Can Intracardiac Echocardiography Reduce Steam Pops During Half-Normal Saline Irrigated Radiofrequency Ablation?

BACKGROUND: Irrigated radiofrequency ablation with half-normal saline can potentially increase lesion size but may increase the risk of steam pops with the risk of emboli or perforation. We hypothesized that pops would be preceded by intracardiac echocardiography (ICE) findings as well as a large impedance fall. METHODS: In 100 consecutive patients undergoing endocardial ventricular arrhythmia radiofrequency ablation with half-normal saline, we attempted to observe the ablation site with ICE. Radiofrequency ablation power was titrated to a 15 to 20 Ohm impedance fall and could be adjusted for tissue whitening and increasing bubble formation on ICE. Steam pops were defined as audible or a sudden explosion of microbubbles on ICE. RESULTS: Of 2190 ablation applications in 100 patients (82% cardiomyopathy, 50% sustained ventricular tachycardia), pops occurred during 43 (2.0%) applications. Sites with pops had greater impedance decreases of 18 [14, 21]% versus 13 [10, 17]% (P<0.001). ICE visualized 1308 (59.7%) radiofrequency sites, and fewer pops occurred when ICE visualized the radiofrequency ablation site (1.4%) compared with without ICE visualization (2.8%; P=0.016). Of the 18 ICE-visible pops, 7 (39%) were silent but recognized as an explosion of bubbles on ICE. With ICE, 89% of pops were preceded by either tissue whitening or a sudden increase in bubbles. In a multivariable model, tissue whitening and a sudden increase in bubbles were associated with steam pops (odds ratio, 7.186; P=0.004, and odds ratio, 29.93; P<0.001, respectively), independent of impedance fall and power. There were no pericardial effusions or embolic events with steam pops. CONCLUSIONS: Steam pops occurred in 2% of half-normal saline radiofrequency applications titrated to an impedance fall and are likely under-recognized without ICE. On ICE, steam pops are usually preceded by tissue whitening or a sudden increase in bubble formation, which can potentially be used to adjust radiofrequency application to help reduce pops.

Safety of ventricular arrhythmia radiofrequency ablation with half-normal saline irrigation.

AIMS: Failure of radiofrequency (RF) ablation of ventricular arrhythmias is often due to inadequate lesion size. Irrigated RF ablation with half-normal saline (HNS) has the potential to increase lesion size and reduce sodium delivery to the patient if the same volume of RF irrigant were used for normal saline (NS) and HNS but could increase risks related to steam pops and lesion size. This study aims to assess periprocedural complications and acute ablation outcome of ventricular arrhythmias ablation with HNS. METHODS AND RESULTS: Prospective assessment of outcomes was performed in 1024 endocardial and/or epicardial RF ablation procedures in 935 consecutive patients (median age 64 years, 71.2% men, 73.4% cardiomyopathy, 47.2% sustained ventricular tachycardia). Half-normal saline was selected at the discretion of the treating physician. Radiofrequency ablation power was generally titrated to a ≤15â€…Ω impedance fall with intracardiac echocardiography monitoring. Half-normal saline was used in 900 (87.9%) and NS in 124 (12.1%) procedures. Any adverse event within 30 days occurred in 13.0% of patients treated with HNS RF ablation including 4 (0.4%) strokes/transient ischaemic attacks and 34 (3.8%) pericardial effusions requiring treatment (mostly related to epicardial access). Two steam pops with perforation required surgical repair (0.2%). Patients who received NS irrigation had less severe disease and arrhythmias. In multivariable models, adverse events and acute success of the procedure were not related to the type of irrigation. CONCLUSION: Half-normal saline irrigation RF ablation with power guided by impedance fall and intracardiac echocardiography has an acceptable rate of complications and acute ablation success while administering half of the saline load expected for NS irrigation.

Stroke and Bleeding Risks of Endocardial Ablation for Ventricular Arrhythmias.

BACKGROUND: Risks of radiofrequency catheter ablation for ventricular arrhythmias include emboli and bleeding complications but data on antithrombotic regimens are limited and guidelines do not specify a systematic approach. OBJECTIVES: This study sought to assess embolic and bleeding complications in relation to pre-periprocedure and post-periprocedure antithrombotic regimens. METHODS: Prospective assessment for complications was performed for 663 endocardial radiofrequency catheter ablation procedures in 616 consecutive patients (median age 64 years [Q1-Q3: 54-73 years], 70.3% men, 71.6% with cardiomyopathy, 44.5% with sustained ventricular tachycardia). RESULTS: There were 2 strokes (0.3%; 95% CI: 0.0%-0.8%), 1 transient ischemic attack (0.15%), and 2 pulmonary emboli (0.3%). There were 39 bleeding complications (5.9%) including 11 pericardial effusions (1.7%), and 28 related to vascular access (4.2%). Consistent with the prevalence of coronary artery disease (47.5%), atrial fibrillation (30.0%), and prior stroke (10.6%), preprocedure, 464 patients (70.0%) were taking antithrombotic agents including 220 (33.2%) taking aspirin alone (ASA), and 163 (24.6%) taking warfarin or a direct acting oral anticoagulant (DOAC). Preprocedure non-ASA antiplatelet use (OR: 2.846; P = 0.011) and DOAC use (OR: 2.585; P = 0.032) were associated with risk of bleeding complications. Following ablation, 49.8% of patients were treated with ASA 325 mg/d and 30.3% received DOACs or warfarin. New DOAC or warfarin administration was initiated in only 6.6% of patients. Overall, 39.7% of patients continued the same preprocedure antithrombotic regimen. CONCLUSIONS: Stroke is a rare complication of radiofrequency catheter ablation for ventricular arrhythmia using ASA 325 mg/d as a minimal postprocedure regimen with more potent regimens for selected patients.

Intracardiac thrombi fluttering like hair in the wind at VT ablation.

INTRODUCTION: Intracardiac echocardiography (ICE) reveals mobile thrombus on implantable electronic device leads in some patients undergoing electrophysiologic procedures. METHODS: ICE was performed in a patient undergoing ventricular tachycardia (VT) ablation. RESULTS: ICE showed extensive mobile thrombi on the implantable cardioverter defibrillator lead. Radiofrequency catheter ablation of VT from perimitral scar was safely performed via a retrograde aortic approach. After the procedure, chronic anticoagulation was initiated. CT-angiography of the chest 2 months later showed no pulmonary emboli. CONCLUSIONS: The significance of these thrombi, as related to chronic pulmonary embolization, warrants further study.