Prognostic Value of Burst Pacing Inducibility Post-Radiofrequency Versus Cryoablation for Paroxysmal Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) inducibility with burst pacing (BP) after radiofrequency ablation (RFA) has been reported to be associated with AF recurrence. In contrast, the relevance of inducibility and recurrence after cryoablation (CRA) is unclear. METHODS: We investigated 367 patients undergoing initial ablation for paroxysmal AF (RFA: 174, CRA: 193). Propensity score matching was conducted, retaining 134 patients in each group. Following pulmonary vein isolation (PVI), the inducibility by BP was tested. Inductions at 250 ppm were defined as low-frequency burst pacing (LFBP) positive, and those at 300 ppm were classified as medium-frequency burst pacing (MFBP) positive. They were followed for 600 days. RESULTS: Forty-eight patients (18%) had AF recurrence. There was no significant difference in the recurrence rate between RFA and CRA (17% vs. 19%, Log-rank p = 0.79). In RFA, significant differences were observed for both LFBP (Log-rank p < 0.001) and MFBP (Log-rank p < 0.001). In contrast, in CRA, there were no significant differences for either LFBP (Log-rank p = 0.39) or MFBP (Log-rank p = 0.19). Multivariable analysis revealed that LFBP-positive (hazards ratio [HR] = 5.75, 95% confidence interval [CI] 2.41-13.7, p < 0.001) was an independent predictor for recurrence with RFA. Acute reconnection (HR = 2.73, 95% CI 1.13-6.56, p = 0.025) was an independent predictor for recurrence with CRA. CONCLUSION: The inducibility by BP after RFA predicted recurrence at both low and medium frequencies. LFBP-positive was an independent predictor of recurrence in multivariable analysis. In contrast, the inducibility by BP after CRA was not a predictor of recurrence. TRAIL REGISTRATION: This study did not require clinical trial registration.

Atrial echo beats as a novel mechanism of periodic fluctuation in cycle length of atrial tachycardia.

Atrial echo beats due to a dual-atrioventricular nodal pathway are a possible cause of fluctuating tachycardia in cycle length (CL) but have not been reported so far. Here, we present a case of an 82-year-old man with symptomatic atrial tachycardia (AT), which was accompanied by periodic fluctuations in atrial sequence at the coronary sinus. Electrophysiological study (EPS) for atrioventricular conduction and three-dimensional (3D) electro-anatomical mapping system explained that the mechanism of periodic fluctuations was due to atrial echo beats through a dual-atrioventricular nodal pathway.

Acute effect of sodium nitroprusside on microvascular dysfunction in patients who underwent percutaneous coronary intervention for acute ST-segment elevation myocardial infarction.

Even in the era of thrombus aspiration and distal protection for ST-segment elevation acute myocardial infarction (STEMI), microvascular dysfunction does exist and improvement of microvascular dysfunction can improve the prognosis and/or left ventricular dysfunction. We evaluated the acute effects of nitroprusside (NTP) on coronary microvascular injury that occurred after primary percutaneous coronary intervention (PCI) for STEMI in 18 patients. The final Thrombolysis in Myocardial Infarction trial (TIMI) flow grade after PCI was 3 in 17 patients and 2 in 1 patient. The index of microcirculatory resistance (IMR) was improved significantly from 76 ± 42 to 45 ± 37 (P = 0.0006) by intracoronary NTP administration. IMR improved to the normal range (IMR < 30) in 9 patients (50%). Higher TIMI flow grade and lower IMR at baseline were observed more frequently in patients whose IMR recovered to normal range after NTP administration. NTP improved the microcirculatory dysfunction at the acute phase in patients who underwent PCI for STEMI and had final TIMI 3 flow in almost all cases.

Sudden Cardiac Arrest Due to Spontaneous Coronary Artery Rupture - A Case Report with a Diagnostic Challenge.

Spontaneous coronary artery rupture (SCAR) is a rare, life-threatening disease, and the diagnosis is often challenging. We herein report a 70-year-old man who suffered sudden cardiac arrest due to SCAR with pericardial fluid. At first, emergent coronary angiography (CAG) failed to detect abnormalities. The emergent operation revealed that the presence of pericardial fluid was caused by bleeding that had spontaneously occurred at the left circumflex artery (LCx). A careful retrospective CAG review showed slight contrast spillage from the distal LCx. SCAR should be suspected in patients with unknown etiology of pericardial effusion, and careful inspection of CAG is necessary.

Idiopathic left ventricular arrhythmias originating adjacent to the left aortic sinus of valsalva: electrophysiological rationale for the surface electrocardiogram.

BACKGROUND: Idiopathic ventricular arrhythmias (VAs) may be amenable to catheter ablation within or adjacent to the left sinus of Valsalva (LSOV). However, features that discriminate these sites have not been defined. The purpose of this study was to determine the electrocardiographic and electrophysiological features of VAs originating within or adjacent to the LSOV. METHODS AND RESULTS: We studied 48 consecutive patients undergoing successful catheter ablation of idiopathic VAs originating from the left coronary cusp (LCC, n = 29), aortomitral continuity (AMC, n = 10) and great cardiac vein or anterior interventricular cardiac vein (Epi, n = 9). A small r wave, or rarely an R wave, was typically observed in lead I during the VAs and pacing in these regions. An S wave in lead V5 or V6 occurred significantly more often during both the VAs and pacing from the AMC than during that from the LCC and Epi (p < 0.05 to 0.0001). For discriminating whether VA origins can be ablated endocardially or epicardially, the maximum deflection index (MDI = the shortest time to the maximum deflection in any precordial lead/QRS duration) was reliable for VAs arising from the AMC (100%), but was less reliable for LCC (73%) and Epi (67%) VAs. In 3 (33%) of the Epi VAs, the site of an excellent pace map was located transmurally opposite to the successful ablation site (LCC = 1 and AMC = 2). CONCLUSIONS: The MDI has limited value for discriminating endocardial from epicardial VA origins in sites adjacent to the LSOV probably due to preferential conduction, intramural VA origins or myocardium in contact with the LCC.

Idiopathic ventricular arrhythmias originating from the papillary muscles in the left ventricle: prevalence, electrocardiographic and electrophysiological characteristics, and results of the radiofrequency catheter ablation.

INTRODUCTION: Idiopathic ventricular arrhythmias (VAs) can originate from the left ventricular (LV) papillary muscles (PAMs). This study investigated the prevalence, electrocardiographic and electrophysiological characteristics, and results of catheter ablation of these VAs, and compared them with other LV VAs. METHODS AND RESULTS: We studied 71 patients with VAs originating from the LV anterolateral and posteroseptal regions among 159 patients undergoing successful catheter ablation of idiopathic LV VAs. PAM VAs were uncommon, rare in a sustained form, and more common from the posterior papillary muscle (PPM) than anterior papillary muscle (APM). A younger age was a good predictor for differentiating left posterior fascicular VAs from PPM VAs. There were several electrocardiographic features that accurately differentiated PAM and LV fascicular VAs from mitral annular VAs. However, an R/S ratio < or =1 in lead V6 in the LV anterolateral region and a QRS duration >160 ms in the LV posteroseptal region were the only reliable predictors for differentiating PAM VAs from LV fascicular VAs. A sharp ventricular prepotential was recorded at the successful ablation site during 42% of the PAM VAs. Radiofrequency current with an irrigated or conventional 8-mm tip ablation catheter was required to achieve a lasting ablation of the PAM VA origins whereas that with a nonirrigated 4-mm tip ablation catheter produced excellent results in LV fascicular and mitral annular VAs. CONCLUSIONS: There are differences in the electrocardiographic and electrophysiological features among VAs originating from these regions that are helpful for their diagnosis and effective catheter ablation.

Difference in percentage of ventricular pacing between two algorithms for minimizing ventricular pacing: results of the IDEAL RVP (Identify the Best Algorithm for Reducing Unnecessary Right Ventricular Pacing) study.

AIMS: Managed ventricular pacing (MVP) and Search AV+ are representative dual-chamber pacing algorithms for minimizing ventricular pacing (VP). This randomized, crossover study aimed to examine the difference in ability to reduce percentage of VP (%VP) between these two algorithms. METHODS AND RESULTS: Symptomatic bradyarrhythmia patients implanted with a pacemaker equipped with both algorithms (Adapta DR, Medtronic) were enrolled. The %VPs of the patients during two periods were compared: 1 month operation of either one of the two algorithms for each period. All patients were categorized into subgroups according to the atrioventricular block (AVB) status at baseline: no AVB (nAVB), first-degree AVB (1AVB), second-degree AVB (2AVB), episodic third-degree AVB (e3AVB), and persistent third-degree AVB (p3AVB). Data were available from 127 patients for the analysis. For all patient subgroups, except for p3AVB category, the median %VPs were lower during the MVP operation than those during the Search AV+ (nAVB: 0.2 vs. 0.8%, P < 0.0001; 1AVB: 2.3 vs. 27.4%, P = 0.001; 2AVB: 16.4% vs. 91.9%, P = 0.0052; e3AVB: 37.7% vs. 92.7%, P = 0.0003). CONCLUSION: Managed ventricular pacing algorithm, when compared with Search AV+, offers further %VP reduction in patients implanted with a dual-chamber pacemaker, except for patients diagnosed with persistent loss of atrioventricular conduction.

Idiopathic focal ventricular arrhythmias originating from the anterior papillary muscle in the left ventricle.

INTRODUCTION: Focal ventricular arrhythmias (VAs) have been reported to arise from the posterior papillary muscle in the left ventricle (LV). We report a distinct subgroup of idiopathic VAs arising from the anterior papillary muscle (APM) in the LV. METHODS AND RESULTS: We studied 432 consecutive patients undergoing catheter ablation for VAs based on a focal mechanism. Six patients were identified with ventricular tachycardia (VT, n = 1) or premature ventricular contractions (PVCs, n = 5) with the earliest site of ventricular activation localized to the base (n = 3) or middle portion (n = 3) of the LV APM. No Purkinje potentials were recorded at the ablation site during sinus rhythm or the VAs. All patients had a normal baseline electrocardiogram and normal LV systolic function. The VAs exhibited a right bundle branch block (RBBB) and right inferior axis (RIA) QRS morphology in all patients. Oral verapamil and/or Na(+) channel blockers failed to control the VAs in 4 patients. VT was not inducible by programmed electrical stimulation in any of the patients. In 4 patients, radiofrequency current with an irrigated or conventional 8-mm-tip ablation catheter was required to achieve a lasting success. Two patients had recurrent PVCs after a conventional radiofrequency ablation with a 4-mm-tip ablation catheter had initially suppressed the arrhythmia. CONCLUSIONS: VAs may arise from the base or middle portion of the APM and are characterized by an RBBB and RIA QRS morphology and focal mechanism. Catheter ablation of APM VAs is typically challenging, and creation of a deep radiofrequency lesion may be necessary for long-term success.

The difference in autonomic denervation and its effect on atrial fibrillation recurrence between the standard segmental and circumferential pulmonary vein isolation techniques.

AIMS: This study examined the difference in autonomic modification (AM) and its effect on paroxysmal atrial fibrillation (PAF) recurrence between segmental pulmonary vein isolation (S-PVI) and circumferential PVI (C-PVI). METHODS AND RESULTS: Successful S-PVI or C-PVI with a basket catheter was achieved in 120 consecutive PAF patients. Serial 24 Holter-recordings were obtained before, immediately, and 1, 3, 6, 12 months after the PVI to analyse the heart rate variability (HRV). Nineteen patients were excluded from analysis because of additional ablation for recurrent PAF after successful PVI. Among the residual 101 patients, 33 had PAF recurrences (S-PVI = 44.0%, C-PVI = 21.6%) at 1 year of follow-up. The root mean square of successive differences and high-frequency power reflecting parasympathetic nervous activity were significantly lower in patients with and without PAF recurrences after C-PVI and patients without PAF recurrences after S-PVI than patients with PAF recurrences after S-PVI (P < 0.005-0.0001). However, there were no significant differences in any HRV parameters in the immediate aftermath of PVI among the patients without PAF recurrences after S-PVI and those with and without PAF recurrences after C-PVI. CONCLUSION: Although additional radiofrequency ablation for AM may be recommended after S-PVI to reduce PAF recurrences, it should be carefully determined after C-PVI.

Vagal modification can be a valid predictor of late recurrence of paroxysmal atrial fibrillation independent of the pulmonary vein isolation technique.

BACKGROUND: Vagal denervation during pulmonary vein isolation (PVI) may reduce paroxysmal atrial fibrillation (PAF) recurrences. Valid predictors of late PAF recurrence after PVI were examined. METHODS AND RESULTS: Successful segmental (S-PVI) or circumferential PVI (C-PVI) was achieved in 120 consecutive PAF patients. The 24-h Holter recordings were obtained before and after PVI. Logistic regression analysis was performed to determine independent predictors of PAF recurrence among the patient characteristics, PVI technique and heart rate variability (HRV). Of the 120 patients, 19 were excluded from analysis because of additional ablation for recurrent PAF after successful PVI. Among the remaining 101 patients, 68 were free from PAF (Group-I) and 33 had late PAF recurrences (Group-II) at 1-year follow-up. The incidence of PAF recurrence and conduction recovery in isolated PVs revealed in the second session was significantly lower for C-PVI (21.6% and 28.1%) than for S-PVI (44.0% and 58.3%) (P<0.05). There were no significant differences in the HRV high-frequency component (HF) reflecting parasympathetic activity or the low/high frequency component (LF/HF) reflecting sympathetic activity between the 2 techniques. By multivariate analysis, the PVI technique, HF and LF/HF were independent predictors of PAF recurrence (P<0.05). CONCLUSIONS: Vagal denervation may prevent late PAF recurrence independent of the PVI technique.

Premature ventricular contractions arising from the intramural ventricular septum.

A 68-year-old man with symptomatic idiopathic premature ventricular contractions (PVCs) underwent electrophysiological testing. Radiofrequency catheter ablation was unsuccessful at the earliest endocardial ventricular activation site in the left coronary cusp. Epicardial mapping via the cardiac veins was then performed. Balloon-occluded coronary sinus venography revealed the small branches of the anterior interventricular vein. Mapping with a microcatheter revealed the earliest ventricular activation and perfect pace map at the distal portion of the septal perforating branch, suggesting an intramural ventricular septal PVC origin. Catheter ablation was abandoned because of the inaccessibility of the ablation catheter to that site via the venous system.

A comprehensive validation of very early rule-out strategies for non-ST-segment elevation myocardial infarction in emergency departments: protocol for a multicentre prospective cohort study.

INTRODUCTION: Recent advances in troponin sensitivity enabled early and accurate judgement of ruling-out myocardial infarction, especially non-ST elevation myocardial infarction (NSTEMI) in emergency departments (EDs) with development of various prediction-rules and high-sensitive-troponin-based strategies (hs-troponin). Reliance on clinical impression, however, is still common, and it remains unknown which of these strategies is superior. Therefore, our objective in this prospective cohort study is to comprehensively validate the diagnostic accuracy of clinical impression-based strategies, prediction-rules and hs-troponin-based strategies for ruling-out NSTEMIs. METHODS AND ANALYSIS: In total, 1500 consecutive adult patients with symptoms suggestive of acute coronary syndrome will be prospectively recruited from five EDs in two tertiary-level, two secondary-level community hospitals and one university hospital in Japan. The study has begun in July 2018, and recruitment period will be about 1 year. A board-certified emergency physician will complete standardised case report forms, and independently perform a clinical impression-based risk estimation of NSTEMI. Index strategies to be compared will include the clinical impression-based strategy; prediction rules and hs-troponin-based strategies for the following types of troponin (Roche Elecsys hs-troponin T; Abbott ARCHITECT hs-troponin I; Siemens ADVIA Centaur hs-troponin I; Siemens ADVIA Centaur sensitive-troponin I). The reference standard will be the composite of type 1 MI and cardiac death within 30 days after admission to the ED. Outcome measures will be negative predictive value, sensitivity and effectiveness, defined as the proportion of patients categorised as low risk for NSTEMI. We will also evaluate inter-rater reliability of the clinical impression-based risk estimation. ETHICS AND DISSEMINATION: The study is approved by the Ethics Committees of the Kyoto University Graduate School and Faculty of Medicine and of the five hospitals where we will recruit patients. We will disseminate the study results through conference presentations and peer-reviewed journals.

Electrocardiographic characteristics of ventricular arrhythmias originating from the junction of the left and right coronary sinuses of Valsalva in the aorta: the activation pattern as a rationale for the electrocardiographic characteristics.

BACKGROUND: Ventricular arrhythmias (VAs) may arise from the aortic sinuses and have electrocardiographic and electrophysiological characteristics that suggest a left (LCC) or right coronary cusp (RCC) origin. However, VAs that arise near the junction of those two cusps (L-RCC) may have unusual features. OBJECTIVES: The purpose of this study was to examine the electrocardiographic and electrophysiological characteristics of VAs arising from the L-RCC. METHODS: We studied 155 patients with idiopathic VAs with either left or right bundle branch block and an inferior QRS axis morphology and five control subjects undergoing a pacing study. RESULTS: For 146 of the 155 patients, the origin determined by the successful ablation site was at the L-RCC in five, LCC in 13, RCC in six, non-coronary cusp in two, right ventricular outflow tract in 108, left ventricular outflow tract in five, left ventricular epicardium in four, and pulmonary artery in three. A qrS pattern in leads V1-V3 was observed only in the VAs with an L-RCC origin. The propagation map revealed that the direction of the propagating wave front from the L-RCC origin produced a vector compatible with a q wave and that the anterior activation to the right ventricular outflow tract via the LCC or RCC formed the r wave. Pacing performed at multiple sites in the aortic root in the control subjects demonstrated that only pacing from the L-RCC could reproduce a qrS pattern in leads V1-V3. CONCLUSIONS: This study revealed that a qrS pattern in leads V1-V3 suggests a site of origin at the L-RCC.

Electroanatomic mapping in the catheter ablation of premature atrial contractions with a non-pulmonary vein origin.

Symptomatic premature atrial contractions (PACs) may be a target for catheter ablation. However, mapping of PACs with an atrial origin may not be easy because of erratic incidence and different sites of origin. Although the technique and efficacy of electroanatomic mapping has been established in stable arrhythmias, electroanatomic mapping of PACs in intermittent arrhythmias has not yet been reported. This article describes a manoeuvre for mapping PACs using an electroanatomic mapping system. Our experience has demonstrated that electroanatomic mapping using an auto-freeze map is feasible during PACs and may be an option for catheter ablation of PACs.

Multiple macroreentrant ventricular tachycardias exhibiting centrifugal endocardial activations from the scar border zone after myocardial infarction.

A 53-year-old man with a ventricular tachycardia (VT) electrical storm during the chronic phase of an extensive anteroseptal myocardial infarction underwent electrophysiologic testing and catheter ablation. An electroanatomical map during 7 induced macroreentrant VTs demonstrated multiple centrifugal endocardial activations from sites that were located at the circumferential border zone of a large scar area. Interestingly, during the radiofrequency catheter ablation of 4 of the VTs, the elimination of the substrate of the previous VTs converted one VT to another probably because those VTs might have shared a central common pathway of the macroreentrant circuit with different exits.

Comparison of uninterrupted anticoagulation with dabigatran etexilate or warfarin in the periprocedural period for atrial fibrillation catheter ablation: Results of the Japanese subgroup of the RE-CIRCUIT trial.

Background: There are limited data on uninterrupted anticoagulation with direct oral anticoagulants during catheter ablation for atrial fibrillation (AF), particularly in Japan. We planned a subgroup analysis of the RE-CIRCUIT study, comparing the use of uninterrupted dabigatran therapy with warfarin therapy during catheter ablation among the Japanese subgroup and with that in the total population. Methods: The RE-CIRCUIT study utilized a prospective, randomized, open-label, blinded endpoint design, and the primary endpoint was the incidence of major bleeding events (MBEs). Patients were randomized to uninterrupted dabigatran 150 mg twice daily or warfarin. In this study, we analyzed the results in Japanese patients. Results: Of 704 enrolled patients in the study, 112 Japanese patients were randomized to dabigatran (n = 65) or warfarin (n = 47). MBEs were experienced by two patients: one in the dabigatran group (1.6%, cardiac tamponade) and one in the warfarin group (2.2%, groin hematoma) (risk difference vs warfarin -0.6%; 95% CI -5.8, 4.7). Within the Japanese subgroup, there were no thromboembolic events in both groups. Conclusion: While not designed to show statistical difference between two treatment groups, our results from the Japanese subgroup supported those from the overall population. Furthermore, this study provided clinical information regarding MBE, especially cardiac tamponade, in Japanese patients.

Electrophysiologic and electrocardiographic characteristics and radiofrequency catheter ablation of focal atrial tachycardia originating from the left atrial appendage.

BACKGROUND: The left atrial appendage (LAA) is one of the major sources of focal atrial tachycardias (ATs). OBJECTIVE: The purpose of this study was to investigate the detailed electrophysiologic characteristics and catheter ablation of focal ATs originating from the LAA. METHODS: The study population consisted of 47 consecutive patients with 50 focal ATs originating from the left atrium (LA): LAA in 13, left pulmonary veins (PVs) in 14, right PVs in 12, and mitral annulus in 11. Programmed electrical stimulation and pharmacologic testing were performed to examine the mechanism of LAA AT. Left atriography was performed prior to radiofrequency ablation to identify the focus in the LAA. RESULTS: The mechanism of LAA AT was automaticity in 11 and triggered activity in 2. The 13 LAA foci were located mainly at the LAA base: 11 on the medial side and 2 on the lateral side. Atrial activation sequences within the distal coronary sinus were helpful in differentiating these LAA foci. The criterion of a negative P wave in leads I and aVL indicating an LAA AT focus was associated with sensitivity of 92.3%, specificity 97.3%, positive predictive value 92.3%, and negative predictive value 97.3%. No complications occurred in any of the 13 patients. All 13 patients were free of atrial arrhythmias without any antiarrhythmic drugs during follow-up of 8 +/- 3 years. CONCLUSION: LAA ATs have typical electrophysiologic and electrocardiographic characteristics that are helpful in guiding radiofrequency catheter ablation.

Macroreentrant ventricular tachycardia mimicking focal ventricular tachycardia in a case with arrhythmogenic right ventricular cardiomyopathy.

A 67-year-old man with ventricular tachycardia (VT) due to arrhythmogenic right ventricular cardiomyopathy (ARVC) underwent electrophysiologic testing. Electroanatomic mapping during the VT seemed to reveal a focal mechanism from near the tricuspid annulus (TA). Several radiofrequency applications delivered at the presumed focus resulted in termination but re-induction of the VT. Additional electroanatomic mapping underneath the TA led to the diagnosis of macroreentrant VT. Several RF applications targeting isolated and late potentials observed there during sinus rhythm eliminated the VT. In ARVC cases, detailed mapping underneath the TA should be performed to reveal the VT mechanism, resulting in suppressing VT recurrences.

Efficacy of electroanatomic mapping in the catheter ablation of premature ventricular contractions originating from the right ventricular outflow tract.

BACKGROUND: Mapping of premature ventricular contractions (PVCs) originating from the right ventricular outflow tract (RVOT) sometimes is not easy because of an unstable incidence and multiple foci of the PVCs. The aim of this study was to evaluate the effectiveness of electroanatomic mapping in catheter ablation of those PVCs. METHODS AND RESULTS: One hundred patients with 134 RVOT origin PVCs were randomly allotted to undergo either conventional (group I; 50 patients with 65 PVCs) or electroanatomic mapping (group II; 50 patients with 69 PVCs). In group II, electroanatomic mapping of the RVOT was performed using auto-freeze maps in patients with frequent PVCs, and pace mapping was performed marking the pacing sites on the remap which was made by extracting the anatomic frame out of the baseline map during sinus rhythm in patients with infrequent PVCs. Successful ablation was achieved in 44 (88%) group I patients and 48 (96%) group II patients (p = 0.14). The fluoroscopy and procedure times and those per PVC morphology were all significantly shorter in group II than group I overall (p < 0.0001 for all comparisons), and in each patient group with infrequent PVCs, frequent PVCs or unstable PVCs (p < 0.05-0.0001). The number of RF applications and that per PVC was significantly smaller in group II than group I (5.3 +/- 1.8 vs 6.2 +/- 2.4, and 4.4 +/- 1.2 vs 5.2 +/- 2.1; p < 0.05). CONCLUSIONS: The use of electroanatomic mapping may reduce the fluoroscopy and procedure times in the ablation of RVOT PVCs, but there is no evidence that it improves the overall efficacy of the procedure.