Lead I R-wave indexes: A novel electrocardiographic criterion for distinguishing the origin of idiopathic premature ventricular contractions from the three subregions of the aortic sinus cusps.

PURPOSE: The current study was conducted to investigate the electrocardiographic (ECG) characteristics of idiopathic premature ventricular contractions (PVCs) originating from the aortic sinus cusp (ASC) and establish a novel ECG criterion to discriminate PVCs originating from the right coronary cusp (RCC), left coronary cusp (LCC), and the left and right coronary cusp junction (LRJ). METHODS: A retrospective analysis was performed on a total of 133 patients with idiopathic PVCs who underwent successful mapping and ablation. The sites of origin (SOO) were confirmed using fluoroscopy and a three-dimensional mapping system during radiofrequency catheter ablation (RFCA). Among the patients, 69 had PVCs originating from the LCC, 39 from the RCC, and 25 from the LRJ. Characteristics of surface 12­lead electrocardiograms (ECGs) recorded during PVCs were analyzed. Q-, R-, S, and R'-wave amplitudes were measured in lead I, and the lead I R-wave indexes (IRa, IRb, IRc, IRd, and IRe) were derived by employing multiplication, subtraction, sum, and division operations on these ECG measurements. Notably, IRb and IRe demonstrated usefulness as ECG indexes for discriminating PVCs originating from RCC, LCC, and LRJ in the ASC. RESULTS: The R- and S-wave amplitudes in lead I exhibited statistically significant differences among the three groups (P < 0.001 and P < 0.001, respectively). In discriminating PVCs originating from the RCC from the other two groups, IRb showed the largest area under the curve (AUC) of 0.813, as assessed by receiver operating characteristic (ROC) analysis, with a cutoff value of ≤0.5 indicating PVCs of RCC origin. The sensitivity and specificity were 80.3% and 78.7%, respectively. For discriminating PVCs arising from the LCC from those in the LRJ group, IRe exhibited the largest AUC of 0.801, with an optimal cutoff value of 0. An IRe value >0 indicated PVCs originating from the LRJ, while an IRe value ≤0 indicated PVCs originating from the LCC. The sensitivity and specificity of the IRe index were 84.0% and 70.7%, respectively. CONCLUSION: Lead I R-wave indexes provided simple and useful ECG criteria for discriminating PVCs originating from the LCC, RCC, and LRJ in the left ventricular outflow tract (LVOT).

Improved accuracy and confidence with multiple-lead recordings from a single-lead mobile electrocardiographic device.

BACKGROUND: Mobile electrocardiograms (mECGs) utilizing smartphone applications are an emerging technology. Typically, a Lead I rhythm strip is recorded. However, interpretation can be difficult in patients with sinus rhythm and low amplitude P-waves (SR-LAP) or atrial flutter (AFL). We hypothesized that patients could independently obtain multi-lead tracings using a commercial mECG device, and that cardiologists who interpreted the multi-lead tracings would make more accurate diagnoses and have more confidence in their interpretation compared to a single lead only. METHODS: Thirty sets of recordings were obtained from 10 patients with either SR-LAP or AFL that was not apparent on Lead I on a standard ECG. Patients recorded Lead I, Lead II, and Lead V1 tracings using AliveCor's KardiaMobile mECG device. Twenty-nine cardiologists reviewed each patient's Lead I tracing, multi-lead tracings (Leads I, II, V1), and 12-lead ECG. Accuracy was noted and each cardiologist rated their level of confidence in their interpretation. RESULTS: All patients were able to record their own single and multi-lead tracings. Single lead, multi-lead, and the 12-lead ECG yielded 36.4%, 84.3%, and 97.7% agreement with the established diagnosis, respectively (P < .01 for each comparison). Overall mean confidence scores (out of a score of 5) were 2.95, 3.50, and 4.47 for single lead, multi-lead, and the 12-lead ECG, respectively (P < .01 for each comparison). CONCLUSIONS: Patients were able to record their own multi-lead mECG tracings. Compared to a single lead recording, multi-lead mECGs significantly improved cardiologists' diagnostic accuracy and confidence in their interpretation approaching that of a standard 12-lead ECG.

Lead I R-wave amplitude to differentiate idiopathic ventricular arrhythmias with left bundle branch block right inferior axis originating from the left versus right ventricular outflow tract.

INTRODUCTION: Differentiation of right versus left ventricular outflow tract (RVOT vs. LVOT) arrhythmia origin with left bundle branch block right inferior axis (LBRI) morphology is relevant to ablation planning and risk discussion. Our aim was to determine if lead I R-wave amplitude is useful for differentiation of RVOT from LVOT arrhythmias with LBRI morphology. METHODS: The R-wave amplitude in lead I was measured in a retrospective cohort of 75 consecutive patients with LBRI pattern ventricular arrhythmias (VAs) successfully ablated from the RVOT (n = 54), LVOT (n = 16), or the anterior interventricular vein (AIV; n = 5). The optimal R-wave threshold was identified and diagnostic indices were compared with the previously reported transitional zone (TZ) index and V2S/V3R index. RESULTS: An R-wave amplitude greater than or equal to 0.1 mV predicted LVOT origin with 75% sensitivity and 98.2% specificity. In comparison, the TZ and V2S/V3R indices had 50% and 68.8% sensitivity, and 75.9% and 88.9% specificity, respectively, for predicting LVOT origin. The area under the curve (AUC) was 0.85 for lead I R-wave amplitude, 0.87 for V2S/V3R, and 0.72 for the TZ index. Of 36 cases with QS in lead I, 30 (83.3%) were from the anterior RVOT, three (8.3%) from the LVOT, and three (8.3%) from the AIV. CONCLUSION: The presence of R-wave amplitude in lead I (≥0.1 mV) is a simple and useful criterion to identify LVOT cusp or endocardium focus in LBRI arrhythmias. A QS pattern in lead I suggests an origin in the anterior RVOT, or less commonly the adjacent LV summit.

Global R-wave peak time for diagnosis of left bundle branch capture.

BACKGROUND: QRS axis deviation and rS configuration in V6 affect the ability of V6 R-wave peak time (RWPT) criterion to discriminate capture type during left bundle branch area pacing (LBBAP). OBJECTIVE: We hypothesized that combining RWPTs from lateral leads: I, aVL, V5, and V6 may better reflect left ventricular activation time and that such a global RWPT may be insensitive to changes in QRS configuration. METHODS: The analysis included 519 ECGs with non-selective left bundle branch pacing (nsLBBP) and 176 ECGs with left ventricular septal pacing (LVSP). Optimal RWPT cutoffs and area under the receiver operating curve (AUC) were determined for each lead and combinations of leads, to find the best RWPT criterion for discriminating nsLBBP from LVSP. Values were reported separately for healthy/diseased left conduction system groups. RESULTS: The highest AUC of 97.1/89.2% was obtained for the global RWPT, which combined leads I and V6. The AUC for single lead RWPT, was highest for lead I, followed by V6, V5, and aVL with AUC of 95.1/87.4%, 93.6/87.1%, 93.0/86.5%, and 84.8/74.6%, respectively. The global RWPT criterion was not affected by variations in QRS configuration, as V6 and I RWPTs often showed opposite responses to changes in axis. In contrast, all single-lead RWPT criteria were sensitive to axis deviation and QRS configuration. Diagnostically optimal RWPT cutoffs for global RWPT and lead I RWPT were 162.5/187.5 ms, and 81.5/90.5 ms, respectively. CONCLUSION: The global RWPT criterion allows a more accurate diagnosis of LBBAP capture type independent of QRS configuration and axis.

Electrocardiographic Markers Indicating Right Ventricular Outflow Tract Conduction Delay as a Predictor of Major Arrhythmic Events in Patients With Brugada Syndrome: A Systematic Review and Meta-Analysis.

Introduction: Risk stratification in Brugada Syndrome (BrS) patients is still challenging due to the heterogeneity of clinical presentation; thus, some additional risk markers are needed. Several studies investigating the association between RVOT conduction delay sign on electrocardiography (ECG) and major arrhythmic events (MAE) in BrS patients showed inconclusive results. This meta-analysis aims to evaluate the association between RVOT conduction delay signs presented by aVR sign and large S wave in lead I, and MAE in BrS patients. Methods: The literature search was performed using several online databases from the inception to March 16th, 2022. We included studies consisting of two main components, including ECG markers of RVOT conduction delay (aVR sign and large S wave in lead I) and MAE related to BrS (syncope/VT/VF/SCD/aborted SCD/appropriate ICD shocks). Results: Meta-analysis of eleven cohort studies with a total of 2,575 participants showed RVOT conduction delay sign was significantly associated with MAE in BrS patients [RR = 1.87 (1.35, 2.58); p < 0.001; I 2= 52%, P heterogeneity = 0.02]. Subgroup analysis showed that aVR sign [RR = 2.00 (1.42, 2.83); p < 0.001; I 2= 0%, P heterogeneity = 0.40] and large S wave in lead I [RR = 1.74 (1.11, 2.71); p = 0.01; I 2= 60%, P heterogeneity = 0.01] were significantly associated with MAE. Summary receiver operating characteristics analysis revealed the aVR sign [AUC: 0.77 (0.73-0.80)] and large S wave in lead I [AUC: 0.69 (0.65-0.73)] were a good predictor of MAE in BrS patients. Conclusion: RVOT conduction delay sign, presented by aVR sign and large S wave in the lead I, is significantly associated with an increased risk of MAE in BrS patients. Hence, we propose that these parameters may be useful as an additional risk stratification tool to predict MAE in BrS patients. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022321090.

Lead I R-wave amplitude to distinguish ventricular arrhythmias with lead V3 transition originating from the left versus right ventricular outflow tract.

BACKGROUND: The electrophysiology algorithm for localizing left or right origins of outflow tract ventricular arrhythmias (OT-VAs) with lead V3 transition still needs further investigation in clinical practice. HYPOTHESIS: Lead I R-wave amplitude is effective in distinguishing the left or right origin of OT-VAs with lead V3 transition. METHODS: We measured lead I R-wave amplitude in 82 OT-VA patients with lead V3 transition and a positive complex in lead I who underwent successful catheter ablation from the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT). The optimal R-wave threshold was identified, compared with the V2 S/V3 R index, transitional zone (TZ) index, and V2 transition ratio, and validated in a prospective cohort study. RESULTS: Lead I R-wave amplitude for LVOT origins was significantly higher than that for RVOT origins (0.55 ± 0.13 vs. 0.32 ± 0.15 mV; p < .001). The area under the curve (AUC) for lead I R-wave amplitude as assessed by receiver operating characteristic (ROC) analysis was 0.926, with a cutoff value of ≥0.45 predicting LVOT origin with 92.9% sensitivity and 88.2% specificity, superior to the V2 S/V3 R index, TZ index, and V2 transition ratio. VAs in the LVOT group mainly originated from the right coronary cusp (RCC) and left and right coronary cusp junction (L-RCC). In the prospective study, lead I R-wave amplitude identified the LVOT origin with 92.3% accuracy. CONCLUSION: Lead I R-wave amplitude provides a useful and simple criterion to identify RCC or L-RCC origin in OT-VAs with lead V3 transition.

Lead-I ECG for detecting atrial fibrillation in patients with an irregular pulse using single time point testing: a systematic review and economic evaluation.

BACKGROUND: Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and is associated with an increased risk of stroke and congestive heart failure. Lead-I electrocardiogram (ECG) devices are handheld instruments that can be used to detect AF at a single time point in people who present with relevant signs or symptoms. OBJECTIVE: To assess the diagnostic test accuracy, clinical impact and cost-effectiveness of using single time point lead-I ECG devices for the detection of AF in people presenting to primary care with relevant signs or symptoms, and who have an irregular pulse compared with using manual pulse palpation (MPP) followed by a 12-lead ECG in primary or secondary care. DATA SOURCES: MEDLINE, MEDLINE Epub Ahead of Print and MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, PubMed, Cochrane Databases of Systematic Reviews, Cochrane Central Database of Controlled Trials, Database of Abstracts of Reviews of Effects and the Health Technology Assessment Database. METHODS: The systematic review methods followed published guidance. Two reviewers screened the search results (database inception to April 2018), extracted data and assessed the quality of the included studies. Summary estimates of diagnostic accuracy were calculated using bivariate models. An economic model consisting of a decision tree and two cohort Markov models was developed to evaluate the cost-effectiveness of lead-I ECG devices. RESULTS: No studies were identified that evaluated the use of lead-I ECG devices for patients with signs or symptoms of AF. Therefore, the diagnostic accuracy and clinical impact results presented are derived from an asymptomatic population (used as a proxy for people with signs or symptoms of AF). The summary sensitivity of lead-I ECG devices was 93.9% [95% confidence interval (CI) 86.2% to 97.4%] and summary specificity was 96.5% (95% CI 90.4% to 98.8%). One study reported limited clinical outcome data. Acceptability of lead-I ECG devices was reported in four studies, with generally positive views. The de novo economic model yielded incremental cost-effectiveness ratios (ICERs) per quality-adjusted life-year (QALY) gained. The results of the pairwise analysis show that all lead-I ECG devices generated ICERs per QALY gained below the £20,000-30,000 threshold. Kardia Mobile (AliveCor Ltd, Mountain View, CA, USA) is the most cost-effective option in a full incremental analysis. LIMITATIONS: No published data evaluating the diagnostic accuracy, clinical impact or cost-effectiveness of lead-I ECG devices for the population of interest are available. CONCLUSIONS: Single time point lead-I ECG devices for the detection of AF in people with signs or symptoms of AF and an irregular pulse appear to be a cost-effective use of NHS resources compared with MPP followed by a 12-lead ECG in primary or secondary care, given the assumptions used in the base-case model. FUTURE WORK: Studies assessing how the use of lead-I ECG devices in this population affects the number of people diagnosed with AF when compared with current practice would be useful. STUDY REGISTRATION: This study is registered as PROSPERO CRD42018090375. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Atrial fibrillation (AF) is the most common type of abnormal heart rhythm. People with AF are more likely to have a serious stroke or die than people without the condition. Many people go to their general practitioner (GP) with the signs or symptoms commonly linked to AF, such as feeling dizzy, being short of breath, feeling tired and having heart palpitations. GPs check for AF by taking the patient's pulse by hand. If the GP thinks that the patient might have AF, a 12-lead electrocardiogram (ECG) test is arranged. Lead-I (i.e. one lead) ECGs are handheld electronic devices that could detect AF more accurately than a manual pulse check. If GPs were to routinely use lead-I ECG devices, people with suspected AF could receive treatment while waiting for the AF diagnosis to be confirmed by a 12-lead ECG. This study aimed to assess whether or not the use of lead-I ECGs in GP surgeries could benefit these patients and offer good value for money to the NHS. All studies that examined how well lead-I ECGs identified people with AF were reviewed, and the economic value of using these devices was assessed. No evidence was found that examined the use of lead-I ECGs for people with signs or symptoms of AF. As an alternative, evidence for the use of lead-I ECGs for people with no symptoms of AF was searched for and these data were used to assess value for money. The study found that using a manual pulse check followed by a lead-I ECG offers value for money when compared with a manual pulse check followed by a 12-lead ECG. This is mostly because patients with AF can begin treatment earlier when a GP has access to a lead-I ECG device.