Inadequacy of fluoroscopy and electrocardiogram in predicting septal position in RVOT pacing - Validation with cardiac computed tomography

Mid-term clinical outcomes of left bundle branch area pacing compared to accurate right ventricular septal pacing

BACKGROUND

Although left bundle branch area pacing (LBBAP) reportedly results in fewer adverse outcomes after implantation than conventional stylet-guided right ventricular septal pacing (RVSP), previous studies have not compared LBBAP with accurate RVSP using a delivery catheter. The aim of this study was to compare clinical outcomes between LBBAP and accurate RVSP among patients with atrioventricular block (AVB).

METHODS

This single-center observational study enrolled 160 patients requiring RV pacing due to symptomatic AVB between September 2018 and December 2021. Primary composite outcomes included all-cause death, hospitalization due to heart failure (HF), and upgrading to biventricular pacing. Secondary composite outcomes included any procedural and postprocedural complications.

RESULTS

Overall, 160 patients were analyzed (LBBAP, n = 81; RVSP, n = 79). No significant differences in baseline characteristics were observed between the two groups. The RV pacing burden at 1 year after implantation was 90.8% ± 20.4% and 86.2% ± 22.6%, respectively (p = 0.21). During a mean follow-up of 840 ± 369 days, the incidence of the primary outcome was significantly lower with LBBAP (4.9%) compared to RVSP (22.8%) (Log-rank p = 0.02). There was no significant difference in the incidence of the secondary outcome between the two groups (3.7% vs. 5.1%, p = 0.65). In the multivariate analysis, baseline QRS duration, RV pacing burden, and LBBAP were independently associated with the primary outcome (baseline QRS duration: hazard ratio [HR], 1.01; 95% confidence interval [CI], 1.00-1.02; p < 0.001; RV pacing burden: HR, 1.01; 95% CI, 1.00-1.02; p < 0.001; LBBAP: HR, 0.45; 95% CI, 0.31-0.64; p < 0.001).

CONCLUSION

In patients requiring frequent RV pacing, LBBAP was associated with reduced adverse clinical outcome compared to accurate RVSP using a delivery catheter.

Exploratory use of intraprocedural transesophageal echocardiography to guide implantation of the leadless pacemaker

Background

Fluoroscopy is the standard tool for transvenous implantation of traditional and leadless pacemakers (LPs). LPs are used to avoid complications of conventional pacemakers, but there still is a 6.5% risk of major complications. Mid-right ventricular (RV) septal device implantation is suggested to decrease the risk, but helpful cardiac landmarks cannot be visualized under fluoroscopy. Transesophageal echocardiography (TEE) is an alternative intraprocedural imaging method.

Objective

The purpose of this study was to explore the spatial relationship of the LP to cardiac landmarks via TEE and their correlations with electrocardiographic (ECG) parameters, and to outline an intraprocedural method to confirm mid-RV nonapical lead positioning.

Methods

Fifty-six patients undergoing implantation of LP with TEE guidance were enrolled in the study. Device position was evaluated by fluoroscopy, ECG, and TEE. Distances between the device and cardiac landmarks were measured by TEE and analyzed with ECG parameters with and without RV pacing.

Results

Mid-RV septal positioning was achieved in all patients. TEE transgastric view (0°-40°/90°-130°) was the optimal view for visualizing device position. Mean tricuspid valve-LP distance was 4.9 ± 0.9 cm, mean pulmonary valve-LP distance was 4.2 ± 1 cm, and calculated RV apex-LP distance was 2.9 ± 1 cm. Mean LP paced QRS width was 160.8 ± 28 ms and increased from 117.2 ± 34 ms at baseline. LP RV pacing resulted in left bundle branch block pattern on ECG and 37.8% QRS widening by 43.5 ± 29 ms.

Conclusion

TEE may guide LP implantation in the nonapical mid-RV position. Further studies are required to establish whether this technique reduces implant complications compared with conventional fluoroscopy.

Risk factors of pacing-induced cardiomyopathy-Insights from lead position

There was no significant difference in the incidence of pacing-induced cardiomyopathy between right ventricular apex pacing group and OpenCurlyQuote;true CloseCurlyQuote; mid-right ventricular septum pacing group. The preoperative left ventricular end-systolic diameter and paced QRS duration were independent predictors of PICM.

Influence of the right ventricular septum/free-wall boundary (hinge) on differentiation of the ventricular lead implantation site

BACKGROUND

The prognosis associated with right ventricular (RV) free-wall pacing is worse than that of septal pacing. Identification of the pacing site using a 12‑lead electrocardiogram (ECG) is controversial and may be influenced by ECG changes within the same septal or free-wall area. The relationship between the diagnostic capabilities of ECG and pacing sites has previously been qualitatively evaluated. However, in this study, this relationship was analyzed quantitatively, and accurate evaluation of the pacing site was determined using computed tomography (CT).

METHODS

Of 779 consecutive outpatients, 65 who underwent pacemaker implantation and thoracic CT were prospectively included and classified into the following groups according to the lead tip position: free-wall, septal, or septum/free-wall boundary (hinge) group. The hinge was used as an anatomical marker, and the distance from the hinge to the lead tip was measured. Under RV pacing, a 12‑lead ECG was obtained. ECG findings were evaluated using three criteria (including lead I, II, and aV_L and precordial leads V₅ and V₆) previously reported to be useful in differentiating pacing sites.

RESULTS

The lead tips were anchored at the free-wall in 10 patients, the septal wall in 19 patients, and the hinge in 32 patients. Paced QRS duration correlated with the distance from the hinge to the lead tip for the free-wall and septum (r = 0.47 and - 0.68, respectively). Estimation of the lead tip implantation site using the ECG algorithm was useful; however, the algorithm's accuracy decreased around the hinge.

CONCLUSIONS

ECG is useful in differentiating pacing sites but is less accurate around the hinge, which may be the reason that the identification of the RV pacing site using ECG remains controversial.

Clinical outcomes in patients with atrioventricular block undergoing pacemaker: 3-year follow-up

PURPOSE

Left ventricular function can be affected by chronic ventricular pacing. Different right ventricular (RV) pacing sites have shown heterogeneous clinical outcomes. We investigated these factors in patients receiving permanent pacemaker (PPM) implants.

METHODS

This multicenter, retrospective analysis of PPM use in South Korea, included all patients undergoing de novo transvenous PPM implantation for atrioventricular block from 2017 to 2019. Clinical characteristics, 12-lead electrocardiograms, echocardiography, and laboratory parameters were evaluated. Composite outcomes are defined by two coprimary endpoints: (1) hospitalizations and (2) cardiac death by heart failure during follow-up period.

RESULTS

There were 167 patients (66 males; overall mean age 75.3 ± 11.9 years), divided into two groups according to the pacing site: 83 apical RV (RVA) vs. 84 septal RV (RVS). There were no significant baseline differences. Paced QRS duration (pQRSd) increased with RVA (168.5 ± 20.1 vs. 159.1 ± 16.3 ms; p < 0.001). Over a median 31-month follow-up, there were 15 hospitalizations and 2 deaths. More patients with RVA were hospitalized or died (16% vs. 5%, respectively; p = 0.049). In Cox proportional regression analysis, pQRSd (hazard ratio [HR] 1.046; 95% confidence interval [CI] 1.004-1.091; p = 0.033), and diastolic dysfunction (HR 7.343; 95% CI 2.035-26.494; p = 0.002) were independent predictors of composite clinical outcomes.

CONCLUSIONS

RVS placement shortened the pQRSd and improved clinical outcomes. However, the determinants of these were pQRSd and diastolic dysfunction. Therefore, clinicians should try to shorten the pQRSd when implanting a PPM, and patients with diastolic dysfunction should be monitored intensively.

Computed tomography validated right ventricular mid-septal lead implantation using right ventricular angiography

BACKGROUND

Right ventricular (RV) mid-septal pacing has been proposed as an alternative to RV apical pacing. Fluoroscopic and electrocardiogram criteria are unreliable for predicting the RV mid-septal lead position. This study aimed to define the optimal RV mid-septal pacing site using RV angiography.

METHODS

We randomized patients undergoing pacemaker implantation (PPM) to the RV angiography-guided group (Group A) or conventional fluoroscopy-guided group (Group F). In Group A, we performed an angiogram in right anterior oblique (RAO 30°), left anterior oblique (LAO 40°), and left lateral (LL) views. We made a 5-segment grid in RAO 30° and LL views and a 3-segment grid in LAO 40° on the angiographic silhouette to define the lead position. Computed tomography (CT) was used to validate the lead tip position in both groups.

RESULTS

We enrolled 53 patients (Group A: 26, Group F: 27) with a mean age of 55.9 ± 12.2 years. CT images validated the lead position in the mid-septum (Group A, 23 [88.5%]; Group F, 11 [40.7%], P = .0003) and anteroseptal (Group A, 3 [11.5%]; Group F, 5 [18.5%], P = .24). In Group F, the lead was in the anterior wall in 9 patients (33.3%) and the right ventricular outflow tract in 2 (7.4%) patients and none in these two positions in Group A. The lead tip in segment one on the angiographic 5-segment grid in RAO 30° and LL views indicated a mid-septal lead position on CT.

CONCLUSIONS

RV angiography is safe and may be used to confirm the mid-septal lead position during PPM.

EHRA expert consensus statement and practical guide on optimal implantation technique for conventional pacemakers and implantable cardioverter-defibrillators: endorsed by the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS), and the Latin-American Heart Rhythm Society (LAHRS)

With the global increase in device implantations, there is a growing need to train physicians to implant pacemakers and implantable cardioverter-defibrillators. Although there are international recommendations for device indications and programming, there is no consensus to date regarding implantation technique. This document is founded on a systematic literature search and review, and on consensus from an international task force. It aims to fill the gap by setting standards for device implantation.

Individualized left anterior oblique projection based on pigtail catheter visualization facilitates leadless pacemaker implantation

BACKGROUND

Pacemaker positioning on the right ventricular (RV) septum during implantation is conventionally conducted utilizing two fixed fluoroscopy angles, a 45° left anterior oblique (LAO) and 35° right anterior oblique projection. However, placement location can be suboptimal, especially for leadless pacemakers (LPMs).

OBJECTIVE

To evaluate the safety and ease of LPM implantation using individualized LAO projection.

METHODS

Consecutive patients undergoing LPM implantation were prospectively included. The angle of the RV septum was recorded for each patient by studying the angle at which an RV pigtail catheter (RV-PC) could be seen edge on. This was then used as the preferred LAO projection angle for that patient. We evaluated the success rate and safety of this method. We also compared the RV septum angle as measured by this method versus that measured by chest CT.

RESULTS

Of the 31 patients (mean age 80.6 ± 7.0 years, 15 females), LPM implantation was successful in 30. The pacemaker was implanted on the RV septum in 29 and on the free wall in one. LPM implantation was abandoned for anatomical reasons in one. Complications were limited to a groin arteriovenous fistula and one deep vein thrombosis. The angle of RV septum as measured by pigtail catheter and chest CT was not significantly different (CT: 54.8 ± 6.0°, RV pigtail catheter: 52.9 ± 6.1°, P = .07).

CONCLUSIONS

Using an RV-PC to determine the preferred angle of LAO projection facilitates differentiation between the RV septum and free wall, which in turn facilitates optimal LPM placement.

Comparison of delivery catheter-based and stylet-based right ventricular lead placement at the right ventricular septum under fluoroscopic guidance judged by cardiac CT (Mt. FUJI): a study protocol for the Mt. FUJI randomised controlled trial

INTRODUCTION

Pacing-induced cardiomyopathy occasionally occurs in patients undergoing pacemaker implantation. Although compared with right ventricular (RV) apical pacing, RV septal pacing can attenuate left ventricular dyssynchrony; the success rate of lead placement on the RV septum using the stylet system is low. Additionally, no randomised controlled trial has addressed the issue regarding the accuracy of RV lead placement on the RV septum using the stylet and delivery catheter systems. This study hypothesises that a newly available delivery catheter system can improve the accuracy of RV lead placement on the RV septum.

METHODS AND ANALYSIS

In a multicentre, prospective, randomised, single-blind, controlled trial, 70 patients with pacemaker indication owing to atrioventricular block will be randomised to either the delivery catheter or stylet group before the pacemaker implantation procedure. The position of the RV lead tip will be assessed using ECG-gated cardiac CT in all patients within 4 weeks after pacemaker implantation. Lead tip positions are classified into three groups: (1) RV septum, (2) anterior/posterior edge of the RV septal wall and (3) RV free wall. The primary endpoint will be the success rate of RV lead tip placement on the RV septum, which will be evaluated using cardiac CT.

ETHICS AND DISSEMINATION

This study will be conducted according to the stipulations of the Helsinki Declaration and the institutional review board of Hamamatsu University School of Medicine. The results of the study will be disseminated at several research conferences and will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

jRCTs042200014; Pre-results.

Localization of right ventricular non-apical lead position: comparison of three-dimensional echocardiography, computed tomography, and fluoroscopic imaging

OBJECTIVE

Right ventricular (RV) septal pacing is considered a better pacing procedure compared with traditional apical pacing. This study aimed to investigate agreement among computed tomography (CT), three-dimensional echocardiography (3D-echo), and fluoroscopy for evaluating the tip of the RV pacing lead in the non-apical position in patients with permanent pacemaker implantation.

METHODS

Fifty-four patients were prospectively enrolled. Data on patients' characteristics and imaging findings were analyzed. The agreement rate in distinguishing the RV septal lead position among the three imaging modalities was determined.

RESULTS

Thirty-three (61%) patients were men and the median age was 76 years. Overall, the agreement rate among the three imaging modalities was 87% (47/54; Kappa ratio: 0.734). The agreement of 3D-echo compared with thoracic CT (Kappa ratio: 0.893) was better than that for thoracic CT and fluoroscopy (Kappa ratio: 0.658). Agreement between fluoroscopy and 3D-echo was lowest (Kappa ratio: 0.632).

CONCLUSIONS

Agreement in evaluating the position of the septal lead between thoracic CT and 3D-echo is better than that between other imaging modalities. Our findings indicate that 3D-echo imaging might be the best imaging tool for defining the tip of the RV non-apical lead position and be useful for guiding positioning of the RV lead.

The usefulness of a delivery catheter system for right ventricular "true" septal pacing

Right ventricular (RV) septum is an alternate site for the placement of RV lead tip instead of RV apex. Recent studies have demonstrated that less than half of the RV leads targeted for septal implantation are placed on the RV septum using a conventional stylet system; new guiding catheter systems have become available for RV lead placement. This study aimed to investigate the usefulness of the delivery catheter system in lead placement on the RV septum when compared with the stylet system. We retrospectively evaluated 198 patients who underwent fluoroscopically guided pacemaker implantation with RV leads targeted to be placed in the RV septum and in whom computed tomography was incidentally and subsequently performed. A delivery catheter was used in 16 patients, and a stylet in 182 patients. The primary endpoint of this study was the success rate of RV lead placement on the RV septum. The proportion of RV lead placement on the RV septum was higher in the delivery catheter group than in the stylet group (100% vs. 44%; p < 0.001). In the stylet group, the lead tips were placed at the hinge in 92 cases (51%) and on the free wall in 9 cases (5%). Paced QRS duration was narrower in the delivery catheter group than in the stylet group (128 ± 16 vs. 150 ± 21 ms, p < 0.01). The delivery catheter system designated for pacing leads may aid in selecting RV septal sites and achieve good physiologic ventricular activation.

Prevention of serious air embolism during cryoballoon ablation; risk assessment of air intrusion into the sheath by catheter selection and change in intrathoracic pressure: An ex vivo study

INTRODUCTION

One cause of cerebral infarction during cryoballoon ablation is the entry of air into a sheath due to the use of inappropriate catheters. It is known that the left atrial pressure of patients with obstructive sleep apnea syndrome can be negative. However, the effects of catheter selection and negative pressure changes in the sheath on air intrusion are not yet well understood. The aim of this study was to evaluate how catheter selection and negative pressure changes affect air intrusion and to perform countermeasures for air intrusion.

METHODS AND RESULTS

This experiment used siphon principle to create negative pressure in the sheath. Noncryoablation catheters (not designed exclusively for cryoballoon ablation) and cryoballoon catheters were investigated. Catheters were inserted into the sheath and then removed. Thereafter, the amount of air in the sheath was measured. For catheters producing significantly larger amounts of air intrusion, the catheters were inserted via a long sheath in the sheath (sheath-in-sheath technique) and the same procedures were repeated. We found that the amount of air intrusion through most of the noncryoablation catheters was significantly larger than that through cryoablation catheters. An increase in the magnitude of negative pressure in the sheath resulted in a proportional increase in air intrusion, but the sheath-in-sheath technique significantly reduced air intrusion.

CONCLUSION

The amount of air intrusion increased when using catheters with complicated tip shapes and thin outer diameters and when the magnitude of negative pressure in the sheath increased. The sheath-in-sheath technique may be an effective countermeasure.

Individualized Left Anterior Oblique Projection: A Highly Reliable Patient-Tailored Fluoroscopy Criterion for Right Ventricular Lead Positioning

BACKGROUND

Classical fluoroscopic criteria for the documentation of septal right ventricular (RV) lead positioning have poor accuracy. We sought to evaluate the individualized left anterior oblique (LAO) projection as a novel fluoroscopy criterion.

METHODS

Consecutive patients undergoing pacemaker or defibrillator implantation were prospectively included. RV lead positioning was assessed by fluoroscopy using posteroanterior, right anterior oblique 30° to rule out coronary sinus positioning, and LAO 40° in the classical group or individualized LAO in the individualized group. Individualized LAO was defined by the degree of LAO that allowed the perfect superposition of the RV apex (using the tip of the RV lead temporarily placed at the apex) and of the superior vena cava-inferior vena cava axis (materialized by a guidewire), hence providing a true profile view of the interventricular septum. Accuracy of fluoroscopy for RV lead positioning was then assessed by comparison with true RV lead positioning using transthoracic echocardiography.

RESULTS

We included 100 patients, 50 in each study group. Agreement between RV lead septal/free wall positioning in transthoracic echocardiography and fluoroscopy was excellent in the individualized group (k=0.91), whereas it was poor in the classical group (k=0.35). Septal/free wall RV lead positioning was correctly identified in 48/50 (96%) patients in the individualized group versus 38/50 (76%) in the classical group (P=0.004). For septal lead positioning, fluoroscopy had 100% Se and 89.5% Sp in the individualized group versus 91.4% Se and 40% Sp in the classical group. Complications and procedural data were comparable in both groups.

CONCLUSION

Individualized LAO is a quick and highly reliable patient-tailored fluoroscopy projection for RV lead positioning.

Paced QRS morphology predicts incident left ventricular systolic dysfunction and atrial fibrillation

BACKGROUND

The prognostic significance of paced QRS complex morphology on surface ECG remains unclear. This study aimed to assess long-term outcomes associated with variations in the paced QRS complex.

METHODS

Adult patients who underwent dual-chamber pacemaker implantation with 20% or more ventricular pacing and a 12-lead ECG showing a paced complex were included. The paced QRS was analyzed in leads I and aVL. Long-term clinical and echocardiographic outcomes were compared at 5 years.

RESULTS

The study included 844 patients (43.1% female; age 75.0 ± 12.1). Patients with a longer paced QRS (pQRS) duration in lead I had a lower rate of atrial fibrillation (HR 0.80; p = 0.03) and higher rate of systolic dysfunction (HR 1.17; p < 0.001). Total pacing complex (TPC) duration was linked to higher rates of ICD implantation (HR 1.18; p = 0.04) and systolic dysfunction (HR 1.22, p < 0.001). Longer paced intrinsicoid deflection (pID) was associated with less atrial fibrillation (HR 0.75; p = 0.01), more systolic dysfunction (HR 1.17; p < 0.001), ICD implantation (HR 1.23; p = 0.04), and CRT upgrade (HR 1.23; p = 0.03). Exceeding thresholds for TPC, pQRS, and pID of 170, 146, and 112 ms in lead I, respectively, was associated with a substantial increase in systolic dysfunction over 5 years (p < 0.001).

CONCLUSIONS

Longer durations of all tested parameters in lead I were associated with increased rates of left ventricular systolic dysfunction. ICD implantation and CRT upgrade were also linked to increased TPC and pID durations. Paradoxically, patients with longer pID and pQRS had less incident atrial fibrillation.

Prognostic impact of lead tip position confirmed via computed tomography in patients with right ventricular septal pacing

BACKGROUND

Although fluoroscopy-guided right ventricular (RV) lead placement in the ventricular septum is a widely performed procedure, variation in true RV lead tip position confirmed via computed tomography (CT) and its prognostic implications in patients with atrioventricular block (AVB) are not well understood.

OBJECTIVE

The purpose of this study was to evaluate the prognostic impact of CT-confirmed RV lead tip position.

METHODS

We retrospectively enrolled 228 consecutive patients (age 77 ± 10 years; 125 men) with AVB who underwent fluoroscopy-guided RV septal lead implantation and thoracic CT after pacemaker implantation. Patients were classified into septal and free-wall groups according to RV lead tip position. The primary endpoint was the composite outcome of cardiac death and heart failure hospitalization.

RESULTS

The RV lead tip was located at the free wall in 18 patients (8%). The primary endpoint occurred in 37 patients (16%) over median follow-up of 41 months. Electrocardiographic analysis found that R amplitude >0.53 mV in lead I was significantly predictive of free-wall pacing, with sensitivity of 70% and specificity of 77%. Multivariate Cox regression analysis demonstrated that the lead tip in the free wall (hazard ratio 2.93; 95% confidence interval 1.21-7.11; P = .018) was an independent predictor of the primary endpoint.

CONCLUSION

Fluoroscopy-guided RV lead placement carries potential risk of unexpected RV free-wall pacing and may increase the risk of cardiac death and heart failure-related hospitalization in patients undergoing RV septal pacing due to AVB and receiving thoracic CT for medical reasons.

Ventricular septal pacing: Optimum method to position the lead

Adverse hemodynamics of right ventricular (RV) pacing is known for years. Several studies have revealed that adverse outcomes of RV apical pacing are directly linked to cumulative percentage of ventricular pacing. Algorithms to minimize ventricular pacing are only effective if there is good atrioventricular (AV) conduction. A need for an alternate site for ventricular pacing is evident in patients with high presumed ventricular pacing burden. Most studied alternate site for ventricular pacing is ventricular septum (outflow tract septum and mid-septum). Conventionally septal position of the ventricular pacing lead is confirmed by fluoroscopic appearance of the lead and characteristics electrocardiographic (ECG) features. However, several recent studies have challenged these fluoroscopic and ECG features as to be inadequate. So, there is need for a systematic approach for septal positioning of the ventricular lead.

Classical fluoroscopy criteria poorly predict right ventricular lead septal positioning by comparison with echocardiography

BACKGROUND

Fluoroscopic criteria have been described for the documentation of septal right ventricular (RV) lead positioning, but their accuracy remains questioned.

METHODS AND RESULTS

Consecutive patients undergoing pacemaker or defibrillator implantation were prospectively included. RV lead was positioned using postero-anterior and left anterior oblique 40° incidences, and right anterior oblique 30° to rule out coronary sinus positioning when suspected. RV lead positioning using fluoroscopy was compared to true RV lead positioning as assessed by transthoracic echocardiography (TTE). Precise anatomical localizations were determined with both modalities; then, RV lead positioning was ultimately dichotomized into two simple clinically relevant categories: RV septal or RV free wall. Accuracy of fluoroscopy for RV lead positioning was then assessed by comparison with TTE. We included 100 patients. On TTE, 66/100 had a septal RV lead and 34/100 had a free wall RV lead. Fluoroscopy had moderate agreement with TTE for precise anatomical localization of RV lead (k = 0.53), and poor agreement for septal/free wall localization (k = 0.36). For predicting septal RV lead positioning, classical fluoroscopy criteria had a high sensitivity (95.5%; 63/66 patients having a septal RV lead on TTE were correctly identified by fluoroscopy) but a very low specificity (35.3%; only 12/34 patients having a free wall RV lead on TTE were correctly identified by fluoroscopy).

CONCLUSION

Classical fluoroscopy criteria have a poor accuracy for identifying RV free wall leads, which are most of the time misclassified as septal. This raises important concerns about the efficacy and safety of RV lead positioning using classical fluoroscopy criteria.

Beware of the coronary arteries with implantable cardiac electronic devices

The transvenous implantation of cardiac devices may sometimes cause serious complications involving the coronary arteries. The left anterior descending artery may be injured during nonapical right ventricular implantation while a right atrial lead may injure the right or circumflex coronary artery. Injury of a left internal mammary graft to a coronary artery may cause myocardial infarction.