Subclinical sinus node dysfunction in patients with atrial fibrillation-Insight from ultrahigh-resolution mapping of human sinoatrial exits.

BACKGROUND: Even a short duration of paroxysmal episodes of atrial fibrillation (AF) is associated with sinus node (SN) remodeling and a reduced SN reserve or dysfunction. The number of earliest atrial activation sites (EASs) during sinus rhythm decreases according to the decrease in the SN reserve. OBJECTIVE: We sought to evaluate the EASs during sinus rhythm using an ultrahigh-density mapping system. METHODS: This study included 35 patients (supraventricular tachycardia [SVT]/paroxysmal atrial fibrillation [PAF]/persistent atrial fibrillation [PsAF] = 5/21/9) who underwent ultrahigh-resolution endocardial mapping of the SN area at rest and during ß-stimulation. The number of EASs was determined by the Lumipoint™ algorithm. RESULTS: The number of EASs was greatest in SVT patients both at rest (SVT/PAF/PsAF = 1.4 ± 0.8/1.0 ± 0/1.0 ± 0, p = .04) and during ß-stimulation (SVT/PAF/PsAF = 2.6 ± 1.0/1.3 ± 0.6/1.0 ± 0, p < .01). The number significantly increased with ß-stimulation as compared to baseline in the PAF patients (p = .02), but not in the PsAF patients. The brain natriuretic peptide (BNP) level was significantly higher in AF than SVT patients (SVT/PAF/PsAF = 12.3 [10.1-14.5]/25.7 [14.8-36.0]/73.4 [57.6-140] pg/ml, p < .01). In the PAF patients, the BNP level was significantly higher in those with unicentric EASs than multicentric EASs during ß-stimulation (28.1 [19.1-46.5] vs. 13.1 [9.4-26.9] pg/ml, p = .03), and the optimal cutoff point for the BNP level predicting unicentric EASs was 21.8 pg/ml (sensitivity 82.6%; specificity 85.7%). CONCLUSIONS: AF patients have a smaller number of EASs and poorer response to ß-stimulation than non-AF patients. An elevated BNP level might predict subclinical SN dysfunction in patients with PAF.

Declines in serum uric acid level after catheter ablation of atrial fibrillation.

BACKGROUND: Few studies have examined whether catheter ablation for AF patients improves biomarkers other than serum levels of brain natriuretic peptide (BNP) and renal function. This study was to explore whether catheter ablation for atrial fibrillation (AF) patients affects uric acid (UA), glucose and lipid metabolism. METHODS AND RESULTS: A total of 206 patients (66.6 ± 10.4 years; 132 men) who underwent initial AF ablation without changes to oral medications were included. Baseline BNP and UA levels significantly decreased at 1 year after ablation (p < 0.05 each). Changes in UA level correlated significantly with pre-procedural UA level (r = 0.57). In multivariable logistic regression modeling, pre-procedural UA level, persistent AF, and hemoglobin A1c (p < 0.05 each) were independent predictors of post-procedural UA level decline. Significant improvements in both persistent and paroxysmal AF patients were identified, and the magnitude of post-procedural serum UA level decline after ablation (ΔUA) was significantly greater in patients with persistent AF (0.8 ± 1.0 mg/dl) than in those with paroxysmal AF (0.2 ± 0.8 mg/dl, p < 0.001). Of the 48 patients with high UA level before procedure, 28 patients showed improvement in UA level to normal range. CONCLUSIONS: Catheter ablation for AF patients significantly improved serum UA levels without obvious influences of heart failure, renal function, or inflammation, suggesting that AF ablation may be effective for AF patients with hyperuricemia. Trial registration The study was approved by the Research Ethics Committee of University of Fukui (no. 20210132) and clinical trial registration (UMIN000044669).

Evaluation of cryoballoon pulmonary vein isolation lesions during the acute and chronic phases using a high-resolution mapping system.

BACKGROUND: An acute cryothermal ablation lesion contains both reversible and irreversible elements. However, differences in lesions created with cryoballoon pulmonary vein isolation (PVI) between the acute and chronic phases have not been fully elucidated. METHODS: We retrospectively analyzed 23 consecutive patients with atrial fibrillation who underwent cryoballoon PVI during the initial procedure followed by a second ablation procedure. In all patients, cryoballoon PVI lesions were evaluated with high-resolution voltage mapping just after PVI (acute phase) and during the second session (chronic phase). We compared the area and width of the non-isolated left atrial posterior wall (NI-LAPW) with voltage ≥ 0.5 mV during both sessions. RESULTS: PVI was successfully achieved in all patients. Cryoballoon PVI lesions were re-evaluated at 11 [2-17] months post-procedure. During the chronic phase, NI-LAPW width became significantly larger at the level of the roof (change, 5.8 ± 5.5 mm; p < 0.001) and at the level of the carina (change, 3.3 ± 7.0 mm; p < 0.05), and NI-LAPW area became significantly larger (change, 1.5 ± 1.9 cm2; p < 0.001) compared with the acute phase. Eight patients without any PV reconnections also had larger NI-LAPW areas (change, 1.3 ± 1.2 cm2; p < 0.05) during the chronic phase. Conduction resumption confined to the right carina was observed in 1 (4.3%) patient who presented with circumferential PVI that included the carina during the first session. CONCLUSION: Acute cryoballoon PVI lesions significantly regressed during the chronic phase. PV reconnections and the isolation area should be carefully re-evaluated during the second procedure.

Evaluation of interatrial conduction pattern after pulmonary vein isolation using an ultrahigh-resolution electroanatomical mapping system.

Interatrial conduction consists of various muscular bundles, including the Bachmann bundle. In this study, we investigated interatrial activation patterns using ultrahigh-resolution left atrial endocardial mapping. This study investigated 58 patients who underwent catheter ablation of atrial arrhythmia via an ultrahigh-resolution mapping system (Rhythmia) at our hospital from May 2020 to January 2021. Left atrial voltage maps and activation maps were acquired after the ablation procedure during right atrial appendage (RAA) pacing. We defined left atrial breakout sites (LABSs) as centrifugal activation patterns shown by the LUMIPOINT Activation Search Tool. The distance between each LABS in the left atrial anterior wall and the superior border of the interatrial septum (DLABS-IAS) was measured on the shell of the electroanatomical map, and anterior LABSs were divided equally into roof- and septal-side groups. Fifty-three (91%) patients underwent cryoballoon pulmonary vein isolation. Ultrahigh-resolution left atrial mapping was successfully performed in all patients (6831 ± 2158 points). A total of 82 LABSs were identified in left atrial anterior wall; 34 patients had single LABS and 24 patients had dual LABSs. The mean DLABS-IAS was 10.3 ± 9.6 mm. Seven patients also exhibited posterior LABS near the interatrial raphe below the right inferior pulmonary vein. Patients with a single roof-side LABS had significantly shorter left atrial activation times than those with a single septal-side LABS (81.6 ± 13.2 ms vs. 93.5 ± 13.7 ms, p < 0.05). Interatrial conduction patterns during RAA pacing varied between patients and affected the left atrial activation time.

Conduction delay across the cavotricuspid isthmus block line caused by the gap near the inferior vena cava: the role of conduction block in the lower lateral right atrium.

The electrophysiological properties of the gap associated with the cavotricuspid isthmus (CTI) block line near the inferior vena cava (IVC) are not fully elucidated. Of 143 patients who underwent CTI block line ablation between September 2020 and April 2021, high-resolution CTI gap mapping was performed for 15 patients. Four patients were identified as having a gap near the IVC (IVC-side gap) despite wide double potentials (DPs) with > 90 ms intervals at the block line. Detailed gap mapping during coronary sinus ostial pacing was performed before and after touch-up ablation. CTI conduction delays caused by an IVC-side gap were classified into 3 patterns: (1) conduction delay at the IVC-side gap without detouring gap conduction, (2) detouring gap conduction due to intrinsic lower lateral right atrium (LLRA)-IVC functional block, and (3) detouring gap conduction due to LLRA-IVC conduction block created by lateral deviation of the CTI ablation line. In Pattern 2, IVC-side gap conduction traveled backward toward the crista terminalis below the LLRA-IVC junction and came back forward again above the border. One patient presented with a head-to-bottom activation pattern of the lateral right atrium (pseudo-CTI block). Pattern 3 was caused by lateral deviation of initial RF deliveries and presented with the same course as intrinsic LLRA-IVC functional block. All patients had wide DP intervals near the tricuspid annulus (mean, 112 ms) and just above the gap site (mean, 109 ms). An IVC-side gap associated with the CTI block line can present with various conduction delay patterns.

Ultra-high resolution mapping of reverse typical atrial flutter: electrophysiological properties of a right atrial posterior wall and interatrial septum activation pattern.

PURPOSE: We aimed to elucidate the right atrial posterior wall (RAPW) and interatrial septum (IAS) conduction pattern during reverse typical atrial flutter (clockwise AFL: CW-AFL). METHODS: This study included 30 patients who underwent catheter ablation of CW-AFL (n = 11) and counter-clockwise AFL (CCW-AFL; n = 19) using an ultra-high resolution mapping system. RAPW transverse conduction block was evaluated by the conduction pattern on propagation maps and double potentials separated by an isoelectric line. The degree of blockade was evaluated by the %blockade, which was calculated by the length of the blocked area divided by the RAPW length. IAS activation patterns were also investigated dependent on the propagation map. RESULTS: The average %blockade of the RAPW was significantly smaller in patients with CW-AFL than those with CCW-AFL (25 [3-74]% vs. 67 [57-75]%, p < 0.05). CW-AFL patients exhibited 3 different RAPW conduction patterns: (1) a complete blockade pattern (3 patients), (2) moderate (> 25% blockade) blockade pattern (2 patients), and (3) little (< 25% blockade) blockade pattern (6 patients). In contrast, the little blockade pattern was not observed in CCW-AFL patients. Of 11 CW-AFL patients, 4, including all patients with an RAPW complete blockade pattern, had an IAS activation from the wavefront from the anterior tricuspid annulus (TA), and 6 had an IAS activation from the wavefronts from both the anterior TA and RAPW. One patient had IAS activation dominantly from the wavefront from the RAPW. CONCLUSIONS: RAPW transverse conduction blockade during CW-AFL was less frequent than during CCW-AFL, which possibly caused various IAS activation patterns.

Early diastolic mitral regurgitation in left ventricular aneurysm.

Diastolic mitral regurgitation is a type of functional mitral regurgitation that develops via a reversal of the left atrioventricular pressure gradient during diastole. This study aimed to explore the mechanism underlying early diastolic mitral regurgitation (EDMR) in patients with left ventricular (LV) aneurysms after anterior myocardial infarction (AMI) by assessing the intraventricular pressure difference using vector flow mapping. We enrolled 23 consecutive patients with LV aneurysms (with and without EDMR) and 15 healthy men as controls. In the control group, LV suction began from the apex during early diastole. In contrast, the blood that pooled in the apical aneurysm during systole generated a relatively higher pressure at the apex than at the basal LV during early diastole; consequently, the pressure reversal phenomenon occurred in the LV. Compared to the EDMR- group, the EDMR + group (n = 7) exhibited a significantly higher diastolic time ratio ([time from the second heart sound to the pressure inversion point]/[total diastolic time]) (P < 0.001). The diastolic time ratio was significantly correlated with log BNP, but not with E/A, E/E', or the left atrial expansion index. In conclusion, EDMR in LV aneurysm may be due to a prolonged diastolic time ratio leading to prolonged pressure inversion in the LV during early diastole.

Safety and durability of cavo-tricuspid isthmus linear ablation in the current era: Single-center 9-year experience from 1078 procedures.

BACKGROUND: Cavo-tricuspid isthmus (CTI) linear ablation is performed not only for atrial flutter (AFL) but empirically during atrial fibrillation (AF) ablation in real-world practice.  PURPOSE: We sought to evaluate the safety and durability of the CTI ablation.  METHODS: This retrospective study included 1078 consecutive patients who underwent a CTI ablation. AFL was documented before or during the procedure in 249 (23.1%) patients, and an empirical CTI and AF ablation were performed in 829 (76.9%) patients.  RESULTS: CTI block was successfully created in 1051 (97.5%) patients with a 10.3 ± 6.6 min total radiofrequency time. Repeat procedures were performed for recurrent arrhythmias in 187 (17.3%) patients at a median of 11.0 (5.0-30.0) months postprocedure, and conduction resumption was identified in 68/174 (39.1%). Among those undergoing a CTI ablation with an AF ablation, the durability was significantly higher in those with than without documented AFL (78.1% vs. 58.2%, p = .031).  The total radiofrequency time was significantly shorter (9.0 ± 5.3 vs. 10.0 ± 6.4 [mins], p = .024) and durability significantly higher (78.1 vs. 58.7[%], p = .043) in the large-tip than irrigated-tip catheter group. Iatrogenic AFL was observed after the empiric CTI ablation in 11 (1.3%) patients. Procedure-related complications occurred in 15 (1.4%) patients. Eight patients experienced coronary artery spasms, including one with ventricular fibrillation following ST elevation on the ward. The other six patients experienced transient atrioventricular block and one experienced cardiac tamponade requiring drainage.  CONCLUSIONS: Despite a high acute CTI ablation success, the conduction block durability was relatively low after the empiric ablation. An empiric CTI ablation at the time of the AF ablation is not recommended.

Premature ventricular contraction originating from the distal left anterior fascicle: The usefulness of a multipolar catheter with small electrodes in mapping presystolic Purkinje potential and pace mapping.

Mapping and localizing presystolic Purkinje potentials are crucial for determining the optimal ablation site for fascicular premature ventricular contractions (PVCs). Here we present a case of PVCs originating from the distal left anterior fascicle (LAF). Activation mapping using a multipolar catheter with small electrodes demonstrated early presystolic Purkinje potentials during the PVCs. A moderately good pace-map match was also obtained near the successful ablation site. This case demonstrates the activation pattern of PVCs originating from the distal LAF and the usefulness of multipolar catheters with small electrodes for the mapping of fascicular PVCs.

Cardiac rehabilitation after catheter ablation of atrial fibrillation in patients with left ventricular dysfunction.

Few studies have examined the efficacy and safety of cardiac rehabilitation in patients with atrial fibrillation (AF) who underwent AF ablation. We explored the feasibility of additional cardiac rehabilitation after AF ablation in patients with a reduced left ventricular ejection fraction (LVEF). Fifty-four patients with heart failure (HF) and a reduced LVEF (HFrEF) (LVEF < 50%; 67.1 ± 11.6 years; 43 men) who underwent initial AF ablation procedures were included. Fourteen (25.9%) patients underwent cardiac rehabilitation (rehabilitation-group) and the remaining 40 (74.1%) did not (non-rehabilitation-group) after the procedure. The rehabilitation-group patients were relatively older, more likely female (p = 0.024), and had more likely a history of an HF hospitalization (p < 0.01) and cardiac device implantation (p = 0.041). The baseline LVEF was significantly lower (p = 0.043) and brain natriuretic peptide (BNP) (p < 0.01) and C-reactive protein (CRP) (p < 0.01) values were significantly higher in the rehabilitation-group. The 6-min walk distance significantly improved after 21.4 ± 11.5 days of cardiac rehabilitation during hospitalization (226.1 ± 155.9 vs. 398.1 ± 77.5 m, p = 0.016) without any adverse events. During an 18.9 ± 6.3 month follow-up period, the freedom from AF recurrence (p = 0.52) and re-hospitalizations due to HF (p = 0.63) were similar between the 2 groups. No death or strokes were observed. During the follow-up period, the LVEF significantly improved similarly in both groups, and the change in the BNP and CRP values significantly decreased in the rehabilitation-group. Despite the rehabilitation-group patients having a more severe HF status, the clinical outcomes and AF freedom were similar between the 2 groups, suggesting the favorable impact of cardiac rehabilitation after AF ablation in HFrEF patients.

Ultrahigh resolution electroanatomical mapping of the transverse conduction of the right atrial posterior wall in cases with and without typical atrial flutter.

INTRODUCTION: The right atrial posterior wall (RAPW) is known to form a conduction barrier during typical atrial flutter (AFL). We evaluated the transverse conduction properties of RAPW in patients with and without typical AFL using an ultrahigh resolution electroanatomical mapping system. METHODS AND RESULTS: This study included 41 patients who underwent catheter ablation of AF, typical or atypical AFL, in whom we performed RAPW mapping with an ultrahigh resolution mapping system during typical AFL and coronary sinus ostial pacing with three different pacing cycle lengths (PCLs) (1) PCL1: PCL within 40 ms of the AFL cycle length in patients with typical AFL or 250-300 ms for those without, (2) PCL2: 400 ms, (3) PCL3: PCL just faster than the sinus rate. Local RAPW conduction block was evaluated by propagation mapping and local double potentials separated by an isoelectric line. The functional block was defined as areas blocked during shorter PCLs but conductive during longer PCLs. The degree of blockade was calculated by dividing the blocked length by RAPW length (%blockade). Only two patients demonstrated a fixed complete RAPW block (100%, %blockade). Thirty-one patients demonstrated a partial block of RAPW, and the %blockade during PCL1-3 was 49.4 ± 19.8%, 39.5 ± 19.2%, and 35.0 ± 22.9% in this group, respectively. Functional block areas were frequently observed above the fixed block area adjacent to the RA-inferior vena cava junction. Transverse conduction block was more frequently observed in patients with typical AFL at any longitudinal level of RAPW. CONCLUSION: RAPW transverse conduction block is lower-side dominant and greater in patients with typical AFL than those without.

A case of outflow tract premature ventricular contractions with very distant exit sites suspected to have a single origin.

Outflow tract premature ventricular contractions sometimes demonstrate multiple exit sites in the right and left outflow tracts with preferential pathways. Here we present a case of outflow tract premature ventricular contractions, which were eliminated by ablation from the right ventricular outflow tract accompanied by additional ablation from the very distant endocardial left ventricular outflow tract. The findings during the ablation indicated there was a single origin with multiple exit sites rather than multiple origins for each QRS morphology. This case illustrates that the preferential pathways can demonstrate very distant multiple exit sites.

Extended Sedentary Time Increases the Risk of All-Cause Death and New Cardiovascular Events in Patients With Diabetic Kidney Disease.

BACKGROUND: Sedentary behavior may be an independent risk factor for cardiovascular events. This study aimed to clarify the effects of extended sedentary time in patients with diabetic kidney disease (DKD) on the risk of all-cause death and new events.Methods and Results:A prospective cohort study was performed over 39 months. The study included 173 patients with DKD who completed the International Physical Activity Questionnaire (IPAQ) (101 men; mean age, 71±11 years); 37 patients (21.4%) were diagnosed with cardiovascular disease (CVD). New events were defined as all-cause death, cerebral stroke, or CVD requiring hospitalization or commencing hemodialysis (HD). Data were analyzed using a multivariate Cox proportional hazard regression model with variables, including sedentary time. There were 34 cases of new events during the observation period, including 4 cases of stroke, 20 cases of CVD, 4 cases of HD implementation, and 6 cases of death. Hazard ratio (HR) calculations for the new event onset group identified sedentary time as a significant independent variable. The independent variable that was identified as a significant predictor of new events was the sedentary time (60 min/day; HR: 1.23, 95% CI: 1.05-1.45, P=0.012). CONCLUSIONS: Extended sedentary time increased the risk of new cardiovascular or renal events and/or all-cause death in patients with DKD.

Phrenic nerve stimulation during right ventricular outflow tract pacing: A rare but possible complication.

Phrenic nerve stimulation (PNS) caused by a right ventricular (RV) lead is an uncommon complication of pacemaker implantations. We demonstrated a case of left PNS caused by an RV lead placed in the RV outflow tract (RVOT). The PNS was dependent on ventricular capture. This case highlighted a risk of PNS even during RVOT pacing.