Feasibility and safety of a three-dimensional anatomic map-guided transseptal puncture for left-sided catheter ablation procedures.

AIMS: Transseptal puncture (TP) for left-sided catheter ablation procedures is routinely performed under fluoroscopic or echocardiographic guidance [transoesophageal echocardiography (TEE) or intracardiac echocardiography (ICE)], although three-dimensional (3D) mapping systems are readily available in most electrophysiology laboratories. Here, we sought to assess the feasibility and safety of a right atrial (RA) 3D map-guided TP. METHODS AND RESULTS: In 104 patients, 3D RA mapping was performed to identify the fossa ovalis (FO) using the protrusion technique. The radiofrequency transseptal needle was visualized and navigated to the desired potential FO-TP site. Thereafter, the interventionalist was unblinded to TEE and the potential FO-TP site was reassessed regarding its convenience and safety. After TP, the exact TP site was documented using a 17-segment-FO model. Reliable identification of the FO was feasible in 102 patients (98%). In these, 114 3D map-guided TP attempts were performed, of which 96 (84%) patients demonstrated a good position and 18 (16%) an adequate position after TEE unblinding. An out-of-FO or dangerous position did not occur. A successful 3D map-guided TP was performed in 110 attempts (97%). Four attempts (3%) with adequate positions were aborted in order to seek a more convenient TP site. The median time from RA mapping until the end of the TP process was 13 (12-17) min. No TP-related complications occurred. Ninety-eight TP sites (85.1%) were in the central portion or in the inner loop of the FO. CONCLUSION: A 3D map-guided TP is feasible and safe. It may assist to decrease radiation exposure and the need for TEE/ICE during left-sided catheter ablation procedures.

Characterization of circumferential antral pulmonary vein isolation areas resulting from pulsed-field catheter ablation.

AIMS: 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. METHODS AND RESULTS: 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). CONCLUSION: 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.

3D mapping of phrenic nerve course for radiofrequency pulmonary vein isolation.

INTRODUCTION: Phrenic nerve (PN) injury is a rare but severe complication of radiofrequency (RF) pulmonary vein isolation (PVI). The objective of this study was to characterize the typical intracardiac course of the PN with a three-dimensional electroanatomic mapping system, to quantify the need for modification of the ablation trajectory to avoid delivering an ablation lesion on sites with PN capture, and to identify very circumscribed areas of common PNC on the routine ablation trajectory of a RF-PVI, allowing fast and effective PN screening for everyday usage. METHODS: We enrolled 137 consecutive patients (63 ± 9 years, 64% men) undergoing PVI. A detailed high output (20 mA) pace-mapping protocol was performed in the right (RA) and left atrium (LA) and adjacent vasculature. RESULTS: The right PN was most commonly captured in the superior vena cava at a lateral (50%) or posterolateral (23%) position before descending along the RA either straight (29%) or with a posterolateral bend (20%). In the LA, beginning deep within the right superior pulmonary vein (RSPV), the right PN is most frequently detectable anterolateral (31%), then descends to the lateral proximal RSPV (23%), and further towards the lateral antral region (15%) onto the medial LA wall (12%). To avoid delivering an ablation lesion on sites with PN capture, modification of ablation trajectory was necessary in 23% of cases, most commonly in the lateral RSPV antrum (81%). No PN injury occurred. CONCLUSION: PN mapping frequently reveals the close proximity of the PN to the ablation trajectory during PVI, particularly in the lateral RSPV antrum. Routine PN pacing should be considered during RF PVI procedures.

Non-invasive body surface electrocardiographic imaging for diagnosis of atrial cardiomyopathy.

AIMS: Atrial cardiomyopathy (ACM) is associated with new-onset atrial fibrillation, arrhythmia recurrence after pulmonary vein isolation (PVI) and increased risk for stroke. At present, diagnosis of ACM is feasible by endocardial contact mapping of left atrial (LA) low-voltage substrate (LVS) or late gadolinium-enhanced magnetic resonance imaging, but their complexity limits a widespread use. The aim of this study was to assess non-invasive body surface electrocardiographic imaging (ECGI) as a novel clinical tool for diagnosis of ACM compared with endocardial mapping. METHODS AND RESULTS: Thirty-nine consecutive patients (66 ± 9 years, 85% male) presenting for their first PVI for persistent atrial fibrillation underwent ECGI in sinus rhythm using a 252-electrode-array mapping system. Subsequently, high-density LA voltage and biatrial activation maps (mean 2090 ± 488 sites) were acquired in sinus rhythm prior to PVI. Freedom from arrhythmia recurrence was assessed within 12 months follow-up. Increased duration of total atrial conduction time (TACT) in ECGI was associated with both increased atrial activation time and extent of LA-LVS in endocardial contact mapping (r = 0.77 and r = 0.66, P < 0.0001 respectively). Atrial cardiomyopathy was found in 23 (59%) patients. A TACT value of 148 ms identified ACM with 91.3% sensitivity and 93.7% specificity. Arrhythmia recurrence occurred in 15 (38%) patients during a follow-up of 389 ± 55 days. Freedom from arrhythmia was significantly higher in patients with a TACT <148 ms compared with patients with a TACT ≥148 ms (82.4% vs. 45.5%, P = 0.019). CONCLUSION: Analysis of TACT in non-invasive ECGI allows diagnosis of patients with ACM, which is associated with a significantly increased risk for arrhythmia recurrence following PVI.

3D mapping for the identification of the fossa ovalis in left atrial ablation procedures: a pilot study of a first step towards an electroanatomic-guided transseptal puncture.

AIMS: Transseptal puncture (TP) for left atrial (LA) catheter ablation procedures is routinely performed under fluoroscopic guidance. To decrease radiation exposure and increase safety alternative techniques are desirable. The aim of this study was to assess whether right atrial (RA) electroanatomic 3D mapping can reliably identify the fossa ovalis (FO) in preparation of TP. METHODS AND RESULTS: Between May 2019 and August 2019, electroanatomic RA mapping was performed before TP in 61 patients with paroxysmal or persistent atrial fibrillation. Three electroanatomic methods for FO identification, mapping catheter-induced FO protrusion, electroanatomic-guided analysis, and voltage mapping, were evaluated and compared with transoesophageal echocardiography (TOE). Mapping catheter-induced FO protrusion was feasible in 60 patients (98%) with a mean displacement of 6.8 ± 2.5 mm, confirmed by TOE, and proofed to be the most valuable and easiest marker for FO identification. Electroanatomic-guided analysis localized the FO midpoint consistently in the lower half (43 ± 7%) and posterior (18.2 ± 4.4 mm) to a line between coronary sinus and vena cava superior. Analysis of RA voltage maps during sinus rhythm (n = 40, low-voltage cut-off value 1.0 and 1.5 mV) allowed secure FO recognition in 33% and 18%, only. A step-by-step approach, combining FO protrusion (first step) with anatomy criteria in case of protrusion failure (second step) would have allowed for the correct localization of a TP site within the FO in all patients. CONCLUSION: Right atrial electroanatomic 3D mapping prior to TP proofed to be a simple tool for FO identification and may potentially be of use in the safe and radiation-free performance of TP prior to LA ablation procedures.

Amplified sinus-P-wave reveals localization and extent of left atrial low-voltage substrate: implications for arrhythmia freedom following pulmonary vein isolation.

AIMS: Presence of arrhythmogenic left atrial (LA) low-voltage substrate (LVS) is associated with reduced arthythmia freedom rates following pulmonary vein isolation (PVI) in persistent atrial fibrillation (AF). We hypothesized that LA-LVS modifies amplified sinus-P-wave (APW) characteristics, enabling identification of patients at risk for arrhythmia recurrences following PVI. METHODS AND RESULTS: Ninety-five patients with persistent AF underwent high-density (>1200 sites) voltage mapping in sinus rhythm. Left atrial low-voltage substrate (<0.5 and <1.0 mV) was quantified in a 10-segment LA model. Amplified sinus-P-wave-morphology and -duration were evaluated using digitized 12-lead electrocardiograms (40-80 mm/mV, 100-200 mm/s). 12-months arrhythmia freedom following circumferential PVI was assessed in 139 patients with persistent AF. Left atrial low-voltage substrate was most frequently (84%) found at the anteroseptal LA. Characteristic changes of APW were related to the localization and extent of LA-LVS. At an early stage, LA-LVS predominantly located to the LA-anteroseptum and was associated with APW-prolongation (≥150 ms). More extensive LA-LVS involved larger areas of LA-anteroseptum, leading to morphological changes of APW (biphasic positive-negative P-waves in inferior leads). Severe LA-LVS involved the LA-anteroseptum, roof and posterior LA, but spared the inferior LA, lateral LA, and LA appendage. In this advanced stage, widespread LVS at the posterior LA abolished the negative portion of P-wave in the inferior leads. The delayed activation of the lateral LA and LA appendage produced the late positive deflections in the anterolateral leads, resulting in the "late-terminal P"-pattern. Structured analysis of APW-duration and -morphology stratified patients to their individual extent of LA-LVS (Grade 1: mean LA-LVS 4.9 cm2 at <1.0 mV; Grade 2: 28.6 cm2; Grade 3: 42.3 cm2; P < 0.01). The diagnostic value of APW-duration for identification of LA-LVS was significantly superior to standard P-wave-amplification (c-statistic 0.945 vs. 0.647). Arrhythmia freedom following PVI differed significantly between APW-predicted grades of LA-LVS-severity [hazard ratio (HR) 2.38, 95% confidence interval (CI) 1.18-4.83; P = 0.015 for Grade 1 vs. Grade 2; HR 1.79, 95% CI 1.00-3.21, P = 0.049 for Grade 2 vs. Grade 3). Arrhythmia freedom 12 months after PVI was 77%, 53%, and 33% in Grades 1, 2 and 3, respectively. CONCLUSION: Localization and extent of LA-LVS modifies APW-morphology and -duration. Analysis of APW allows accurate prediction of LA-LVS and enables rapid and non-invasive estimation of arrhythmia freedom following PVI.

The Duration of the Amplified Sinus-P-Wave Identifies Presence of Left Atrial Low Voltage Substrate and Predicts Outcome After Pulmonary Vein Isolation in Patients With Persistent Atrial Fibrillation.

OBJECTIVES: Left atrial (LA) low-voltage substrate (LVS) potentially slows intra-atrial conduction, which might identify patients at risk for arrhythmia recurrence following pulmonary vein isolation (PVI). BACKGROUND: Up to 50% of patients with persistent atrial fibrillation (AF) have arrhythmia recurrence following PVI, mostly due to arrhythmogenic LA LVS. METHODS: Seventy-two patients with persistent AF underwent electrocardioversion to sinus rhythm and high-density voltage mapping of the left atrium. Invasively measured LA activation time and P-wave duration (PWD; total PWD and LA PWD [measured from -dV/dt in leads V1 and V2 until the end of the P-wave]) on amplified (40 to 50 mm/mV, 100 to 200 mm/s) digitized 12-lead electrocardiography (ECG) were compared with the extent of LA LVS (<0.5 and <1. 0mV). Freedom from arrhythmia following PVI was evaluated in 143 patients with persistent AF stratified according to amplified PWD before ablation. RESULTS: LA LVS resulted in regional conduction delay, which increased LA activation time (r = 0.79). LA PWD strongly correlated with LA activation time (r = 0.96) and LA LVS (r = 0.80). As the first (right atrial) portion of the P-wave (from P-wave beginning until -dV/dt in leads V1 and V2) was not affected by LA LVS, total PWD correlated with LA LVS (r = 0.84). PWD ≥150 ms identified advanced LA LVS with 94.3% sensitivity and 91.7% specificity. One-year arrhythmia freedom following PVI-only was significantly higher in patients with PWD <150 ms (n = 73) compared with those with prolonged PWD ≥150 ms (n = 70) (72.0% vs. 40.8%; p = 0.003). CONCLUSIONS: Advanced arrhythmogenic LVS is associated with significant intra-atrial conduction delay, which is accurately measurable by prolongation of PWD on amplified 12-lead ECG. PWD ≥150 ms during sinus rhythm measured prior to ablation identifies patients with persistent AF who are at increased risk for arrhythmia recurrence following PVI.

Novel Electrocardiographic Criteria for Real-Time Assessment of Anterior Mitral Line Block: "V1 Jump" and "V1 Delay".

OBJECTIVES: This study hypothesized that P-wave morphology and timing under left atrial appendage (LAA) pacing change characteristically immediately upon anterior mitral line (AML) block. BACKGROUND: 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. METHODS: 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). RESULTS: 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). CONCLUSIONS: V1 jump and V1 delay are novel real-time electrocardiography criteria allowing fast and straightforward assessment of AML block during ablation for perimitral flutter.

Important reduction of the radiation dose for pulmonary vein isolation using a multimodal approach.

Aims: The number of pulmonary vein isolation (PVI) ablation procedures is steadily increasing worldwide resulting in a substantial radiation exposure to patients and operators. The aim of our study was to reduce radiation exposure during these procedures to a critical amount without compromising patient safety. Methods and results: First, we assessed radiation exposure for primary PVI procedures over time (2005-2015) at the University Heart Center Freiburg-Bad Krozingen. Second, we prospectively evaluated in 52 patients, the efficacy and safety of a novel radiation reduction program (particularly applying an enhanced fluoroscopy pulse dose-reduction and optimized 3D-mapping system use). In 2035 primary PVI procedures, radiation exposure, assessed as estimated effective dose (eED in mSv, dose area product * 0.002 * conversion factor for females), fluoroscopy-time, and procedure-time decreased significantly from 2005 to 2015 (e.g. eED decreased from 9.3 (interquartile range (IQR) 6.4-13.4) mSv to 0.9 (IQR 0.5-1.6) mSv, p for trend <0.001). Importantly, application of the enhanced radiation reduction program further reduced eED to 0.4 mSv (IQR 0.3-0.6, P < 0.001 vs. control), a value not significantly different from slow-pathway ablation procedures (P = 0.41). Multiple linear regression analysis identified the radiation reduction program as the only independent variable associated with a decrease in radiation exposure. Conclusion: Radiation exposure during PVI decreased over the last decade and can further be reduced significantly by the implementation of an enhanced radiation reduction program.

Ablation of Persistent Atrial Fibrillation Targeting Low-Voltage Areas With Selective Activation Characteristics.

BACKGROUND: Complex-fractionated atrial electrograms and atrial fibrosis are associated with maintenance of persistent atrial fibrillation (AF). We hypothesized that pulmonary vein isolation (PVI) plus ablation of selective atrial low-voltage sites may be more successful than PVI only. METHODS AND RESULTS: A total of 85 consecutive patients with persistent AF underwent high-density atrial voltage mapping, PVI, and ablation at low-voltage areas (LVA < 0.5 mV in AF) associated with electric activity lasting > 70% of AF cycle length on a single electrode (fractionated activity) or multiple electrodes around the circumferential mapping catheter (rotational activity) or discrete rapid local activity (group I). The procedural end point was AF termination. Arrhythmia freedom was compared with a control group (66 patients) undergoing PVI only (group II). PVI alone was performed in 23 of 85 (27%) patients of group I with low amount (< 10% of left atrial surface area) of atrial low voltage. Selective atrial ablation in addition to PVI was performed in 62 patients with termination of AF in 45 (73%) after 11 ± 9 minutes radiofrequency delivery. AF-termination sites colocalized within LVA in 80% and at border zones in 20%. Single-procedural arrhythmia freedom at 13 months median follow-up was achieved in 59 of 85 (69%) patients in group I, which was significantly higher than the matched control group (31/66 [47%], P < 0.001). There was no significant difference in the success rate of patients in group I with a low amount of low voltage undergoing PVI only and patients requiring PVI+selective low-voltage ablation (P = 0.42). CONCLUSIONS: Ablation of sites with distinct activation characteristics within/at borderzones of LVA in addition to PVI is more effective than conventional PVI-only strategy for persistent AF. PVI only seems to be sufficient to treat patients with left atrial low voltage < 10%.

Relationship between MDCT-imaged myocardial fat and ventricular tachycardia substrate in arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Myocardial fibrofatty infiltration is a milieu for ventricular tachycardia (VT) in arrhythmogenic right ventricular cardiomyopathy (ARVC) and can be depicted as myocardial hypodensity on contrast-enhanced multidetector computed tomography (MDCT) with high spatial and temporal resolution. This study aimed to assess the relationship between MDCT-imaged myocardial fat and VT substrate in ARVC. METHODS AND RESULTS: We studied 16 patients with ARVC who underwent ablation and preprocedural MDCT. High-resolution imaging data were processed and registered to high-density endocardial and epicardial maps in sinus rhythm on 3-dimensional electroanatomic mapping (3D-EAM) (626±335 and 575±279 points/map, respectively). Analysis of the locations of low-voltage and fat segmentation included the following endocardial and epicardial regions: apex, mid (anterior, lateral, inferior), and basal (anterior, lateral, inferior). The location of local abnormal ventricular activities (LAVA) was compared with fat distribution. RV myocardial fat was successfully segmented and integrated with 3D-EAM in all patients. The κ agreement test demonstrated a good concordance between the epicardial low voltage and fat (κ=0.69, 95% CI 0.54 to 0.84), but fair concordance with the endocardium (κ=0.41, 95% CI 0.27 to 0.56). The majority of LAVA (520/653 [80%]) were located within the RV fat segmentation, of which 90% were not farther than 20 mm from its border. Registration of MDCT allowed direct visualization of the coronary arteries, thus avoiding coronary damage during epicardial radiofrequency delivery. CONCLUSIONS: The integration of MDCT-imaged myocardial fat with 3D-EAM provides valuable information on the extent and localization of VT substrate and demonstrates ablation targets clustering in its border region.

Mechanisms of pulmonary vein reconnection after radiofrequency ablation of atrial fibrillation: the deterministic role of contact force and interlesion distance.

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.

Transseptal access for left atrial ablation: the catheter-probing techniques are not without risk.

BACKGROUND: Transseptal puncture (TP) is a prerequisite for LA ablations. LA access can be gained by catheter probing in case of PFO (trans-PFO method) or puncture of the interatrial septum (IAS) using a transseptal needle. A 2nd access can again be gained via PFO, a 2nd TP or catheter probing of the previous puncture site (probe-TS method). This study investigates the risk factors and complications related to the mode of transseptal access. METHODS AND RESULTS: From August 2010 to August 2012, a total of 544 LA ablations, were performed. The mode of LA access was either a double TP or a single TP followed by the probe-TS or the trans-PFO method, respectively. TP was always guided by TEE and was successfully performed without complications in all cases. In contrast, 6/410 patients (1.5%) in whom catheter probing was performed (probe-TS, n = 4, trans-PFO, n = 2) had a dissection of the superior IAS originating from inside the oval fossa (n = 5) or perforation above the oval fossa (n = 1). Perforation into the pericardial space occurred in 4/6 patients, leading to one cardiac tamponade. In 5/6 patients, LA ablation was successfully completed, after repeated TP, despite effective anticoagulation. Patients with complications had the following characteristics: LA size 46 ± 4 mm, persistent AF (5/6), a repeat transseptal procedure (3/6) and a right-sided pouch (RSP, 5/6). CONCLUSIONS: Interatrial septum dissection/perforation, occasionally with perforation into the pericardial space, is an unreported complication of TP, especially with the catheter-probing techniques. An RSP is an unrecognized risk factor in this context and can be visualized by TEE.

Do atrial differences in endothelial damage, leukocyte and platelet activation, or tissue factor activity contribute to chamber-specific thrombogenic status in patients with atrial fibrillation?

BACKGROUND: Thrombi form mainly in the left rather than the right atria of patients with atrial fibrillation (AF), the reason of this predilection being unknown. OBJECTIVE: The purpose of this study was to investigate whether atrial-specific differences in endothelial damage, leukocyte activation, platelet stimulation, and tissue factor activity occur in patients with AF. METHODS: Twenty-two patients (16 men, 6 women; age 56 ± 8 years; 16 paroxysmal AF, 6 persistent AF) with AF undergoing pulmonary vein isolation were investigated. Blood samples from the left and the right atrium were obtained at the start of the procedure. Microparticles (MPs) released by apoptotic/stimulated cells were measured by capture assays. Their procoagulant abilities were quantified by functional prothrombinase and tissue factor assays and their cellular origin were determined (endothelium, platelet, leukocyte). Platelet reactivity was evaluated by whole blood flow cytometry for expression of platelet P-selectin (CD62P), active glycoprotein IIb/IIIa receptor (PAC-1). Platelet aggregation was evaluated using ADP, TRAP and collagen-induced whole blood aggregometry. RESULTS: There were no atrial-specific differences in the levels of total procoagulant MPs, leukocyte-derived-MPs or platelet-derived MPs. Conversely, endothelial-derived MPs and tissue factor activity and collagen-induced platelet aggregation were slightly elevated in the right atrium (P < 0.05). CONCLUSIONS: Our data show no evidence for increased thrombogenic status in the left atrium that would account for its greater propensity for thrombus formation in patients with AF.

Enhanced efficiency of a novel porous tip irrigated RF ablation catheter for pulmonary vein isolation.

INTRODUCTION: Irrigated tip radiofrequency (RF) catheter ablation is the most frequently used technology for pulmonary vein isolation (PVI). The purpose of this study was to compare the efficiency and the safety of 2 different open irrigated tip RF ablation catheters. METHODS AND RESULTS: A total of 160 patients with symptomatic AF (29% persistent, 68% male, 61 ± 10 years) were randomized to circumferential PVI using 2 different irrigated tip catheters: (1) the novel Thermocool SF(®) with a porous tip (56 holes) or (2) the Thermocool(®) catheter with 6 irrigation holes at the distal tip in both power- and temperature-controlled modes. PVI procedural time and RF duration were significantly shorter with SF(®) versus Thermocool(®) catheter: 104.5 versus 114 minutes (P = 0.023) and 35.4 minutes versus 39.9 minutes (P < 0.001), respectively. Similarly, the total fluoroscopy time and dose were shorter with SF(®) versus. Thermocool(®) catheter: 21 minutes versus 24 minutes (P = 0.02) and 1014.5 µGy*m(2) versus 1377 µGy*m(2) (P < 0.0001), respectively. Irrigation volume was lower with SF(®): 600 mL versus 1100 mL, (P < 0.0001) and the rates of complications were not significantly different (0.6% vs 0.49%, P = 0.66). At 20.5 ± 7.5 months follow-up, there were no significant differences with regard to arrhythmia freedom between SF(®) (59.2%) and TC® groups (59.3%), (P = 0.61). CONCLUSIONS: Using the novel irrigated tip SF catheter, PVI is achieved within a shorter ablation and procedural durations. The underlying mechanisms and potential differences in RF lesion size remain to be elucidated.

Sinus node disease in subjects with type 1 ECG pattern of Brugada syndrome.

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.