Lead V1 Research Articles

Is There a Relationship Between TP-e/QT Ratio and Spinal Anesthesia-Related Cardiovascular Events in Pregnant Women?

Introduction and Objective: Prolonged TPe interval has been reported to reflect the abnormal distribution of ventricular repolarization which can be used as a marker of ventricular arrhythmias. Since prolonged TPe/QT ratio is associated with cardiac pathologies, it is thought that it may also be associated with cardiovascular adverse events that occur during and after spinal anesthesia. The aim of this study is to investigate whether there is a relationship between prolonged TPe/QT ratio, which is routine preoperative non-invasive patient data that can be evaluated easily, and perioperative adverse cardiovascular events during cesarean section in pregnant women undergoing spinal anesthesia.
 Materials and Methods: Voluntary consent was obtained for our study in which 144 pregnant women who were planned for elective cesarean section were included. QT interval was measured based on the initial point where the Q wave or the R wave in the absence of the Q wave started to the last point where the T wave ended. TPe interval measurement was based on the peak point of the T wave and the end point of the T wave convexity. Lead V5 was primarily used for TPe measurement. TPe/QT ratios were calculated in Microsoft office excel program. Patients' demographic characteristics, heart rate, systolic, diastolic and mean arterial pressures were recorded every five minutes intraoperatively.
 Results: A weak positive correlation was found between the height variable and the Tpe/QT ratio (p=0.022, r=0.191). As the height increased, the TPe/QT ratio increased. Although it did not reach the level of statistical significance, we found that the TPe/QT ratio was longerin cases with intraoperative bradycardia and hypotension than in cases without complications. The TPe/QT ratio was above 0.21 in patients who developed bradycardia and hypotension. Examination of the correlation between the amount of ephedrine use and TPe/QT ratio revealed a weak positive correlation (p=0.012, r=0.208).
 Conclusion: TPe/QT ratio is a novel cardiac marker with high predictive power, is non-invasive, quite inexpensive, and very practical to measure in the early detection of cardiac events, especially arrhythmia. This novel predictive marker can be used in anesthesia practice, preoperative examination and patient follow-up in the intraoperative operating room to predict fatal cardiac arrhythmias or intraoperative hypo/hypertension. 
 Keywords: Spinal anesthesia, pregnancy, TPe/QT ratio, cardiovascular event

Terminal T-wave concordance is associated with SYNTAX score among left bundle branch block patients suspected of acute coronary syndrome without modified Sgarbossa criteria.

Timely and precise diagnosis of ischemic cardiac events based on electrocardiogram is challengeable among patients with Left Bundle Branch Block (LBBB). The present study aimed to assess the correlation between SYNTAX score and terminal T-wave morphologies among LBBB patients suspected of Acute Coronary Syndrome (ACS) without modified Sgarbossa criteria. This cross-sectional study was conducted on the LBBB patients suspected of ACS without modified Sgarbossa criteria. Binary logistic regression was used to assess the correlation of ischemic heart disease (IHD, SYNTAX score > 0) and SYNTAX score categories with terminal T-wave morphologies including T-wave direction in lead V6 and terminal T-wave concordance in leads I, V5, and V6. This study was done on 93 patients with the mean age of 62.4 ± 9.6 years. More than half of the patients were female (58.1%, 95% CI: 47.4% to 68.2%). Among the participants with IHD, the SYNTAX score categories were correlated to discordant terminal T-wave in leads I, V5, and V6 (OR = 5.71, 95% CI: 1.04 to 31.28, p = 0.04). Among the LBBB patients with acute ischemic cardiac events without modified Sgarbossa criteria, those with discordant terminal T-waves in leads I, V5, or V6 had higher SYNTAX scores and might require more invasive coronary revascularization techniques such as Coronary Artery Bypass Graft (CABG) surgery.

Assessment of the efficacy of the electrocardiographic P-wave peak time in predicting atrial high rate episode in patients with cardiac implantable electronic devices.

The incidence of atrial high-rate episode (AHRE) is high among patients with cardiac implantable electronic devices (CIEDs). In this context, the objective of this study is to evaluate the efficacies of P-wave indices (PWIs) obtained from the surface electrocardiography (ECG) in predicting future AHRE development. The study sample consisted of 158 patients with CIEDs. The study group was divided into two subgroups according to the presence of AHRE during device interrogation. PWIs were calculated using the surface ECG. There was no significant difference between the groups in the P-wave indices (PWIs), i.e., minimum P-wave duration (PWDmin), maximum P-wave duration (PWDmax) and P-wave dispersion (PWDIS). On the other hand, P-wave peak time in V1 lead (PWTV1) and P-wave peak time in D2 lead (PWPTD2) were significantly higher in the AHRE group than in the non-AHRE group. The study findings revealed that novel ECG parameters PWPTV1 and PWPTD2 had high prognostic value in predicting patients likely to develop AHRE.

Electric Field of the Heart on the Thorax Surface in Highly Trained Athletes during Initial Ventricular Activity

The article is focused on the study of the electrical remodeling of the “sports heart” using multichannel ECG mapping to make a more detailed and informative analysis of the excitation of the myocardium remodeled by sport activity. The study of the heart electrical activity was carried out from 64 unipolar electrodes on the thorax surface synchronously with standard limb leads in highly trained cross-country skiers (n = 15) and young non-trained men (n = 19) at rest. The amplitude-temporal and spatiotemporal characteristics of the electric field of the heart were measured. By the typical distribution of areas of the negative and positive cardiac potentials the durations of depolarization and its individual phases were estimated. ECGII was used to determine the duration of the R-R, PQ (PR), QRS, QT, QTc intervals; in the unipolar lead V5 the R-wave peak time (RWPTV5) was measured. In athletes, the duration of PQII, QTII, QTcII, RWPTV5 intervals were statistically significantly longer than in non-trained men. Analysis of the electrical field of the heart showed a difference in the ratio of the phases of ventricular depolarization in athletes and non-trained individuals at rest. The onset of ventricular depolarization and the first inversion of cardiac potential in athletes were significantly earlier than in non-trained people, while the completion and total duration of the period of ventricular depolarization did not differ. In skiers, the duration of the first inversion was significantly longer than in non-trained individuals; a tendency to shortening of the second period of stable location of potentials on the thorax surface was also shown. The use of surface ECG mapping made it possible to reveal differences in the spatiotemporal organization of heart ventricular depolarization between cross-country skiers and non-trained men at rest. The results of the study may be useful in the analysis of the electrical remodeling of the heart in athletes training the physical quality of endurance.

Sinus rhythm QRS morphology reflects right ventricular activation and anatomical ventricular tachycardia isthmus conduction in repaired tetralogy of Fallot

Patients with repaired tetralogy of Fallot (TOF) are at risk for ventricular tachycardia (VT) related to well-described anatomical isthmuses. The purpose of this study was to explore QRS morphology as an indicator of anatomical isthmus conduction. Patients with repaired TOF and complete right bundle branch block referred for transcatheter pulmonary valve replacement (PVR) or presenting with sustained VT underwent comprehensive 3-dimensional mapping in sinus rhythm. Electrocardiographic characteristics were compared to right ventricular (RV) activation and anatomical isthmus conduction properties. Twenty-two patients (19 pre-pulmonary valve replacement and 3 clinical VT) underwent comprehensive 3-dimensional mapping (median 39 years; interquartile range [IQR] 27-48 years; 12 [55%] male). Septal RV activation (median 40 ms; IQR 34-46 ms) corresponded to the nadir in lead V1 and free wall activation (median 71 ms; IQR 64-81 ms) to the transition point in the upstroke of the R' wave. Patients with isthmus block between the pulmonary annulus and the ventricular septal defect patch and between the ventricular septal defect patch and the tricuspid annulus (when present), were more likely to demonstrate lower amplitude R' waves in lead V1 (5.8 mV vs 9.4 mV; P = .005), QRS fragmentation in lead V1 (15 [94%] vs 2 [13%]; P < .001), and terminal S waves in lead aVF (15 [94%] vs 6 [40%]; P < .001) than those with intact conduction. During catheter ablation, these QRS changes developed during isthmus block. For patients with repaired TOF, the status of septal isthmus conduction was evident from sinus rhythm QRS morphology. Low-amplitude, fragmented R' waves in lead V1 and terminal S waves in the inferior leads were related to septal isthmus conduction abnormalities, providing a mechanistic link between RV activation and common electrocardiographic findings.

Predictors of implantation failure in left bundle branch area pacing using a lumenless lead in patients with bradycardia.

Left bundle branch area pacing (LBBAP) is a novel conduction system pacing technique. In this multicenter study, we aimed to evaluate the procedural success, safety, and preoperative predictors of procedural failure of LBBAP. LBBAP was attempted in 285 patients with pacemaker indications for bradyarrhythmia, which were mainly atrioventricular block (AVB) (68.1%) and sick sinus syndrome (26.7%). Procedural success and electrophysiological and echocardiographic parameters were evaluated. LBBAP was successful in 247 (86.7%) patients. Left bundle branch (LBB) capture was confirmed in 54.7% of the population. The primary reasons for procedural failure were the inability of the pacemaker lead to penetrate deep into the septum (76.3%) and failure to achieve shortening of stimulus to left ventricular (LV) activation time in lead V6 (18.4%). Thickened interventricular septum (odds ratio [OR], 2.48; 95% confidence interval [CI], 1.15-5.35), severe tricuspid regurgitation (OR, 8.84; 95% CI, 1.22-64.06), and intraventricular conduction delay (OR, 8.16; 95% CI, 2.32-28.75) were preoperative predictors of procedural failure. The capture threshold and ventricular amplitude remained stable, and no major complications occurred throughout the 2-year follow-up. In patients with ventricular pacing burden >40%, the LV ejection fraction remained high regardless of LBB capture. Successful LBBAP was affected by abnormal cardiac anatomy and intraventricular conduction. LBBAP is feasible and safe as a primary strategy for patients with AVB, depending on ventricular pacing.

Electrocardiographic Characteristics of Ventricular Arrhythmias Originating from Different Areas Adjacent to the Mitral Annulus.

This study aimed to explore the electrocardiographic (ECG) characteristics of ventricular arrhythmias (VAs) arising from epicardial and endocardial areas adjacent to the mitral annulus (MA). This study involved 283 patients with MA-VAs who received radiofrequency catheter ablation at the center. The ECG characteristics of these patients were analyzed retrospectively. The origin of MA-VAs was judged based on the ECG variables. Among all MA-VAs, intrinsicoid deflection time (IDT) > 77 ms or maximum deflection index (MDI) > 0.505 predicted the VAs arising from the epicardium (sensitivity of 70.20% and 73.51%, specificity of 94.70% and 82.58%, positive predictive value (PPV) of 93.81% and 82.84%, and negative predictive value (NPV) of 73.53% and 73.15%). Among all epicardial MA-VAs, the RV1/RV2 ratio > 0.87 predicted the VAs originating from the epicardial anteroseptal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 62.86%, 98.06%, 91.67%, and 88.60%, respectively. Among all endocardial MA-VAs, Q(q)R(r) morphology in lead V1 predicted the VAs arising from the endocardial septal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 92.98%, 100%, 100%, and 94.94%, respectively. Among all endocardial septal MA-VAs, a predominant positive wave in lead II and a predominant negative wave in lead III predicted the VAs arising from the endocardial midseptal portion adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 86.04%, 100%, 100%, and 70.00%, respectively. the ECG characteristics of VAs from the different sites adjacent to the MA can enable judging the arrhythmia's origin and designing the ablation plan accordingly.

Diverse QRS morphology reflecting variations in lead placement for left bundle branch area pacing.

Left bundle branch area pacing (LBBAP) is a potential alternative to His bundle pacing. This study aimed to investigate the impact of different septal locations of pacing leads on the diversity of QRS morphology during non-selective LBBAP. Non-selective LBBAP and left ventricular septal pacing (LVSP) were achieved in 50 and 21 patients with atrioventricular block, respectively. The electrophysiological properties of LBBAP and their relationship with the lead location were investigated. QRS morphology and axis showed broad variations during LBBAP. Echocardiography demonstrated a widespread distribution of LBBAP leads in the septum. During non-selective LBBAP, the qR-wave in lead V1 indicated that the primary location for pacing lead was the inferior septum (93%). The non-selective LBBAP lead was deployed deeper than the LVSP lead in the inferior septum. The Qr-wave in lead V1 with the inferior axis in aVF suggested pacing lead placement in the anterior septum. The penetration depth of the non-selective LBBAP lead in the anterior septum was significantly shallower than that in the inferior septum (72 ± 11 and 87 ± 8%, respectively). In lead V6, the deep S-wave indicated the time lag between the R-wave peak and the latest ventricular activation in the coronary sinus trunk, with pacemaker leads deployed closer to the left ventricular apex. Different QRS morphologies and axes were linked to the location of the non-selective LBBAP lead in the septum. Various lead deployments are feasible for LBBAP, allowing diversity in the conduction system capture in patients with atrioventricular block.

Electrical Synchrony Optimization for Left Bundle Branch Area Pacing in Patients With Bradycardia and Heart Failure

Left bundle branch area pacing (LBBAP) has emerged as a promising physiological pacing modality. This study was designed to investigate the acute impact of the atrioventricular delay (AVD) on cardiac electrical characteristics and identify an optimal range of AVDs for LBBAP to achieve electrical atrioventricular and interventricular synchrony. Patients indicated for ventricular or biventricular pacing were studied during routine follow-ups at least 3months after LBBAP implantation. Patients were excluded if they had a complete AV block or persistent atrial fibrillation. AVD was programed from 40 to 240ms or until intrinsic conduction occurred. Optimal AVD was determined by the electrocardiography criteria, including QRS duration, reduced R-wave in lead V1, reduced notching or slurring in lateral leads, and more desirable precordial QRS transition. A total of 38 patients (age 68.7 ± 10.3years; 16 male (42%); 18 dual-chamber pacemakers and 20 cardiac resynchronization therapy devices; average follow-up period 15.1 ± 10.2months) were included. The fusion of LBBAP and intrinsic right ventricular conduction occurred in 21 patients with corresponding optimal AVD determined. A great proportion (∼85%) of the optimal AVDs ranged from 50% to 80% of the observed atrium-to-left bundle branch-sensing (A-LBBS) intervals. The linear correlation between the optimal AVD and corresponding A-LBBS interval (optimal AVD=0.84×[A-LBSs interval] - 36ms) produced R=0.86 and p <0.0001. In conclusion, AVD selection during LBBAP greatly impacted the ventricular electrical characteristics and the optimal AVD was linearly correlated with the corresponding A-LBBS interval.

Bilateral Bundle Branch Block.

Left bundle branch block (LBBB) and right bundle branch block (RBBB) are classic manifestations of bundle branch conduction disorders. However, a third form that is uncommon and underrecognized may exist that has features and pathophysiology of both: bilateral bundle branch block (BBBB). This unusual form of bundle branch block exhibits an RBBB pattern in lead V1 (terminal R wave) and an LBBB pattern in leads I and aVL (absence of S wave). This unique conduction disorder may confer an increased risk of adverse cardiovascular events. BBBB patients may be a subset of patients that respond well to cardiac resynchronization therapy.

Activation recovery interval as an electrocardiographic repolarization index to detect doxorubicin-induced cardiotoxicity

BackgroundIt has been reported that early detection and treatment of cancer therapy- related cardiac dysfunction (CTRCD) improves its prognosis. The detailed relationships between electrocardiographic repolarization indices and decreased left ventricular function in CTRCD have not been elucidated. We closely assessed such relationships in patients with doxorubicin (DOX)-induced CTRCD. MethodsThis retrospective, single-center, cohort study included 471 consecutive patients with malignant lymphoma who received chemotherapy including DOX. Of them, 17 patients with CTRCD and 68 patients without CTRCD who underwent 12‑lead electrocardiogram and an echocardiogram before and after chemotherapy were eventually analyzed. The fluctuations of the following electrocardiographic repolarization indices were evaluated in lead V5: QT, JT, T peak to T end interval (Tp-e), and activation recovery interval (ARI). These indices were corrected by heart rate with the Fridericia formula. ResultsThe median period from the end of chemotherapy to the diagnosis of the CTRCD group was 346 days (IQR 170–1283 days). After chemotherapy, the QT interval was significantly prolonged in both with and without CTRCD groups compared with that before chemotherapy (pre QTc vs. post QTc in CTRCD group, 386 ± 27 ms vs. 411 ± 37 ms, p = 0.03, pre QTc vs. post QTc in non-CTRCD group, 388 ± 24 ms vs. 395 ± 25 ms, p = 0.04, respectively). ARIc after chemotherapy was characteristically observed only in the CTRCD group (pre ARIc vs. post ARIc in CTRCD group, 258 ± 53 ms vs. 211 ± 28 ms, p = 0.03, pre ARIc vs. post ARIc in non-CTRCD group, 221 ± 19 ms vs. 225 ± 23 ms, NS, respectively) and had negative correlations with left ventricular ejection fraction (r = −0.56, p < 0.001). Using the receiver-operating characteristic curve, the relationship between ARIc and CTRCD morbidity was examined. The optimal cut-off point of ARIc prolongation between before and after chemotherapy was 18 ms (sensitivity 75 %, specificity 79 %, area under the curve 0.76). ConclusionsARIc prolongation may be useful in the early detection of developing late-onset chronic DOX-induced CTRCD and lead to early treatment for cardiac protection.

Electrocardiographic characteristics of right-bundle-branch-block premature ventricular complexes predicting absence of left ventricular scar in athletes with apparently structural normal heart.

Left ventricular scar is an arrhythmic substrate that may be missed by echocardiography and diagnosed only by cardiac magnetic resonance (CMR), which is a time-consuming and expensive imaging modality. Premature ventricular complexes (PVCs) with a right-bundle-branch-block (RBBB) pattern are independent predictors of late gadolinium enhancement (LGE) but their positive predictive value is low. We studied which electrocardiographic features of PVCs with an RBBB pattern are associated with a higher probability of the absence of an underlying LGE. The study included 121 athletes (36 ± 16 years; 48.8% men) with monomorphic PVCs with an RBBB configuration and normal standard clinical investigations who underwent CMR. LGE was identified in 35 patients (29%), predominantly in those with PVCs with a superior/intermediate axis (SA-IntA) compared to inferior axis (IA) (38% vs. 10%, P = 0.002). Among patients with SA-IntA morphology, the contemporary presence of qR pattern in lead aVR and V1 was exclusively found in patients without LGE at CMR (51.0% vs. 0%, P < 0.0001). Among patients with IA, the absence of LGE correlated to a narrow ectopic QRS (145 ± 16 vs. 184 ± 27 msec, P < 0.001). Among athletes with apparently idiopathic PVCs with a RBBB configuration, the presence of a concealed LGE at CMR was documented in 29% of cases, mostly in those with a SA-IntA. In our experience, the contemporary presence of qR pattern in lead aVR and V1 in PVCs with RBBB/SA-IntA morphology or, on the other hand, a relatively narrow QRS in PVCs with an IA, predicted absence of LGE.

New ECG Algorithm for the Prediction of Culprit Vessel in Acute Myocardial Infarction Involving Lateral Part of the Ventricle: Ilkay Classification.

Isolated lateral myocardial infarction sometimes does not meet ST-segment elevation myocardial infarction (STEMI) criteria according to contiguous leads. This condition could cause late diagnosis and the need for revascularization therapy. To accurately predict the occlusion of lateral surface of the left ventricle, we defined a new electrocardiogram (ECG) algorithm by using angiographic and electrocardiographic correlations. This was a retrospective, multicenter observational study. The study population consisted of 200 patients with STEMI affecting lateral surface of myocardium, between 2021 and 2022. According to the coronary angiography results, we identified 74 eligible patients for study protocol. The study patients were divided into two groups: isolated DB (14 patients) or circumflex obtuse marginal group (60 patients). ST depression in lead V2 had high positive predictive values for the prediction of obtuse marginal occlusion (positive predictive values (PPV), 100%; negative predictive value (NPV), 90%). ST elevation in V2 in ECG, in conjunction with ST depression in lead III had high positive predictive values for prediction of diagonal branch of LAD. Moreover, the presence of hyperacute T wave (≥10 mm) in lead V2 and ≥2 mm ST depression in lead III had large diagonal branch of LAD (PPV, 98%; NPV, 100%). However, <10 mm T wave in lead V2 and <2 mm ST depression in lead III had small diagonal branch of LAD. We comprehensively classified the lateral STEMI definition through new electrocardiographic scheme as Ilkay classification, whereby we could accurately predict infarct-related artery and its occlusion level in lateral myocardial infarction.

Predictors of atrial fibrillation post coronary artery bypass graft surgery: new scoring system

BackgroundAtrial fibrillation (AF) following coronary artery bypass graft surgery (CABG) is common and results in significant increases in hospital stay and financial encumbrance.ObjectiveDetermine and use the predictors of postoperative AF...

Identification of patients with dilated phase of hypertrophic cardiomyopathy using a convolutional neural network applied to multiple, dual, and single lead electrocardiograms.

This study sought to develop an artificial intelligence-derived model to detect the dilated phase of hypertrophic cardiomyopathy (dHCM) on digital electrocardiography (ECG) and to evaluate the performance of the model applied to multiple-lead or single-lead ECG. This is a retrospective analysis using a single-center prospective cohort study (Shinken Database 2010-2017, n=19,170). After excluding those without a normal P wave on index ECG (n=1,831) and adding dHCM patients registered before 2009 (n=39), 17,378 digital ECGs were used. Totally 54 dHCM patients were identified of which 11 diagnosed at baseline, 4 developed during the time course, and 39 registered before 2009. The performance of the convolutional neural network (CNN) model for detecting dHCM was evaluated using eight-lead (I, II, and V1-6), single-lead, and double-lead (I, II) ECGs with the five-fold cross validation method. The area under the curve (AUC) of the CNN model to detect dHCM (n=54) with eight-lead ECG was 0.929 (standard deviation [SD]: 0.025) and the odds ratio was 38.64 (SD 9.10). Among the single-lead and double-lead ECGs, the AUC was highest with the single lead of V5 (0.953 [SD: 0.038]), with an odds ratio of 58.89 (SD:68.56). Compared with the performance of eight-lead ECG, the most similar performance was achieved with the model with a single V5 lead, suggesting that this single-lead ECG can be an alternative to eight-lead ECG for the screening of dHCM.

The Diagnostic Accuracy of Electrocardiogram in Differentiating Takotsubo Cardiomyopathy in Patients Presenting as Anterior Wall St-Segment Elevation Myocardial Infarction and Taking Coronary Angiography as Gold Standard

Myocardial infarction: Myocardial infarction is the irreparable damage to heart muscles resulting in necrosis &amp; is the leading cause of death; resulting in 500,000-700,000 important deaths related to the coronary artery occur each year. Cardiovascular disease is the most common reason resulting in premature mortality as well as morbidity among various ethnic group of white, black and Hispanic populations. Takotsubo Cardiomyopathy: TCM is a condition that affects the heart reversible syndrome, characteristic of decrease(hypokinesia)/ near absent movement (akinesia) of distal half of interventricular septum &amp; cardiac apex showed as apical ballooning on echocardiogram with absence of an obstructive defect in epicardial coronary arteries following an emotional disturbance. Objective: To determine the diagnostic accuracy of electrocardiographic findings (elevation &lt; 1mm Takotsubo cardiomyopathy can be identified in lead V1 in patients who have anterior wall ST-segment elevation myocardial infarction by taking coronary angiography as gold standard. Design: Cross-sectional survey Subjects &amp; Methods: Using 250 incidences in the sample, and a 95% confidence level, a 13% error margin, and the anticipated percentage of Takotsubo cardiomyopathy i.e, 18% by using 74.2% sensitivity and 80.6% specificity of electrocardiographic findings i.e, ST-elevation of &gt; 1mm in V1 in the detection of Takotsubo cardiomyopathy when myocardial infarction with ST-elevation in the anterior wall is the presenting symptom and coronary angiography as gold standard2. Results: The patients were 49 + 13 years old on average. Sensitivity &amp; specificity of ECG criteria were 40.78% &amp; 78.65%. The positive &amp; negative predictive values were 43.28% &amp; 76.5% respectively. Practical Implication: Our study showed negative association of ST-elevation of &gt;1mm in ECG lead V1 to differentiate TC from anterior wall myocardial infarction. Further studies should be done to probe into the diagnostic accuracy of ECG in differentiating TC from acute anterior wall myocardial infarction. Conclusion: Electrocardiography is not diagnostic for distinguishing acute anterior wall pain from Takotsubo cardiomyopathy myocardial infarction so additional investigations need to be performed to diagnose the Takotsubo Cardiomyopathy. Keywords: Myocardial infarction, Takotsubo cardiomyopathy, Electrocardiogram, diagnostic accuracy Coronary angiography.

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

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Ministère de la Santé Française Background 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. Materials and Methods 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 (included in the logiciel CalECG). 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. Results 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 &amp;gt;113 ms (AUROC 0.69 (95% CI [0.58-0.8])) was associated with a 3-fold increased risk of major event (HR =3.49 (95% CI [1.72-7.09]), p=0.001). Conclusion 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.

Electrocardiographic markers of subclinical atrial fibrillation detected by implantable loop recorder

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The LOOP Study was funded by Innovation Fund Denmark [grant number 12-1352259], The Research Foundation for the Capital Region of Denmark, The Danish Heart Foundation [grant number 11-04-R83-A3363-22625], Aalborg University Talent Management Program, Arvid Nilssons Fond, Skibsreder Per Henriksen, R og Hustrus Fond, the European Union’s Horizon 2020 program [grant number 847770], Læge Sophus Carl Emil Friis og hustru Olga Doris Friis’ Legat, and an unrestricted grant from Medtronic. Background Atrial fibrillation (AF) is a well-known and treatable risk factor for stroke, which has sparked a substantial interest in AF screening. However, further insights into subclinical AF development are warranted to inform strategies of screening and subsequent clinical management upon AF detection. Purpose This study sought to identify 12-lead electrocardiogram (ECG) parameters associated with the onset, burden and progression of subclinical AF detected by long-term continuous monitoring. Methods We included AF-naïve individuals aged 70-90 years with ≥1 additional stroke risk factors (hypertension, diabetes, heart failure, or prior stroke) who underwent implantable loop recorder (ILR) monitoring in the LOOP Study. Using data from daily ILR recordings and computerized analysis of baseline ECG, we studied empirically selected ECG parameters for AF detection (≥6 minutes), cumulative AF burden, long-lasting AF (≥24 hours), and AF progression. Results Of 1370 individuals included, 419 (30.6%) developed AF during follow-up, with a mean cumulative AF burden of 1.5% [95% confidence interval (CI): 1.2-1.8%]. Several P-wave-related and ventricular ECG parameters were associated with new-onset AF as well as 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 the risk of AF episode ≥24 hours. Among AF patients, we observed an overall reduction in cumulative AF burden over time (incidence rate ratio 0.70 [95% CI: 0.51-0.96]), whereas IAB was related to an increased risk of progression to AF episodes ≥24 hours (hazard ratio 1.86 [95% CI: 1.02-3.39]). Further spline analysis revealed longer PWD to also be associated with this progression in AF duration. Conclusions We identified several ECG parameters associated with new-onset AF detected by ILR. Especially PWD and IAB were robustly related to the onset and the burden of subclinical AF as well as progression over time.

Left-to-right atrioventricular activation delay, a novel measure of AV-conduction, predicts clinical outcomes in non-LBBB patients

Abstract Funding Acknowledgements Type of funding sources: None. Background The PR-interval reflects atrial and atrioventricular activation. A prolonged PR has been linked to heart failure (HF), atrial fibrillation and mortality. This might at least in part be the consequence of compromised cardiac performance (e.g. left ventricular filling). On the other hand, very long PR may just be a marker of advanced heart disease. Alternative measures that account for atrial and ventricular activation might better predict adverse hemodynamic consequences of delayed atrioventricular conduction. The DEEPER-PR mechanistic pilot study suggested that various novel measures of AV conduction are associated with Doppler-derived cardiac performance. However, the clinical significance of these novel parameters is unknown. Study objective: To examine the association of novel measures of AV conduction with clinical outcomes in a HFrEF population with non-LBBB and a wide QRS (non-LBBB ICD-only MADIT-CRT subset). Methods Time intervals from anonymized scanned baseline 12-lead ECGs from the Multicenter Automatic Defibrillator Implantation Trial – Cardiac Resynchronization Therapy (MADIT-CRT), non-LBBB patients (n=537) were assessed in detail using ImageJ (public domain software provided by NIH). The primary endpoint of the study was the combined endpoint of heart failure (HF) or death events. The earliest onset of atrial activation (P wave onset), zero crossing of the P wave in lead V1, earliest onset of the QRS complex, time interval to the first peak of the R wave in V1 and V6, and QRS width were determined. The PR interval and 8 novel parameters (see figure 1) were measured and calculated accordingly. Bivariate non-parametric correlations were calculated to ascertain the associations between these covariates. In addition, Kaplan-Meier analyses by quintiles of all AV delay measures, and multivariable Cox regression analyses were performed among ICD-only patients (n=209) to determine the associated risk regarding of the combined MADIT-CRT clinical outcome of HF events or death. Results Weak correlations were found between the AV delay variables (figure 2). Four of the variables (P0PV1, P0R, PePV6, PR) were significantly associated to the risk of HF or death with the upper quintile defining a high-risk HF population, as compared to quintiles 1 to 4 (see figure 3). This indicated a threshold behavior of the associations. P0PV1 was the most powerful risk predictor (Chi-square=16.31, HR for Q5 vs. Q1-4=3.12, CI=1.80-5.41, p&amp;lt;0.001), followed by PRmax (Chi-square=13.19, HR for Q5 vs. Q1-4=2.81, CI=1.61-4.92, p&amp;lt;0.001), P0R (Chi-square=10.42, HR=2.54, CI=1.44-4.48, p=0.001), and PePV6 (Chi-square=7.96, HR for Q5 vs. Q1-4=2.2, CI=1.29-4.07, p=0.005). Conclusion This post-hoc ECG-based study identified in MADIT-CRT non-LBBB patients the left-to-right atrioventricular activation delay (P0PV1) as the most powerful risk predictor of HF or death. Prospective evaluation of this measure is warranted.

Catheter ablation of ventricular premature depolarizations originating from the mid interventricular septum: Significance of electrocardiographic morphology for predicting origin

Ventricular premature depolarizations (VPDs) originating from the mid interventricular septum (IVS) adjacent to the atrioventricular annulus between the His bundle and the coronary sinus ostium (mid IVS VPDs) have not been characterized. The aim of this study was to investigate the electrophysiological characteristics of mid IVS VPDs. Thirty-eight patients with mid IVS VPDs were enrolled. VPDs were divided into different types according to precordial transition of the electrocardiogram (ECG) and QRS morphology in lead V1. Four types of VPDs were divided. The precordial transition zone appeared earlier and earlier from types 1 to 4. The notch in lead V1 moved gradually backward, and its amplitude gradually became higher, resulting in the transition from left to right bundle branch block morphology in lead V1 from types 1 to 4. Based on activation and pace mapping, ablation response, and 3830 electrode pacing morphology in the mid IVS, the 4 types of ECG morphology corresponded to an origin in the right endocardial side, right/mid intramural region, left intramural region, and left endocardial side of the mid IVS, respectively. An intramural origin was identified for 50% of VPDs. Eighty-nine percent of mid IVS VPDs could be eliminated. Bilateral ablation (waiting for delayed efficacy) or bipolar ablation was sometimes needed for intramural VPDs. Mid IVS VPDs were found to have unique electrophysiological characteristics. The ECG characteristics of mid IVS VPDs were important in terms of prediction of its exact origin, the choice of ablation method, and the likelihood of treatment being successful.