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24 citation(s) found for "Zyl, JI van".

Atrial fibrillation in partial anomalous pulmonary venous return: right atrial drainage from one vein and epicardial conduction from another vein
Bhalla, Jaideep Singh , Zyl, Martin van , Madhavan, Malini , Bhalla, Jaideep

Mayo Clinic

EP Europace | February 1, 2022 | Volume: 24 | Issue: 9 | Pages: 1459-1459

10.1093/europace/euac006 | PMID 35357427 Get It

High-Dose Methotrexate Is Not Associated with Reduction in CNS Relapse in Patients with Aggressive B-Cell Lymphoma: An International Retrospective Study of 2300 High-Risk Patients
Villa, Diego , Bobillo, Sabela , Smedby, Karin Ekstroem, Eyre, Toby A. , Cwynarski, Kate , Caporn, Paris L., Zyl, Joan Van, Puckrin, Robert , Stewart, Douglas A. , Thanarajasingam, Gita , Joffe, Erel , Eloranta, Sandra , Maliske, Seth , Poonsombudlert, Kittika , Guo, Xiao, Hapgood, Greg , Manos, Kate , Gilbertson, Michael , Streit, Isaac T, Scott, Hamish W , Ku, Matthew , Mel, Sanjay De , Yong, Kar Ying , Liu, Xin , Mokoonlall, Mridula , McVilly, Nicholas L., Johnston, Anna , Brunner, Matthew, Ku, Matthew , Lewis, Katharine L. , Jakobsen, Lasse Hjort , Savage, Kerry J. , Klánová, Magdalena , Trněný, Marek , Bishton, Mark , Fox, Christopher P. , Tun, Aung M. , Djebbari, Faouzi , Harrysson, Sara , Sehn, Laurie H. , Hawkes, Eliza A. , Khwaja, Jahanzaib , Minson, Adrian , Dickinson, Michael , Øvlisen, Andreas Kiesbye , Gregory, Gareth P. , Streit, Isaac T., Talaulikar, Dipti , Brunner, Matthew J, Pophali, Priyanka A. , Maurer, Matthew J. , El‐Galaly, Tarec Christoffer , Cheah, Chan Y.

Mayo Clinic

Blood | November 23, 2021 | Volume: 138 | Issue: Supplement 1 | Pages: 181-181

10.1182/blood-2021-146737 Get It

Abstract Introduction Central nervous system relapse (secondary central nervous system lymphoma -SCNS) is an uncommon but devastating complication of aggressive B-cell lymphoma. Patients (Pts) with CNS-IPI 4-6 are at greatest risk (10.2% at 2 years). Intravenous high-dose methotrexate (HD-MTX) is widely used to mitigate SCNS risk but data supporting this practice are limited. Methods We performed a multicentre, retrospective study at 21 sites in Australia, Asia, North America and Europe. Chart or registry review was performed for consecutively diagnosed pts with diffuse large B-cell lymphoma (DLBCL) and CNS-IPI 4-6, high grade B-cell lymphoma (HGBL) with rearrangements of MYC+BCL2 and/or BCL6 and primary breast/testicular DLBCL irrespective of CNS-IPI. Pts were diagnosed between 2000-2020, 18-80 years at diagnosis, and treated with curative intent anti-CD20 based chemo-immunotherapy. Pts with CNS involvement at diagnosis were excluded. HD-MTX was defined as at least one cycle of intravenous MTX at any dose. Time to SCNS was calculated from date of diagnosis (all-pts), and from the end of frontline systemic lymphoma therapy, defined as 6x21 days from diagnosis (complete response (CR-pts)), until SCNS, systemic relapse, death, or censoring, whichever came first. Cumulative risk of SCNS was computed using the Aalen-Johansen estimator treating death and systemic relapses as competing events. Adjusted cumulative risks were obtained by using an inverse probability of treatment weighting approach. The average treatment effect was computed as the difference in adjusted 5-year risk of SCNS. Results - 2300 and 1455 pts were included in the all-pts and CR-pts analyses, respectively. Baseline demographics and details of therapy are summarised in Table 1. Except for a predominance of males, pts ≤60 years and pts with ECOG 0-1 in the HD-MTX vs no HD-MTX groups, the demographics and treatments were well balanced. At a median follow up of 5.9 years (range 0.0-19.1) and 5.5 years from diagnosis (range 0.0-18.7), 201/2300 and 84/1455 pts experienced CNS events in the all-pts and CR-pts analyses respectively. For all-pts(n=2300), CNS-IPI was 4-6 in 2052(89.2%), with R-CHOP-like therapy given to 93.8%. 410 pts (17.8%) received HD-MTX (265 HD-MTX alone, 145 in combination with intrathecal methotrexate (IT-MTX);435 received IT-MTX alone;1455 received neither. There were 32/410 and 169/1890 SCNS events, with median time from diagnosis to SCNS of 8.8 and 6.7 months in the HD-MTX and no HD-MTX groups respectively. 5-year OS was 70% (95% CI, 65-76%) and 55% (95% CI 53-57%) in HD-MTX and no HD-MTX groups respectively. There was no difference in the adjusted 5-year risk of SCNS between the HD-MTX and no HD-MTX groups (8.4% vs 9.1%, adjusted hazard ratio [HR] 0.71, p=0.100) (Figure 1). For CR-pts(n=1455), CNS-IPI was 4-6 in 1267(87.0%), with R-CHOP-like therapy given to 93.3%. 284 pts (19.5%) received HD-MTX (170 HD-MTX alone, 114 with IT-MTX);298 received IT-MTX alone;873 received neither. There were 16/284 and 68/1171 SCNS events, with median time from diagnosis to SCNS of 11.0 and 10.3 months in the HD-MTX and no HD-MTX groups respectively. 5-year OS was 74%(95% CI 67-81%) and 75%(95% CI 72-78%) in the HD-MTX groups and no HD-MTX groups respectively (adjusted HR 1.08, p=0.622). There was no difference in the 5-year risk of CNS relapse between the HD-MTX and no HD-MTX groups 5.0% vs 6.0% (adjusted HR 1.03, p=0.903) (Figure 2). Exploratory analysis of the impact of HD-MTX among the highest risk groups CNS IPI 5 (n=368), CNS-IPI 6 (n=59) and CNS-IPI 6 plus all pts with testicular, renal or adrenal involvement (n=349) did not reveal differences in SCNS rates in HD-MTX treated pts. Additional subgroup analyses will be presented at the meeting. Conclusions To our knowledge, this is the largest study of the efficacy of HD-MTX in reducing SCNS events focusing exclusively on high-risk pts. The overall incidence of CNS relapse observed was consistent with previous reports in similar patient cohorts at 9%. The use of HD-MTX did not lower SCNS rates overall or when analysis was confined to CR pts at completion of curative intent therapy to compensate for potential immortal bias associated with HD-MTX therapy. Despite the limitations of the non-randomized and retrospective design, it appears unlikely that HD-MTX is associated with a clinically meaningful reduction in SCNS rates in pts with high risk for SCNS. Figure 1 Figure 1. Disclosures Lewis: AstraZeneca: Consultancy, Honoraria; Novartis: Patents & Royalties: Conference attendance; Janssen: Honoraria, Patents & Royalties: Conference attendance; Roche: Consultancy, Honoraria. Villa: Janssen: Honoraria; Gilead: Honoraria; AstraZeneca: Honoraria; AbbVie: Honoraria; Seattle Genetics: Honoraria; Celgene: Honoraria; Lundbeck: Honoraria; Roche: Honoraria; NanoString Technologies: Honoraria. Bobillo: F. Hoffmann-La Roche Ltd: Consultancy, Speakers Bureau; Gilead: Speakers Bureau. Ekstroem Smedby: Takeda: Consultancy; Janssen Cilag: Research Funding. Savage: Merck: Consultancy, Honoraria, Other: Institutional clinical trial funding; BMS: Consultancy, Honoraria, Other: Institutional clinical trial funding; AbbVie: Consultancy, Honoraria; Roche: Research Funding; Takeda: Other: Institutional clinical trial funding; Servier: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Beigene: Other: Institutional clinical trial funding; Genentech: Research Funding. Eyre: Beigene: Honoraria, Research Funding; Incyte: Consultancy; Secura Bio: Consultancy, Honoraria; Janssen: Honoraria; Gilead/KITE: Honoraria, Other: Travel support for conferences, Research Funding, Speakers Bureau; Loxo Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Other: Travel to conferences; AstraZeneca: Honoraria, Research Funding; Roche: Consultancy, Honoraria. Cwynarski: Incyte: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Atara: Consultancy; Celgene: Consultancy; Takeda: Consultancy, Other: travel to scientific conferences, Speakers Bureau; Kite, a Gilead Company: Consultancy, Other: travel to scientific conferences, Speakers Bureau; Janssen: Consultancy, Other: travel to scientific conferences; Roche: Consultancy, Other: travel to scientific conferences, Speakers Bureau; BMS/Celgene: Other: travel to scientific conferences. Stewart: Teva: Honoraria; Sandoz: Honoraria; Amgen: Honoraria; AstraZeneca: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Gilead: Honoraria; Abbvie: Honoraria; Janssen: Honoraria; Roche: Honoraria. Bishton: Gilead: Honoraria, Other: Travel grants; AbbVie: Honoraria, Other: Travel grants; Celgene/BMS: Honoraria, Other: travel grants; Celltrion: Honoraria, Other: Travel grants; Takeda.: Honoraria, Other: Travel grants . Fox: F. Hoffmann-La Roche Ltd: Consultancy, Membership on an entity's Board of Directors or advisory committees. Joffe: Epizyme: Consultancy; AstraZeneca: Consultancy. Eloranta: Janssen Pharmaceutical NV: Other: NV. Sehn: Genmab: Consultancy; Novartis: Consultancy; Debiopharm: Consultancy. Manos: Bristol-Myers Squibb: Other: Travel and meetings. Hawkes: Specialised Therapeutics: Consultancy; Gilead: Membership on an entity's Board of Directors or advisory committees; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Antigene: Membership on an entity's Board of Directors or advisory committees; Regeneron: Speakers Bureau; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck KgA: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Janssen: Speakers Bureau. Minson: Novartis: Research Funding; Hoffman La Roche: Research Funding. Dickinson: Celgene: Research Funding; Amgen: Honoraria; Takeda: Research Funding; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, accommodation, expenses, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Øvlisen: Abbvie: Other: Travel expenses. Gregory: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel fees, Speakers Bureau; Janssen: Consultancy; Novartis: Consultancy. Ku: Roche: Consultancy; Antegene: Consultancy; Genor Biopharma: Consultancy. Talaulikar: Roche: Honoraria, Research Funding; Jansenn: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; EUSA Pharma: Honoraria, Research Funding. Maurer: Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Genentech: Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees, Research Funding; Nanostring: Research Funding. El-Galaly: Abbvie: Other: Speakers fee; ROCHE Ltd: Ended employment in the past 24 months. Cheah: Roche: Consultancy, Honoraria, Other: advisory and travel expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: advisory; MSD: Consultancy, Honoraria, Other: advisory, Research Funding; Gilead: Consultancy, Honoraria, Other: advisory; Ascentage pharma: Consultancy, Honoraria, Other: advisory; Beigene: Consultancy, Honoraria, Other: advisory; AbbVie: Research Funding; Celgene: Research Funding; AstraZeneca: Consultancy, Honoraria, Other: advisory; Loxo/Lilly: Consultancy, Honoraria, Other: advisory; TG Therapeutics: Consultancy, Honoraria, Other: advisory.
Activation Pattern During His-Bundle Pacing
Yasin, Omar , Bush, Jaime, Vaidya, Vaibhav R. , Tri, Jason , Zyl, Martin van , Xiao, Peilin , Scheuermann, Cory, Asirvatham, Samuel J. , Cha, Yong‐Mei , Asirvatham, Samuel J , Xiao, Peilin , Han, Jie

Mayo Clinic

No container title available | July 11, 2021 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.22541/au.162602806.64990926/v1 Get It

Abstract 12776: Long Term Mortality With Right Ventricular Apical Versus Septal Pacing
Witt, Chance M. , Lenz, Charles J., Shih, Henry, Ebrille, Elisa , Rosenbaum, Andrew , Aung, Htin , Zyl, Martin van , Manocha, Kevin K. , Deshmukh, Abhishek , Hodge, David O. , Aung, Htin, Asirvatham, Samuel J. , McLeod, Christopher J.

Mayo Clinic

Circulation | July 3, 2021 | Volume: 132 | Issue: suppl_3 | Pages: No page available

10.1161/circ.132.suppl_3.12776 Get It

Introduction: Right ventricular apical (RVA) pacing appears to have detrimental effects on cardiac function and long term outcomes. Right ventricular non-apical (RVNA) pacing, especially in the septal position, has been postulated as an alternative that may lead to less morbidity and mortality. Prior studies have shown conflicting results and been limited by small numbers and short follow-up. We aimed to determine if right ventricular septal lead position was associated with a reduction in long-term mortality compared to RVA lead position. Methods: Patients who underwent dual-chamber pacemaker implantation from 2004 through 2013 were evaluated for right ventricular lead position based on chest radiographs. Lead positions were divided in to apical or non-apical. Non-apical lead positions were subdivided to isolate a septal lead position group. Mortality was compared between these groups. Results: During the study period, 3456 patients underwent dual-chamber pacemaker placement and had images appropriate for lead position evaluation. The group was 53.5% male with a mean age of 74 ± 13 years. RVNA lead position was found in 976 (28.2%) patients, including 243 (7.0%) with a septal position. There was no significant difference in age or prior heart failure diagnosis between groups. Kaplan-Meier survival analysis did not reveal a significant difference in mortality between patients with RVA versus RVNA lead position during 5 year follow-up (p = 0.82). However, septal lead position was associated with a significantly lower mortality compared with RVA position (p = 0.03) (figure). Conclusions: Right ventricular septal lead position is associated with a lower long-term mortality than RVA lead position. This has substantial implications regarding the preferred site for ventricular pacing lead placement.
A sound method for axillary vein access
Zyl, Martin van , Deshmukh, Abhishek , van Zyl, Martin , Deshmukh, Abhishek J

Mayo Clinic

Journal of Cardiovascular Electrophysiology | December 18, 2020 | Volume: 32 | Issue: 2 | Pages: 466-467

10.1111/jce.14839 | PMID 33337565 Get It

A Sound Method for Axillary Vein Access
Zyl, Martin van , Deshmukh, Abhishek

Mayo Clinic

No container title available | December 5, 2020 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.22541/au.160722565.59453010/v1 Get It

Ultrasound guided venous access Is important to minimize pneumothorax and unnecessary incisions in patients undergoing device implant.
A cool modality to restore sinus rhythm
Yasin, Omar , Sugrue, Alan , Zyl, Martin van , Ladejobi, Adetola, Tri, Jason , Rynbrandt, J, Seifert, Gregory J., Sanders, R., Pedersen, Joanne, Yngsdal, Lisa, Ladewig, Dorothy J., Taubel, R, Ritrivi, Charles, Asirvatham, S, Friedman, Paul A. , Rynbrandt, Jeff, Seifert, Greg

Mayo Clinic

European Heart Journal | November 26, 2020 | Volume: 41 | Issue: Supplement_2 | Pages: No page available

10.1093/ehjci/ehaa946.0551 Get It

Abstract Background Slowing electrical conduction by cooling the myocardium can be used for defibrillation. We previously demonstrated the efficacy of a small cold device placed in oblique sinus (OS) in terminating atrial fibrillation (AF). However, the parameters needed to achieve effective atrial defibrillation are unknown. Purpose Assess effect of the size of cooled myocardium on frequency of AF termination in acute canine animal models. Methods Sternotomy was performed under general anesthesia in 10 acute canine experiments. AF was induced using rapid atrial pacing and intra-myocardial epinephrine and acetylcholine injections. Once AF sustained for at least 30s, either a cool (7–9°C) or placebo (body temperature) device was placed in the OS. Four device sizes were tested; ½X½, ¾X¾, and 1X1 inch devices and two ¾X¾ inch devices placed side by side simultaneously. Time to AF termination was recorded. Chi-squared or Fisher's exact test were used to compare the frequency of arrhythmia termination with cooling versus placebo. Results A total of 166 applications were performed (89 cool vs 77 placebo) in 10 animal experiments. Overall, AF terminated in 82% of the cooling applications vs. 67.5% of placebo (P=0.03, Figure 1). For the ½X½ inch device 88% of cold applications restored sinus rhythm vs. 63.6% for placebo (P=0.05). The frequency of sinus restoration for cold ¾X¾, 1X1 and two ¾X¾ side by side devices was 86.7%, 83.3% and 70% respectively. Time to sinus restoration when achieved was within three minutes was also not significantly changed. Conclusion Placing a cool device in the oblique sinus can terminate AF and efficacy is not affected by the size of device. Funding Acknowledgement Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): MediCool Technologies
Activation pattern during his pacing: how close are we to normal physiology?
Yasin, Omar , Vaidya, Vaibhav R. , Tri, Jason , Zyl, Martin van , Ladejobi, Adetola, Scheuermann, Carolin, Bush, J , Taubel, R, Pedersen, Joanne, Yngsdal, Lisa, Asirvatham, S, Cha, Y, Xiao, Ping , Han, Jin

Mayo Clinic

European Heart Journal | November 26, 2020 | Volume: 41 | Issue: Supplement_2 | Pages: No page available

10.1093/ehjci/ehaa946.0804 Get It

Abstract Background His bundle pacing aims to mimic the activation pattern of normal conduction to maintain ventricular synchrony. However, selective His capture can be challenging, and the activation sequence during His pacing may not replicate normal conduction. Purpose Compare the right ventricular (RV) and left ventricular (LV) activation pattern in sinus rhythm and His bundle pacing. Methods Baseline LV and RV map was created in sinus rhythm using Rhythmia mapping system (Boston Scientific Corporation) in canine animal model. Medtronic 3830 lead was placed near the bundle of His under fluoroscopic, intracardiac echocardiogram, and electroanatomic guidance. Conduction system capture was confirmed by observing a QRS duration <120ms and an isoelectric segment between pacing artifact and QRS on surface ECG. Repeat LV and RV activation map was obtained during His pacing. Average QRS, HV and pacing to V intervals were calculated with standard deviation. Results Mapping was performed successfully in four animals. At baseline, the average QRS duration was 44±2.6ms and HV interval was 32±4.2ms. Earliest site of myocardial activation was in the mid-septal LV region. The earliest RV myocardial activation was also at the septum closer to the apex, but later than the LV (Figure1A). With His pacing, the average QRS duration was 70±17.0ms and the average stim to V interval was 31±8.7ms. During His pacing, the earliest site of activation was in the RV septum, with an activation pattern from base to apex in both the RV and LV. Conclusion Unlike normal physiology, the activation pattern during conduction system pacing is from base to apex with earliest site in the RV. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Mayo Clinic
Injectable conductive hydrogel restores conduction through ablated myocardium
Zyl, Martin van , Pedrotty, Dawn , Kuzmenko, Volodymyr , Sämfors, Sanna, Livia, Christopher , Vaidya, Vaibhav R. , Sugrue, Alan , Behfar, Atta , Asirvatham, Samuel J. , Gatenholm, Paul , Kapa, Suraj , van Zyl, Martin , Livia, Christopher , Vaidya, Vaibhav , Sugrue, Alan , Asirvatham, Samuel J , Gatenholm, Paul , Kapa, Suraj , Behfar, Atta , Karabulut, Erdem , McLeod, Christopher J.

Mayo Clinic

Journal of Cardiovascular Electrophysiology | September 23, 2020 | Volume: 31 | Issue: 12 | Pages: 3293-3301

10.1111/jce.14762 | PMID 32966655 Get It

AbstractIntroductionTherapies for substrate‐related arrhythmias include ablation or drugs targeted at altering conductive properties or disruption of slow zones in heterogeneous myocardium. Conductive compounds such as carbon nanotubes may provide a novel personalizable therapy for arrhythmia treatment by allowing tissue homogenization.MethodsA nanocellulose carbon nanotube‐conductive hydrogel was developed to have conduction properties similar to normal myocardium. Ex vivo perfused canine hearts were studied. Electroanatomic activation mapping of the epicardial surface was performed at baseline, after radiofrequency ablation, and after uniform needle injections of the conductive hydrogel through the injured tissue. Gross histology was used to assess distribution of conductive hydrogel in the tissue.ResultsThe conductive hydrogel viscosity was optimized to decrease with increasing shear rate to allow expression through a syringe. The direct current conductivity under aqueous conduction was 4.3 × 10−1 S/cm. In four canine hearts, when compared with the homogeneous baseline conduction, isochronal maps demonstrated sequential myocardial activation with a shift in direction of activation to surround the edges of the ablated region. After injection of the conductive hydrogel, isochrones demonstrated conduction through the ablated tissue with activation restored through the ablated tissue. Gross specimen examination demonstrated retention of the hydrogel within the tissue.ConclusionsThis proof‐of‐concept study demonstrates that conductive hydrogel can be injected into acutely disrupted myocardium to restore conduction. Future experiments should focus on evaluating long‐term retention and biocompatibility of the hydrogel through in vivo experimentation.
Injectable conductive hydrogel restores conduction through ablated myocardium
Zyl, Martin van , Pedrotty, Dawn , Karabalut, Erdem, mfors, Sanna S, Livia, Chris, Vaidya, Vaibhav R. , Sugrue, Alan , Gatenholm, Paul , Kuzmenko, Volodymyr , Livia, Christopher , McLeod, Christopher J. , Behfar, Atta , Asirvatham, Samuel J. , Kapa, Suraj

Mayo Clinic

No container title available | July 6, 2020 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.22541/au.159406900.02369826 Get It

Abstract Introduction: Therapies for substrate-related arrhythmias include ablation or drugs targeted at altering conductive properties or disruption of slow zones in heterogeneous myocardium. Conductive compounds such as carbon nanotubes may provide a novel personalizable therapy for arrhythmia treatment by allowing tissue homogenization. Methods: A nanocellulose-carbon nanotube conductive hydrogel was developed to have conduction properties similar to normal myocardium. Ex vivo perfused canine hearts were studied. Electroanatomic activation mapping of the epicardial surface was performed at baseline, after radiofrequency ablation, and after uniform needle injections of the conductive hydrogel through the injured tissue. Gross histology was used to assess distribution of conductive hydrogel in the tissue. Results: The conductive hydrogel viscosity was optimized to decrease with increasing shear rate to allow expression through a syringe. The DC conductivity under aqueous conduction was 4.3·10-1 S/cm. In 4 canine hearts, when compared to the homogeneous baseline conduction, isochronal maps demonstrated sequential myocardial activation with a shift in direction of activation to surround the edges of the ablated region. After injection of conductive hydrogel, isochrones demonstrated conduction through the ablated tissue with activation similar to baseline in all 4 hearts. Gross specimen examination demonstrated retention of the hydrogel within the tissue. Conclusions: This proof-of-concept study demonstrates that conductive hydrogel can be injected into acutely disrupted myocardium to restore conduction. Future experiments should focus on evaluating long-term retention and biocompatibility of the hydrogel through in vivo experimentation.