Lead V1 Research Articles

Sinus rate and QRS duration on lead V1 predict major events in Brugada syndrome

Arrhythmic risk stratification remains a major challenge in asymptomatic Brugada patients. Many studies have evaluated risk stratification performance based on a single or a few ECG-derived parameters measured manually. We aimed to assess the predictive value of multi ECG parameters measured automatically in patients with Brugada syndrome. We performed a prospective, multicenter cohort study including Brugada patients with at least one available type 1 ECG (either spontaneously or drug-induced) between January 2005 and November 2021. Paper ECG were first digitized and then automatically analyzed using the Glasgow and Bravo algorithms. Clinical data and Brugada related events at diagnosis and during follow-up were collected. Sudden cardiac death, aborted cardiac arrest and appropriate ICD therapy in the VF zone were considered as major events. The predictive value of clinical and ECG parameters for symptomatic status was assessed using uni- and multivariate Cox models. ECGs from 301 Brugada patients (77% male, mean age at diagnosis 43 years, follow-up 7 ± 5.6 years) were analyzed. Brugada-related symptoms (cardiac syncope or major event) occurred in 23% of patients before diagnosis and 11% during follow-up (incidence: 1.57%/year). After multivariate Cox analysis, only 2 baseline ECG (without Ajmaline) parameters were significantly associated with major events: RR interval (HR = 1.01 [95%CI 1–1.01], P = 0.002) and QRS duration in lead V1 (HR = 1.04 [95%CI 1–1.07], P = 0.038). QRS prolongation in lead V1 > 113 ms (AUROC 0.69 [95%CI 0.58–0.8], Fig. 1) was associated with a 3-fold increased risk of major event [Fig. 2] (HR = 3.49 (95% CI [1.72–7.09], P = 0.001). Many previously described ECG parameter were not associated with major event in Brugada patients after multi-parameter evaluation. Sinus rate and QRS duration on lead V1 were independent risk factor. These results need to be validated on an external cohort. The predictive value of ECG parameters in Brugada syndrome should be assessed using automated multiparametric quantification.

PO-05-156 DIFFERENTIATING RIGHT VENTRICULAR FROM LEFT VENTRICULAR OUTFLOW TRACT PREMATURE VENTRICULAR COMPLEXES WITH A NOVEL QS PATTERN IN LEAD V1.

Many ECG algorithms for localization of premature ventricular complex (PVC) origin are complex requiring the use of multiple features to achieve high sensitivity and specificity. Simpler diagnostic ECG features may be easier to use and more widely adopted. We hypothesized that a single ECG feature of QS pattern in lead V1 will be specific for PVC localization to the right ventricular outflow tract. All patients at St. Vincent Hospital, Indianapolis from January 01, 2018 to December 31, 2019 that underwent a catheter ablation for outflow tract PVCs were retrospectively evaluated. PVC location was confirmed based on the successful ablation site. For the purpose of this study a QS pattern in V1 was defined if there was no initial R wave and no notching on the downstroke of the Q wave. A total of 63 patients underwent ablation of 70 different PVCs. The median age was 55.6 (interquartile range 47.9, 63.5) years old and included 38 (60.3%) females. Of the 70 PVCs, 47 (67.1%) were right ventricular and 23 (32.9%) were left ventricular outflow tract. A QS pattern was present in 23 (32.8%) of PVCs. Of these 23 PVCs with QS pattern, 22 were right ventricular outflow tract and only 1 localized to the left ventricular outflow tract. The QS pattern in lead V1 had a specificity of 95.6% and sensitivity of 46.8% in identifying a right ventricular outflow tract PVC origin. The novel QS pattern in lead V1 is simple to use and has high specificity for localizing PVC origin to the right ventricular outflow tract.

PO-02-013 EFFICACY OF LEFT BUNDLE BRANCH PACING IN PATIENTS WITH DIFFERENT LEFT BUNDLE BRANCH BLOCK MORPHOLOGIES

Left bundle branch pacing (LBBP) is a novel technique to deliver cardiac resynchronization therapy (CRT) by correcting intrinsic LBBB to achieve electrical and mechanical resynchrony. Whether the efficacy of LBBP is different across different LBBB morphologies has not been reported. To explore the efficacy of LBBP in patients with different LBBB morphologies. Consecutive patients who received LBBP due to either heart failure (HF) with LBBB or atrioventricular block accompanied with a LBBB pattern escape rhythm were recruited. The changes of QRS duration (ΔQRSd) and left ventricular activation time (ΔLVAT) were compared before and after LBBP. Relationships of ΔQRSd and ΔLVAT with cardiac function in HF patients were also explored. HF patients were followed up for at least 6 months. Electrical resynchrony and cardiac function were compared based on 4 major LBBB morphological criteria. Comparison 1: LBBB meeting Strauss criteria vs not; Comparison 2: presence of q wave in lead I and aVL vs not; Comparison 3: presence of QS vs rS morphology of QRS in lead V1; and Comparison 4: presence of S wave in lead V6 vs not. A total of 82 patients were enrolled from January 2018 to August 2022. In Comparison 1, 59 patients had LBBB meeting Strauss criteria vs 23 not meeting criteria. Patients with LBBB meeting Strauss criteria had greater reduction in QRSd (56.95±24.10ms vs 36.83±32.16ms, P<0.05) and LVAT (56.47±14.90ms vs 41.52±17.13ms, P<0.001). Forty-two HF patients met the Strauss criteria had greater LVEF improvement (19.92±6.89% vs 12.41±13.10%, P<0.05) compared to those not meeting the criteria. Comparison 4 included 61 patients without S wave in lead V6 and these patients exhibited better electrical synchrony after LBBP (ΔQRSd: -55.18±24.79ms vs -40.05±33.67ms, P<0.05; ΔLVAT: -55.74±14.70ms vs -41.67±18.55ms, P<0.05) than patients with S wave in V6. Among them, 51 patients without S wave in V6 had HF and showed greater LVEF improvements than those with S wave in V6 (ΔLVEF: 18.65±10.13% vs 6.61±7.78%, P<0.05). Correlation analyses showed significant associations between both ΔQRSd (R=0.55, P <0.001) and ΔLVAT (R=0.39, P <0.01) with LVEF improvement. In multivariate analysis, ΔQRSd>53 ms is an independent predictor of cardiac super response (LVEF improvement>15%). LBBB pattern meeting the Strauss criteria and absence of S wave in lead V6 can predict better electrical resynchrony and LVEF improvement by LBBP.

PO-03-049 SUBACUTE MIGRATION OF LEFT BUNDLE BRANCH PACING LEAD INTO THE LEFT VENTRICLE

RV pacing is associated with increased risk for systolic dysfunction. Conduction system pacing has emerged as an alternative. His bundle pacing is limited by higher capture threshold, reducing battery life, and concerns of increasing thresholds over time. LBBP is a promising alternative, however limited data exist on associated complications. We report a case of LBBP complicated by subacute migration into the LV presenting with increasing threshold. A 78 yoM with symptomatic bradycardia and chronotropic incompetence referred for PPM underwent implantation of DC-PPM with left bundle lead. A Medtronic SelectSecure 3830 lead was advanced into a C315 sheath and positioned at the LV septum. Pace mapping defined a candidate site for LBBP (W in V1). Lead was screwed into the septum. Unipolar impedance prior to deployment was 820Ω. After 5 turns paced QRSd 140ms with qR morphology in lead V1, R waves 12.4mV, unipolar impedance 760Ω, threshold 0.75V at 0.4ms. This was accepted as nonselective LBBP. He began to have chest thumping on POD 3. Device showed elevated ventricular threshold, decreasing impedance, and stable sensing. ECG showed broad notched R wave in V1 consistent with LV pacing. CT revealed migration of the lead, coursing through the IVS into the LV myocardium with tip terminating along the inferior LV wall. Lead tip was possibly puncturing through the myocardium and within the epicardial fat. There was no effusion Lead was removed with manual traction in the EP suite. Heart border remained unchanged on fluoroscopy. Transthoracic echo showed no effusion. New lead was positioned with active fixation in the RV apical septum away from the prior position. Lead showed suitable parameters without diaphragmatic stimulation. LBBP can be an alternative to HB, RV, and CRT pacing. LBBP involves placing the lead deep within the IVS and close to the LV subendocardium. Septal perforation is often recognized during the procedure, however, the risk of late perforation must be considered. In our case, timing of lead migration is unclear as parameters during implant suggested adequate LB capture but reported diaphragmatic capture at day 3, before threshold increase. It demonstrates important findings:1.Acute decrease in unipolar impedance may not be a sensitive marker for septal perforation as it did not change appreciably in our case; 2.ECG/CXR in follow up can help identify lead migration; 3.Migrated leads can be safely removed in the EP suite without need for surgical backup

PO-03-029 LEFT BUNDLE BRANCH AREA PACING LEARNING CURVE AND OUTCOMES IN A BEGINNER IMPLANTER

Left bundle branch area pacing (LBBAP) is a rapidly growing conduction system pacing technique. However, little is known about the learning curve of LBBAP implants in a beginner implanter. We sought to determine acute procedural success rate, implant characteristics, and complications of a single operator implanting LBBA pacing devices in his first year of unsupervised practice. All patients who underwent pacemaker and CRT device implants at our center by a single operator (TC) were reviewed. LBBAP was defined as the presence of R’ in lead V1, and LV activation time (LVAT) <= 80 msec (stim to peak in V6) in the paced QRS complex. Charts were retrospectively reviewed to determine rates of LBBA capture, procedure duration, fluoroscopy time, lead dislodgement, and lead revision rates. LBBA pacing was attempted in 80 patients. Medtronic C315 sheath was used to deliver a Medtronic 3830 lead to the LBBA in all cases. LBBA capture was obtained in 69/80 (86%) patients. Mean paced QRS duration was 131 +/- 13 msec. and mean LVAT was 66 +/- 11 msec. For the first 20 implants, mean procedure duration was 104 +/-32 minutes, and mean fluoroscopy time was 11 +/- 6 minutes. Subsequent 60 implants had significantly lower mean procedure duration (82 +/- 21 mins, p < 0.01) and fluoroscopy time (8 +/- 4 mins, p = 0.01). Overall, mean procedure duration was 88 +/- 26 minutes, and mean fluoroscopy time was 9 +/- 5 minutes. Rate of LBBA capture increased from 70% for the first 20 implants to 92% for the last 60 implants. No significant differences were observed in QRS duration and LVAT time between the first 20 and last 60 implants. Three lead dislodgements occurred, all of which occurred prior to the 15th procedure. One patient required lead revision for increasing pacing thresholds. In this single center, retrospective study of a single operator in his first year of unsupervised practice, LBBA pacing was achieved in majority of patients. Rate of lead dislodgement and need for lead revision were low. Procedural success rate increased while procedure duration, fluoroscopy use, and complications decreased after 20 implants.

PO-04-013 A CASE OF INTERMITTENT ANODAL CAPTURE AFTER LEFT BUNDLE AREA PACING

Left bundle area pacing (LBAP) is emerging as a reliable form of conduction system pacing (CSP) that can be beneficial in cardiac resynchronization therapy (CRT). We present a case of intermittent anodal capture noted after septal lead insertion in a patient undergoing LBAP. N/A An 80-year-old male with hypertension, COPD, and sick sinus syndrome who had undergone dual chamber pacemaker implantation in 2007, had known atrial lead fracture since 2020, now presented with heart failure syndrome (EF dropped from 60% to 15%). A coronary angiogram showed non-obstructive coronary artery disease. As such decision was made for fractured atrial lead extraction and implantation of new atrial lead to provide AV synchrony as well as upgrading the device to biventricular ICD, given the persistent low ejection fraction. During the procedure, coronary sinus anatomy was found unsuitable for lead insertion, and hence LBAP was opted for instead. LBAP lead was placed at an appropriate septal location with QRS morphology in lead V1 changing from an initial “W” pattern to notching as the lead was advanced with an appropriate rise in thresholds. QRS duration decreased to 144 milliseconds; however, intermittently variable QRS morphologies were noted. In LBAP, anodal capture can occur during bipolar configuration where the tip of the lead (cathode) is capturing the left bundle, and the ring (anode) starts capturing the right bundle area. This happens when the lead is penetrating the interventricular septum (IVS) enough for the ring portion to come into contact with the right septal area. In our patient, note the different QRS morphologies in lead V1 (Panel A). The right bundle morphology QRS (marked red) is the expected result of LB pacing, while the left bundle morphology QRS (marked green) is likely occurring from concurrent anodal capture of the right bundle. The QRS duration is noted to be somewhat narrower when the left bundle morphology is present, as would be expected when both bundles are simultaneously captured (LB by the tip and RB by the ring) (Panel B). It is unclear whether such a phenomenon as anodal capture of the RB along with concurrent LB pacing can be of any clinical significance and needs further research.

PE-454609-1 MYOCARDIAL WORK IN VENTRICULAR PREEXCITATION

Ventricular preexcitation alters the electromechanical activation sequence and may induce left ventricular (LV) contractile discoordination and pathologic remodelling in selected cases. To evaluate LV myocardial work before and after accessory pathway (AP) ablation in patients with WPW preexcitation and to compare them to normal controls. Mechanical activation mapping and myocardial work calculation was performed in 11 pediatric patients with the WPW syndrome/pattern and left sided or paraseptal APs undergoing catheter ablation (successful in 10/11) and 8 healthy age-matched controls using speckle tracking echocardiography and the GE ECHOPAC version 204.57.0.745 software with the integrated AFI module. An 18-segmental echocardiographic LV model was used. Global LV myocardial work efficiency (GWE) was calculated as the ratio of global constructive work to the sum of global constructive and global wasted work (GWW). The time from delta wave onset to R wave peak in lead V6 (delta to R) was used to quantify the degree of preexcitation. Before ablation GWW was higher (164 vs 102 mmHg%, P=0.015) and GWE lower (median 91 vs 94%, P=0.010) in patients vs controls. After successful ablation GWW decreased from 164 to 93 mmHg% (P=0.006) and GWE increased from 91.1 to 94.0 % (P=0.006). GWE tended to correlate negatively with the delta to R interval (R=0.59, P=0.056). Before ablation, segmental WE increased with distance from ventricular AP insertion from median 69.5 % at AP location to 98.0 % in distant segments (P<0.001). After ablation, WE was equally distributed among LV segments (Figure). Mechanical activation mapping localized APs with a median (IQR) segmental distance of 0 (0-1) segments from the EP mapped location. Ventricular preexcitation induces significant LV myocardial work inefficiency in segments adjacent to AP which correlates with the degree of preexcitation and is normalized after ablation. The amount of wasted work in asymptomatic preexcitation may be considered when assessing the potential for pathologic LV remodelling or discussing the indication for prophylactic ablation. Mechanical activation mapping may be used to localize manifest APs.

AP-452681-3 VENTRICULAR TACHYCARDIA ORIGINATING NEAR THE HIS-BUNDLE: ELECTROCARDIOGRAPHIC, CATHETER ABLATION CHARACTERISTICS AND LONG-TERM OUTCOME

Ventricular Arrhythmias (VAs) not uncommonly originate from the Para Hisian (PH) region. The clinical and electrophysiological (EP) characteristics of these VAs are important to recognize given risk of injury to the conduction system. Define the clinical and EP characteristics of these VAs and long-term outcome of catheter ablation. 43 patients (Pts.) had VAs activation mapped to the PH region. The electrocardiographic and EP characteristics of these PH VAs were compared in 50 patients with VAs originating from right ventricular outflow tract (RVOT). Mean QRS width was narrower in PH VAs (P=0.02) and the R wave amplitude was lower in the inferior leads (P = 0.01) as compared to RVOT VAs. PH VAs had an R wave amplitude greater in lead I (P= 0.001) and lead aVL (P= 0.02) than RVOT VAs. For PH VAs earliest in RV, the R wave amplitude ratio in leads II/III was greater than those in LV (P= 0.02). All left sided PH VAs (12pts) had early transition (≤Lead V2) and were infra-hisian in location. 27/31 Right sided VAs had later transition (≥ Lead V3), 22 (70%) were infra-hisian and 9 (30%) were supra-hisian in location. Inferior Lead discordance was seen in 75% of all pts and was similar in left and right sided VAs. Radiofrequency ablation (RFA) was used upfront in 39 pts. Cryo-ablation used upfront in 2 pts and after RFA in 1 pt. In 30 pts (70%) VAs were eliminated; 9 (21%) had significant suppression (≤5% total residual burden) and 3 (9%) had acute recurrence (<48 hours) and 1 pt. ablation was not attempted given immediate proximity to HB. During follow up of 46±8 months, EF normalized in 37/43 (85%). 2 Pts. developed transient heart block with no treatment needed and 1 with pre-existing pacemaker (PM) had complete heart block. 2 required PM implantations at 39 ± 2 months post ablation due to conduction system disease unrelated to ablation. VAs originating near the His-bundle have distinctive ECG characteristics which aid in recognition and mapping. Catheter ablation can generally be performed safely and effectively.

PO-04-201 A CASE OF PVC OCCURRING RIGHT BUNDLE BRANCH BLOCK AND PR INTERVAL PROLONGED DURING ETHANOL ABLATION VIA THE CORONARY VENOUS SYSTEM

Ethanol ablation via the coronary venous system (CVS) has been reported to be effective and safe as a novel therapy for ventricular arrhythmias, especially for the epicardial and intramural origin sites. Previous studies reported no heart block complications during retrograde coronary venous ethanol ablation, neither atrioventricular block (AVB) nor other types of conductive system block. N/A A 67-year-old female with symptomatic and drug-refractory premature ventricular contractions (PVCs) was admitted for ablation therapy. The PVC burden was 31.7%. The 12-lead ECG showed a PVC with LBBB, inferior axis with a precordial transition in lead V3, and QS pattern in lead I. The QRS duration of PVC was 143ms. The Q-wave ratio of lead aVL/aVR was 1.47. Endocardial mapping was performed using a 3.5mm open-irrigated-tip catheter (ThermoCool, Biosense Webster, CA, USA). The earliest activation time was -8ms and -10ms pre-QRS at the septal aspect of right ventricular outflow tract (RVOT) and the left coronary sinus (LCC), respectively (Fig 1A). Ablation with 35-40W, 45-50°C was attempted but no response. We considered it might be an intramural origin site. The CVS angiography was performed and the ablation catheter was positioned in LCC for reference (Fig 1B). The earliest activation time (-27ms) was mapped in a septal branch of the anterior interventricular vein (AIV) with a 3.3F quadripolar catheter and local pace mapping matched well. Selective angiography confirmed the quadripolar catheter was in the septal branch rather than AIV (Fig 1C-D). A balloon was used to deliver ethanal and prevent its backflow to AIV. 1ml 96% ethanol was infused slowly (Fig 1E-F). PVC was eliminated immediately as soon as the ethanol infusion. But we noticed the PR interval prolonged from 178 to 190ms. More ethanol was injected carefully to consolidate the effect but we stopped infusion after a total of 2.5ml ethanol because the ECG showed complete RBBB and PR interval prolonged further to 202ms. RBBB and I° AVB were persistent during the whole hospitalization for 3 days. However, at 1-month follow-up, the QRS morphology returned to normal and the PR interval shortened to 172ms (Fig 1G). 24-hour Holter showed no recurrence. Ethanol ablation via the CVS also might induce heart block complications due to the adjacent anatomical position with the conductive system, even though it might be reversible. Operators should be cognizant of the potential risk.

PO-04-206 THE TRANSFERABLE ARTIFICIAL INTELLIGENT MODEL BASED ON ELECTROCARDIOGRAM: A PROSPECTIVE OBSERVATIONAL STUDY TOWARD HOME-BASED APPLICATION OF SINGLE-LEAD ECG IN IDENTIFYING HEART FAILURE WITH LOW LEFT VENTRICULAR EJECTION FRACTION

Although heart failure with reduced ejection fraction (HFrEF) can benefit from treatment, it remains underdiagnosed due to the limited accessibility of echocardiography. Several studies have shown that artificial intelligent (AI) models of 12 leads ECG can successfully identify ventricular dysfunction. However, such models are hard to deploy for frequent surveillance of the left ventricular ejection fraction (LVEF), especially under the home-based scenario. We aimed to design a prospective study that used a single-lead 30-second ECG recorded and operated by patients to transfer and test an AI model constructed with convolutional neural network (CNN) analysis of standard 12-lead ECG from a retrospective single medical center cohort. In addition, we also try to leverage the short-term heart rate variability (HRV) to improve the sensitivity and specificity of the model. The 12-lead ECGs of sinus rhythm with LVEF measuring within 90 days of the recording date were included. The dataset was split into training and validation sets at a ratio of 7:3 without patient overlapping. To select feasible models of single-lead ECG for identifying LVEF of 45% or lower, we trained the CNN models using single-lead ECG recorded from each lead placement as input. The models with the top 3 performances were transferred to the corresponding lead of the single-lead ECG datasets acquired prospectively to validate their generalizability. Among all single-lead ECG models trained from 56479 recordings of 33010 patients, the AUC of the top 3 ranked models (lead aVR, I, and V5) were 0.89, 0.88, and 0.88, respectively. While aVR is impossible to derive from single-lead placement, we applied the models of lead I, V5, and lead II instead. For the prospective single-lead ECG datasets, 144 patients with an average age of 64 years old were recruited, and the models were tested. No significant drop in the performance of the lead I model was shown (AUC=0.88). Furthermore, adding HRV to the lead I model can improve overall accuracy (AUC=0.92) and sensitivity and specificity of the optimal cutting threshold. With the assistance of AI algorithm, single-lead ECG recorded and operated by patients from a wristband performed well in detecting low LVEF of 45% or lower. This simple approach can provide an inexpensive and convenient tool for the home-based monitoring of LVEF, and the tool's effectiveness warrants further study.

PO-03-009 3830 LEAD TIP POSITION ON COMPUTED TOMOGRAPHY AND ELECTROPHYSIOLOGIC OUTCOMES IN LEFT BUNDLE BRANCH AREA PACING

Prior studies have evaluated the impact of lead tip distance from the LV blood pool on pacing parameters during left bundle branch area pacing (LBBAP). Few studies to date have evaluated lead tip angulation within the interventricular septum (IVS) in relation to pacing morphology on surface 12-lead ECG. To establish the observed lead tip trajectories within the interventricular septum encountered during LBBAP. Patients who underwent LBBAP implantation between 02/2019-07/2022 were retrospectively analyzed. Patients who underwent computed tomography (CT) of the chest or thorax post-implantation for any indication were included for analysis. Lead distance from the mitral annulus, lead tip distance from LV blood pool (DEBP), lead tip angle of incidence (AOI), and post-implantation electrocardiographic and pacing parameters were analyzed (Figure 1a). 38 pts were identified, out of whom 37 pts had CT images available for analysis. In the 20 pts with contrast enhanced imaging, DEBP was 2.1±1.8mm. Average observed AOI was 10.9±20.6 degrees in the axial plane (long axis; Figure 1b) and 12.4±22.2 degrees in the saggital plane (short axis; Figure 1c). Lead impedance at time of implant did not correlate strongly with axial or sagittal angle of incidence (R2=0.01 and 0.03 respectively) or with distance from LV endocardial blood pool (R2=0.04). The most commonly encountered lead insertion locations included the mid-septal (22, 59.5%), basal septal (4, 10.8%), and mid antero-septal (3, 8.1%) positions (Figure 1d). Average lead tip distance from the AV annulus was 36.6±8.2mm. Mean paced QRSd for the basal, mid, and apical cohorts were 122.5±8.1ms, 118.5±10.7ms, and 120±15.9ms, respectively. Left ventricular activation time in lead V6 numerically decreased for more apical positions, with basal, mid and apical values of 84.4±11.9ms, 73.9±10.6ms, and 69.5±6.0ms, respectively. Lead threshold, impedance, and sensed R waves were stable at time of 2 year follow-up. No analyzed patients underwent lead revision. Multiple lead tip orientations are observed in relation to the IVS during successful LBBAP. More apical lead tip positioning may result in numerically lower LVAT values, despite similar overall QRS duration.

PO-05-135 SIGNAL-AVERAGED ECG IN THE NORDIC ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY REGISTRY: ASSOCIATION WITH PREVALENT LIFE-THREATENING ARRHYTHMIAS AND ASCERTAINMENT OF CLINICAL DIAGNOSIS.

In arrhythmogenic right ventricular cardiomyopathy (ARVC), minor depolarization criteria by TFC2010 include ventricular late potentials (LP) assessed using signal-averaged ECG (SAECG) and terminal activation duration (TAD). TAD is measured from a standard V1 lead, which favors its use in clinical practice, however its ability to fully replace LP in ARVC workup is not clear. 1. To assess the association between TAD and LP and the prevalence of life-threatening ventricular arrhythmias in patients with ARVC. 2. To assess diagnostic impact of SAECG by characterizing the subgroup of patients, who would not have received definite ARVC diagnosis if LP were not considered. Patients with definite ARVC or genotype-positive family members who underwent SAECG were included (n=358, 47% women, age 41±16 years, 43% probands, 67% definite ARVC). LP and TAD were defined according to TFC2010 criteria. TFC score was calculated by assigning 2 points for major and 1 for minor criterium. Ventricular tachycardia (VT) was defined as sustained VT, aborted cardiac arrest or appropriate ICD shock. Logistic regression adjusted for clinical covariates was used to test association of TAD and LP with prevalent VT. In a subgroup of patients with TFC score 4, i.e. minimally required for diagnosis, patients who would be reclassified into borderline category if LP not considered (LP-dependent, n=38) were compared with those who had TFC score 4 regardless of LP (LP-independent, n=30) in terms of proband status, prevalence of imaging criteria and VT. LP were found in 209 patients (58%); TAD in 65 (18%); 90 patients had prevalent VT (25%). LP was associated with prevalent VT (OR=2.5 95%CI 1.2-5.3; Sensitivity 84%, Specificity 50%) while TAD was not (OR=1.6 95%CI 0.7-3.6; Sensitivity 32%, Specificity 87%). In the LP-dependent group, 9 of 14 (64 %) probands had prevalent VT, 7 (50%) survived cardiac arrest and 4 (29%) were genotype-positive. Clinical characteristics did not demonstrate significant differences between LP-dependent and LP-independent subgroups. LP is independently associated with VT and is more sensitive than TAD in identification of patients with prevalent VT. LP were critical for ascertainment of ARVC diagnosis required for initiation of family screening in 9% probands. Although the diagnostic impact of LP varies depending on SAECG availability, our data support its use as a sensitive non-invasive diagnostic tool.

Effusive-constrictive pericarditis as first manifestation of late-onset systemic lupus erythematosus: an atypical case with grave prognosis

BackgroundSystemic lupus erythematosus (SLE) is a multisystem autoimmune disease that has a great diversity of clinical presentations and occurs mostly in young women. However, late-onset SLE does exist and seldom presents with an atypical case, including pericardial effusion (PE).Case presentationA 64 years old Asian woman presented with weakness all over the body and slight breathlessness for the past 2 days before the hospital admission. Her initial vital signs are 80/50 mmHg for blood pressure and a respiration rate of 24 breaths/min. Rhonchi were heard on the left lung and pitting edema on both legs. No evidence of any skin rash. Laboratory examination displayed anemia, hematocrit decrement, and azotemia. A 12-lead ECG demonstrated left-axis deviation with low voltage (Fig. 1). Chest X-ray showed left massive pleural effusion (Fig. 2). Transthoracic echocardiography revealed biatrial enlargement, normal EF 60%, diastolic dysfunction grade II, and thickening of the pericardium with mild circumferential PE corresponding with effusive-constrictive pericarditis (Fig. 3). The patient also brought CT angiography and cardiac MRI result, which confirmed pericarditis with PE. Treatment was initiated in ICU with fluid resuscitation of normal saline. The patient’s routine oral treatments, including furosemide, ramipril, colchicine, and bisoprolol, were carried on. An autoimmune workup was performed by a cardiologist and demonstrated an elevation in antinuclear antibody/ANA (IF) of 1:100, which finally unveiled a diagnosis of SLE. Pericardial effusion is one critical condition to consider, despite it being an uncommon presentation in late-onset SLE. Mild pericarditis in an SLE case can be treated with corticosteroid administration. Colchicine also has been found to reduce the risk of pericarditis recurrence. However, an atypical presentation from this case led to a slightly delayed treatment that escalated the morbidity and mortality risk. The patient had a sudden cardiac arrest and passed away 3 days after being treated.Fig. 1Initial electrocardiogram demonstrated left-axis deviation, low voltage QRS complex and T-wave inversion on lead V1–V3Fig. 2Chest radiograph showed left massive pleural effusionFig. 3Transthoracic echocardiogram displayed increased left ventricular filling pressure with diastolic dysfunction grade III, mild circumferential pericardial effusion with adjacent pleural effusionConclusionsAtypical presentation during late-onset SLE, mainly in the form of pericardial effusion even constrictive pericarditis, should be taken into a consideration since they are a scarce feature in SLE patients. Swift recognition and prompt treatment are important for the optimal outcome.

Electrocardiographic markers of subclinical atrial fibrillation detected by implantable loop recorder: insights from the LOOP Study.

Insights into subclinical atrial fibrillation (AF) development are warranted to inform the strategies of screening and subsequent clinical management upon AF detection. Hence, this study sought to characterize the onset and progression of subclinical AF with respect to 12-lead electrocardiogram (ECG) parameters. We included AF-naïve individuals aged 70-90 years with additional stroke risk factors who underwent implantable loop recorder (ILR) monitoring in the LOOP Study. Using data from daily ILR recordings and the computerized analysis of baseline ECG, we studied empirically selected ECG parameters for AF detection (≥6 min), cumulative AF burden, long-lasting AF (≥24 h), and AF progression. Of 1370 individuals included, 419 (30.6%) developed AF during follow-up, with a mean cumulative AF burden of 1.5% [95% CI: 1.2-1.8]. Several P-wave-related and ventricular ECG parameters were associated with new-onset AF and with cumulative AF burden in AF patients. P-wave duration (PWD), P-wave terminal force in Lead V1, and interatrial block (IAB) further demonstrated significant associations with long-lasting AF. Among AF patients, we observed an overall reduction in cumulative AF burden over time (IRR 0.70 [95% CI: 0.51-0.96]), whereas IAB was related to an increased risk of progression to AF ≥24 h (HR 1.86 [95% CI: 1.02-3.39]). Further spline analysis also revealed longer PWD to be associated with this progression in AF duration. We identified several ECG parameters associated with new-onset subclinical AF detected by ILR. Especially PWD and IAB were robustly related to the onset and the burden of AF as well as progression over time.

Crochet Leads the Way

The crochetage sign—a notch near the R-wave peak in the inferior leads—in conjunction with right axis deviation, complete or incomplete right bundle branch block, and right ventricular hypertrophy (R/S ratio >1 in lead V1) on 12-lead electrocardiogram are highly suggestive of atrial septal defect. (Level of Difficulty: Intermediate.)

High predictive value of paced QRS frequency in verification of left bundle branch pacing.

Left bundle branch area pacing (LBBAP) is a newer technique to deliver more synchronous left ventricular activation. Several criteria have been proposed, but not fully validated, to confirm LBBAP during implantation of the pacing lead. Spectral analysis has been used to characterize the frequency components of the clinical QRS utilizing the Fourier transform algorithm. We hypothesized that higher frequency content of the paced QRS complex may show predictive value of successful LBBAP. We evaluated 84 patients with ejection fraction > 50%, who underwent LBB lead placement (n = 42) using ≥ 1 current criteria and right ventricular midseptal (RVsp) lead placement (n = 42) from 2000 to 2022. Time frequency analysis (Matlab) was used to determine the frequency content of the paced QRS complex. The centroid frequency (CF), which is the weighted average QRS frequency, was calculated. Patients in RVsp group had a longer paced QRS duration (155.6 ± 28.0 vs 127.1 ± 17.2, p < 0.002) compared to the LBBAP group. Of all standard ECG leads, the paced QRS in V2 gave the greatest difference of the CF of the LBBAP group at 8.8 ± 1.6 Hz versus 5.7 ± 0.7 Hz of the RVsp group. This difference was significant by both univariate (p < 0.003) and multivariate (p < 0.010) analysis. Predictive value of the CF for successful LBB pacing in lead V2 was highest with an AUC of 0.98. The sensitivity and specificity were 88.1% and 97.6%, respectively. Spectral analysis predicts successful LBBAP with higher frequency content when compared to RVsp pacing. Given the limitations to the current criteria to confirm LBBAP, intraprocedural use of frequency content analysis of the paced QRS complex in patients may prove useful at verifying LBB capture if verified by prospective clinical trials.

Association of abnormal p-wave parameters with brain MRI morphology: The atherosclerosis risk in communities neurocognitive study (ARIC-NCS).

Recent evidence indicates that abnormal P-wave parameters (PWPs)-ECG markers of atrial myopathy-are associated with incident dementia, independent of atrial fibrillation (AF) and clinical ischemic stroke. However, the mechanisms remain unclear and may include subclinical vascular brain injury. Hence, we evaluated the association of abnormal PWPs with brain MRI correlates of vascular brain injury in the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS). ARIC-NCS participants who underwent 3T brain MRI scans in 2011-2013 were included. PWPs were measured from standard 12-lead ECGs. Brain MRI outcomes included cortical infarcts, lacunar infarcts, cerebral microhemorrhages, brain volumes, and white matter disease (WMD) volume. We used weighted multivariable logistic and linear regression to evaluate the associations of abnormal PWPs with brain MRI outcomes. Among 1715 participants (mean age, 76.1 years; 61% women; 29% Black), 797 (46%) had ≥1 abnormal PWP. After multivariable adjustment, including adjusting for prevalent AF, abnormal P-wave terminal force in lead V1 (aPTFV1) and prolonged P-wave duration (PPWD) were associated with increased odds of both cortical (OR 1.41; 95% CI, 1.14 to 1.74 and OR 1.30; 95% CI, 1.04 to 1.63, respectively) and lacunar infarcts (OR 1.36; 95% CI, 1.15 to 1.63 and OR 1.37; 95% CI, 1.15 to 1.65, respectively). Advanced interatrial block (aIAB) was associated with higher odds of subcortical microhemorrhage (OR 2.04; 95% CI, 1.36 to 3.06). Other than a significant association between aPTFV1 with lower parietal lobe volume, there were no other significant associations with brain or WMD volume. In this exploratory analysis of a US community-based cohort, ECG surrogates of atrial myopathy are associated with a higher prevalence of brain infarcts and microhemorrhage, suggesting subclinical vascular brain injury as a possible mechanism underlying the association of atrial myopathy with dementia.

Left bundle branch area pacing: How to prevent a coronary venous fistula.

Left bundle branch area pacing: How to prevent a coronary venous fistula.

Development and Validation of a Novel Prognostic Tool to Predict Recurrence of Paroxysmal Atrial Fibrillation after the First-Time Catheter Ablation: A Retrospective Cohort Study

There is no gold standard to tell frustrating outcomes after the catheter ablation of paroxysmal atrial fibrillation (PAF). The study aims to construct a prognostic tool. We retrospectively analyzed 315 patients with PAF who underwent first-time ablation at the Second Xiangya Hospital of Central South University. The endpoint was identified as any documented relapse of atrial tachyarrhythmia lasting longer than 30 s after the three-month blanking period. Univariate Cox regression analyzed eleven preablation parameters, followed by two supervised machine learning algorithms and stepwise regression to construct a nomogram internally validated. Five factors related to ablation failure were as follows: female sex, left atrial appendage emptying flow velocity ≤31 cm/s, estimated glomerular filtration rate <65.8 mL/(min·1.73 m2), P wave duration in lead aVF ≥ 120 ms, and that in lead V1 ≥ 100 ms, which constructed a nomogram. It was correlated with the CHA2DS2-VASc score but outperformed the latter evidently in discrimination and clinical utility, not to mention its robust performances in goodness-of-fit and calibration. In addition, the nomogram-based risk stratification could effectively separate ablation outcomes. Patients at risk of relapse after PAF ablation can be recognized at baseline using the proposed five-factor nomogram.

The R-wave amplitude in V1 on baseline electrocardiogram correlates with the occurrence of high-degree atrioventricular block following left bundle branch block after transcatheter aortic valve replacement.

Several procedural and electrocardiogram (ECG) parameters have been associated with the occurrence of high-degree atrioventricular block (AVB) requiring permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR). We hereunder sought to assess if the baseline R-wave amplitude in V1 ECG lead of patients with normal QRS duration undergoing TAVR is associated with a higher patient's risk for developing high-degree AVB following left bundle branch block (LBBB). In this retrospective single-centre study in 720 consecutive patients who underwent TAVR, 141 (19.6%) patients with normal QRS duration developed a new LBBB after TAVR. The 24 (17%) patients who underwent PPI for reasons other than high-degree AVB were excluded from further analysis. In the remaining 117 study patients, 14 (12%) developed high-degree AVB requiring PPI (Group 1) while the remaining 103 (88%) patients did not (Group 2). There were no significant differences in baseline demographic or procedural characteristics nor in PR interval, QRS duration, and QRS axis between these two groups. The incidence of left anterior hemiblock was higher in Group 1 (3 of 14, 21.4%) than that in Group 2 (9 of 103, 8.7%), but the difference was not statistically significant (P = 0.156). The R-wave amplitude in V1 was smaller in Group 1 than that in Group 2 (0.029 ± 0.04 mV vs. 0.11 ± 0.14 mV, P = 0.0316). In the receiver-operating characteristics analysis, the cutoff for R-wave amplitude pre-TAVR was 0.03 mV, area under the curve = 0.7219 (P = 0.0002). The R-wave amplitude in lead V1 during baseline ECG in patients with normal QRS duration may predict the occurrence of high-degree AVB following new LBBB after TAVR.