Conduction system pacing, a European survey: insights from clinical practice.

AIMS: The field of conduction system pacing (CSP) is evolving, and our aim was to obtain a contemporary picture of European CSP practice. METHODS AND RESULTS: A survey was devised by a European CSP Expert Group and sent electronically to cardiologists utilizing CSP. A total of 284 physicians were invited to contribute of which 171 physicians (60.2%; 85% electrophysiologists) responded. Most (77%) had experience with both His-bundle pacing (HBP) and left bundle branch area pacing (LBBAP). Pacing indications ranked highest for CSP were atrioventricular block (irrespective of left ventricular ejection fraction) and when coronary sinus lead implantation failed. For patients with left bundle branch block (LBBB) and heart failure (HF), conventional biventricular pacing remained first-line treatment. For most indications, operators preferred LBBAP over HBP as a first-line approach. When HBP was attempted as an initial approach, reasons reported for transitioning to utilizing LBBAP were: (i) high threshold (reported as >2 V at 1 ms), (ii) failure to reverse bundle branch block, or (iii) > 30 min attempting to implant at His-bundle sites. Backup right ventricular lead use for HBP was low (median 20%) and predominated in pace-and-ablate scenarios. Twelve-lead electrocardiogram assessment was deemed highly important during follow-up. This, coupled with limitations from current capture management algorithms, limits remote monitoring for CSP patients. CONCLUSIONS: This survey provides a snapshot of CSP implementation in Europe. Currently, CSP is predominantly used for bradycardia indications. For HF patients with LBBB, most operators reserve CSP for biventricular implant failures. Left bundle branch area pacing ostensibly has practical advantages over HBP and is therefore preferred by many operators. Practical limitations remain, and large randomized clinical trial data are currently lacking.

Optimizing radiofrequency ablation of paroxysmal and persistent atrial fibrillation by direct catheter force measurement-a case-matched comparison in 198 patients.

BACKGROUND: Sufficient electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). OBJECTIVE: We assessed the impact of direct catheter force measurement on acute procedural parameters and outcome of RFCA for paroxysmal and persistent atrial fibrillation (AF). METHODS: Ninety-nine consecutive patients (70% men) with paroxysmal (63.6%) or persistent AF underwent left atrial RFCA using a 3.5-mm open-irrigated-tip (OIT) catheter with contact force measurement capabilities (group 1). For comparison a case-matched cohort with standard OIT catheters was used (99 patients; group 2). Case matching included gender, type of AF, number or RFCA procedures, and type of procedure. RESULTS: Procedural data showed a significant decline in radiofrequency ablation time from 52 ± 20 to 44 ± 16 minutes (P = 0.003) with a remarkable mean reduction in overall procedure time of 34 minutes (P = 0.0001; 225.8 ± 53.1 vs 191.9 ± 53.3 minutes). In parallel, the total fluoroscopy time could be significantly reduced from 28.5 ± 11.0 to 19.9 ± 9.3 minutes (P = 0.0001) as well as fluoroscopy dose from 74.1 ± 58.0 to 56.7 ± 38.9 Gy/cm(2) (P = 0.016). Periprocedural complications were similar in both groups. CONCLUSIONS: The use of contact force sensing technology is able to significantly reduce ablation, procedure, and fluoroscopy times as well as dose in RFCA of AF in a mixed case-matched group of paroxysmal and persistent AF. Energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact. Additionally 12-month outcome data showed increased efficacy. Such time saving and equally safe technology may have a relevant impact on laboratory management and increased cost effectiveness.

Is Conduction System Pacing Going to Be the New Gold Standard for Cardiac Resynchronization Therapy?

The current gold standard in device therapy for advanced heart failure (HF), which has been firmly established in HF management for more than 25 years, is classical biventricular pacing (BiV-CRT). In the last decade, a new pacing modality called conduction system pacing (CSP) has emerged as a variant for advanced cardiac device therapy. It provides pacing with preserved intrinsic cardiac activation by direct stimulation of the specific cardiac conduction system. The term CSP integrates the modalities of HIS bundle pacing (HBP) and left bundle branch area pacing (LBBAP), both of which have provided convincing data in smaller randomized and big non-randomized studies for the prevention of pacemaker-induced cardiomyopathy and for providing effective cardiac resynchronization therapy in patients with classical CRT-indication (primary approach or after failed CRT). Recent American guidelines proposed the term "cardiac physiological pacing" (CPP), which summarizes CSP including left ventricular septal pacing (LVSP), a technical variant of LBBAP together with classical BiV-CRT. The terms HOT-CRT (HIS-optimized CRT) and LOT-CRT (LBBP-optimized CRT) describe hybrid technologies that combine CSP with an additional coronary-sinus electrode, which is sometimes useful in patients with advanced HF and diffuse interventricular conduction delay. If CSP continues providing promising data that can be confirmed in big, randomized trials, it is likely to become the new gold standard for patients with an expected high percentage of pacing (>20%), possibly also for cardiac resynchronization therapy. CSP is a sophisticated new treatment option that has the potential to raise the term "cardiac resynchronization therapy" to a new level. The aim of this review is to provide basic technical, anatomical, and functional knowledge of these new pacemaker techniques in order to facilitate the understanding of the different modalities, as well as to provide an up-to-date overview of the existing randomized and non-randomized evidence, particularly in direct comparison to right ventricular and classical biventricular pacing.

Pulmonary Vein Isolation for Atrial Fibrillation: Comparison of a Very High-Power Very Short-Duration (vHPvSD) Ablation Protocol versus a Hybrid Ablation Approach-Procedural and Mid-Term Outcome Data.

Background: Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is a standard-of-care treatment in the rhythm control strategy of symptomatic atrial fibrillation (AF). Ablation protocols, varying in the power and duration of energy delivery, have changed rapidly in recent years. Very high-power very short-duration ablation (vHPvSD) is expected to shorten procedural times compared to conventional ablation approaches. However, the existing data suggest that this might come at the cost of lower first-pass isolation rates, a predictor of poor ablation long-term outcomes. This study aims to compare a vHPvSD protocol to a hybrid strategy, in which the power and duration of the energy transfer are adapted depending on the anatomical location. Methods: We retrospectively analyzed procedural and outcome data from 93 patients (55 vHPvSD vs. 38 hybrid) scheduled for de novo pulmonary vein isolation. A vHPvSD ablation protocol (90 Watt (W), 4 s) was compared to a hybrid protocol using vHPvSD on the posterior wall and 50 W HPSD (high-power short-duration) ablation guided by the Ablation Index along the remaining spots. Results: Ablation times were significantly shorter in the vHPvSD cohort (5.4 min. vs. 14.2 min, p < 0.001), thus resulting in a significant reduction in the overall procedural duration (91 min vs. 106 min, p = 0.003). The non-significant slightly higher first-pass isolation rates in the vHPvSD cohort (85% vs. 76%, p = 0.262) did not affect freedom from AF 6 months after the procedure (83% vs. 87%, p = 0.622). Conclusions: vHPvSD helps in shortening the PVI procedural duration, thus neither affecting first-pass isolation rates nor freedom from atrial tachyarrhythmia recurrence at 6 months after the index procedure.

MediGuide in supraventricular tachycardia: initial experience from a multicentre registry.

AIMS: Currently, fluoroscopy-based catheter visualization is the standard modality in invasive electrophysiological procedures. Recently a new technology for non-fluoroscopic visualization of diagnostic (since 2010) and ablation catheters (since May 2012) has been introduced. The MediGuide™-Technology (MediGuide) projects catheter tips on prerecorded cine loops in a high time resolution. METHODS AND RESULTS: We report on MediGuide-based supraventricular tachycardia (SVT) cases [atrioventricular nodal reentry tachycardia (AVNRT), atrioventricular reentry tachycardia (AVRT), Wolff-Parkinson-White syndrome (WPW), ectopic atrial tachycardia (EAT) and typical atrial flutter) from two European centres. In all patients, diagnostic and/or ablation catheters with a special sensor were used to perform the ablation procedures. All procedural data such as acute success, duration of the procedure, fluoroscopy time, and dose and patients' characteristics were analyzed and compared with conventionally ablated patients (n = 1865). Procedure-related complications during the hospital stay were recorded. A total of 24 consecutive patients were analyzed: no significant difference to the control group was seen in the baseline characteristics. The MediGuide patients were predominantly male (66%), aged 58 ± 14 years and were ablated for 6 AVNRT (25%), 4 AVRT/WPW (17%), 1 EAT (4%), and 13 typical atrial flutter (54%). The acute success rate was 100% (98% in the control group, n.s.). The median fluoroscopy time was 0.5 ± 1.4 min (10.2 ± 9.6 in the control group, P < 0.001), the median fluoroscopy dose was 187 ± 554 cGy cm(2) (996 ± 2593 cGy cm(2), P < 0.05). Mean procedure time was 70 ± 25 min (60 ± 36 min, n.s.). No complications during the hospital stay were recorded. CONCLUSION: In several different forms of supraventricular tachycardias the MediGuide-Technology contributed to a dramatic reduction in irradiation exposure. With a median fluoroscopy time of 30 s all SVT cases were effectively performed with no complications; the fluoroscopy burden can be significantly reduced not only for the patient but also for the nurses and the physicians performing the case. The overall procedure times are not prolonged due to the use of MediGuide Technology compared with a control group of >1800 patients undergoing conventional ablation procedures.

Asymptomatic cerebral lesions during pulmonary vein isolation under uninterrupted oral anticoagulation.

AIMS: Left atrial radiofrequency ablation has been shown to carry a risk of asymptomatic cerebral lesions. No data exist in patients under continued oral anticoagulation during the ablation procedure. The aim of this study was to quantify the amount of silent cerebral lesions assessed by pre-procedural and post-procedural magnetic resonance imaging (MRI) in patients under therapeutic international normalized ratio (INR) and to identify clinical or procedural parameters that correlate with cerebral embolism. METHODS AND RESULTS: A total of 131 consecutive patients undergoing catheter ablation for paroxysmal (n = 80, 61.1%) or persistent (n = 51, 38.9%) atrial fibrillation were included in the study. Pulmonary vein antrum isolation (PVI), roofline, mitral isthmus line, and complex fractionated atrial electrogram (CFAE) ablation using 3.5 mm open-irrigated tip catheters were performed, as needed. All patients underwent pre-procedural and post-procedural cerebral MRI. Post-procedural MRI revealed new embolic lesions in 16 patients (12.2%), all of them asymptomatic. Clinical parameters showing a significant correlation with cerebral embolism in univariate analysis were age (P = 0.027), persistent atrial fibrillation (vs. paroxysmal; P = 0.039), and spontaneous echo contrast in transesophageal echocardiography (P = 0.029). Significant procedural parameters were electric cardioversion (P = 0.041), PVI only (P = 0.008), and ablation of complex atrial electrograms (P = 0.005). Independent risk factors in multivariate analysis were age (P = 0.009), spontaneous echo contrast (P = 0.029) and CFAE ablation (P = 0.006). CONCLUSION: Radiofrequency ablation in patients under continued oral therapeutic anticoagulation is associated with a substantial risk of silent embolism detected by cerebral MRI. Therefore, continuation of oral anticoagulation is not able to prevent cerebral embolism. A variety of different clinical and procedural factors seem to contribute to the risk of cerebral lesions.

Clinical impact of an open-irrigated radiofrequency catheter with direct force measurement on atrial fibrillation ablation.

BACKGROUND: Electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). OBJECTIVE: We assessed the impact of direct catheter force measurement on acute procedural parameters during RFCA of atrial fibrillation (AF). METHODS: Fifty consecutive patients (28 male) with paroxysmal AF who underwent their first procedure of circumferential pulmonary vein (PV) isolation (PVI) were assigned to either RFCA using (1) a standard 3.5-mm open-irrigated-tip catheter or (2) a catheter with contact force measurement capabilities. Using the endpoint of PVI with entry and exit block, acute procedural parameters were assessed. RESULTS: Procedural data showed a remarkable decline in ablation time (radiofrequency time needed for PVI) from 50.5 ± 15.9 to 39.0 ± 11.0 minutes (P = 0.007) with a reduction in overall procedure duration from 185 ± 46 to 154 ± 39 minutes (P = 0.022). In parallel, the total energy delivered could be significantly reduced from 70,926 ± 19,470 to 58,511 ± 14,655 Ws (P = 0.019). The number of acute PV reconnections declined from 36% to 12% (P = 0.095). CONCLUSIONS: The use of contact force sensing technology is able to significantly reduce ablation and procedure times in PVI. In addition, energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact. Procedural efficacy and safety of this new feature have to be evaluated in larger cohorts.

Very High-Power Short-Duration (HPSD) Ablation for Pulmonary Vein Isolation: Short and Long-Term Outcome Data.

BACKGROUND: Circumferential pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is a standard of care intervention for patients with symptomatic atrial fibrillation (AF). During follow-up, a substantial number of patients need a redo procedure due to reconnections on the basis of insufficient non-transmural ablation lesions. High-power short-duration ablation (HPSD) is expected to create efficient lesions while causing fewer complications than in conventional RFA settings. The aim of this study was to compare one-year outcome data of very HPSD (90 Watt, 4 s) to a strategy using 50 Watt HPSD ablation guided by the CLOSE protocol using the Ablation Index (AI), an arbitrary unit composed of power, contact force and ablation time. METHODS: We retrospectively analyzed short and long-term (median follow-up 23.2 ± 9.9 months) outcome data from 52 patients that were scheduled for first-do-symptomatic PVI. A very HPSD ablation protocol with 90 Watt and a 4 s duration cut-off was compared to an HPSD CLOSE approach (50 Watts; AI 550 at the anterior LA wall; AI 400 at the posterior LA wall, the roof and the floor) in terms of freedom from AF recurrence in a long-term electrocardiogram (ECG) over a five days surveillance period. To gain an impression of the subjective sense of wellbeing, the Atrial Fibrillation Effects on QualiTy-of-Life (AFEQT) score was recorded. RESULTS: Overall freedom from AF was found in 81% (90 W 4 s) vs. 87.5% (50 W), (p = 0.52). There were 3 AF recurrences during the blanking period (90 W 4 s) vs. 1 (50 W). Within each population, one patient was scheduled for a redo-PVI-procedure. The AFEQT score was in favor of the 90 Watt 4 s approach (86.1 vs. 77.5; p = 0.37). CONCLUSION: Within our relatively small studied population, we found hints that in addition to shortening ablation times and radiation exposure without significantly increasing the rate of relevant intraprocedural complications, very high power short-duration ablation (90 W 4 s) provides comparable efficacy rates after one year.

Atrial Fibrillation Ablation in Heart Failure Patients.

Atrial Fibrillation (AF) and Heart Failure (HF) are closely linked to each other, as each can be either the cause of or the result of the other. Successfully treating one of the two entities means laying the basis for treating the other one as well. Management of patients with AF and HF can be challenging and should primarily adhere to available guidelines. Concerning AF, medication is limited and causes many side effects, leading to low medical adherence. Several smaller studies, summarized in a big meta-analysis, provide evidence that ablation of AF in HF patients is crucial for improving quality of life, reducing HF hospitalizations, and reducing death, provided the LVEF is at least 25% or higher. In advanced HF, alternative treatment options (including assist devices, heart transplant) might still be the better option. Early rhythm control should be taken into consideration, as there is evidence that it is associated with better cardiovascular outcome.

Successful ablation of bifocal premature ventricular complexes from both left bundle branches triggering polymorphic ventricular tachycardia in long QT syndrome 2: a case report.

BACKGROUND: A 19-year-old woman with an established diagnosis of long QT syndrome (LQTS) 2 and underlying KCNH2-mutation was referred to our centre for recurrent polymorphic ventricular tachycardia (VT) and ventricular fibrillation (VF) refractory to medical therapy and bilateral thoracic sympathectomy. CASE SUMMARY: Holter monitoring revealed a relevant premature ventricular complex (PVC) burden of two different morphologies. One PVC was originating from the left anterior fascicle, the other from the left posterior fascicle. Radiofrequency ablation resulted in complete suppression of both spontaneous PVC morphologies with a favourable clinical course over the next 2 years. DISCUSSION: This case presents two interesting insights: firstly, the consistent bigeminal pattern of the torsade de pointes triggering PVC. These were retrieved from the device interrogation and correlated with the pattern that was seen at the time of the procedure. Secondly, PVC morphologies suggested an origin from both the left ventricular (posterior and anterior) fascicles, which have not been described so far. This was confirmed by the preceding Purkinje potentials seen at the successful ablation sites in sinus rhythm and during PVC. Ablation of triggering PVCs causing recurrent VT/VF in LQTS 2 is feasible and effective over a mid-term follow-up.

Cerebral thromboembolic risk in atrial fibrillation ablation: a direct comparison of vitamin K antagonists versus non-vitamin K-dependent oral anticoagulants.

PURPOSE: Cerebral thromboembolic events are well-known complications of pulmonary vein isolation (PVI) and can manifest as stroke or silent cerebral embolic lesions. The aim of this study was to compare the incidence of cerebral embolic lesions (including silent cerebral embolism and stroke) after AF ablation in patients on vitamin K antagonists versus patients on non-vitamin K-dependent oral anticoagulants, and to identify corresponding clinical and procedural risk factors. METHODS: A total of 421 patients undergoing PVI were prospectively included into the study. Of these, 43.7% were on VKA and 56.3% on NOAC treatment (dabigatran, rivaroxaban, apixaban, and edoxaban). In the NOAC group, 38% of patients had an interruption of anticoagulation for 24-36 h. All patients underwent pre- and postprocedural cerebral magnetic resonance imaging. RESULTS: Periprocedural cerebral lesions occurred in 13.1% overall. Of these, three (0.7%) resulted in symptomatic cerebrovascular accidents and 52 (12.4%) in silent cerebral embolic lesions. Incidence of cerebral lesions was significantly higher in patients on NOAC compared with VKA (16% vs. 9.2%, respectively, p = 0.04), and in patients who had intraprocedural cardioversions compared with no cardivoersions (19.5% vs. 10.4%, respectively, p = 0.03). In multivariate analysis, both parameters were found to be independent risk factors for cerebral embolism. No significant difference between interrupted and uninterrupted NOAC administration could be detected. CONCLUSIONS: In patients undergoing AF ablation, we identified the use of NOAC and intraprocedural cardioversion as independent risk factors for the occurrence of periprocedural cerebral embolic lesions.

Feasibility of catheter ablation renal denervation in "mild" resistant hypertension.

Renal denervation (RDN) has been proposed as a novel interventional antihypertensive technique. However, existing evidence was mainly from patients with severe resistant hypertension. The authors aimed to evaluate the efficacy of RDN in patients with resistant hypertension with mildly elevated blood pressure (BP). Studies of RDN in patients with mild resistant hypertension (systolic office BP 140-160 mm Hg despite treatment with three antihypertensive drugs including one diuretic, or mean systolic BP by 24-hour ambulatory BP measurement [ABPM] 135-150 mm Hg) were included. Two observational and one randomized cohort were identified (109 patients in the RDN group and 36 patients in the control group). Overall, the mean age of patients was 62±10 years, and 69.7% were male. Before-after comparison showed that RDN significantly reduced ABPM as compared with the baseline systolic ABPM, from 146.3±13 mm Hg at baseline to 134.6±14.7 mm Hg at 6-month follow-up and diastolic ABPM from 80.8±9.4 mm Hg at baseline to 75.5±9.8 mm Hg at 6-month follow up (both P<.001). This significant effect was not observed in the control group. Between-group comparison showed a greater change in ABPM in the RDN group as compared with that in the control group (change in systolic ABPM: -11.7±9.9 mm Hg in RDN vs -3.5±9.6 mm Hg in controls [P<.001]; change in diastolic ABPM: -5.3±6.3 mm Hg in RDN vs -2.1±5.5 mm Hg in control [P=.007]). RDN was also associated with a significantly decreased office systolic/diastolic BP and reduced number of antihypertensive medications. No severe adverse events were found during follow-up. RDN seems feasible to treat patients with mild resistant hypertension.

Feasibility and safety of uninterrupted periprocedural apixaban administration in patients undergoing radiofrequency catheter ablation for atrial fibrillation: Results from a multicenter study.

BACKGROUND: Periprocedural anticoagulation management with uninterrupted warfarin and a "therapeutic" international normalized ratio is the best approach for reducing both thromboembolic and bleeding complications in the setting of catheter ablation for atrial fibrillation (AF). OBJECTIVE: The purpose of this study was to evaluate the safety and feasibility of uninterrupted apixaban in this setting. METHODS: This was a prospective multicenter registry of AF patients undergoing radiofrequency catheter ablation at 4 institutions in United States and Europe with uninterrupted apixaban. These patients were compared with an equal number of patients, matched for age, gender, and type of AF, undergoing AF ablation on uninterrupted warfarin. The apixaban group was comprised of consecutive patients who had taken their last dose of apixaban the morning of the procedure. A subset of 29 patients in the apixaban group underwent diffusion magnetic resonance imaging (dMRI) to detect silent cerebral ischemia. RESULTS: A total of 400 patients (200 patients in each group) were included in the study. The average age was 65.9 ± 9.9 years, 286 (71.5%) were male, and 334 (83.5%) had nonparoxysmal AF. There were no statistical differences with regard to major complications (1% vs 0.5%, P = 1), minor complications (3.5% vs 2.5%, P = .56), or total bleeding complications (4.5% vs 3%, P = .43) between the apixaban and warfarin groups. There were no symptomatic thromboembolic complications. All dMRIs were negative for "new" silent cerebral ischemia in the apixaban group. CONCLUSION: Uninterrupted apixaban administration in patients undergoing AF ablation seems to be feasible and effective in preventing clinical and silent thromboembolic events without increasing the risk of major bleeding.