The cornerstone of pulmonary vein (PV) isolation (PVI) is a wide-area circumferential ablation (WACA) resulting in an antral PVI area. Pulsed-field ablation (PFA) is a new nonthermal 'single-shot' ...PVI technique resulting in well-characterized posterior isolation areas. However, information on circumferential PVI area is lacking. Thus, we sought to characterize the circumferential antral PVI areas after PFA-PVI.
Atrial fibrillation (AF) patients underwent fluoroscopy-guided PVI with a pentaspline PFA catheter. Ultra-high-density voltage maps using a 20-polar circular mapping catheter were created before and immediately after PVI to identify and quantify (i) insufficient isolation areas per antral PV segment (10-segment model) and (ii) enlarged left atrial (LA) isolation areas (beyond the antral PV segments) per LA region (8-region model). The PFA-PVI with pre- (5469 ± 1822 points) and post-mapping (6809 ± 2769 points) was performed in 40 consecutive patients age 62 ± 6 years, 25/40 (62.5%) paroxysmal AF. Insufficient isolation areas were located most frequently in the anterior antral PV segments of the left PVs (62.5-77.5% of patients) with the largest extent (median ≥0.4 cm2) located in the same segments (segments 2/5/8). Enlarged LA isolation areas were located most frequently and most extensively on the posterior wall and roof region (89.5-100% of patients; median 1.1-2.7 cm2 per region).
Fluoroscopy-guided PFA-PVI frequently results in insufficient isolation areas in the left anterior antral PV segments and enlarged LA isolation areas on the posterior wall/roof, which both may be extensive. To optimize the procedure, full integration of PFA catheter visualization into three-dimensional-mapping systems is needed.
Mechanisms of Pulmonary Vein Reconnection After Radiofrequency Ablation of Atrial Fibrillation
Introduction
Pulmonary vein reconnection (PVR) is an important cause of AF recurrence after ablation. ...With the advent of force sensing catheters, catheter–tissue contact can be determined quantitatively. Since contact force (CF) plays a major role in determining the characteristics of RF lesion, we prospectively assessed the mechanisms of PVR with regard to catheter‐contact and lesion distances in patients undergoing AF ablation.
Methods and Results
Forty symptomatic AF patients underwent wide circumferential PV isolation (PVI) with SmartTouch™ CF catheter. The exact locations of acute PVI and spontaneous or adenosine‐provoked PVR were annotated on CARTO. One thousand nine hundred and twenty‐six RF lesions isolated 153 PVs. PVR occurred in 35 (23%) PVs: 22 (63%) adenosine‐provoked and 13 (37%) spontaneous. CF was significantly lower at PVR versus PVI sites for RF lesions within 6 mm from these sites: mean CF 5 versus 11 g (P < 0.0001) and force–time integral (FTI) 225 versus 415 gs (P < 0.0001); 86% of PVR occurred with a mean CF < 10 g (FTI < 400 gs); and the remaining 14% occurred at ablation sites with a long interlesion distance (≥5 mm) despite mean CF ≥ 10 g. Eighty percent of PVR sites were located anteriorly. There were no significant differences in regard to arrhythmia freedom between the patients without (69%) versus with PVR (67%; P = 1.0).
Conclusions
Acutely durable PVI can be achieved when RF lesions are delivered with a mean CF ≥ 10 g and an interlesion distance <5 mm. The majority of PVR occur anteriorly due to inadequate CF or long interlesion distances.
Experimental data suggest that use of cryoablation in pulmonary vein isolation (PVI) is associated with less cell damage and less thrombus formation compared to radiofrequency (RF) energy.
The ...purpose of this study was to test the hypothesis that cryoablation significantly reduces markers of cell damage, platelet activation, and inflammation in patients undergoing PVI for treatment of atrial fibrillation (AF).
Sixty patients with symptomatic drug-resistant AF (age 56 ± 9 years, 48 males, 38 with paroxysmal AF) were randomly assigned to undergo PVI using either an open irrigated-tip RF catheter or a cryoballoon. Markers of cell damage (high-sensitive troponin T hs-TnT, microparticles), platelet activation (platelet reactivity by aggregometry, expression of platelet surface proteins P-selectin and activated glycoprotein GP IIb/IIIa), and inflammatory response (high-sensitive C-reactive protein hs-CRP) were determined before and up to 48 hours after the procedure.
PVI resulted in a significant rise in hs-TnT, microparticles, markers of platelet activation, and hs-CRP over time, with distinct temporal patterns for each parameter. However, after Bonferroni correction for repeated measurements, no significant differences were noted in these parameters between patients treated with cryoablation or RF energy. Procedural time was significantly shorter in patients treated with cryoballoon (177 ± 30 minutes vs 200 ± 46 minutes, P = .03), with no differences in fluoroscopic time, periprocedural complications, or success rate.
Cryoablation and RF energy result in a comparable rise of markers of cell damage, platelet activation and inflammatory response. The data do not support the concept of an improved safety profile for cryoablation in PVI.
We report on 4 patients (aged 57 to 77 years; 3 men) who developed drug-refractory, repetitive ventricular tachyarrhythmias after acute myocardial infarction (MI). All episodes of ventricular ...arrhythmias were triggered by monomorphic ventricular premature beats (VPBs) with a right bundle-branch block morphology (RBBB).
Left ventricular (LV) mapping was performed to attempt radiofrequency (RF) ablation of the triggering VPBs. Activation mapping of the clinical VPBs demonstrated the earliest activation in the anteromedial LV in 1 patient and in the inferomedial LV in 2 patients. Short, high-frequency, low-amplitude potentials were recorded that preceded the onset of each extrasystole by a maximum of 126 to 160 ms. At the same site, a Purkinje potential was documented that preceded the onset of the QRS complex by 23 to 26 ms during sinus rhythm. In 1 patient, only pace mapping was attempted to identify areas of interest in the LV. Six to 30 RF applications abolished all local Purkinje potentials at the site of earliest activation and/or perfect pace mapping and suppressed VPBs in all patients. No episode of ventricular tachycardia or fibrillation has recurred for 33, 14, 6, and 5 months in patients 1, 2, 3, and 4, respectively.
Incessant ventricular tachyarrhythmias after MI may be triggered by VPBs. RF ablation of the triggering VPBs is feasible and can prevent drug-resistant electrical storm, even after acute MI. Catheter ablation of the triggering VPBs may be used as a bailout therapy in these patients.
Recent data have shown a high incidence of the early repolarization pattern confined in inferolateral leads in patients with idiopathic ventricular fibrillation.
The purpose of the present study was ...to investigate the prevalence and the prognostic significance of the early repolarization pattern in inferolateral leads in patients with Brugada syndrome.
Clinical, genetic, and electrophysiologic data from 290 individuals (223 males, mean age 48.3 +/- 14.2 years) with a spontaneous or drug-induced type 1 electrocardiogram (ECG) pattern of Brugada syndrome and structurally normal hearts were analyzed. Twelve-lead ECGs were evaluated for the presence of early repolarization pattern, which was defined as J-point elevation of at least 0.1 mV from baseline in at least two inferior or lateral leads. Follow-up data were obtained for all subjects.
An early repolarization pattern manifested as notched or slurred J-point elevation mainly in lateral leads was observed in 35 subjects (12%). The prevalence of the early repolarization pattern was significantly higher in male subjects (P = .004). During a mean follow-up period of 44.9 +/- 27.5 months, 22 subjects (8%) displayed an arrhythmic event including sudden cardiac death. There were no significant differences regarding spontaneous ECG type of Brugada syndrome, symptoms, family history of sudden cardiac death, and positive genetic test between subjects with and without the early repolarization pattern. The presence of early repolarization pattern was not associated with arrhythmic events during follow-up (Hazard ratio HR 1.090; 95% confidence interval 0.349-3.403; P = .882).
The early repolarization pattern in inferolateral leads is not an uncommon finding in Brugada syndrome. In our population, the early repolarization features were not associated with a worse outcome in subjects with Brugada syndrome.
Linear radiofrequency ablation at the cavotricuspid isthmus (CTI) is the treatment of choice for typical flutter. Despite a high acute success rate, reconduction through the CTI may occur in ...approximately 15% of patients and eventually lead to flutter recurrence.
The purpose of this study was to test the hypothesis that injection of adenosine may reveal transient CTI reconduction and predict early relapse of permanent CTI conduction.
Thirty-one patients with CTI-dependent flutter (mean age 65 ± 11 years, 87% male, ejection fraction 55% ± 11%) were included in the study. CTI ablation was performed using an open-irrigated ablation catheter. Bidirectional conduction block was confirmed using conventional criteria. Subsequently, transisthmus conduction was reevaluated after adenosine injection. During a 30-minute waiting period, permanent recovery of CTI conduction was monitored. During a mean follow-up of 6 ± 3 months, clinical recurrences of typical flutter were assessed.
Bidirectional isthmus block was achieved in all patients. Injection of 16 ± 3 mg adenosine IV induced transient second- or third-degree AV block in all patients. An adenosine-induced brief sequence reversal at the right lateral wall occurred in 6 of 31 patients (19%) and revealed transient CTI reconduction. Among these 6 patients, 4 (67%) had permanent recovery of transisthmus conduction in the subsequent waiting period; the remaining 2 patients (33%) had clinical recurrence of common flutter. Importantly, no patient without adenosine-mediated dormant transisthmus conduction (25/31 81%) showed permanent recovery during the waiting period or clinical flutter recurrence during follow-up.
Adenosine-induced "dormant transisthmus conduction" precedes early relapse of permanent CTI conduction. Patients without "dormant transisthmus conduction" develop no recovery of conduction during the postablation waiting period. Routine use of adenosine for assessment of ablation lines may help to reduce the clinical recurrence of the underlying arrhythmia.
This study hypothesized that P-wave morphology and timing under left atrial appendage (LAA) pacing change characteristically immediately upon anterior mitral line (AML) block.
Perimitral flutter ...commonly occurs following ablation of atrial fibrillation and can be cured by an AML. However, confirmation of bidirectional block can be challenging, especially in severely fibrotic atria.
The study analyzed 129 consecutive patients (66 ± 8 years, 64% men) who developed perimitral flutter after atrial fibrillation ablation. We designed electrocardiography criteria in a retrospective cohort (n = 76) and analyzed them in a validation cohort (n = 53).
Bidirectional AML block was achieved in 110 (85%) patients. For ablation performed during LAA pacing without flutter (n = 52), we found a characteristic immediate V1 jump (increase in LAA stimulus to P-wave peak interval in lead V1) as a real-time marker of AML block (V1 jump ≥30 ms: sensitivity 95%, specificity 100%, positive predictive value 100%, negative predictive value 88%). As V1 jump is not applicable when block coincides with termination of flutter, absolute V1 delay was used as a criterion applicable in all cases (n = 129) with a delay of 203 ms indicating successful block (sensitivity 92%, specificity 84%, positive predictive value 90%, negative predictive value 87%). Furthermore, an initial negative P-wave portion in the inferior leads was observed, which was attenuated in case of additional cavotricuspid isthmus ablation. Computational P-wave simulations provide mechanistic confirmation of these findings for diverse ablation scenarios (pulmonary vein isolation ± AML ± roof line ± cavotricuspid isthmus ablation).
V1 jump and V1 delay are novel real-time electrocardiography criteria allowing fast and straightforward assessment of AML block during ablation for perimitral flutter.
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Introduction: High‐density three‐dimensional (3D) mapping of the pulmonary vein (PV)‐left atrial (LA) junction was performed to characterize spontaneous PV activity in humans.
Methods and Results: ...The activation patterns of ectopic beats and of the initial 2 seconds of atrial fibrillation (AF) from the PVs were analyzed using a 64‐poles basket catheter. A focal mechanism was defined as a discrete site of early and centrifugal activation. Continuous activity was considered as an activation covering ≥80% of the tachycardia beat‐to‐beat cycle length within the mapping field. In 35 patients, 123 spontaneous focal ectopic beats that did not induce AF and 95 that did induce AF were mapped. The mean coupling interval of ectopic discharges not inducing AF was 281 ± 70 msec versus 236 ± 90 msec for ectopies initiating AF (P ≤ 0.01). The first ectopic activity of all 218 arrhythmogenic events showed exclusively a focal mechanism. During the 95 episodes of AF initiation, one or two ectopic beats from the PVs initiated AF in the LA in 39%, a stable focal tachycardia was recorded in 14%, continuous activity with important changes in cycle length (35 ± 15 msec) suggestive of decremental or fibrillatory conduction was found in 18%, and in 29% the activation pattern could not be classified. No stable and sustained reentrant circuit could be identified by our mapping tool in the PV‐LA junction.
Conclusions: Arrhythmogenic activity from PVs in humans is predominantly due to discrete focal activity.
Abstract Background The spectrum of phenotypes related to mutations of the SCN5A gene include Brugada syndrome (BS), long QT syndrome, progressive cardiac conduction defect, and sinus node disease ...(SND). The present study investigated the incidence of SND in subjects with type 1 electrocardiogram (ECG) pattern of BS. Methods and results The study population consisted of 68 individuals (55 males, mean age 44.8 ± 12.8 years) with spontaneous ( n = 27) or drug-induced ( n = 41) type 1 ECG pattern of BS. Twenty-eight subjects were symptomatic with a history of syncope (41.2%). SND was observed in 6 symptomatic subjects (8.8%), and was mainly attributed to sino-atrial block with sinus pauses. Two patients were initially diagnosed with SND, and received a pacemaker. Patients with SND displayed an increased P-wave duration in leads II and V2, PR interval in leads II and V2, QRS duration in leads II and V2, and increased QTc interval in lead V2 ( p < 0.05). AH and HV intervals as well as corrected sinus node recovery time (cSNRT) were significantly prolonged in subjects with SND ( p < 0.05). During a mean follow-up period of 5.0 ± 3.6 years, five subjects with a history of syncope suffered appropriate implantable cardioverter defibrillator (ICD) discharges due to ventricular arrhythmias (7.4%). None of those diagnosed with SND suffered syncope or ICD therapies. Conclusion SND is not an uncommon finding in subjects with type 1 ECG pattern of BS. The occurrence of SND in relatively young patients may deserve meticulous investigation including sodium channel blocking test.
Previous studies have demonstrated an overlap between the arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) and Brugada syndrome (BS). Conduction delay in the right ventricle has ...been demonstrated in both entities.
This study investigated specific ARVC/D electrocardiographic (ECG) markers in subjects with spontaneous or drug-induced type 1 ECG pattern of BS.
The study population consisted of 47 apparently healthy individuals (38 men, mean age 44.1 ± 13.3 years) with spontaneous (n = 17) or drug-induced (n = 30) type 1 ECG phenotype of BS. The clinical records of these individuals were retrospectively analyzed.
Fifteen subjects (31.9%) were symptomatic, with a history of syncope. A family history of BS or sudden cardiac death was reported in 10 (21.3%) and 8 (17.0%) cases, respectively. Epsilon-like waves in leads V1-V3 were observed in 6 subjects (12.7%). Epsilon-like waves were seen in spontaneous type 1 ECGs in 2 cases and after sodium channel blocking test in 4 cases. In baseline ECGs, localized prolongation (>110 ms) of the QRS complex in leads V1-V3, QRS duration ratio in (V1+V2+V3)/(V4+V5+V6) ≥ 1.2, and prolonged S wave upstroke (>55 ms) in leads V1-V3 were seen in 48.8%, 29.8%, and 40.4% of subjects, respectively. Epsilon-like waves and delayed S wave upstroke were more commonly observed in subjects with family history of BS (P = .014 and P = .038, respectively).
Specific ECG markers that reflect ventricular conduction delay in ARVC/D are commonly observed in subjects with spontaneous or drug-induced type 1 ECG pattern of BS as well. These depolarization abnormalities may be related to subtle underlying structural abnormalities.
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