Atrioventricular Node Ablation Research Articles

Clinical outcomes of leadless pacemaker: a systematic review.

Transvenous pacemakers are associated with a significant amount of complications. Leadless pacemakers (LP) are emerging as an alternative to conventional devices. This article provides a systematic review of patient eligibility, safety and clinical outcomes of the LP devices. A systematic search for articles describing the use of LP was conducted. Out of two databases, 24 articles were included in the qualitative analysis. These articles comprised a total of 4739 patients, with follow-up times of 1-38 months. Further information was obtained from 10 more studies. From a population of 4739 patients included in the qualitative analysis, 4670 LP were implanted with success (98.5%). A total of 248 complications were described (5.23%) during the follow-up. The most common were pacing issues such as elevated thresholds, dislodgements or battery failure (68 patients), events at the femoral access site such as hemorrhage, hematoma or pseudoaneurysms (64 patients) and procedure related cardiac injuries such as cardiac perforation, tamponade or pericardial effusion (47 patients). There were 360 deaths during the follow-up and 11 were described as procedure or device related. Four studies presented the strategy of using a combined approach of atrioventricular node ablation (AVNA) and LP implantation. Leadless pacemakers seem to have a relatively low complication rate. These devices may be a good option in patients with an indication for single-chamber pacing, in patients with conditions precluding conventional transvenous pacemaker implantations. Studies directly comparing LP and transvenous pacemakers and data on longer follow-up periods are needed.

Mid-term feasibility, safety and outcomes of left bundle branch pacing-single center experience.

His bundle pacing (HBP) has evolved as the most physiological form of pacing but associated with limitations. Recently, left bundle branch pacing (LBBP) is emerging as an effective alternative strategy for HBP. Our study was designed to assess the feasibility, efficacy, electrophysiological parameters, and mid-term outcomes of LBBP in Indian population. All patients requiring permanent pacemaker implantation for symptomatic bradycardia and heart failure were prospectively enrolled. Echocardiography, QRS duration, pacing parameters, left bundle (LB) potentials, paced QRS duration, and peak left ventricular activation time (pLVAT) were recorded. LBBP was successful in 93 out of 99 patients (94% acute success). Mean age was 62.6 ± 13years, male 59%, diabetes 69%, and coronary artery disease 65%. Follow-up duration was 4.8months (range1-12months). Indication for pacing included atrioventricular (AV) block 43%, cardiac resynchronization therapy 44%, and AV node ablation 4%. LB potential was noted in 37 patients (40%). QRS duration reduced from 144.38 ± 34.6 at baseline to 110.8 ± 12.4ms after LBBP (p < 0.0001). Pacing threshold was 0.59 ± 0.22V and sensed R wave 14.14 ± 7.19mV, and it remained stable during follow-up. Lead depth in the septum was 9.62mm. LV ejection fraction increased from 44.96 to 53.3% after LBBP (p < 0.0001). One died due to respiratory tract infection on follow up. LBBP is a safe and effective strategy (94% acute success) of physiological pacing. The pacing parameters remained stable over a period of 12months follow-up. LBBP can effectively overcome the limitations of HBP.

Comparison of Atrial Remodeling Caused by Sustained Atrial Flutter Versus Atrial Fibrillation

BackgroundAtrial flutter (AFL) and atrial fibrillation (AF) are associated with AF-promoting atrial remodeling, but no experimental studies have addressed remodeling with sustained AFL. ObjectivesThis study aimed to define the atrial remodeling caused by sustained atrial flutter (AFL) and/or atrial fibrillation (AF). MethodsIntercaval radiofrequency lesions created a substrate for sustained isthmus-dependent AFL, confirmed by endocavity mapping. Four groups (6 dogs per group) were followed for 3 weeks: sustained AFL; sustained AF (600 beats/min atrial tachypacing); AF superimposed on an AFL substrate (AF+AFLs); sinus rhythm (SR) with an AFL substrate (SR+AFLs; control group). All dogs had atrioventricular-node ablation and ventricular pacemakers at 80 beats/min to control ventricular rate. ResultsMonitoring confirmed spontaneous AFL maintenance >99% of the time in dogs with AFL. At terminal open-chest study, left-atrial (LA) effective refractory period was reduced similarly with AFL, AF+AFLs and AF, while AF vulnerability to extrastimuli increased in parallel. Induced AF duration increased significantly in AF+AFLs and AF, but not AFL. Dogs with AF+AFLs had shorter cycle lengths and substantial irregularity versus dogs with AFL. LA volume increased in AF+AFLs and AF, but not dogs with AFL, versus SR+AFLs. Optical mapping showed significant conduction slowing in AF+AFLs and AF but not AFL, paralleling atrial fibrosis and collagen-gene upregulation. Left-ventricular function did not change in any group. Transcriptomic analysis revealed substantial dysregulation of inflammatory and extracellular matrix-signaling pathways with AF and AF+ALs but not AFL. ConclusionsSustained AFL causes atrial repolarization changes like those in AF but, unlike AF or AF+AFLs, does not induce structural remodeling. These results provide novel insights into AFL-induced remodeling and suggest that early intervention may be important to prevent irreversible fibrosis when AF intervenes in a patient with AFL.

P429The efficacy of electrical cardioversion of long-standing persistent or permanent atrial fibrillation in cardiac resynchronization therapy recipients

Abstract Funding Acknowledgements Institute of Cardiology statutory grant (grant no.: 2.30/VII/13) Background Atrial fibrillation (AF) and heart failure (HF) often co-exist and influence each other. The presence of AF is often regarded as a marker of HF severity. Moreover, AF in cardiac resynchronization therapy (CRT) recipients hinders the CRT effectiveness in HF treatment by the reduction of the percentage of biventricular paced beats (BiVp%). Sinus rhythm (SR) restoration makes CRT more effective in HF treatment which may protect AF recurrence. Purpose To establish the effectiveness of electrical external cardioversion (EEC) in CRT patients with long-standing persistent AF or permanent, pre-treated with amiodarone. Methods The population of the study comprised of the Pilot-CRAfT study participants (NCT01850277), that is patients with CRT, long-standing persistent or considered as permanent AF and BiVp ≤ 95% who were randomly assigned to the "rhythm control" or the "rate control" strategy. The inclusion criteria included an AF paroxysm lasting at least 6 months. Both treatment arms received amiodarone beginning with the loading dose. Subsequently, patients assigned to the rhythm control strategy underwent electrical cardioversion. Rate control strategy included pharmacotherapy and atrioventricular node ablation, as needed. The follow up visit was performed 3 months after the enrolment visit. The EEC effectiveness, an AF recurrence within the 3 month period, BiVp% changes, the EEC parameters and the EEC related complications were analysed. Results Out of 48 participants enrolled in the Pilot-CRAfT study, 25 patients were assigned to the rhythm control arm. The mean age of the rhythm control arm patients was 69,5 years , the mean left ventricular ejection fraction was 30,6% , the mean left atrium diameter was 53 mm and the median duration of persistent AF was 16 months. SR was obtained in 12 out of 20 (60%) patients who underwent the EEC . On the 3 month visit 8 patients remained in SR (40%). In patients with an AF paroxysm lasting less than 1 year the success rate was 100% vs 50% in the AF lasting 1 year at least (p = 0,11 ). After 3 months, SR remained in 100% vs 25% of patients, respectively (p =0,015.). The effectiveness of anterior-posterior EEC electrodes placement was 20% and it was 71% for the anterior-lateral patch location . The EEC resulted in significant BiVp% rise - also in the whole intention-to-treat (ITT) group: 88,58% before the EEC vs 96,68% after the EEC (p = 0,002). No severe adverse events of the EEC were observed. Conclusions The electrical cardioversion of persistent atrial fibrillation lasting more than 6 months in patients with severe HF and treated with CRT is characterised by modest success rate, even after the amiodarone pre-treatment. However, the ECC ensures significant rise in BiVp% close to 97%, even in the whole EEC group based on the ITT principle. The AF paroxysm duration &amp;lt;1 year and the anterior-posterior patch placement may ensure better EEC efficacy in this group of patients.

P508Biventricular pacing versus His bundle pacing after atrioventricular node ablation in heart failure patients with permanent atrial fibrillation and narrow QRS

Abstract Background Atrioventricular (AV) node ablation with biventricular (BiV) pacemaker implantation is a feasible rate control strategy for symptomatic permanent atrial fibrillation (AF) with rapid ventricular response and tachycardia-induced heart failure (HF). However, certain controversy exists since BiV pacing delivers non-physiological ventricular resynchronization and does not return left ventricular (LV) activation times to those seen in individuals with intrinsically narrow QRS. Permanent His bundle pacing (HBP) is a physiological alternative to conventional and BiV pacing. By capturing the native conduction system, depolarization of the ventricles through the His-Purkinje system induces normal synchronous ventricular activation. Purpose The aim of the study was to compare short-term outcomes between BiV pacing and HBP after AV node ablation in HF patients with symptomatic permanent AF and narrow QRS. Methods A total of 25 consecutive HF patients with permanent AF and narrow QRS (≤110 ms) who underwent AV node ablation in conjunction with BiV pacing or HBP in our centre were enrolled. Post-implant QRS duration, echocardiographic data, and New York Heart Association (NYHA) functional class were assessed in short-term follow-up. Results Among 25 HF patients (aged 68 ± 7 years, 52% female, QRS 96 ± 9 ms, LVEF 37 ± 7%, NYHA II-IV), 13 received BiV pacing and 12 HBP. Implant and ablation procedures were acutely successful in both groups. In BiV group 1 patient had a LV lead dislodgement and 1 patient in the HBP group had an acute HB lead threshold increase after AV node ablation. In HBP group post-implant QRS duration was shorter compared to BiV (103 ± 15 ms vs. 177 ± 13 ms, p &amp;lt; 0.001). At a median follow-up of 6 months, patients treated with HBP had greater increase in LV ejection fraction compared to BiV (44 ± 10 vs. 37 ± 6, p = 0.045). A trend toward greater reduction of LV volumes (EDV 119 ± 54 ml vs. 153 ± 33 ml, p = 0.07; ESV 75 ± 34 ml vs. 97 ± 26 ml, p = 0.09) and improvement of NYHA class (2.1 ± 0.7 vs. 2.7 ± 0.8, p = 0.08) was also observed in HBP group compared to BiV group. Conclusion In rate control refractory HF patients with permanent AF and narrow QRS atrioventricular node ablation in conjunction with HBP demonstrated superior electrical resynchronization and greater increase in LV ejection fraction compared to BiV pacing. Larger prospective studies are warranted to address clinical outcomes between both pace and ablate strategies.

P1163Correction of septal flash excursion with his bundle pacing

Abstract Funding Acknowledgements Grant from the Catalan Society of Cardiology Background His bundle pacing (HBP) directly stimulates the conduction system and could therefore correct asynchrony and evolve as a more physiological pacing approach. Septal flash (SF) is a fast contraction and relaxation of the septum occurring during the isovolumetric contraction period. It is a specific marker of cardiac dyssynchrony. Purpose Evaluate whether HBP corrects SF in patients with an indication for CRT or RV pacing. Methods A cohort of 20 consecutive patients undergoing HBP at our center was analyzed. HBP indications were: Group A (n = 3): left bundle branch block (LBBB) and left ventricular (LV) dysfunction (LV ejection fraction [LVEF] &amp;lt; 35%); Group B (n = 14): LV dysfunction (LVEF &amp;lt; 50%) and atrio-ventricular block requiring permanent pacing; Group C (ablate&amp;pace, n = 3): atrio-ventricular node ablation due to rapid atrial fibrillation. Patients in groups B and C had a RV backup lead implanted, in line with current recommendations. The presence of SF was analyzed in 2D-echocardiography at 15 days post-implant. SF excursion was quantified using M-mode in parasternal short and long axis views as the highest amplitude of the early inward motion. Baseline SF excursion was determined during intrinsic rhythm (group A) or RV pacing (groups B and C). For each patient, the pair of measurements (baseline, HBP) in the axis with the highest baseline SF was selected. Results Mean LVEFs were 21 ± 8%, 32 ± 6%, and 41 ± 18% for groups A, B and C, respectively. HBP shortened QRS duration by 42 ± 15 ms and 45 ± 23 ms in groups A (Baseline QRS - HBP QRS) and B + C (RV pacing QRS - HBP QRS), respectively. At baseline, all patients except 1 had SF (Fig. 1A). The mean SF excursion was 4.3 ± 1.9 mm, with SF excursion being larger in group A than in the RV-paced groups (6.3 ± 1.5 mm vs. 3.9 ± 1.8 mm for groups A and B + C, respectively, p = 0.04). HBP abolished SF in 3 patients (15%) and, on average, decreased SF excursion by 2.3 mm (95% CI 1.3-3.2), irrespective of pacing indication (Fig. 1B). The degree of SF excursion reduction after HBP significantly correlated with QRS shortening (r = 0.53, p = 0.024) (Fig 1C). Conclusions In conclusion, we show that HBP results in acute correction or decrease of SF, thereby improving LBBB- or RV-induced mechanical dyssynchrony. Abstract Figure. Septal Flash and His pacing

Atrial Fibrillation Management in Heart Failure: Interrupting the Vicious Cycle

In this review article, we aim to describe the pathophysiology of concomitant atrial fibrillation and both left and right heart failure, as well as pronounce the prognosis of having these two conditions simultaneously. This review also summarizes the current management of atrial fibrillation including stroke and thromboembolism prevention in the presence of systolic and diastolic heart failure. While rhythm control strategy is not superior to rate control strategy in atrial fibrillation patients without heart failure, catheter ablation for atrial fibrillation has shown to improve outcomes in patients with coexisting heart failure. Atrial fibrillation is the most common arrhythmia that frequently coexists with heart failure. The incidence of one condition increases in the presence of the other posing a significant treatment challenge. Despite ample advancement in management strategies of atrial fibrillation and heart failure, this combination is associated with higher morbidity and mortality when found in the same patient. The treatment goal in these patients is to improve quality of life by controlling symptoms and to prevent thromboembolism with appropriate anticoagulation. Catheter ablation is a promising treatment option for symptomatic patients with depressed ventricular function. Finally, pacing with cardiac resynchronization therapy after AV nodal ablation should be considered when strict control of ventricular rate is desired in atrial fibrillation patients who meet the criteria for device implantation.

Joint Mexican position document on the treatment of atrial fibrillation.

Atrial fibrillation (AF) is a frequent arrhythmia; its prevalence is near 2% in the general population; in Mexico, more than one-half million people are affected. AF needs to be considered as a public health problem. Because AF is an independent risk factor associated with mortality, due to embolic events, heart failure, or sudden death; early diagnosis is of utmost importance. In unstable patients with a recent onset of AF, electrical cardioversion should be practiced. In stable patients, once thromboembolic measures have been taken, it is necessary to assess whether it is reasonable to administer an antiarrhythmic drug to restore sinus rhythm or performed electrical cardioversion. For recidivating cases of paroxysmal and persistent presentation, the most effective strategy is performed pulmonary vein isolation with either radiofrequency or cryoballoon energy. Permanent AF is that in which recovery of sinus rhythm is not possible, the distinguishing feature of this phase is the uncontrollable variability of the ventricular frequency and could be treated pharmacologically with atrioventricular (AV) nodal blockers or with a VVIR pacemaker plus AV nodal ablation. The presence of AF has long been associated with the development of cerebral and systemic (pulmonary, limb, coronary, renal, and visceral) embolism. The prevention of embolisms in "valvular" AF should perform with Vitamin K antagonists (VKA). For patients with AF not associated with mitral stenosis or a mechanical valve prosthesis, a choice can be made between anticoagulant drugs, VKA, or direct oral anticoagulants. Antiplatelet agents have the weakest effect in preventing embolism.

Indications for His bundle and left bundle branch pacing

His bundle pacing (HBP) allows ventricular excitation through the entire cardiac conduction system, resulting in abetter synchronicity and efficacy of contraction compared to myocardial pacing. Due to better, dedicated implantation tools and exact practical implantation recommendations, HBP has developed into aform of stimulation that can be successfully applied with reasonable time and effort in >90% of patients. The rate of lead dislodgement and threshold increase is similar to conventional pacemaker systems. Despite arather weak data base and apaucity of randomized trials, HBS represents an alternative to conventional right or biventricular pacing in the following conditions: (1)high-degree atrioventricular (AV) block with expected ventricular pacing >20% of the time, (2)AV block1stdegree with long PQ (alone or in combination with intermittent 2nd to 3rd degree AV block or sick sinus syndrome), (3)AV node ablation due to refractory atrial fibrillation, and (4)upgrade in pacing-induced cardiomyopathy. Moreover, HBP may be useful in context with cardiac resynchronization therapy (CRT). Left bundle branch block below the level of His represents alimitation of HBP. Therefore, more recently left bundle branch pacing (LBBP) has been introduced to correct left bundle branch block. LBBP seems to be possible in awider anatomic area and may be easier to implant. However, LBBP requires active screw-in of the lead deep into the ventricular septum. Experience with this new technique is limited, particularly regarding long-term performance.

His-Purkinje conduction system pacing and atrioventricular node ablation.

His-Purkinje conduction system pacing (HPCSP) in the form of His bundle pacing and left bundle branch pacing allows normal ventricular activation, thereby preventing the adverse consequences of right ventricular pacing. One potential area where HPCSP could be used is in the field of atrioventricular (AV) node ablation in patients with atrial fibrillation refractory to medical therapy and/or catheter ablation. His bundle pacing has been established for several years, with centres from North America, Europe and China publishing their experience. The differing patterns of His bundle capture are clearly described with established guidance as to how to implant such systems. Left bundle branch pacing has only recently been reported, but there are several advantages with better pacing parameters and lower risk of threshold change after AV node ablation. Six studies have been identified in the literature which describe the experience of His bundle pacing in patients requiring AV node ablation. Overall the results are positive and favour this new technique; however, they are limited by low numbers of patients and non-randomised study design. An observational study was recently published demonstrating better outcomes with left bundle branch pacing in asmall number of patients with left ventricular dysfunction and atrial fibrillationthat underwent AV node ablation. HPCSP has thepotential to be the primary pacing modalityin patients with atrial fibrillationrequiring AV node ablation. However, it is essential that this is confirmed in large randomised clinical trials.

Keeping pace with the competition: His bundle versus biventricular pacing in heart failure.

His bundle pacing (HBP) has emerged as a novel method to achieve electrical resynchronization in bundle branch block and as an alternative means to deliver cardiac resynchronization therapy (CRT). There are now data on HBP in CRT-eligible patients from cohort studies and a single pilot randomized controlled trial (RCT). Early clinical data regarding HBP in heart failure have demonstrated echocardiographic and functional improvement similar to traditional biventricular pacing (BiV), mostly when utilized as a bailout to traditional BiV-CRT. A single pilot RCT, His-SYNC, showed a trend toward greater echocardiographic response in an on-treatment analysis, but was underpowered. No large RCTs have reported long-term clinical outcomes. In order to realize any benefit from HBP, output-dependent morphology changes must be demonstrated to ensure the conduction system capture is present. There may be a role for corrective HBP in patients with right bundle branch block and after atrioventricular node ablation, which is theoretically more desirable than traditional BiV. Importantly, however, HBP is likely not to benefit patients with nonspecific intraventricular conduction delay. HBP is emerging as an alternative strategy for CRT and may have a role in patients in whom traditional BiV is not achievable or ineffective.

Abstract 341: Population-level Insights Into 30-day Mortality in Medicare Beneficiaries After Inpatient and Outpatient Catheter Ablation for Atrial Fibrillation

Background: Recent inpatient data abstracted from the National Inpatient Sample and/or National Readmissions Database have shown higher than expected (0.46%) 30-day mortality rates of AF ablation prior to 2016. AF ablation has been increasingly coded as an outpatient procedure and primarily as of late 2015. Prior studies did not include some of these outpatient ablation cases. As such, more complete data on mortality and health-disparity outcomes for combined inpatient and outpatient-coded AF ablation is lacking. The purpose of our study was to assess updated 30-day mortality rates following inpatient or outpatient AF ablation following coding changes with ICD-10. Patients were also stratified by demographics and geographic region. Method: Data were abstracted from the 2017 inpatient and outpatient Medicare institutional claims files. AF was identified based on primary or secondary ICD-10 diagnosis codes. Inpatient procedures were identified by matching a CPT code for AF ablation that occurred on the same day as a primary or secondary ICD-10-PCS code for AF ablation. Outpatient AF ablation was identified using the CPT code. AV nodal ablation or a pacemaker procedure on the same day as AF ablation were excluded. AF ablation had to occur within the first 11 months of the calendar year to allow 30-day mortality data for all patients. We used the Medicare Master Beneficiary Summary File to further stratify beneficiaries by sex, race, and ethnicity, and geographic region. Mortality rates are shown as frequency and percent, compared using the chi-square test. Results: In 2017, a total of 40,373 AF ablations (58% men) were identified, of which 30,539 (75.6%) were coded as outpatient. The mean age in years was 71.5 (SD = 7.1), and median age was 71 (21 to 100). In total, 294 patients died within 30 days of procedure (0.73%, 95% CI: 0.65% to 0.82%). The 30-day mortality rate was higher following inpatient coded procedures compared to outpatient coded procedures (2.34% vs. 0.21%, p &lt; .001). Further, higher 30-day mortality rates were observed for male patients compared to female patients (0.83% vs. 0.59%, p = .006) as well as in non-white patients compared to white patients (1.32% vs. 0.69%, p &lt; .001). Finally, 30-day mortality rates differed by region (South: 0.85%, Midwest: 0.81%, Northeast: 0.56%, and West: 0.51%; p = .007). Conclusion: Overall 30-day mortality post-AF ablation appears high, particularly following inpatient coded AF ablation. Most notably, it is significantly higher than the recent estimate of 0.46% mortality risk following AF ablation from primarily inpatient data. The findings of higher mortality in males, in the non-white population, and in certain regions of the US are notable. Further studies are needed to understand the factors impacting mortality.

His-bundle pacing is the best approach to physiological pacing.

His-bundle pacing is the best approach to physiological pacing.

Abstract P111: Sex Differences in Rate or Rhythm Control and Outcomes Among Elderly Patients With Atrial Fibrillation

Introduction: Women with atrial fibrillation (AF) experience greater symptomatology, worse quality of life, and have a higher risk of stroke as compared to men, but are less likely to receive rhythm control for the treatment of AF. Whether these differences exist in elderly patients with AF, and whether sex modifies the effectiveness of rhythm versus rate control therapy has not been assessed. Methods: We studied 135,850 men and 139,767 women 75 years or older diagnosed with AF in the MarketScan Medicare database between 2007-2015. Rate control was defined as use of rate control medication or atrioventricular node ablation. Rhythm control was defined by use of anti-arrhythmics, catheter ablation or cardioversion. Participants on both rate and rhythm were coded under rhythm control. We used multivariable logistic and Cox regression models to estimate 1) the association of sex and treatment strategy (within 30-day post AF diagnosis and entire follow-up) and, 2) the association of treatment strategy with incident heart failure, stroke and major bleeding. Results: Men were on average (SD) 82.5 (5.2) years old and women 83.8 (5.6) years, respectively. Women were less likely to receive rhythm control treatment as compared to men in the 30-day post AF diagnosis period (22% vs 27%), (OR 0.91, 95% CI 0.88, 0.94) and over the entire duration of follow-up (28% vs 32%) (HR 0.93, 95% CI 0.90, 0.96). Rhythm (vs. rate) control was associated with a higher risk of heart failure in women [HR 1.41, 95% CI 1.34, 1.49] than in men [HR, 1.21 95% CI 1.15, 1.28] (p for multiplicative interaction &lt; 0.001, Table ). Sex did not modify associations between treatment and incident stroke or major bleeding events. Conclusion: Women aged 75 years and older were less likely to be prescribed rhythm control as compared to men, and experienced higher risk of heart failure than men when receiving rhythm (vs rate) control. Future studies will need to delve into the mechanisms underlying these differences.

HIS BUNDLE PACING COMBINED WITH ATRIOVENTRICULAR NODAL ABLATION: A NOVEL STRATEGY FOR REFRACTORY HEART FAILURE LED BY ATRIAL FIBRILLATION COMPLICATED WITH HYPERTROPHIC CARDIOMYOPATHY

Atrioventricular nodal (AVN) ablation with permanent biventricular (BiV) pacing is recommended for difficult rate control of atrial fibrillation (AF). The novel His bundle pacing might be a better solution to overcome the possible iatrogenic dis-synchrony caused by the placement of the BiV leads. A

AV NODAL ABLATION IMPROVES LEFT VENTRICULAR REMODELING AND SURVIVAL IN PATIENTS WITH ATRIAL FIBRILLATION UNDERGOING CARDIAC RESYNCHRONIZATION THERAPY (CRT) IMPLANTATION

AV nodal (AVN) ablation is often considered as a last line treatment option in patients with poorly controlled AF. However, small studies have suggested its utility in patients undergoing CRT implantation with concomitant history of AF. Its role in improving LVEF and long term survival is not well

Differential contributions of atrial tachycardia and ventricular response to AF-promoting refractoriness and conduction remodeling

AF can cause atrial remodeling via fast atrial and/or ventricular rate; their relative role is unknown. To analyze the specific roles of atrial tachycardia vs. high ventricular rate in AF on atrial remodeling. Four groups of 12 dogs were followed for 3 wks: 600 bpm atrial tachypacing (ATP) maintaining AF (AF w/o AVB), ATP with AV node ablation (AF + AVB), 160 bpm ventricular pacing (V160) reproducing the ventricular rate during AF, and sinus rhythm with AVB/V-pacing at 80 bpm (CTL). At terminal open-chest study, electrophysiological remodeling was observed ( Fig. 1 A) with left atrial (LA) reduced effective refractory period in AF w/o AVB and AF + AVB groups vs. V160 and CTL. AF induction vulnerability to single extrastimuli was increased in AF w/o AVB and AF + AVB vs. CTL, but was unchanged in V160. Burst pacing induced AF duration was significantly increased in AF w/o AVB (14 ± 9 min, P < 0.05) but not in AF + AVB (6 ± 9 min) or V160 (2 ± 5 min) vs. CTL (5 ± 4 s). Conduction velocity was decreased in AF w/o AVB (74 cm/s, P < 0.05) vs. CTL (129 cm/s), to a greater extent than in AF + AVB and V160 (91 and 92 cm/s) ( Fig. 1 B). Collagen was upregulated in AF w/o AVB vs. CTL ( P < 0.01, Fig. 1 C). Fibrosis assessed by Masson Trichrome was increased in AF w/o AVB (18 ± 6%), AF + AVB (12 ± 5%) and V160 (12 ± 4%) vs. CTL (3 ± 1%, P < 0.05). SCN5A was decreased equally in AF w/o AVB, AF + AVB and V160 vs. CTL ( Fig. 1 D). Connexin43 mRNA and protein expression was reduced in AF w/o AVB vs. other groups ( Fig. 1 D). Both atrial tachycardia and ventricular response contribute to AF-promoting electrical and structural remodeling, with distinctive roles that need to be considered in preventive strategies.

Can chronic his bundle pacing be safely started in centers with lack of experience of this technique? Mid-term data from a multicentric registry

Right ventricular pacing (RVP) induces ventricular asynchrony in patients with normal QRS and increases the risk of heart failure and atrial fibrillation on long-term. His bundle pacing (HBP) is a physiological alternative to RVP. Interest in HBP has been hampered in part by technical challenges and limited implantation tool set. Recent studies showed that it was feasible and safe in expert centers with a vast experience of HBP. These results may not apply to less experienced centers. To evaluate feasibility and safety of permanent His bundle pacing in hospitals with limited technical training to this technique and to evaluate stability of His bundle capture (HBC) thresholds. We included all patients who underwent pacemaker implantation with attempt of HBP in 3 hospitals between September 2017 and January 2019. All the 5 operators were novice for HBP. HBC thresholds were recorded at 3 months and 9 months follow-up. HPB was successful in 62 of 69 patients (89.9%); selective HBC was obtained in 48 patients while nonselective HBC occurred in 14 patients. Indication for pacemaker implantation was atrioventricular conduction disease in 39 patients, sinus node dysfunction in 6 patients and AV nodal ablation for non-controlled atrial arrhythmias in 24 patients. The mean procedure duration was 75 ± 8 min, and mean fluoroscopy duration was 10 ± 2 min The mean HBC threshold was 1.39 ± 0.26 V and did not increase at 3 months follow-up (1.08 ± 0.25 V, n = 48 patients) and 9 months follow-up (1.37 ± 0.31 V, n = 14 patients). Only 7 patients had HBC threshold > 2.5 V/0.5ms. There was no pericardial effusion, no pneumothorax and no device infection. Ventricular lead revision was required at 3 months in one patient for sudden threshold increase, without obvious dislodgement ( Fig. 1 ). His bundle pacing performed by novice operators to this technique appeared feasible and safe. The mean HBC threshold did not increase at 3 months and 9 months follow-up.

Effect of Beta-blockers on Tachycardia in Patients with Pulmonary Embolism.

HypothesisBeta-blockers (BBs) lower the heart rate, which may mask the diagnosis of pulmonary embolism (PE) since one of the main clinical diagnoses of PE is tachycardia. The endpoint of our retrospective study is to determine if the pre-existing use of (BB) significantly affects the utility of these scoring criteria in diagnosing PE.IntroductionDiagnosing PE is a challenge because of the non-specificity of its symptoms and signs. The initial step is to assess the patient’s likelihood of having a PE. This involves using a scoring system to stratify patients into different levels of risk of having PE (for example, as ‘low,’ ‘moderate,’ or ‘high’ risk). Some of the commonly used criteria are Wells’ Score, Geneva Score, and Pulmonary Embolism Rule-out Criteria (PERC) Rule (Charlotte Rule).MethodologyThis retrospective study was conducted at St. Francis Medical Center. Subjects were taken from a patient population with a new diagnosis of PE (between 2010 and 2017) on the basis of computed tomography angiography (CTA) of the chest. Patients with sepsis or septic shock, heart block, atrioventricular (AV) nodal ablation, pacemaker placement, or taking more than one AV nodal blocker were excluded from the study. Subjects were categorized on the basis of beta-blocker consumption.ResultOut of a total of 170 cases, 71 patients were taking beta-blockers and 99 patients were not taking beta-blockers. Among the participants taking BBs, 30.4% had a heart rate <60 and 55.8% had a heart rate between 60 and 100.ConclusionBBs significantly obviate tachycardia in patients with PE. It falsely decreases the Wells’ Score and the Geneva Score and results in the inappropriate fulfilling of PERC criteria.

Acute and long-term outcomes of left-sided atrioventricular node ablation in patients with atrial fibrillation.

To present our experience regarding acute and long-term outcomes of left-sided atrioventricular node (AVN) ablation in patients with atrial fibrillation (AF). A total of 47 patients with AF in whom left-sided AVN ablation via retroaortic approach as a first-line approach were enrolled in this retrospective study. Indications for AVN ablation were high ventricular rate refractory to medical therapy, inappropriate implantable cardioverter defibrillator (ICD) shocks, or loss of cardiac resynchronization therapy (CRT) pacing. Both acute and long-term outcomes were assessed for all participants. Left-sided AVN ablation was successfully performed in 46/47 (98%) patients without any procedural complication. In the remaining 1 patient (2%), right-sided AVN ablation was performed. No mortality was observed within 30days of the procedure. Upgrade to CRT was performed in 9 (19%) of the patients. During the median 22.5months of follow-up, all-cause mortality was 25%. Device interrogations on the last clinical visit revealed complete AV block and intrinsic ventricular rate of < 40bpm in all patients. Left-sided AVN ablation is a safe and effective procedure without recurrence during long-term follow-up.