Project description:Catheter ablation has become the cornerstone of the treatment of ventricular arrythmias. Nevertheless, it is crucial to recognize the adverse effects of such treatment. We present a case of an incidental diagnosis of ventricular pseudoaneurysms after catheter ablation for treatment of drug-refractory nonsustained runs of ventricular tachycardia. (Level of Difficulty: Advanced.).
Project description:Despite the good cooling effect of the contact-force porous catheter, the risk of steam pops (SP) remains one of the major concerns in high-power circumferential pulmonary vein isolation (CPVI). This study aimed to investigate the prevalence, predictors and possible mechanisms of SPs in CPVI. Patients experiencing SPs in de novo high-power CPVI were 1:3 matched by non-SP patients with gender, age (±5 years) and left atrial diameter (LAD) (±5 mm) to compare the ablation parameters of SP and non-SP lesions. Catheter tip displacement (Tipdisp) was compared between "edge-of-ridge" and "PV-side-of-ridge" placement at anterior and roof segments of the left pulmonary vein (PV). SPs occurred in 11 (1.57%) of 701 patients, including 6 at the antero-superior left PV, 2 at the roof, 1 at the postero-superior left PV, 1 at the bottom left PV and 1 at the antero-superior aspect of the right PV. There was significantly shorter RF delivery duration (13.9 ± 6.3 vs. 23.3 ± 6.0 s), greater Δimpedance (17.6 ± 6.7 vs. 6.7 ± 4.1 Ω) and lower ablation index (357.7 ± 68.8 vs. 430.2 ± 30.7) in SP patients than those in non-SP patients. Δimpedance >12 Ω during ablation could predict SP occurrence. Tipdisp was greater in "PV-side-of-ridge" than that in "edge-of -ridge" placement (3.2 ± 1.6 mm vs. 2.0 ± 0.8 mm) at antero-superior and roof segments of the left PV. The prevalence of SP was 1.57% in high-power CPVI procedures, with the most common site at the antero-superior segment of the left PV. Δimpedance was a significant predictor of SP occurrence. "PV-side-of-ridge" ablation at antero-superior and roof segments of left PV might predispose to SP occurrence due to excessive tissue coverage.
Project description:A radiofrequency ablation (RFA) needle integrated with a temperature sensor (T-sensor) and pressure sensor (P-sensor) is designed and utilized for real-time internal steam pop monitoring during RFA. The characteristics of the sensor-integrated RFA needle (sRFA-needle) are investigated quantitatively using a pressure chamber system, and the feasibility and usability of the needle in preclinical and clinical trials is demonstrated. The sharp changes in the temperature and normalized pressure sensor signals induced by the abrupt release of hot and high-pressure steam can be clearly monitored during the steam pop phenomena. The basic mechanism of the preliminary steam pop is hypothesized and verified using in situ ultrasound imaging data and computational analysis data of the RFA procedure. Moreover, the usability of the system in clinical trials is investigated, and the steam pop phenomena during the RFA procedure are detected using T-sensor and P-sensor. The results confirm that the sensor integration on the medical needle can provide critical data for safer and more effective medical practices.
Project description:Steam pop (SP) refers to audible sound related to the intramyocardial explosion when tissue temperatures reach 100 °C. In this case the SP was recorded using intracardiac echocardiography (ICE), using Sound-star probe and Smart-touch catheter with ablation index (AI) module (Biosense-Webster Inc., Diamond-Bar, CA, USA). Guided by the anatomical reconstruction (EAM) and electrograms, we applied radiofrequencies (RF) in a "point-by-point" along the entire line on cavo-tricuspid-isthmus (CTI) using a target of an AI ≥500. The tip-tissue force recorded was 12-18 g and a power of 35 W. ICE imaging was important so that the anatomical position of the catheter tip can be precisely monitored. During RF, ICE showed a growing, hyperechogenic intramyocardial bubble at the catheter-tissue interface. ICE imaging showed a hyperechogenic intramyocardial formation at the moment of occurrence of the SP. ICE imaging showed that the formation suddenly expanded to a sphere over the course of several seconds. After SP we reduced the RF output energy from 35 W to 30 W. After RF line on CTI the patient had no complications and no recurrence of atrial flutter was recorded. <Learning objective: The use of intracardiac echocardiography during cavo-tricuspid-isthmus ablation permits the detection of the increase of microbubbles before steam pop formation.>.
Project description:PurposeRadiofrequency ablation is a curative treatment option for very early-stage or earlystage hepatocellular carcinoma (HCC). However, percutaneous radiofrequency ablation (PRFA) for subphrenic tumors is technically challenging. Laparoscopic radiofrequency ablation (LRFA) has been used to overcome this disadvantage. This study compared the treatment outcomes between LRFA and PRFA for subphrenic HCC.MethodsThis retrospective study screened patients who underwent PRFA or LRFA for subphrenic HCC between 2013 and 2018. Therapeutic outcomes, including local tumor progression (LTP), intrahepatic distant recurrence (IDR), extrahepatic metastasis (EM), disease-free survival (DFS), and overall survival (OS), were compared between the two groups.ResultsThirty patients in the PRFA group and 23 patients in the LRFA group were included. LTP was observed in six patients in the PRFA group (20%), but in no patients in the LRFA group. The cumulative LTP rates at 1, 3, and 5 years were 3.7%, 23.4%, and 23.4%, respectively, in the PRFA group and 0.0% in the LRFA group (P=0.015). The IDR, EM, and DFS rates were not significantly different between the two groups (P=0.304, P=0.175, and P=0.075, respectively). The OS rates at 1, 3, and 5 years were 96.6%, 85.7%, and 71.6%, respectively, in the PRFA group and 100%, 95.7%, and 95.7%, respectively, in the LRFA group (P=0.049).ConclusionLRFA demonstrated better therapeutic outcomes than did PRFA for subphrenic tumors in terms of LTP and OS. Therefore, LRFA can be considered as the first-line treatment option for subphrenic HCC.
Project description:PurposeA novel ablation catheter capable of local impedance (LI) monitoring (IntellaNav MiFi OI, Boston Scientific) has been recently introduced to clinical practice. We aimed to determine the optimal LI drops for an effective radiofrequency ablation during cavo-tricuspid isthmus (CTI) ablation.MethodsThis retrospective observational study enrolled 50 consecutive patients (68 ± 9 years; 34 males) who underwent a CTI ablation using the IntellaNav MiFi OI catheter, guided by Rhythmia. The LI at the start of radiofrequency applications (initial LI) and minimum LI during radiofrequency applications were evaluated. The absolute and percentage LI drops were defined as the difference between the initial and minimum LIs and 100× absolute LI drop/initial LI, respectively.ResultsA total of 518 radiofrequency applications were analyzed. The absolute and percentage LI drops were significantly greater at effective ablation sites than ineffective sites (median, 15 ohms vs 8 ohms, P < .0001; median, 14.7% vs 8.3%, P < .0001). A receiver-operating characteristic analysis demonstrated that at optimal cutoffs of 12 ohms and 11.6% for the absolute and percentage LI drops, the sensitivity and specificity for predicting the effectiveness of the ablation were 66.5% and 88.2%, and 65.1% and 88.2%, respectively. Finally, bidirectional conduction block along the CTI was achieved in all patients.ConclusionsDuring the LI-guided CTI ablation, the effective RF ablation sites exhibited significantly greater absolute and percentage LI drops than the ineffective RF ablation sites. Absolute and percentage LI drops of 12 ohms and 11.6% may be suitable targets for effective ablation.
Project description:BackgroundBased on data from studies of atrial fibrillation ablations, optimal parameters for the TactiCath (TC; St. Jude Medical, Inc) force-sensing ablation catheter are a contact force of 20 g and a force-time integral of 400 g·s for the creation of transmural lesions. We aimed to evaluate TC in pediatric and congenital heart disease patients undergoing ablation.Methods and resultsComprehensive chart and case reviews were performed from June 2015 to March 2016. Of the 102 patients undergoing electrophysiology study plus ablation, 58 (57%) underwent ablation initially with a force-sensing catheter. Patients had an average age of 14 (2.4-23) years and weight of 58 (18-195) kg with 15 patients having abnormal cardiac anatomy. Electrophysiology diagnoses for the +TC group included 30 accessory pathway-mediated tachycardia, 24 atrioventricular nodal reentrant tachycardia, and 7 other. Baseline generator settings included a power of 20 W, temperature of 40°, and 6 cc/min flow during lesion creation with 11 patients (19%) having alterations to parameters. Seventeen patients (30%) converted to an alternate ablation source. A total of 516 lesions were performed using the TC with a median contact force of 6 g, force-time integral of 149 g·s, and lesion size index of 3.3. Median-term follow-up demonstrated 5 (10%) recurrences with no acute or median-term complications.ConclusionsTactiCath can be effectively employed in the treatment of pediatric patients with congenital heart disease with lower forces than previously described in the atrial fibrillation literature. Patients with atrioventricular nodal reentrant tachycardia or atrioventricular reciprocating tachycardia may not require transmural lesions and the TC may provide surrogate markers for success during slow pathway ablation.
Project description:Adenomyosis is a common benign gynecologic condition characterized by ectopic endometrial glands and stroma in the myometrium causing pain (dysmenorrhea) and abnormal uterine bleeding. New interventional techniques have been introduced over recent years. This study evaluates the treatment success and side effects of radiofrequency ablation. An electronic literature search in the PubMed, Scopus, and ScienceDirect databases was carried out on the outcomes of pain reduction and, secondarily, on abnormal uterine bleeding, reintervention, reproductive outcome, imaging outcome, and complications. There was a mean decrease in dysmenorrhea pain scores by -63.4 ± 9.0% at 12 months. Data on other outcome parameters were sparse. No major complications were reported. Radiofrequency ablation represents a promising minimally invasive and organ-preserving treatment in patients with symptomatic adenomyosis. It is associated with clinically meaningful improvement of adenomyosis-related pain in the short term.