Seung Young Roh

Catheter Ablation of Atrial Fibrillation in Patients With Chronic Lung Disease

Background— Chronic lung disease (CLD) is one of the important underlying diseases of atrial fibrillation (AF). The outcomes after radiofrequency catheter ablation of AF in patients with CLD have not yet been reported. We investigated the electroanatomic alterations in pulmonary veins (PVs) in CLD patients with AF and assessed their effect on the outcomes of radiofrequency catheter ablation of AF. Method and Results— We assessed 15 patients who had CLD and underwent radiofrequency catheter ablation of AF. CLD included chronic obstructive pulmonary disease, a tuberculosis-destroyed lung, and interstitial lung disease. For controls, we selected 60 sex-, age-, and procedure era–matched non-CLD patients who received radiofrequency catheter ablation for AF (4 controls for each CLD patient). Eight patients had chronic obstructive pulmonary disease, 6 had a tuberculosis-destroyed lung, and 1 had interstitial lung disease. PV morphology in the affected lung was altered significantly, ie, obliteration, pulling of the PVs toward the destroyed lung, or compensatory bulging of the PV antrum. These alterations were related to arrhythmogenicity in 6 (40%) of 15 patients with CLD. Non-PV foci were more common in the CLD group (4/15, 26.7%) than in the control group (3/60, 5.0%; P=0.025). All non-PV foci were located in the right atrium. The AF recurrence rate in the CLD group (26.7%, 4/15) was similar to that in the control group (18.3%, 11/60; P=0.45). Conclusions— Significant alteration of PV anatomy was related to arrhythmogenicity, and non-PV foci from the right atrium were commonly observed in the CLD group. Radiofrequency catheter ablation can be performed safely for AF in CLD patients with a comparable success rate to that in patients with normal lungs.

The Mechanism of and Preventive Therapy for Stroke in Patients with Atrial Fibrillation

Atrial fibrillation is a major cardiac cause of stroke, and a pathogenesis involving thrombus formation in patients with atrial fibrillation is well established. A strategy for rhythm control that involves catheter ablation and anticoagulation therapy is evolving. A strategy for rhythm control that restores and maintains sinus rhythm should reduce the risk of ischemic stroke that is associated with atrial fibrillation; however, this is yet to be proven in large-scale randomized controlled trials. This paper reviews the emerging role of rhythm control therapy for atrial fibrillation to prevent stroke.

Atrial fibrillation cycle length as a predictor for the extent of substrate ablation

AIMSnAtrial fibrillation (AF) cycle length (CL) has been demonstrated to be one of the predictors for termination during ablation for AF. We evaluated the AF CL gradient between right atrium (RA) and left atrium (LA) and their mean AF CL in predicting the extent of substrate ablation.nnnMETHODS AND RESULTSnOne-hundred and thirty-six patients undergoing first ablation for persistent AF were studied. Stepwise ablation, sequentially in the following order: pulmonary veins (PV), LA, and RA, was performed to achieve AF termination. Stepwise ablation terminated AF in 110 patients (81%). In the AF termination group, AF was terminated by PV isolation (PVI) (Group P), PVI plus LA ablation (Group L), and PVI plus LA plus RA ablation (Group R) in 14 patients (13%), 49 patients (44%), and 47 patients (43%), respectively. Group R had much shorter mean AF CL than Group L (156 ± 18 vs. 174 ± 24 ms, P < 0.001) and mean AF CL in Group L was much shorter than Group P (174 ± 24 vs. 209 ± 36 ms, P = 0.004). The RA to LA AF CL gradient was not significantly different between left-side ablation (Group P + Group L) and additional RA ablation (Group R) (P = 0.177). Mean AF CL >180.50 ms predicted AF termination by PVI (Group P) with 79% sensitivity and 84% specificity while mean AF CL >165.25 ms predicted AF termination by left-side ablation (Group P + Group L) with 67% sensitivity and 75% specificity. After a mean follow-up of 15 ± 7 months, freedom from arrhythmia recurrence was significantly higher in left-side ablation (Group P + Group L) than additional RA ablation (Group R) (P = 0.024).nnnCONCLUSIONnBaseline mean AF CL may identify the subset of patients in whom persistent AF can be terminated by different extent of substrate ablation, which may in turn predict the chance of recurrence. However, baseline RA to LA AF CL gradient cannot predict the need for additional RA ablation.

Long‐term Outcome of Catheter Ablation for Atrial Fibrillation in Patients with Apical Hypertrophic Cardiomyopathy

Atrial fibrillation (AF) is a common manifestation in cases of hypertrophic cardiomyopathy (HCM). Catheter ablation (CA) for AF in patients with asymmetric septal HCM (SeHCM) is selectively effective and often needs a repeat procedure. Apical HCM (ApHCM) has a better prognosis than SeHCM. However, the outcome of CA for AF in patients with ApHCM is unclear.

Atrial Fibrillation: Relationship between Left Atrial Pressure and Left Atrial Appendage Emptying Determined with Velocity-encoded Cardiac MR Imaging

Purpose To investigate the relationship between left atrial appendage (LAA) blood flow determined with cardiac magnetic resonance (MR) imaging and left atrial pressure (LAP) estimated from invasive catheter measurements in patients with atrial fibrillation (AF). Materials and Methods This retrospective study was approved by the institutional review board, and patients provided written informed consent. Seventy-seven patients with AF (mean age, 57.8 years ± 9.8; range, 31-76 years) underwent cardiac MR imaging and catheter-based measurement of LAP, sequentially. Velocity-encoded (VENC) cardiac MR imaging was performed perpendicular to the ostium of the LAA. The maximum blood flux (in milliliters per second) from the LAA to the left atrium (LA) as determined with VENC MR imaging was defined as LAA emptying. Patients were classified into two groups: those with elevated LAP (peak LAP ≥19 mm Hg) and those with nonelevated LAP (peak LAP <19 mm Hg). Receiver operating characteristic curves were used to determine the cut-off values of LAA emptying in the assessment of the LAP status. Results LAA emptying showed a significantly inverse relationship (P < .01) with the peak LAP. Patients with elevated LAP showed significantly less LAA emptying than did patients with nonelevated LAP (mean, 39.3 mL/sec ± 13.7 vs 61.2 mL/sec ± 20.7, respectively; P < .01). In the assessment of elevated LAP with use of VENC MR imaging in normal sinus rhythm, the LAA emptying cut-off value of 47 mL/sec had a sensitivity of 75.0%, specificity of 87.5%, positive predictive value of 66.6%, and negative predictive value of 91.3%. At multivariate analysis, the odds ratio of low LAA emptying (<47 mL/sec) was independently associated with elevated LAP. Conclusion Evaluation of LAA emptying with use of VENC MR imaging is helpful for assessing the LAP status of patients with AF.

Non-Vitamin K antagonist oral anticoagulants versus warfarin for the prevention of spontaneous echo-contrast and thrombus in patients with atrial fibrillation or flutter undergoing cardioversion: A trans-esophageal echocardiography study

Spontaneous echo-contrast (SEC) and thrombus observed in trans-esophageal echocardiography (TEE) is known as a strong surrogate marker for future risk of ischemic stroke in patients with atrial fibrillation (AF) or atrial flutter (AFL). The efficacy of non-vitamin K antagonist oral anticoagulants (NOAC) compared to warfarin to prevent SEC or thrombus in patients with AF or AFL is currently unknown. AF or AFL patients who underwent direct current cardioversion (DCCV) and pre-DCCV TEE evaluation from January 2014 to October 2016 in a single center were analyzed. The prevalence of SEC and thrombus were compared between patients who received NOAC and those who took warfarin. NOAC included direct thrombin inhibitor and factor Xa inhibitors. Among 1,050 patients who were considered for DCCV, 424 patients anticoagulated with warfarin or NOAC underwent TEE prior to DCCV. Eighty patients who were anticoagulated for less than 21 days were excluded. Finally, 344 patients were included for the analysis (180 warfarin users vs. 164 NOAC users). No significant difference in the prevalence of SEC (44.4% vs. 43.9%; p = 0.919), dense SEC (13.9% vs. 15.2%; p = 0.722), or thrombus (2.2% vs. 4.3%; p = 0.281) was observed between the warfarin group and the NOAC group. In multivariate analysis, there was no association between NOAC and risk of SEC (odds ratio [OR]: 1.4, 95% CI: 0.796–2.297, p = 0.265) or thrombus (OR: 3.4, 95% CI: 0.726–16.039, p = 0.120). In conclusion, effectiveness of NOAC is comparable to warfarin in preventing SEC and thrombus in patients with AF or AFL undergoing DCCV. However, numerical increase in the prevalence of thrombus in NOAC group warrants further evaluation.

Long-Term Clinical Comparison of Procedural End Points After Pulmonary Vein Isolation in Paroxysmal Atrial Fibrillation: Elimination of Nonpulmonary Vein Triggers Versus Noninducibility

Background: Pulmonary vein isolation (PVI) is effective for maintenance of sinus rhythm in 50% to 75% of patients with paroxysmal atrial fibrillation, and it is not uncommon for patients to require additional ablation after PVI. We prospectively evaluated the relative effectiveness of 2 post-PVI ablation strategies in paroxysmal atrial fibrillation. Methods and Results: A total of 500 patients (mean age, 55.7±11.0 years; 74.6% male) were randomly assigned to undergo ablation by 2 different strategies after PVI: (1) elimination of non-PV triggers (group A, n=250) or (2) stepwise substrate modification including complex fractionated atrial electrogram or linear ablation until noninducibility of atrial tachyarrhythmia was achieved (group B, n=250). During a median follow-up of 26.0 months, 75 (32.2%) patients experienced at least 1 episode of recurrent atrial tachyarrhythmia after the single procedure in group A compared with 105 (43.8%) patients in group B (P value in log-rank test of Kaplan–Meier analysis: 0.012). Competing risk analysis showed that the cumulative incidence of atrial tachycardia was significantly higher in group B compared with group A (P=0.007). With the exception of total ablation time, there were no significant differences in fluoroscopic time or procedure-related complications between the 2 groups. Conclusions: Elimination of triggers as an end point of ablation in patients with paroxysmal atrial fibrillation decreased long-term recurrence of atrial tachyarrhythmia compared with a noninducibility approach achieved by additional empirical ablation. The post-PVI trigger test is thus a better end point of ablation for paroxysmal atrial fibrillation.

Long-term clinical outcomes of catheter ablation in patients with atrial fibrillation predisposing to tachycardia-bradycardia syndrome: a long pause predicts implantation of a permanent pacemaker

BackgroundThere is a controversy as to whether catheter ablation should be the first-line therapy for tachycardia-bradycardia syndrome (TBS) in patients with atrial fibrillation (AF).MethodsWe aimed to investigate long-term clinical outcomes of catheter ablation in patients with TBS and AF. Among 145 consecutive patients who underwent catheter ablation of AF with TBS, 121 patients were studied.ResultsAmong 121 patients, 11 (9.1%) received implantation of a permanent pacemaker during a mean 21xa0months after ablation. Length of pause on termination of AF was significantly greater in patients who received pacemaker implantation after ablation than those who underwent ablation only (7.9u2009±u20093.5 vs. 5.1u2009±u20092.1xa0s, pu2009<u20090.001). Using a multivariate model, a long pause of 6.3xa0s or longer after termination of AF was associated with the requirement to implant a permanent pacemaker after ablation (HR 1.332, 95% CI 1.115-1.591, pu2009=u20090.002).ConclusionThis study suggests that, in patients with AF predisposing to TBS, long pause on termination of AF predicts the need to implant a permanent pacemaker after catheter ablation.

The Role of Intravenous Dopamine on Hemodynamic Support during Radiofrequency Catheter Ablation of Poorly Tolerated Idiopathic Ventricular Tachycardia

Background and Objectives Hemodynamically unstable idiopathic ventricular tachycardias (VTs) are a challenge for activation or entrainment mapping technique. Mechanical circulatory support is an option, but is not always readily available. In this study, we investigated the safety and efficacy of hemodynamic support using intravenous (IV) dopamine solely during radiofrequency catheter ablation (RFCA) of hemodynamically unstable VT. Subjects and Methods Seven out of 86 patients with hemodynamically unstable idiopathic VT underwent de novo RFCA using dopamine in our single center. They were included in the study and reviewed retrospectively to investigate the procedural characteristics and outcomes. Results All patients were male, and the mean age was 50.7±5.3 years. One patient had implantable cardioverter-defibrillator for the secondary prevention. No evidence of myocardial ischemia was found in all patients. During the procedure, the mean blood pressure during VT without dopamine was 52.3±4.1 mmHg and increased to 82.6±3.8 mmHg after administering dopamine (Δ28.8±3.2 mmHg; total average dopamine dosage was 1266.1±389.6 mcg/kg). In all patients, activation mapping was safely applied, and VTs were terminated during energy delivery. Non-inducibility of clinical VT was achieved in all cases. There was no evidence of deterioration due to hypoperfusion during the peri-procedural period. No recurrence of ventricular tachyarrhythmias was observed in any of the patients, during a median follow-up of 23.0±6.1 months. Conclusion Hemodynamic support using IV dopamine during RFCA of hemodynamically unstable idiopathic VT facilitated detailed mapping to guide successful ablation.

Value of adenosine test to reveal dormant conduction or adenosine-induced atrial fibrillation after pulmonary vein isolation

Recent studies investigating the implications of additional ablation guided by dormant pulmonary vein (PV) conduction testing using adenosine showed conflicting results, and the data about atrial fibrillation (AF) recurrence after trigger site elimination in adenosine‐induced AF are still lacking.