. We have proposed a three-class hierarchical specificity model for sub-typing the depressive disorders (comprising psychotic, melancholic and non-melancholic depression), with specificity referring to two clinical features (psychotic symptoms and psychomotor disturbance or PMD) separating the first two classes from a residual non-melancholic class. METHOD: Subjects were aged 65 years or more, non-demented and being treated for depression. Extensive clinical assessment was undertaken, while several standardised measures were administered. 'Bottom up' analyses were data driven, while 'top down' analyses respected DSM-III-R decision rules. Dimensional and categorical multivariate analyses sought to identify features differentiating psychotic depression (PD), melancholic depression (MEL) and a residual non-melancholic (NON-MEL) class. RESULTS: Of the 123 referred patients (having a mean age of 75.6 years), 46 had DSM-defined PD, 46 had MEL and 31 were assigned as NON-MEL. Mean total CORE scores (measuring PMD) more clearly distinguished the groups than scores on two depression severity measures. Psychotic depression was best distinguished from melancholic depression by psychotic features, as well as more severe PMD and anhedonia. Melancholic depression was best distinguished from non-melancholic depression by PMD, terminal insomnia and pathological guilt. CONCLUSION: The specificity of PMD to the definition of the psychotic and melancholic depression was confirmed in our elderly depressed sample. Clinical features identified as distinguishing psychotic, melancholic and non-melancholic depression were broadly consistent with findings from our previous studies involving younger subjects and with our three-class hierarchical model.


Subject(s)
Depressive Disorder/psychology , Aged , Depressive Disorder/classification , Humans , Models, Psychological , Psychotic Disorders/classification , Psychotic Disorders/psychology
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