Durability of CLOSE-Guided Pulmonary Vein Isolation in Persistent Atrial Fibrillation: A Prospective Remapping Study.

BACKGROUND: Recurrence of paroxysmal atrial fibrillation (AF) following pulmonary vein isolation (PVI) is presumably caused by pulmonary vein (PV) reconnections. However, there is little data available on the durability of PVI and incidence of arrhythmia recurrence in patients with persistent AF. OBJECTIVES: The purpose of this study was to evaluate the lesion durability by means of an a priori planned remapping procedure in patients with persistent AF undergoing CLOSE-guided PVI. METHODS: In a prospective study, we included patients with symptomatic, persistent AF undergoing CLOSE-guided radiofrequency ablation. Irrespective of AF recurrence, a redo procedure was mandated 6 months following the index procedure to evaluate PV reconnections. The outcome of AF ablation was based on clinical recurrence and 7-day Holter electrocardiogram 3 and 6 months after the index procedure and 3, 6, and 12 months after the redo procedure. RESULTS: Of 30 patients included, 26 (81% men; median age 68 years) underwent the planned remapping study a median of 6 months after the index procedure, whereas 4 patients without recurrence refused a repeat procedure. In total, 78 of 102 (76%) PVs showed durable isolation and 15 patients (58%) presented complete isolation of all PVs. Beyond the blanking period, 6 of 26 patients (23%) had arrhythmia recurrence before the redo procedure. Recurrence had occurred in 33% of patients with complete isolation of all veins and in 9% of patients with PV reconnections (P = 0.197). After re-PVI in patients with PV reconnections and additional ablation in patients with recurrence but durable PVI, 17 of 26 patients (65%) were free of arrhythmia after 12 months. CONCLUSIONS: In patients with persistent AF, CLOSE-guided PVI resulted in durable rate of PVI on a per-vein and per-patient level of 76% and 58%, respectively. Arrhythmia recurrence was numerically higher in patients with durable PVI compared with patients without.

Patient characteristics, predictors and outcome of pacemaker patients upgraded to an implantable cardioverter defibrillator.

AIMS: Pacemaker (PM) patients may require a subsequent upgrade to an implantable cardioverter defibrillator (ICD). Limited data exists on this patient population. We sought to characterize this population, to assess predictors for ICD upgrade, and to report the outcome. METHODS: From our prospective PM and ICD implantation registry, all patients who underwent PM and/or ICD implantations at our center were analyzed. Patient characteristics and outcomes of PM patients with subsequent ICD upgrade were compared to age- and sex-matched patients with de novo ICD implantation, and to PM patients without subsequent upgrade. RESULTS: Of 1'301 ICD implantations, 60 (5%) were upgraded from PMs. Median time from PM implantation to ICD upgrade was 2.6 years (IQR 1.3-5.4). Of 2'195 PM patients, 28 patients underwent subsequent ICD upgrades, corresponding to an estimated annual incidence of an ICD upgrade of at least 0.33%. Lower LVEF (p = .05) and male sex (p = .038) were independent predictors for ICD upgrade. Survival without death, transplant and LVAD implantation were worse both for upgraded ICD patients compared to matched patients with de novo ICD implantation (p = .05), as well as for PM patients with subsequent upgrade compared to matched PM patients not requiring an upgrade (p = .036). CONCLUSIONS: One of 20 ICD implantations are upgrade of patients with a PM. At least one of 30 PM patients will require an ICD upgrade in the following 10 years. Predictors for ICD upgrade are male sex and lower LVEF at PM implantation. Upgraded patients have worse outcomes.

Validation of a clinical model for predicting left versus right ventricular outflow tract origin of idiopathic ventricular arrhythmias.

BACKGROUND: Prediction of the chamber of origin in patients with outflow tract ventricular arrhythmias (OTVA) remains challenging. A clinical risk score based on age, sex and presence of hypertension was associated with a left ventricular outflow tract (LVOT) origin. We aimed to validate this clinical score to predict an LVOT origin in patients with OTVA. METHODS: In a two-center observational cohort study, unselected patients undergoing catheter ablation (CA) for OTVA were enrolled. All procedures were performed using an electroanatomical mapping system. Successful ablation was defined as a ≥80% reduction of the initial overall PVC burden after 3 months of follow-up. Patients with unsuccessful ablation were excluded from this analysis. RESULTS: We included 187 consecutive patients with successful CA of idiopathic OTVA. Mean age was 52 ± 15 years, 102 patients (55%) were female, and 74 (40%) suffered from hypertension. A LVOT origin was found in 64 patients (34%). A score incorporating age, sex and presence of hypertension reached 73% sensitivity and 67% specificity for a low (0-1) and high (2-3) score, to predict an LVOT origin. The combination of one ECG algorithm (V2 S/V3 R-index) with the clinical score resulted in a sensitivity and specificity of 81% and 70% for PVCs with R/S transition at V3 . CONCLUSION: The published clinical score yielded a lower sensitivity and specificity in our cohort. However, for PVCs with R/S transition at V3, the combination with an existing ECG algorithm can improve the predictability of LVOT origin.

Acute and long-term outcomes of quadripolar IS-4 versus bipolar IS-1 left ventricular leads in cardiac resynchronization therapy: A retrospective registry study.

BACKGROUND: The implantation procedure of left ventricular (LV) leads and the management of cardiac resynchronization therapy (CRT) patients can be challenging. The IS-4 standard for CRT offers additional pacing vectors compared to bipolar leads (IS-1). IS-4 leads improve procedural outcome and may also result in lower adverse events during follow-up (FU) and improve clinical outcome in CRT patients. Further long-term FU data comparing the two lead designs are necessary. METHODS: In this retrospective, single-center study we included adult patients implanted with a CRT-Defibrillator (CRT-D) or CRT-Pacemaker (CRT-P) with a quadripolar (IS-4 group) or bipolar (IS-1 group) LV lead and with available ≥3 years clinical FU. The combined primary endpoint was a combination of predefined, lead-related adverse events. Secondary endpoints were all single components of the primary endpoint. RESULTS: Overall, 133 patients (IS-4 n = 66; IS-1 n = 67) with a mean FU of 4.03 ± 1.93 years were included. Lead-related adverse events were less frequent in patients with an IS-4 lead than with an IS-1 lead (n = 8, 12.1% vs. n = 23, 34.3%; p = .002). The secondary outcomes showed a lower rate of LV lead deactivation/explantation and LV lead dislodgement/dysfunction (4.5% vs. 22.4%; p = .003; 4.5% vs. 17.9%; p = .015, respectively) in the IS-4 patient group. Less patients suffered from unresolved phrenic nerve stimulation with an IS-4 lead (3.0% vs. 13.4%; p = .029). LV lead-related re-interventions were fewer in case of an IS-4 lead (6.1% vs. 17.9%; p = .036). CONCLUSION: In this retrospective analysis, the IS-4 LV lead is associated with lower lead-related complication rates than the IS-1 lead at long-term FU.

Validation of the accuracy of contact force measurement by contemporary force-sensing ablation catheters.

INTRODUCTION: Contact force sensing catheters are widely used for ablation of cardiac arrhythmias. They allow quantification of catheter-to-tissue contact, which is an important determinant for lesion formation and may reduce the risk of complications. The accuracy of these sensors may vary across the measurement range, catheter-to-tissue angle, and amongst manufacturers. We aim to compare the accuracy and reproducibility of four different force sensing ablation catheters. METHODS: A measurement setup containing a heated saline water bath with an integrated force measurement unit was constructed and validated. Subsequently, we investigated four different catheter models, each equipped with a unique measurement technology: Tacticath Quartz (Abbott), AcQBlate Force (Biotronik/Acutus), Stablepoint (Boston Scientific), and Smarttouch SF (Biosense Webster). For each model, the accuracy of three different catheters was measured within the range of 0-60 g and at contact angles of 0°, 30°, 45°, 60°, and 90°. RESULTS: In total, 6685 measurements were performed using 4 × 3 catheters (median of 568, interquartile range: 511-606 measurements per catheter). Over the entire measurement-range, the force measured by the catheters deviated from the real force by the following absolute mean values: Tacticath 1.29 ± 0.99 g, AcQBlate Force 2.87 ± 2.37 g, Stablepoint 1.38 ± 1.29 g, and Smarttouch 2.26 ± 2.70 g. For some models, significant under- and overestimation of >10 g were observed at higher forces. Mean absolute errors of all models across the range of 10-40 g were <3 g. CONCLUSION: Contact measured by force-sensing catheters is accurate with 1-3 g deviation within the range of 10-40 g. Significant errors can occur at higher forces with potential clinical consequences.

Pulsed-field ablation for the treatment of left atrial reentry tachycardia.

BACKGROUND: We describe our initial experience using a multipolar pulsed-field ablation catheter for the treatment of left atrial (LA) reentry tachycardia. METHODS: We included all patients with LA reentry tachycardia treated with PFA at our institution between September 2021 and March 2022. The tachycardia mechanism was identified using 3D electro-anatomical mapping (3D-EAM). Subsequently, a roof line, anterior line, or mitral isthmus line was ablated as appropriate. Roof line ablation was always combined with LA posterior wall (LAPW) ablation. Positioning of the PFA catheter was guided by a 3D-EAM system and by fluoroscopy. Bidirectional block across lines was verified using standard criteria. Additional radiofrequency ablation (RFA) was used to achieve bidirectional block as necessary. RESULTS: Among 22 patients (median age 70 (59-75) years; 9 females), we identified 27 LA reentry tachycardia: seven roof dependent macro-reentries, one posterior-wall micro-reentry, twelve peri-mitral macro-reentries, and seven anterior-wall micro-reentries. We ablated a total of 20 roof lines, 13 anterior lines, and 6 mitral isthmus lines. Additional RFA was necessary for two anterior lines (15%) and three mitral isthmus lines (50%). Bidirectional block was achieved across all roof lines, 92% of anterior lines, and 83% of mitral isthmus lines. We observed no acute procedural complications. CONCLUSION: Ablation of a roof line and of the LAPW is feasible, effective, and safe using this multipolar PFA catheter. However, the catheter is less suited for ablation of the mitral isthmus and the anterior line. A focal pulsed-field ablation catheter may be more effective for ablation of these lines. This study shows the feasibility to ablate linear lesions with a multipolar pulsed-field ablation catheter. 27 left atrial reentry tachycardia were treated in 22 patients.

Conduction System Pacing Today and Tomorrow.

Conduction system pacing (CSP) encompassing His bundle (HBP) and left bundle branch area pacing (LBBAP) is gaining increasing attention in the electrophysiology community. These relatively novel physiological pacing modalities have the potential to outperform conventional pacing approaches with respect to clinical endpoints, although data are currently still limited. While HBP represents the most physiological form of cardiac stimulation, success rates, bundle branch correction, and electrical lead performance over time remain a concern. LBBAP systems may overcome these limitations. In this review article, we provide a comprehensive overview of the current evidence, implantation technique, device programming, and follow-up considerations concerning CSP systems. Moreover, we discuss ongoing technical developments and future perspectives of CSP.

Clinical Outcomes in Patients With Dilated Cardiomyopathy and Ventricular Tachycardia.

BACKGROUND: Recurrent ventricular tachycardia (VT) due to dilated cardiomyopathy (DCM) is difficult to treat, and long-term outcome data are limited. OBJECTIVES: The aim of this study was to identify predictors of mortality or heart transplantation (HTx) and VT recurrence. METHODS: Consecutive patients with DCM accepted for radiofrequency catheter ablation (RFCA) of VT at 9 centers were prospectively enrolled and followed. RESULTS: Of 281 consecutive patients (mean age 60 ± 13 years, 85% men, mean left ventricular ejection fraction [LVEF] 36% ± 12%), 35% had VT storm, 20% had incessant VT, and amiodarone was unsuccessful in 68%. During follow-up of 21 months (IQR: 6-30 months), 67 patients (24%) died or underwent HTx, and 138 (49%) had VT recurrence (45 within 30 days, defined as early); the 4-year rate of VT recurrence or mortality or HTx was 70%. Independent predictors of mortality or HTx were early VT recurrence (HR: 2.92; 95% CI: 1.37-6.21; P < 0.01), amiodarone at discharge (HR: 3.23; 95% CI: 1.43-7.33; P < 0.01), renal dysfunction (HR: 1.92; 95% CI: 1.01-3.64; P = 0.046), and LVEF (HR: 1.36; 95% CI: 1.0-1.84; P = 0.052). LVEF ≤32% identified patients at risk for mortality or HTx (area under the curve: 0.75). Mortality or HTx per 100 person-years was 40.4 events after early, compared with 14.2 events after later VT recurrence and 8.5 events with no VT recurrence after RFCA (P < 0.01 for both). Patients with early recurrence and LVEFs ≤32% had a 1-year rate of mortality or HTx of 55%. VT recurrence was predicted by prior implantable cardioverter-defibrillator shocks, basal anteroseptal VT origin, and procedural failure but not LVEF. CONCLUSIONS: Patients with DCM needing RFCA for VT are a high-risk group. Following RFCA, approximately one-half remain free of VT recurrence. Early VT recurrence with LVEF ≤32% identifies those at very high risk for mortality or HTx, and screening for mechanical support or HTx should be considered. Late VT recurrence after RFCA does not predict worse outcome.

Efficacy and safety of a novel cryoballoon ablation system: multicentre comparison of 1-year outcome.

AIMS: The aim of the study was to compare the 1-year efficacy and safety of a novel cryoballoon (NCB) ablation system (POLARx; Boston Scientific) for pulmonary vein isolation (PVI) compared with the standard cryoballoon (SCB) system (Arctic Front, Medtronic). METHODS AND RESULTS: Consecutive patients with atrial fibrillation (AF) undergoing PVI using the NCB and the SCB at two centres were included. We report 1-year efficacy after 12 months, short-term safety and hospitalizations within the blanking period, and predictors for AF recurrence. In case of repeat procedures, pulmonary vein (PV) reconnection patterns were characterized. Eighty patients (age 66 ± 10 years, ejection fraction 57 ± 10%, left atrial volume index 39 ± 13 mL/m2, paroxysmal AF in 64%) were studied. After a single procedure and a follow-up of 12 months, 68% in the NCB group and 70% in the SCB group showed no recurrence of AF/atrial tachycardias (P = 0.422). One patient in the NCB group suffered a periprocedural stroke with full recovery. There were no differences regarding hospitalizations during follow-up between the groups. PV reconnection observed during 12 repeat procedures (4 NCB, 8 SCB) pattern was comparable between the groups with more reconnections in the right-sided compared with the left-sided PVs. CONCLUSION: In this multicentre study comparing two currently available cryoballoon ablation systems for PVI, no differences were observed in the efficacy and safety during a follow-up of 12 months.

Validation of a multipolar pulsed-field ablation catheter for endpoint assessment in pulmonary vein isolation procedures.

AIMS: To validate the performance of a multipolar pulsed-field ablation (PFA) catheter compared to a standard pentaspline 3D-mapping catheter for endpoint assessment of pulmonary vein isolation (PVI). PFA for PVI using single-shot devices combines the benefits of high procedural efficacy and safety. A newly available multipolar PFA catheter allows real-time recording of pulmonary vein (PV) signals during PVI. METHODS AND RESULTS: Patients undergoing first PVI using PFA with the standard ablation protocol (eight applications per PV) were studied. Entrance and exit block (10 V/2 ms) were assessed using the PFA catheter. Subsequently, a high-density 3D electroanatomical bipolar voltage map (3D-EAM) was constructed using a standard pentaspline 3D-mapping catheter. Additional PFA applications were delivered only after confirmation of residual PV connection by 3D-EAM. In 56 patients, 213 PVs were targeted for ablation. Acute PVI was achieved in 100% of PVs: in 199/213 (93%) PVs with the standard ablation protocol alone and in the remaining 14 PVs after additional PFA applications. The accuracy of PV assessment with the PFA catheter after the standard ablation protocol was 91% (194/213 veins). In 5/213 (2.3%) PVs, the PFA catheter incorrectly indicated PV-isolation. In 14/213 (6.6%), the PFA catheter incorrectly indicated residual PV-conduction due to high-output pace-capture. Lowering the output to 5 V/1 ms reduced this observation to 0.9% (2/213) and increased the overall accuracy to 97% (206/213). CONCLUSION: A novel multipolar PFA catheter allows reliable endpoint assessment for PVI. Due to its design, far-field sensing and high-output pace-capture can occur. Lowering the pacing output increases the accuracy from 91 to 97%.

Evolution of tricuspid valve regurgitation after implantation of a leadless pacemaker: A single center experience, systematic review, and meta-analysis.

INTRODUCTION: Conventional transvenous pacemaker leads may interfere with the tricuspid valve leaflets, tendinous chords, and papillary muscles, resulting in significant tricuspid valve regurgitation (TR). Leadless pacemakers (LLPMs) theoretically cause less mechanical interference with the tricuspid valve apparatus. However, data on TR after LLPM implantation are sparse and conflicting. Our goal was to investigate the prevalence of significant TR before and after LLPM implantation. METHODS: Patients who received a leadless LLPM (Micra™ TPS, Medtronic) between May 2016 and May 2021 at our center were included in this observational study if they had at least a pre- and postinterventional echocardiogram (TTE). The evolution of TR severity was assessed. Following a systematic literature review on TR evolution after implantation of a LLPM, data were pooled in a random-effects meta-analysis. RESULTS: We included 69 patients (median age 78 years [interquartile range (IQR) 72-84 years], 26% women). Follow-up duration between baseline and follow-up TTE was 11.4 months (IQR 3.5-20.1 months). At follow-up, overall TR severity was not different compared to baseline (p = .49). Six patients (9%) had new significant TR during follow-up after LLPM implantation, whereas TR severity improved in seven patients (10%). In the systematic review, we identified seven additional articles that investigated the prevalence of significant TR after LLPM implantation. The meta-analysis based on 297 patients failed to show a difference in significant TR before and after LLPM implantation (risk ratio 1.22, 95% confidence interval 0.97-1.53, p = .11). CONCLUSION: To date, there is no substantial evidence for a significant change in TR after implantation of a LLPM.

Differences in Atrial Remodeling in Hypertrophic Cardiomyopathy Compared to Hypertensive Heart Disease and Athletes' Hearts.

Background: Hypertrophic cardiomyopathy (HCM), hypertensive heart disease (HHD) and athletes' heart share an increased prevalence of atrial fibrillation. Atrial cardiomyopathy in these patients may have different characteristics and help to distinguish these conditions. Methods: In this single-center study, we prospectively collected and analyzed electrocardiographic (12-lead ECG, signal-averaged ECG (SAECG), 24 h Holter ECG) and echocardiographic data in patients with HCM and HHD and in endurance athletes. Patients with atrial fibrillation were excluded. Results: We compared data of 27 patients with HCM (70% males, mean age 50 ± 14 years), 324 patients with HHD (52% males, mean age 75 ± 5.5 years), and 215 endurance athletes (72% males, mean age 42 ± 7.5 years). HCM patients had significantly longer filtered P-wave duration (153 ± 26 ms) and PR interval (191 ± 48 ms) compared to HHD patients (144 ± 16 ms, p = 0.012 and 178 ± 31, p = 0.034, respectively) and athletes (134 ± 14 ms, p = 0.001 and 165 ± 26 ms, both p < 0.001, respectively). HCM patients had a mean of 4.9 ± 16 premature atrial complexes per hour. Premature atrial complexes per hour were significantly more frequent in HHD patients (27 ± 86, p < 0.001), but not in athletes (2.7 ± 23, p = 0.639). Left atrial volume index (LAVI) was 43 ± 14 mL/m2 in HCM patients and significantly larger than age- and sex-corrected LAVI in HHD patients 30 ± 10 mL/m2; p < 0.001) and athletes (31 ± 9.5 mL/m2; p < 0.001). A borderline interventricular septum thickness ≥13 mm and ≤15 mm was found in 114 (35%) HHD patients, 12 (6%) athletes and 3 (11%) HCM patients. Conclusions: Structural and electrical atrial remodeling is more advanced in HCM patients compared to HHD patients and athletes.

Importance of electromagnetic interactions between ICD and VAD devices-Mechanistic assessment.

BACKGROUND: Implanted cardioverter defibrillators (ICDs) and left ventricular assist devices (LVADs) are established interventions that prolong life in advanced heart failure, but their combination has not been demonstrated as beneficial. Electromagnetic interference (EMI) produced by a LVAD can preclude ICD interrogation with external programmers. We undertook a systematic evaluation of the LVAD-ICD interaction "in-vitro" to clarify the extent of this interaction. METHODS: Using explanted ICDs and VADs in a mock physiological rig, we assessed interrogation and reprogramming of ICD devices in the presence of a running LVAD. When connectivity between the ICD programmer and the ICD failed, we attempted three different techniques to re-establish connectivity: (1) Electromagnetic shielding of the ICD with a pseudo-faraday cage; (2) altering the LVAD speed; and (3) increasing the distance between the VAD and the ICD. RESULTS: We tested a total of 24 ICDs from different manufacturers in the presence of the Heartware (HW) and HeartMate 3 (HM3) LVADs. With HW, we only observed interaction with Biotronik ICD devices at very close range (0-6 cm). With HM3, only Medtronic ICD devices showed no interaction. Interactions could be mitigated by increasing the VAD-ICD distance. CONCLUSIONS: LVADs, notably the HM3, produce EMI that interferes with the communication between an ICD and its respective programmer. This may need to be considered when choosing the type of VAD to implant in patients with a previously implanted left-sided ICD. The only safe way to regain connectivity is to increase the distance between the VAD and the ICD, with patients raising their arm above their head.

Dexmedetomidine versus propofol for operator-directed nurse-administered procedural sedation during catheter ablation of atrial fibrillation: A randomized controlled study.

BACKGROUND: Operator-directed nurse-administered (ODNA) sedation with propofol (PRO) is the preferred sedation technique for catheter ablation of atrial fibrillation (AF) in many centers. OBJECTIVE: The purpose of this study was to investigate whether dexmedetomidine (DEX), an α2-adrenergic receptor agonist, is superior to propofol. METHODS: We randomized 160 consecutive patients undergoing first AF ablation to ODNA sedation by DEX (DEX group) vs PRO (PRO group), according to a standardized protocol. Patients were unaware of treatment allocation. The primary endpoint was a composite of inefficient sedation, termination/change of sedation protocol or procedure abortion, hypercapnia (transcutaneous CO2 >55 mm Hg), hypoxemia (SpO2 <90%) or intubation, prolonged hypotension (systolic blood pressure <80 mm Hg), and sustained bradycardia necessitating cardiac pacing. Secondary endpoints were the components of the primary endpoint and patient satisfaction with procedural sedation, as assessed by a standardized questionnaire given the day after ablation. RESULTS: The primary endpoint occurred in 15 DEX group and 25 PRO group patients (19% vs 31%; P = .068). Hypercapnia was significantly more frequent in PRO group patients (29% vs 10%; P = .003). There was no significant difference for the other components of the primary endpoint, and no procedure was aborted. Patient satisfaction was significantly better among PRO group patients (visual analogue scale 0-100; median 100 in PRO group vs median 93 in DEX group; P <.001). CONCLUSION: Efficacy of ODNA sedation with DEX was not different from that with PRO. Hypercapnia occurs less frequently with DEX, but patient satisfaction is better with PRO sedation. In selected patients, DEX may be used as an alternative to PRO for ODNA sedation during AF ablation.

Leadless atrioventricular synchronous pacing in an outpatient setting: Early lessons learned on factors affecting atrioventricular synchrony.

BACKGROUND: Leadless pacemakers (PMs) capable of atrioventricular (AV) synchronous pacing have recently been introduced. Initial feasibility studies were promising but limited to just a few minutes of AV synchronous pacing. Real-world, long-term data on AV synchrony and programming adjustments affecting AV synchrony in outpatients are lacking. OBJECTIVE: The purpose of this study was to investigate AV synchrony and influences of PM programming adjustments in outpatients with leadless VDD PMs. METHODS: All patients who received a leadless VDD PM (Micra™ AV, Medtronic) between July 2020 and May 2021 at our center were included in this observational study. AV synchrony was assessed repeatedly postoperatively and during follow-up using Holter electrocardiographic (ECG) recordings. AV synchrony was defined as a QRS complex preceded by a p wave within 300 ms. The impact of programming changes during follow-up on AV synchrony was studied. RESULTS: A total of 816 hours of Holter ECG from 20 outpatients were analyzed. During predominantly paced episodes (≥80% ventricular pacing), median AV synchrony was 91% [interquartile range (IQR) 34%-100%] when patients had sinus rates 50-80/min. Median AV synchrony was lower when patients had sinus rates >80/min [33% (29%-46%); P <.001]. During a stepwise optimization protocol, AV synchrony could be improved (P <.038). Multivariate analysis showed that a shorter maximum A3 window end (P <.001), lower A3 threshold (P = .046), and minimum A4 threshold (P <.001) improved AV synchrony. CONCLUSION: Successful VDD pacing in the outpatient setting during higher sinus rates is more difficult to achieve than can be presumed based on initial feasibility studies. The devices often require multiple reprogramming to maximize AV sequential pacing.

Technical and procedural comparison of two different cryoballoon ablation systems in patients with atrial fibrillation.

PURPOSE: The aim was to report procedural and technical differences of a novel cryoballoon (NCB) ablation catheter for pulmonary vein isolation (PVI) compared to the standard cryoballoon (SCB) catheter. METHODS: Consecutive patients with atrial fibrillation (AF) undergoing PVI using the NCB and the SCB were included. Procedural parameters, technical differences, acute efficacy, and safety are reported. RESULTS: Eighty patients (age 66 ± 10 years, ejection fraction 57 ± 10%, left atrial volume index 40 ± 6 ml/m2) were studied. With the NCB, 156 of 158 PVs (99%) were isolated compared to isolation of 159 of 159 PVs (100%) with the SCB. The median number of freezes in the NCB and the SCB group was 6 (IQR 5-8) and 5 (IQR 4-7), respectively (p = 0.051), with 73% and 71% of the PVs isolated with a single freeze, respectively. Nadir temperature and temperature at isolation were - 59 ± 6 °C and - 45 ± 17 °C in the NCB group and - 46 ± 7 °C and - 32 ± 23 °C in the SCB group, respectively (both p < 0.001) with no difference in time to isolation (TTI). Procedural differences were observed for the total procedure time (84 ± 29 min in the NCB group and 65 ± 17 min in the SCB group, p = 0.003). There was a peri-procedural stroke in one patient in the NCB group. Differences in catheter design were observed that may account for the differences in temperature recordings and ice cap formation. CONCLUSIONS: Acute efficacy and TTI were similar with the NCB compared to the SCB. Measured temperatures were lower with the NCB, most likely due to differences in catheter design.

Age and Sex Specific Prevalence of Clinical and Screen-Detected Atrial Fibrillation in Hospitalized Patients.

BACKGROUND: The prevalence of atrial fibrillation (AF) is high in older patients. The present study aimed to estimate the age and sex specific prevalence of clinical and screen-detected atrial fibrillation (AF) in hospitalized patients. METHODS: The STAR-FIB cohort study was a prospective cohort study recruiting participants from a large source population of hospitalized patients aged 65-84 years. The estimated size of the source population was 26,035 (95% CI 25,918-26,152), and 795 consenting patients without clinical AF were included in the cohort study after stratification by sex and age (49.2% females; mean age 74.7 years). Patients in the cohort study underwent three seven-day Holter ECGs in intervals of two months to screen for AF. RESULTS: In the source population, the estimated prevalence of clinical AF was 22.2% (95% CI 18.4-26.1), 23.8% for males (95% CI 20.9-26.6) and 19.8% for females (95% CI 17.3-22.4; p for difference between sexes, 0.004). There was a linear trend for an increase in the prevalence of clinical AF with increasing age, overall and in both sexes. In the cohort study, AF was newly diagnosed in 38 patients, for an estimated prevalence of screen-detected AF of 4.9% overall (95% CI 3.3-6.6), 5.5% in males (95% CI 3.2-7.8) and 4.0% in females (95% CI 2.0-6.0; p for difference between sexes, 0.041). The estimated prevalence of screen-detected AF in the source population was 3.8% overall, 4.2% in males and 3.2% in females. CONCLUSION: In a large hospital-based patient population aged 65-84 years, the prevalence of clinical AF and of screen-detected AF was 22.2% and 3.8%, respectively, and significantly higher in males than females.

Efficacy and safety of ethanol infusion into the vein of Marshall for mitral isthmus ablation.

INTRODUCTION: Chemical ablation by retrograde infusion of ethanol into the vein of Marshall (VOM-EI) can facilitate the achievement of mitral isthmus block. This study sought to describe the efficacy and safety of this technique. METHODS AND RESULTS: Twenty-two consecutive patients (14 males, median age 71 years) with attempted VOM-EI for mitral isthmus ablation were included in the study. VOM-EI was successfully performed with a median of 4 ml of 96% ethanol in 19 patients (86%) and the mitral isthmus was successfully blocked in all (100%). Touch up endocardial and/or epicardial ablation after VOM-EI was necessary for 12 patients (63%). Perimitral flutter was present in 12 patients (63%) during VOM-EI and terminated or slowed by VOM-EI in 4 and 3 patients, respectively. The low-voltage area of the mitral isthmus region increased from 3.1 cm2 (interquartile range [IQR] 0-7.9) before to 13.2 cm2 (IQR: 8.2-15.0) after VOM-EI and correlated significantly with the volume of ethanol injected (p = .03). Median high-sensitive cardiac troponin-T increased significantly from 330 ng/L (IQR: 221-516) the evening of the procedure to 598 ng/L (IQR: 382-769; p = .02) the following morning. A small pericardial effusion occurred in three patients (16%), mild pericarditis in one (5%), and uneventful VOM dissection in two (11%). After a median follow-up of 3.5 months (IQR: 3.0-11.0), 10 of 18 patients (56%) with VOM-EI and available follow-up had arrhythmia recurrence. Repeat ablation was performed in five patients (50%) and peri-mitral flutter diagnosed in three (60%). CONCLUSION: VOM-EI is feasible, safe, and effective to achieve acute mitral isthmus block.

Pre-procedural arrhythmia burden and the outcome of catheter ablation of idiopathic premature ventricular complexes.

BACKGROUND: Radiofrequency catheter ablation of idiopathic premature ventricular complexes (PVCs) is an effective method for eliminating symptoms and preventing/reversing arrhythmia-induced cardiomyopathy. One reason for procedural failure is low PVC frequency during the procedure. We aimed to investigate the relation between pre-procedural PVC burden and outcome of idiopathic PVC catheter ablation. METHODS: Patients who underwent idiopathic PVC ablation between 2013 and 2019 at two tertiary referral centers were retrospectively included. All procedures were performed using irrigated-tip ablation catheters and a 3D electro-anatomical mapping system. Sustained ablation success was defined as a ≥80% reduction of pre-procedural PVC burden determined by 24h-Holter at follow-up. RESULTS: Overall, 254 patients (median age 54 years [IQR 42-64]; 47% male) were enrolled. The median pre-ablation PVC-burden was 22% (IQR 11-31%), which was reduced to a post-ablation PVC burden of 0.3% (IQR 0-4%) after a median of 90 days. Sustained ablation success was achieved in 182 patients (72%). Pre-procedural PVC burden did not differ between patients with sustained ablation success and recurrence during follow-up (median 21% vs. 22%, p = .76). When assessed in pre-ablation PVC-burden groups of ≤5%, 6-15%, 16-30%, and ≥31%, sustained ablation success was achieved in 67%, 75%, 71%, and 72%, respectively, with no significant difference (p = .89). Sustained ablation outcome for PVC-burden ≤5% versus >5% showed no difference either (67% vs. 72%, p = .52). CONCLUSIONS: Pre-procedural Holter-determined PVC burden does not predict the outcome of idiopathic PVC ablation. Thus, catheter ablation may be a reasonable first choice also for patients with symptomatic yet rare PVCs.

The SilenT AtRial FIBrillation (STAR-FIB) study programme - design and rationale.

AIMS OF THE STUDY: Anticoagulation of patients with screen-detected atrial fibrillation may prevent ischaemic strokes. The STAR-FIB study programme aims to determine the age- and sex-specific prevalence of silent atrial fibrillation and to develop a clinical prediction model to identify patients at risk of undiagnosed atrial fibrillation in a hospitalised patient population. METHODS: The STAR-FIB study programme includes a prospective cohort study and a case-control study of hospitalised patients aged 65–84 years, evenly distributed for both age and sex. We recruited 795 patients without atrial fibrillation for the cohort study (49.2% females; median age 74.8 years). All patients had three serial 7-day Holter ECGs to screen for silent atrial fibrillation. The primary endpoint will be any episode of atrial fibrillation or atrial flutter of ≥30 seconds duration. The age- and sex-specific prevalence of newly diagnosed atrial fibrillation will be estimated. For the case-control study, 120 patients with paroxysmal atrial fibrillation were recruited as cases (41.7% females; median age 74.6 years); controls will be randomly selected from the cohort study in a 2:1 ratio. All participants in the cohort study and all cases were prospectively evaluated including clinical, laboratory, echocardiographic and electrical parameters. A clinical prediction model for undiagnosed atrial fibrillation will be derived in the case-control study and externally validated in the cohort study. CONCLUSIONS: The STAR-FIB study programme will estimate the age- and sex-specific prevalence of silent atrial fibrillation in a hospitalised patient population, and develop and validate a clinical prediction model to identify patients at risk of silent atrial fibrillation.