His-ventricular Interval Research Articles

The Transcatheter Aortic Valve Replacement-Conduction Study: The Value of the His-Ventricular Interval in Risk Stratification for Post-TAVR Atrioventricular-Block

BackgroundThere is no clear consensus regarding the optimal risk stratification of high-degree atrioventricular block (HDAVB) after transcatheter aortic valve replacement (TAVR). MethodsThis prospective study sought to determine the utility of the pre- and post-TAVR His-ventricular (HV) interval in the risk stratification of post-TAVR HDAVB. One hundred twenty-one patients underwent an electrophysiology study before and after TAVR. The primary outcome was HDAVB requiring pacemaker implantation within 30 days post-TAVR. A separate retrospective cohort was analyzed to determine the postoperative interval at which the risk of HDAVB is reduced to <5%. ResultsHDAVB occurred in 12 (10%) patients. Baseline right bundle branch block (RBBB) (odds ratio [OR]: 13.6), implant depth >4 mm (OR: 3.9), use of mechanically- or self-expanding valves (OR: 6.3), and post-TAVR HV > 65 ​ms (OR: 4.9) were associated with increased risk of HDAVB, whereas PR intervals and pre-TAVR HV were not. In patients without baseline RBBB or new persistent left bundle branch block (LBBB), not one patient with post-TAVR HV < 65 ​ms developed HDAVB. In the separate retrospective cohort (N = 1049), the risk of HDAVB is reduced (<5%) on postoperative days 4 and 3 in patients with pre-TAVR RBBB and post-TAVR persistent LBBB, respectively. ConclusionsBaseline RBBB, new persistent LBBB, implant depth >4 mm, and a post-TAVR HV ≥ 65 ​ms were associated with a higher risk of post-TAVR HDAVB, whereas an HV ≤ 65 ​ms was associated with a lower risk. The pre-TAVR HV was not associated with our outcome, and the delta HV did not have practical incremental prognostic value. Among those without pre-TAVR RBBB or post-TAVR persistent LBBB, no patients with post-TAVR HV < 65 ​ms developed HDAVB.

Is electrophysiological study a novel predictor for permanent pacemaker implantation after transcatheter aortic valve implantation?

Despite advancements in valve technology and increased clinical experience, complications related to conduction defects after transcatheter aortic valve implantation (TAVR) have not improved as rapidly as expected. In this study, we aimed to predict the development of complete atrioventricular (AV) block and bundle branch block during and after the TAVR procedure and to investigate any changes in the cardiac conduction system before and after the procedure using electrophysiological study. A total of 30 patients who were scheduled for TAVR at our cardiovascular council were planned to be included in the study. TAVR was performed on patients at Erciyes University Medical Faculty Hospital as a single center between May 2019 and August 2020 Diagnostic electrophysiological study was performed before the TAVR procedure and after its completion. Changes in the cardiac conduction system during the preprocedure, intra-procedure, and postprocedure periods were recorded. Significant increases in baseline cycle length, atrial-His (AH) interval, his-ventricular (HV) interval and atrioventricular (AV) distance were observed before and after the TAVR procedure (p = 0.039, p < 0.001, p = 0.018, p < 0.001, respectively). During the TAVR procedure, the preprocedural HV interval was longer in patients who developed AV block and bundle branch block compared to those who did not and this difference was statistically significant (p = 0.024). ROC curve analysis revealed that a TAVR preprocedure HV value >59.5 ms had 86% specificity and 75% sensitivity in detecting AV block and bundle branch block (AUC = 0.83, 95% CI: 0.664-0.996, p = 0.013). The preprocedure HV distance was 98 ± 10.55ms in the group with permanent pacemaker implantation and the mean value in the group without permanent pacemaker implantation was 66.27 ± 15.55 ms, showing a borderline significant difference (p = 0.049). The prolongation of HV interval in patients with AV block and bundle branch block suggests that the block predominantly occurs at the infra-hisian level. Patients with longer preprocedural HV intervals should be closely monitored for the need for permanent pacemaker implantation after the TAVR procedure.

Electrophysiological evaluation following development of new and persistent left bundle branch block after transcatheter aortic valve replacement: A single center pilot study.

New and persistent left bundle branch block (NP-LBBB) following Transcatheter Aortic Valve Replacement (TAVR) is an ongoing concern with incidence ranging from as low as 4% to up to 65% (varying for different types of valves). Such patients are at risk of developing high-grade atrioventricular block (HAVB) warranting permanent pacemaker (PPM) implantation. However, currently, there are no consensus guidelines or large prospective studies to risk stratify these patients for safer discharge after TAVR. To provide insight from a single center study on using modified electrophysiology (EP) study to risk stratify post-TAVR patients to outpatient monitoring for low-risk versus pacemaker implantation for high-risk patients. Between June 2020 and March 2023, all patients who underwent a TAVR procedure (324 patients) at our institution were screened for development of NP-LBBB post-operatively. Out of 26 patients who developed NP-LBBB, after a pre-specified period of observation, 18 patients were deemed eligible for a modified EP study to assess His-Ventricular (HV) interval. 11 out of 18 patients (61.1%) had normal HV interval (HV<55ms). Three out of 18 patients (16.7%) had HV prolongation (55ms<HV<70ms) without significant HV prolongation (defined as an increase in HV interval>30%) with intra-procedural procainamide challenge. Four out of 18 patients (22.2%) had significant HV prolongation (HV>70ms) warranting PPM implantation based on a multidisciplinary approach and shared decision-making with the patients. Total of 50% of patients discharged with PPM (two out of four patients) were noted to be pacemaker dependent based on serial device interrogations. All patients who did not receive PPM were discharged with ambulatory monitoring with 30-day event monitor and did not develop HAVB on serial follow-up. Normal HV interval up to 55ms on modified EP study after TAVR and development of NP-LBBB can be utilized as a threshold for risk stratification to facilitate safe discharge. The optimal upper limit of HV interval threshold remains unclear in determining appropriate candidacy for PPM.

Ventricular pacing burden in patients with left bundle branch block after transcatheter aortic valve replacement therapy

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Electrophysiological (EP) testing has been proposed in the latest ESC guidelines for cardiac pacing to identify LBBB patients with infrahisian conduction delay (IHCD) after transcatheter aortic valve replacement (TAVR). While in general IHCD is defined by a His-ventricular (HV) interval of &amp;gt; 55ms, a cut-off of ≥ 70ms to trigger pacemaker (PM) implantation has been proposed in the latest ESC guidelines. The ventricular pacing (VP) burden during follow-up in such patients is largely unknown. Purpose To assess the VP burden during follow-up of patients receiving PM therapy for LBBB after TAVR based on an HV interval &amp;gt; 55 ms and ≥ 70ms. Methods All patients with new-onset or pre-existing LBBB after undergoing TAVR at a tertiary referral center underwent EP testing the day after TAVR. In patients with a prolonged HV interval (&amp;gt;55 ms), PM implantation was performed by a trained electrophysiologist in a standardized fashion. All devices were programmed to avoid unnecessary VP by specific algorithms (e.g., AAI-DDD). Results 701 patients underwent TAVR at our university hospital between October 2014 and November 2021. 177 patients presented with new-onset or pre-existing LBBB the day following TAVR and underwent EP testing. An HV interval &amp;gt; 55 ms was found in 58 patients (33%) and an HV interval ≥ 70 ms in 21 patients (12%). 51 patients (mean age 84 ± 6.2 years, 45% women) agreed to receive a PM, out of which 20 (39%) patients had an HV Interval over 70 ms. Atrial fibrillation was present in 53% of the patients. A dual chamber PM was implanted in 39 (77%), and a single chamber pacemaker in 12 (23%) patients, respectively. Median FU was 21 months (IQR 11-41). The median VP burden overall was 3%. The median VP burden was numerically higher in patients with an HV ≥70 ms (6.5% [0.8 - 52]) than in those with an HV between 55 and 69 ms (2% [0 – 17], p = 0.23). 31% of patients had a VP burden &amp;lt;1%, 27% 1-5% and 41% &amp;gt; 5% (Figure). The median HV intervals in patients with VP burden &amp;lt;1%, 1-5% and &amp;gt;5% were 66 (IQR 62 -70) ms, 66 (IQR 63 – 74) ms and 68 (IQR 60 – 72) ms respectively, p= 0.52. When only assessing patients with an HV interval 55-69 ms, 36% demonstrated a VP burden of &amp;lt;1%, 29% of 1-5% and 35% of &amp;gt;5 %. In patients with an HV Interval ≥ 70ms, 25% demonstrated a VP burden &amp;lt;1%, 25% of 1-5% and 50% of &amp;gt;5 %, p=0.64 (Table). Conclusion VP burden can be significant in patients with LBBB after TAVR and an HV interval of &amp;gt; 55 ms. Further studies are warranted to define the optimal cut-off to trigger PM implantation in patients with LBBB after TAVR.

Marked first-degree AV block may lead to complete AV block development

Abstract Funding Acknowledgements Type of funding sources: None. Background First-degree atrioventricular (AV) block (PR interval &amp;gt;200 ms) is considered a benign condition with rare progression to a higher degree AV block. The site of block is determined with electrophysiological (EP) study and measurement of His-ventricular (HV) interval, with normal values below 55 ms. Prolonged HV interval &amp;gt; 70 ms is predictive of higher-grade AV block development. Marked first-degree AV block with a PR &amp;gt; 300 ms may lead to symptoms such as fatigue, poor exercise tolerance and palpitations. When symptoms are correlated to the conduction delay, permanent pacemaker (PPM) implantation to restore AV synchrony should be considered. In the Framingham heart study, patients with first-degree AV block had a threefold higher risk of PPM implantation. However, there is no data on the HV intervals and the rate of progression of conduction disorder in patients with marked first-degree AV block. Purpose To assess the predictive value of HV interval measurement in patients with marked first-degree AV block for progression to a higher-degree conduction disorder. Methods We prospectively evaluated consecutive patients with symptomatic marked first-degree AV block that underwent a PPM implantation. His electrograms were recorded during the implantation, and HV intervals were measured from the first deflection of the His signal to the earliest onset of ventricular activation on a 12-lead surface ECG. Patients were followed for 6 months with three out-patient visits, during which the PPM was temporarily inhibited to check for intrinsic AV conduction. Results Seventeen patients were evaluated between January 2020 and September 2022. Ten patients (59%) were male, and 7 (41%) were female, with an average age of 61 ± 19 years. All patients had markedly prolonged PR interval (383 ± 47 ms) and narrow QRS complex (100 ± 16 ms). Three patients (17%) had intermittent type 1 second-degree AV block, right bundle branch block was recorded in two (12%) and left anterior fascicular block in four (24%) patients. Except for one patient with a corrected atrial septal defect, there were no echocardiographic signs of structural heart disease with a left ventricular ejection fraction of 61 ± 5%. The HV intervals were on the upper limit of normal values at 54 ± 6ms and no patient had an HV interval above 70 ms. Two patients (12%) developed complete AV block during follow-up: one female, and one male, 28 and 83 years old, respectively, with a PR interval 392 and 363 ms, QRS 104 and 94 ms, and HV 57 and 48 ms. None of the two had any additional conduction blocks at the time of PPM implant. Conclusion In our cohort of patients with symptomatic first-degree AV block (PR&amp;gt;300 ms), two patients (12%) developed complete AV block despite normal HV intervals at the time of implant. Closer monitoring, beyond only EP measurements, of patients with markedly prolonged PR intervals is warranted for the potential progression of conduction disorder.

Sex-specific differences in infranodal conduction properties in patients undergoing transcatheter aortic valve replacement

Abstract Funding Acknowledgements Type of funding sources: None. Background Electrophysiological (EP) testing has been proposed for risk stratification of patients with left bundle branch block (LBBB) after transcatheter aortic valve replacement (TAVR). A uniform cut-off of 70ms for the His-Ventricular (HV) interval has been proposed to trigger pacemaker implantation. However, sex-specific periprocedural data regarding infranodal conduction properties are lacking. Purpose We aimed to compare the HV interval in men and women undergoing TAVR. Methods We analyzed consecutive prospectively included patients undergoing TAVR between June 2020 and June 2021 at a tertiary referral center. EP testing was performed in all patients pre- and post-valve deployment and in the case of LBBB additionally for a third time the following day. Results 127 patients were included (81 ± 7 years, 46% female). Median HV interval pre-valve deployment was 43 [37-50] ms vs 46 [42-53] ms in women and men, respectively (p=0.016). Nine patients underwent peri-procedural pacemaker (PM) implantation for third-degree AV-block. The median HV interval post-valve deployment was 54 [42-59] ms in women and 56 [51-61] ms in men (p=0.038). The median HV interval the day following TAVR in patients with LBBB was 45 [41-49] ms in women and 50 [48-62] ms in men (p=0.048). An HV interval ≥ 55 ms and ≥70 ms was present the day following TAVR in seven patients (24%, two females) and three patients (10%, one female). (Figure) Conclusion Women have shorter HV intervals pre-and post-valve-deployment as well as the day following TAVR compared to men. Further studies evaluating sex-specific cut-offs for the HV interval are warranted.

Pitfalls and limitations in the assessment of the HV interval in a transcatheter aortic valve replacement population. A prospective analysis

Abstract Funding Acknowledgements Type of funding sources: None. Introduction identification of patients with new-onset conduction disturbances at risk of AV-block remains a major unmet challenge in Transcatheter Aortic Valve Replacement (TAVR). His-Ventricular interval (HVI) measurement has been proposed in patients at risk. However, the HVI assessment is often overlooked, performed as a single assessment without active mapping, and even single-catheter assessment is sometimes performed. Purpose To systematically evaluate HVI measurements in a post TAVR population, in search of methodological pitfalls as related to outcomes Methods Consecutive patients who underwent HVI assessment post-TAVR between June 2014 and December 2021. HV interval was classified as normal (&amp;lt;55), intermediate (55-70) and abnormal (&amp;gt;70 ms). Incremental atrial pacing was performed whenever possible. All tracings were reviewed by two blinded operators. Pitfalls in the assessment of atrioventricular conduction were categorized into types 1 to 5, as reported in Table 1. In sinus rhythm, only proximal HVI were considered defined as the concomitant recording of a near-field atrial signal. Results 90 cases were analyzed; median age 81 years1 [76 – 86] years; 37 (41%) male. The median HV interval was 54 [50 – 65] ms. An abnormal HV interval, exceeding the 55 and 70ms cut-off values, was found in 41 (45.9%) and 13 (14.8%) patients, respectively. At least one pitfall was found in 15 patients (16%). Short-term AV block occurred in 3 patients in sinus rhythm in whom no incremental pacing was performed, and in 2 patients with AF despite normal or borderline HVI in both groups. Conclusions Pitfalls in the assessment of the HVI are often observed after TAVR. Identification of infra- and especially intra-His disorders requires careful mapping and must be an active process on behalf of the operator. Our results call into question the value of the HV assessment using a single catheter or in patients with atrial fibrillation, considering the value of incremental atrial pacing and the inherent limitations in AF to assess the most proximal His or intraHis block.

Optimization of the atrioventricular delay in conduction system pacing.

In patients receiving conduction system pacing (CSP), it is not well established how to program the sensed atrioventricular delay (sAVD), with respect to the type of capture obtained (selective, nonselective His-bundle [HB]capture or left bundle branch [LBB]capture). The aim of this study was to acutely assess the effectiveness of an electrophysiology (EP)-guided method for sAVD optimization by comparing it with the echocardiogram-guided optimization. Consecutive patients undergoing HB or LBB pacing were enrolled. The EP-guided sAVD was defined as the sAVD leading to a PR interval of 150 ms on surface electrocardiogram (ECG). In HB pacing patients, EP-guided sAVD was obtained subtracting the time from the onset of the P wave on ECG to the local atrial electrogram (EGM) recorded by the atrial lead (right atrial sensing latency, RASL) and the His-ventricular interval from 150 ms; in LBB pacing patients, subtracting RASL from 150 ms. Transmitral flow assessment by pulsed wave Doppler was used to find the echo-optimized sAVD by a modified iterative method. The discordance between the EP-guided and the echo-optimized sAVD was recorded. Seventy-one patients were enrolled: 12 with selective, 32 nonselective HB capture, and 27 LBB capture. Overall, the rate of concordance between the EP-guided and the echo-optimized sAVD was 71.8%, with no significant differences between the three groups. In CSP patients, an optimal sAVD can be programmed, in more than 70% of cases, considering only simple EGM intervals to obtain a physiological PR interval on surface ECG.

Ventricular pacing burden in patients with left bundle branch block after transcatheter aortic valve replacement therapy.

Electrophysiological testing has been proposed in the latest European Society of Cardiology (ESC) guidelines for cardiac pacing to identify left bundle branch block (LBBB) patients with infrahisian conduction delay (IHCD) after transcatheter aortic valve replacement (TAVR). While in general IHCD is defined by a His-ventricular (HV) interval of >55 ms, a cut-off of ≥70 ms to trigger pacemaker (PM) implantation has been proposed in the latest ESC guidelines. The ventricular pacing (VP) burden during follow-up in such patients is largely unknown. As such, we aimed to assess the VP burden during follow-up of patients receiving PM therapy for LBBB after TAVR based on an HV interval > 55 ms and ≥70 ms. All patients with new-onset or pre-existing LBBB after undergoing TAVR at a tertiary referral center underwent EP testing the day after TAVR. In patients with a prolonged HV interval (>55 ms), PM implantation was performed by a trained electrophysiologist in a standardized fashion. All devices were programmed to avoid unnecessary VP by specific algorithms (e.g., AAI-DDD). 701 patients underwent TAVR at the University Hospital of Basel. One hundred seventy-seven patients presented with new-onset or pre-existing LBBB the day following TAVR and underwent EP testing. An HV interval > 55 ms was found in 58 patients (33%) and an HV interval ≥ 70 ms in 21 patients (12%). 51 patients (mean age 84 ± 6.2 years, 45% women) agreed to receive a PM, out of which 20 (39%) patients had an HV Interval over 70 ms. Atrial fibrillation was present in 53% of the patients. A dual chamber PM was implanted in 39 (77%), and a single chamber PC in 12 (23%) patients, respectively. Median follow-up was 21 months. The median VP burden overall was 3%. The median VP burden was not significantly different between patients with an HV ≥ 70 ms (6.5 [0.8-52]) and those with an HV between 55 and 69 ms (2 [0-17], p = .23). 31% of patients demonstrated a VP burden < 1%, 27% 1%-5% and 41% > 5%. The median HV intervals in patients with VP burdens < 1%, 1%-5% and >5% were 66 (IQR 62-70) ms, 66 (IQR 63-74) ms and 68 (IQR 60-72) ms, respectively, p = .52. When only assessing patients with an HV interval 55-69 ms, 36% demonstrated a VP burden of <1%, 29% of 1%-5% and 35% of >5%. In patients with an HV Interval ≥ 70 ms, 25% demonstrated a VP burden < 1%, 25% of 1%-5% and 50% of >5% %, p = .64 (Figure). In patients with LBBB after TAVR and IHCD defined by an HV interval > 55 ms, VP burden is relevant in a non-negligible amount of patients during follow-up. Further studies are warranted to define the optimal cut-off value for the HV interval or to develop risk models incorporating HV measurements and other risk factors to trigger PM implantation in patients with LBBB after TAVR.

PO-03-110 NEW INSIGHTS FROM HIS VENTRICULAR INTERVALS IN PATIENTS UNDERGOING TAVR AND IMPLICATIONS FOR PERMANENT PACING

Trans catheter aortic valve replacement (TAVR) represents a revolutionary treatment for patients with severe symptomatic aortic stenosis who are at high surgical risk. The rate of periprocedural complications has decreased over time. However, the incidence of conduction disease requiring permanent pacemaker (PPM) implantation has failed to decrease. The decision for PPM for conduction disease post TAVR is usually made based on ECG. It’s not uncommon for patients with conduction disease without evidence for infra-nodal block to receive a PPM, and pacing has been shown to have deleterious effects. To assess the utility of His Ventricular Interval (HVI) studies in predicting the need for PPM implantation. We included patients who underwent assessment of the AV nodal (AH interval) and the HVI pre and/or post TAVR and were continuously monitored until discharge and after discharge for 2 weeks. Repeat EP study was performed in the presence of new conduction disease during in-hospital or as an outpatient. PPM was recommended in the presence of complete heart block (CHB), infra-Hisian block or with an HV > 70 ms (discretion of the physician). Patients receiving PPM before 30 days were documented. Total of 71 patients who had pre and post TAVR EP study had follow up for at least 30 days. The Cohort predominantly male with an average age of 77 years. Forty-six patients received Edwards and 25 Medtronic valve. A total of 6 patients received PPM, 5 out of 6 within the index hospitalization, and 1 patient 5 days post discharge. Four out of 6 patients with PPM had Edwards and 2 out of 6 had Medtronic valve. Four out of 6 patient who received PPM, developed CHB during TAVR and HVI post TAVR was not measured; in 1 patient HVI could not be measured reliably because of atrial fibrillation and the other had normal pre and post HVI. Ten of 71 patients had pre-existing Bundle Branch Block (BBB). Four had right bundle branch block (RBBB) of which 1 required PPM, and 6 had left bundle branch block (LBBB) of which 1 required PPM. Six of 71 patients had new BBB post TAVR. 5 developed LBBB of which 2 required PPM, and 1 developed RBBB of which none required PPM In patients undergoing TAVR, pre and post TAVR EP study is very useful in determining the need for PPM. In the absence of significant infra-Hisian disease, Pre-TAVR RBBB or LBBB and new RBBB or LBBB are not an indication for PPM.Tabled 1HVI in pre-existing (Old)and post TAVR (new) Bundle Branch block (PO-03-110)Pre-existing LBBBPre-existing RBBBPost-TAVR (new) LBBBPost-TAVR (new) RBBBPatientPre-HVI (ms)Post-HVI (ms)PPM (yes/no)PatientPre-HVI (ms)Post-HVI (ms)PPM (yes/no)PatientPre-HVI (ms)Post-HVI (ms)PPM (yes/no)PatientPre-HVI (ms)Post-HVI (ms)PPM (yes/no)16063no155CHByes15255no14043no25060no25053no24871no35558yes35055no35058yes44548no44045no46063no55560no54859yes66373no Open table in a new tab

Prediction of conduction disturbances in patients undergoing transcatheter aortic valve replacement

AimTranscatheter aortic valve replacement (TAVR) can cause intraventricular conduction disturbances (ICA), particularly left bundle branch block (BBB) and high-degree atrioventricular block (HAVB). The aim of this study was to investigate clinical, anatomical, procedural, and electrophysiological parameters predicting ICA after TAVR.MethodsPatients with severe aortic stenosis (n = 203) without pacing devices undergoing TAVR with a self-expanding (n = 103) or balloon-expanding (n = 100) valve were enrolled. Clinical and anatomical parameters, such as length of the membranous septum (MS) and implantation depth, were assessed. His-ventricular interval (HVi) before and after implantation was determined. 12-lead-electrocardiograms (ECG) before, during and after 3 and 30 days after TAVR were analyzed for detection of any ICA.ResultsAmong 203 consecutive patients (aortic valve area 0.78 ± 0.18 cm2, age 80 ± 6 years, 54% male, left ventricular ejection fraction 52 ± 10%), TAVR led to a significant prolongation of infranodal conduction in all patients from 49 ± 10 ms to 59 ± 16 ms (p = 0.01). The HVi prolongation was independent of valve types, occurrence of HAVB or ICA. Fifteen patients (7%) developed HAVB requiring permanent pacemaker (PPM) implantation and 63 patients (31%) developed ICA within 30 days. Pre-existing BBB (OR 11.64; 95% CI 2.87–47.20; p = 0.001), new-onset left BBB (OR 15.72; 95% CI 3.05–81.03; p = 0.001), and diabetes mellitus (OR 3.88; 95% CI 1.30–15.99; p = 0.02) independently predicted HAVB requiring PPM. Neither pre-existing right BBB, a prolonged postHVi, increases in PR duration, any of the TAVR implantation procedural and anatomic nor echocardiographic characteristics were predictive for later HAVB.ConclusionsNew-onset left BBB and diabetes mellitus independently predicted HAVB requiring PPM after TAVR and helped to identify patients at risk. Electrophysiologic study (EPS) of atrioventricular conduction was neither specific nor predictive of HAVB and can be skipped.Trial registration numberNCT04128384 (https://www.clinicaltrials.gov).Graphical abstract

A supraventricular tachycardia and the response to parahisian pacing: What is the mechanism?

A 21-year-old man underwent an electrophysiological study because of a documented supraventricular tachycardia (SVT). Baseline atrial-His and His-ventricular intervals were normal, and programmed ventricular extrastimulation (VES) demonstrated decremental ventriculoatrial (VA) conduction with a concentric atrial activation sequence (Figure 1A ). An SVT was induced during programmed atrial stimulation with an identical atrial activation sequence as that during VES, but attempts at right ventricular (RV) entrainment consistently terminated the tachycardia (Figure 1B). The His-RV catheter was removed, and a mapping catheter was inserted instead to perform parahisian pacing. The response is shown in Figure 2A . Based on these electrophysiological findings, what is the mechanism of this tachycardia and the most appropriate interpretation of the parahisian pacing response? Figure 2A: Response to parahisian pacing. B: Recovery from the mechanical bump of the bypass tract (BT). From the third beat, the BT potential emerges, with shortening of the ventriculoatrial (VA) interval. Arrows indicate BT potentials. HA = His-atrial; SA = stimulus-atrial; other abbreviations as in Figure 1. View Large Image Figure Viewer Download Hi-res image

Narrow QRS complex tachycardia with and without ventriculoatrial block: What is the mechanism?

A 39-year-old woman with no structural heart disease underwent an electrophysiology study (EPS) to assess recurrent supraventricular tachycardia (SVT). The electrocardiogram did not show any preexcitation. The baseline atrio-His and His-ventricular intervals were 108 and 43 ms. Ventricular pacing demonstrated concentric, decremental ventriculoatrial (VA) conduction, and the single jump changed the earliest atrial activation site (EAAS) from the His bundle region to the proximal coronary sinus (CS) region.

Para-Hisian pacing in a patient with a long RP tachycardia-What is the mechanism?

A 29-year-old man underwent a diagnostic electrophysiology study because of a recurrent symptomatic long RP supraventricular tachycardia (SVT). Twelve-lead electrocardiography and echocardiography were normal. Atrio-His (AH) and His-ventricular intervals measured 86 and 52 ms, respectively. The patient had retrograde ventriculoatrial (VA) activation that was midline and decremental. Para-Hisian pacing repeatedly induced his clinical SVT (Figure 1, top). The response to His-refractory ventricular premature depolarizations and entrainment from the ventricle are shown (Figure 1, middle and bottom).

A narrow QRS complex tachycardia: What is the mechanism?

A 45-year-old man complained of recurrent episodes of palpitations. Twelve-lead electrocardiograms revealed a long RP and regular narrow QRS complex tachycardia. The baseline atrio-His and His-ventricular intervals were 130 and 55 ms, respectively. A narrow QRS complex tachycardia with a cycle length of 407 ms was reproducibly induced by a single atrial or ventricular extrastimulus. During the tachycardia, the atrial activation sequence with earliest activation in the proximal coronary sinus was identical to the retrograde atrial activation sequence during right ventricular pacing.

Delayed termination and transformation of a supraventricular tachycardia—What is the mechanism?

A 75-year-old woman underwent a diagnostic electrophysiology study because of a recurrent, symptomatic, drug-refractory supraventricular tachycardia (SVT). The 12-lead electrocardiogram showed only mild PR prolongation. Atrio-His and His-ventricular intervals measured 140 and 45 ms, respectively. She demonstrated retrograde ventriculoatrial activation that was earliest at the anteroseptum and decremental. Single atrial extrastimulation and spontaneous atrial premature depolarizations (APDs) repeatedly induced a short RP SVT.

Tachycardia atrial cycle length equal to that during sinus rhythm: What is the mechanism?

A 64-year-old woman with frequent palpitations presented for atrial fibrillation radiofrequency catheter ablation (RFCA). She had not been administered any antiarrhythmic medication before admission to the hospital. After RFCA, a routine electrophysiological study was performed. Three catheters were positioned: a quadripolar catheter at the high right atrium (HRA), a quadripolar catheter at the His bundle region, and a decapolar catheter in the coronary sinus (CS) (CS 7-8 at the CS ostium). The baseline sinus cycle length was 628 milliseconds (ms), the atrial-His (AH) interval was 87 ms, and the His-ventricular (HV) interval was 52 ms. Antegrade atrioventricular (AV) nodal conduction showed decremental and dual pathways during atrial extrastimulus testing, but no tachycardia was induced. Retrograde ventriculoatrial (VA) conduction showed VA disassociation. Figure 1 shows a narrow QRS complex tachycardia with AV 1:1 conduction that was induced by two spontaneous ventricular extrasystoles. The corresponding intracardiac recording showed that the atrial cycle length oscillated between 627?30 ms (recorded by the HRA catheter) and 626?33 ms (recorded by the CS 7-8 catheter), which was approximately the same as that during sinus rhythm (SR) (Figure 2). How was the tachycardia induced and what is the mechanism of the tachycardia? This article is protected by copyright. All rights reserved.

Arrhythmias Utilizing ConcealedNodoventricular or His-Ventricular Pathways: AStructuredApproach to Diagnosis and Management.

This study sought to describe the electrophysiologic characteristics, diagnostic maneuvers, and treatment of a series of arrhythmias using concealed nodoventricular (cNV) or His-ventricular (cHV) pathways. Confirming the presence and participation of cNV or cHV pathways in tachyarrhythmias is challenging. We present 4 cases of tachycardias with a participatory cNV or cHV pathway. The first patient had a narrow complex tachycardia with ventriculoatrial dissociation. Findings of an entrainment pacing from the right ventricle and fused premature ventricular complexes suggested cNV pathway involvement. The second patient had nonsustained narrow complex tachycardia with more ventricular than atrial complexes. The tachycardia exhibited an anterograde His-right bundle (RB) activation sequence and normal His-ventricular (HV) interval and consistently terminated with fused ventricular extra stimuli, suggesting cNV pathway participation. The third patient had a wide complex tachycardia (WCT) with either a right or left bundle branch block pattern. The WCT showed an eccentric His-RB activation sequence and short HV interval and terminated with fused premature ventricular complexes, suggesting a cHV (or concealed fasciculoventricular) pathway involvement. The fourth patient had a WCT with alternating bundle branch block morphologies with a short HV interval. Entrainment from the basal right ventricle demonstrated fusion and a short postpacing interval, suggesting cHV(or fasciculoventricular) pathway involvement. Ablation at the proximal RB rendered the tachycardia noninducible. A structured approach can help diagnose and treat cNV or cHV pathways. We emphasize the importance of evaluating both the His-RB activation pattern and HV interval during sinus rhythm and tachycardia as well as the ventricular pacing study.

Conduction delays after transcatheter aortic valve implantation with balloon-expandable prosthesis and high implantation technique

Performing transcatheter aortic valve implantation with high implantation technique, i.e. with an aorto-ventricular ratio > 60/40, reduces the need of permanent pacemaker implantation. Valve calcification and prosthesis oversizing are predictors of permanent pacemaker implantation, but there are no available data on their role when transcatheter aortic valve implantation is performed with an aorto-ventricular ratio > 60/40. The aim of this study was to evaluate the effect of leaflets/annulus calcification and prosthesis oversizing on the incidence of permanent pacemaker implantation after transcatheter aortic valve implantation with a high implantation technique. Transcatheter aortic valve implantation was performed in 48 patients implanting a balloon-expandable transcatheter heart valve with an aorto-ventricular ratio > 60/40. Calcium burden was assessed by preprocedural multidetector computed tomography. An invasive electrophysiological study was performed before and after transcatheter aortic valve implantation. Five patients (10.4%) needed permanent pacemaker implantation. At univariate analysis, baseline right bundle branch block and postprocedural PR, QRS and His-ventricular interval elongation significantly predicted permanent pacemaker implantation (p < 0.05). Receiver-operating characteristic curve analysis showed a correlation between transcatheter heart valve oversizing and permanent pacemaker implantation need, with the best cut-off being 17% (AUC = 0.72, p = 0.033). Linear regression analysis demonstrated that QRS complex elongation was related to total, left and non-coronary leaflet calcification (p < 0.05). This study demonstrates that, when transcatheter aortic valve implantation is performed using a balloon-expandable transcatheter heart valve deployed with an aorto-ventricular ratio > 60/40, the presence of leaflets/annulus calcification or the need to oversize the prosthesis correlate with the occurrence of pathological cardiac conduction delays.

Non-invasive predictors for infranodal conduction delay in patients with left bundle branch block after TAVR

AimsLeft bundle branch block (LBBB) is the most common conduction disorder after transcatheter aortic valve replacement (TAVR) with an increased risk of atrioventricular (AV) block. The aim of the current study was to identify non-invasive predictors for infranodal conduction delay in patients with LBBB.MethodsWe analyzed consecutive patients undergoing TAVR with pre-existing or new-onset LBBB between August 2014 and August 2020. His ventricular (HV) interval measurement was performed on day 1 after TAVR. Baseline, procedural, as well as surface and intracardiac electrocardiographic parameters were included. Infranodal conduction delay was defined as HV interval > 55 ms.ResultsOf 825 patients screened after TAVR, 151 patients (82 ± 6 years, 39% male) with LBBB were included. Among these, infranodal conduction delay was observed in 25%. ΔPR (difference in PR interval after and before TAVR), PR and QRS duration after TAVR were significantly longer in the group with HV prolongation. In a multivariate analysis in patients with sinus rhythm (n = 123), ΔPR (OR per 10 ms increase: 1.52; 95%CI: 1.19–2.01; p = 0.002) was the only independent factor associated with infranodal conduction delay. A change in PR interval by 20 ms yielded a specificity of 83% and a sensitivity of 46%, with a negative predictive value of 84% and a positive predictive value of 45% to predict HV prolongation.ConclusionsSimple analysis of surface ECG and a calculated ΔPR < 20 ms can be used as predictor for the absence of infranodal conduction delay in post-TAVR patients with LBBB.Graphical abstract