Thermal Ablative Procedures in the Treatment of Heart Arrhythmia

AbstractIn the last several years, quite a few papers on the joint question of transport, tortuosity and percolation have appeared in the literature, dealing with passage of miscellaneous liquids or electrical currents in different media. However, these methods have not been applied to the passage of action potential in heart fibrosis (HF), which is crucial for problems of heart arrhythmia, especially of atrial tachycardia and fibrillation. In this work we address the HF problem from these aspects. A cellular automaton model is used to analyze percolation and transport of a distributed-fibrosis inflicted heart-like tissue. Although based on a rather simple mathematical model, it leads to several important outcomes: (1) It is shown that, for a single wave front (as the one emanated by the heart's sinus node), the percolation of heart-like matrices is exactly similar to the forest fire case. (2) It is shown that, on the average, the shape of the transport (a question not dealt with in relation to forest fire, and deals with the delay of action potential when passing a fibrotic tissue) behaves like a Gaussian. (3) Moreover, it is shown that close to the percolation threshold the parameters of this Gaussian behave in a critical way. From the physical point of view, these three results are an important contribution to the general percolation investigation. The relevance of our results to cardiological issues, specifically to the question of reentry initiation, are discussed and it is shown that: (A) Without an ectopic source and under a mere sinus node operation, no arrhythmia is generated, and (B) A sufficiently high refractory period could prevent some reentry mechanisms, even in partially fibrotic heart tissue.

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F2.3 Focal infection in oral cavity of patient with extrasystolic heart arrhythmia

International Journal of Antimicrobial Agents ◽

10.1016/s0924-8579(05)80305-x ◽

2005 ◽

Vol 26 ◽

pp. S107

Keyword(s):

Oral Cavity ◽

Heart Arrhythmia ◽

Focal Infection

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Detection of Heart Arrhythmia Using Hybrid Neural Networks

2020 IEEE REGION 10 CONFERENCE (TENCON) ◽

10.1109/tencon50793.2020.9293831 ◽

2020 ◽

Author(s):

Shreeven Kommireddy ◽

Piyush Raj Pandey ◽

Raghu Kishore NeeliSetti

Keyword(s):

Neural Networks ◽

Heart Arrhythmia ◽

Hybrid Neural Networks

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Bilateral trigeminal neuralgia: a 14-year experience with microvascular decompression

Journal of Neurosurgery ◽

10.3171/jns.1988.68.4.0559 ◽

1988 ◽

Vol 68 (4) ◽

pp. 559-565 ◽

Cited By ~ 59

Author(s):

Ian F. Pollack ◽

Peter J. Jannetta ◽

David J. Bissonette

Keyword(s):

Trigeminal Neuralgia ◽

Posterior Fossa ◽

Microvascular Decompression ◽

Pain Control ◽

Symptom Control ◽

Sensory Loss ◽

Content Type ◽

Cranial Nerve Dysfunction ◽

Ablative Procedures ◽

Fine Print

✓ Thirty-five patients with trigeminal neuralgia (TN) bilaterally underwent posterior fossa microvascular decompression (MVD) between 1971 and 1984. They comprised 5.0% of a larger series of 699 patients with TN who underwent MVD during that interval. Compared to the subgroup of 664 patients with only unilateral symptoms, the population with bilateral TN included a greater percentage of females (74% vs. 58%, p < 0.1), a higher rate of “familial” TN (17% vs. 4.1%, p < 0.001), and an increased incidence of additional cranial nerve dysfunction (17% vs. 6.6%, p < 0.05) and hypertension (34% vs. 19%, p < 0.05). Of the 35 patients with bilateral TN, 10 underwent bilateral MVD (22 procedures) and 25 underwent unilateral MVD (30 procedures). In the latter patients, pain on the nonoperative side was well controlled with medication alone or had previously been treated by ablative procedures. Good or excellent pain control was achieved after one MVD was performed in 40 of the 45 sides treated (89%), and was maintained 1, 5, and 10 years after surgery in 82%, 66%, and 60%, respectively, based on life-table analysis. Six of 10 patients with recurrent symptoms underwent repeat unilateral MVD. Good or excellent long-term pain control was maintained in all six. With these repeat procedures included, symptom control at 1, 5, and 10 years after initial surgery was maintained in 87%, 78%, and 78% of the treated sides, respectively. Overall, 26 of 35 patients (74%) maintained good or excellent pain relief throughout the duration of the study (mean follow-up period 75 months) without resumption of regular medication usage. Although preoperative neurological deficits resulting from previous ablative procedures were seen in the majority of patients before MVD, no patient developed new major trigeminal sensory loss or masseter weakness after MVD. Operative mortality was zero. The results indicate that posterior fossa MVD is an effective and relatively safe treatment for the majority of patients with bilateral “idiopathic” TN, avoiding the risks of bilateral trigeminal nerve injury seen with other approaches.

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A pilot study of the combination of checkpoint inhibition with ablation in subjects with biliary tract cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2021.39.15_suppl.e16150 ◽

2021 ◽

Vol 39 (15_suppl) ◽

pp. e16150-e16150

Author(s):

Rebecca Wetzel ◽

M. Cecilia Monge B. ◽

Changqing Xie ◽

Donna Mabry-Hrones ◽

Santhana Webb ◽

...

Keyword(s):

Biliary Tract ◽

Immune Checkpoint ◽

Locally Advanced ◽

Primary Objective ◽

Tumor Ablation ◽

Biliary Tract Carcinoma ◽

Checkpoint Inhibition ◽

Immune Checkpoint Inhibition ◽

Extrahepatic Cholangiocarcinoma ◽

Ablative Procedures

e16150 Background: Immune checkpoint inhibition has demonstrated modest activity in biliary tract carcinoma (BTC). Augmentation of the immune response by ablative procedures to improve efficacy of immune checkpoint inhibition has been previously demonstrated in hepatocellular carcinoma, however the outcome of the combination of immune checkpoint inhibition with tremelimumab (anti-CTLA4) and durvalumab (anti-PD1) with ablation in advanced biliary tract carcinoma is unclear. The primary objective of this study was to establish the efficacy via 6-month progression-free survival (PFS) of combining tremelimumab and durvalumab in patients with advanced BTC either alone or with tumor ablation. Secondary objectives were safety and feasibility of combination treatment. An exploratory objective was overall survival (OS). Methods: Eligible patients had histologically confirmed advanced or unresectable BTC (intra- or extrahepatic cholangiocarcinoma, gallbladder cancer, or ampullary cancer) who had progressed on, been intolerant to, or refused prior chemotherapy. Disease had to be technically amenable to cryoablation with at least two measurable lesions. Adequate organ function and an ECOG of 0 or 1 were required. Patients were treated with tremelimumab and durvalumab with or without tumor ablation. Tremelimumab and durvalumab were administered intravenously every 28 days for four cycles followed by durvalumab every 28 days until disease progression. Cryoablation was performed on day 36. Patients were imaged every 8 weeks and response was defined per RECIST v 1.1 criteria. Results: In total, 22 patients have been enrolled into the BTC cohort. Half underwent ablation and half received immunotherapy alone. The median age was 59 years (range 21-80). All patients had received prior systemic chemotherapy, locally advanced disease was present in 68% of patients. Median PFS was 2.1m and median OS was 5.6 m. DCR was 45% (SD). Median OS and PFS was similar in the group that received ablation vs immunotherapy alone with a median OS of 6.8 m vs 6.7 m and 2.0 m vs 2.7 m respectively. The most common grade 3- 4 adverse events were lymphopenia (27%), increased AST (41%), increased alkaline phosphatase (32%) and elevated bilirubin (27%). Conclusions: Combination checkpoint inhibition combined with tumor ablative procedures is a safe and effective treatment strategy for patients with advanced BTC, however the addition of ablative therapy may not enhance efficacy in this small cohort of patients. Results illustrate the poor prognosis of advanced BTC and may represent a non-chemotherapeutic approach to treatment in this patient population. Further studies are warranted to identify patient populations most likely to respond to these interventions. Clinical trial information: NCT02821754.

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Sevoflurane Has No Effect on Sinoatrial Node Function or on Normal Atrioventricular and Accessory Pathway Conduction in Wolff-Parkinson-White Syndrome during Alfentanil/Midazolam Anesthesia

Anesthesiology ◽

10.1097/00000542-199901000-00010 ◽

1999 ◽

Vol 90 (1) ◽

pp. 60-65 ◽

Cited By ~ 33

Author(s):

Michael D. Sharpe ◽

Daniel J. Cuillerier ◽

John K. Lee ◽

Magdi Basta ◽

Andrew D. Krahn ◽

...

Keyword(s):

Cycle Length ◽

Sinoatrial Node ◽

Sinus Node ◽

Accessory Pathway ◽

Atrioventricular Node ◽

Conduction Time ◽

White Syndrome ◽

The Right ◽

Ablative Procedures ◽

Wolff Parkinson White Syndrome

Background The effects of sevoflurane on the electrophysiologic properties of the human heart are unknown. This study evaluated the effects of sevoflurane on the electrophysiologic properties of the normal atrioventricular conduction system, and on the accessory pathways in patients with Wolff-Parkinson-White syndrome, to determine its suitability as an anesthetic agent for patients undergoing ablative procedures. Methods Fifteen patients with Wolff-Parkinson-White syndrome undergoing elective radiofrequency catheter ablation were studied. Anesthesia was induced with alfentanil (20-50 microg/kg) and midazolam (0.15 mg/kg), and vecuronium (20 mg) and maintained with alfentanil (0.5 to 2 microg x kg(-1) x min(-1)) and midazolam (1 or 2 mg every 10-15 min, as required). An electrophysiologic study measured the effective refractory period of the right atrium, atrioventricular node, and accessory pathway; the shortest conducted cycle length of the atrioventricular node and accessory pathway during atrial pacing; the effective refractory period of the right ventricle and accessory pathway; and the shortest retrograde conducted cycle length of the accessory pathway during ventricular pacing. Parameters of sinoatrial node function included sinus node recovery time, corrected sinus node recovery time, and sinoatrial conduction time. Intraatrial conduction time and the atrial-His interval were also measured. Characteristics of induced reciprocating tachycardia, including cycle length, atrial-His, His-ventricular, and ventriculoatrial intervals, also were measured. Sevoflurane was administered to achieve an end-tidal concentration of 2% (1 minimum alveolar concentration), and the study measurements were repeated. Results Sevoflurane had no effect on the electrophysiologic parameters of conduction in the normal atrioventricular conduction system or accessory pathway, or during reciprocating tachycardia. However, sevoflurane caused a statistically significant reduction in the sinoatrial conduction time and atrial-His interval but these changes were not clinically important. All accessory pathways were successfully identified and ablated. Conclusions Sevoflurane had no effect on the electrophysiologic nature of the normal atrioventricular or accessory pathway and no clinically important effect on sinoatrial node activity. It is therefore a suitable anesthetic agent for patients undergoing ablative procedures.

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