AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram

The value of septal rebound stretch analysis for the prediction of volumetric response to cardiac resynchronization therapy

AIMS

Patient selection for cardiac resynchronization therapy (CRT) may be enhanced by evaluation of systolic myocardial stretching. We evaluate whether systolic septal rebound stretch (SRSsept) derived from speckle tracking echocardiography is a predictor of reverse remodelling after CRT and whether it holds additive predictive value over the simpler visual dyssynchrony assessment by apical rocking (ApRock).

METHODS AND RESULTS

The association between SRSsept and change in left ventricular end-systolic volume (ΔLVESV) at 6 months of follow-up was assessed in 200 patients. Subsequently, the additive predictive value of SRSsept over the assessment of ApRock was evaluated in patients with and without left bundle branch block (LBBB) according to strict criteria. SRSsept was independently associated with ΔLVESV (β 0.221, P = 0.002) after correction for sex, age, ischaemic cardiomyopathy, QRS morphology and duration, and ApRock. A high SRSsept (≥optimal cut-off value 2.4) also coincided with more volumetric responders (ΔLVESV ≥ -15%) than low SRSsept in the entire cohort (70.0% and 56.4%), in patients with strict LBBB (83.3% vs. 56.7%, P = 0.024), and non-LBBB (70.7% vs. 46.3%, P = 0.004). Moreover, in non-LBBB patients, SRSsept held additional predictive information over the assessment of ApRock alone since patients that showed ApRock and high SRSsept were more often volumetric responder than those with ApRock but low SRSsept (82.8% vs. 47.4%, P = 0.001).

CONCLUSION

SRSsept is strongly associated with CRT-induced reduction in left ventricular end-systolic volume and holds additive prognostic information over QRS morphology and ApRock. Our data suggest that CRT patient selection may be improved by assessment of SRSsept, especially in the important subgroup without strict LBBB.

CLINICAL TRIAL REGISTRATION

The MARC study was registered at clinicaltrials.gov: NCT01519908.

Increasing modified CHA2DS2-VASc risk score is associated with acute cardiac injury in hospitalised COVID-19 patients

BACKGROUND

Prediction of hospital mortality in patients with COVID-19 by the CHA2DS2VASc (M-CHA2DS2VASc) has been recently shown. Because COVID-19 patients with acute cardiac injury have higher mortality compared to those without, we assumed that this risk score may also predict acute cardiac injury in these patients.

METHODS

In this retrospective, single centre cohort study, we included 352 hospitalised patients with laboratory-confirmed COVID-19 and divided into three groups according to M-CHA2DS2VASc risk score which was created by changing gender criteria of the CHA2DS2VASc from female to male (Group 1, score 0-1 (n = 142); group 2, score 2-3 (n = 138) and group 3, score ≥4 (n = 72)).

RESULTS

As the M-CHA2DS2VASc risk score increased, acute cardiac injury was also significantly increased (Group 1, 11.3%; group 2, 48.6%; group 3, 76%; p < 0.001). The higher M-CHA2DS2VASc tertile had higher prevalence of arrhythmias compared to lower tertile. The multivariate logistic regression analysis showed that M-CHA2DS2VASc risk score, admission to intensive care unit and invasive mechanical ventilation were independent predictors of acute cardiac injury (p = 0.001, odds ratio 1.675 per scale for M-CHA2DS2VASc). In receiver operating characteristic analysis, M-CHA2DS2VASc risk score was able to predict acute cardiac injury (Area under the curve value for acute cardiac injury was 0.80; p < 0.001).

CONCLUSION

Admission M-CHA2DS2VASc risk score was associated with acute cardiac injury in hospitalised patients with COVID-19.

Occurrence and Persistency of Conduction Disturbances during Transcatheter Aortic Valve Implantation

Background and Objectives: Conduction disturbances such as left bundle branch block (LBBB) and complete atrio-ventricular block (cAVB) are relatively frequent complications following trans-catheter aortic valve implantation (TAVI). We investigated the dynamics of these conduction blocks to further understand luxating factors and predictors for their persistency. Materials and Methods: We prospectively included 157 consecutive patients who underwent a TAVI procedure. Electrocardiograms (ECGs) were obtained at specific time points during the TAVI procedure and at follow-up until at least six months post-procedure. Results: Of the 106 patients with a narrow QRS complex (nQRS) before TAVI, ~70% developed LBBB; 28 (26.4%) being classified as super-transient (ST-LBBB), 20 (18.9%) as transient (T-LBBB) and 24 (22.6%) as persistent (P-LBBB). Risk of LBBB was higher for self-expandable (SE) than for balloon-expandable (BE) prostheses and increased with larger implant depth. During the TAVI procedure conduction disturbances showed a dynamic behavior, as illustrated by alternating kinds of blocks in 18 cases. Most LBBBs developed during balloon aortic valvuloplasty (BAV) and at positioning and deployment of the TAVI prosthesis. The incidence of LBBB was not significantly different between patients who did and did not undergo BAV prior to TAVI implantation (65.3% and 74.2%, respectively (p = 0.494)). Progression to cAVB was most frequent for patients with preexisting conduction abnormalities (5/34) patients) and in patients showing ST-LBBB (6/28). Conclusions: During the TAVI procedure, conduction disturbances showed a dynamic behavior with alternating types of block in 18 cases. After a dynamic period of often alternating types of block, most BBBs are reversible while one third persist. Patients with ST-LBBB are most prone to progressing into cAVB. The observation that the incidence of developing LBBB after TAVI is similar with and without BAV suggests that a subgroup of patients has a substrate to develop LBBB regardless of the procedure.

Impact of electrophysiological features acquired after anatomical repair of congenital corrected transposition of the great arteries on late mortality and ventricular dysfunction

OBJECTIVES

In patients with anatomically repaired congenitally corrected transposition of the great arteries, the impact of electrophysiological features on postoperative ventricular dysfunction remains less well known. Our goal was to investigate the role of fragmented QRS and QRS duration in mortality and systemic ventricular dysfunction after anatomical repair of corrected transposed great arteries.

METHODS

Consecutive patients who underwent anatomical repair in our institution from January 2005 to December 2017 were enrolled in this retrospective analysis. Fragmented QRS was defined as ≥1 discontinuous deflections in narrow QRS complexes, and ≥2 in wide QRS complexes, in 2 contiguous electrocardiogram leads. The primary end point was a composite of all-cause mortality and systemic ventricular dysfunction.

RESULTS

A total of 74 patients were included. Among them, 30, 15 and 29 underwent the Senning arterial switch, the Senning Rastelli and the hemi-Mustard/bidirectional Glenn/Rastelli procedures, respectively. The primary end point occurred in 9 (12.2%) patients and included 7 late deaths and 2 cases of late-onset systemic ventricular dysfunction. Fragmented QRS and QRS prolongation were noted in 19 (25.7%) and 21 (28.4%) patients, respectively. In patients with the primary end point, QRS fragmentation (6/9 vs 10/65; P < 0.001) and QRS prolongation (6/9 vs 15/65; P = 0.013) were noted more frequently than in patients without the primary end point. No statistical differences in these electrocardiogram findings were found among patients treated with 3 surgical strategies.

CONCLUSIONS

Appearance of QRS fragmentation or QRS prolongation is associated with death or ventricular dysfunction in anatomically repaired corrected transposition of the great arteries. Although there is a trend that QRS fragmentation and QRS prolongation appear more frequently in patients who had the Senning-arterial switch operation, there is no statistically significant difference associated with these electrocardiogram features among varied procedures.

Newly acquired complete right bundle branch block early after heart transplantation is associated with lower survival

Aims

Right bundle branch block (RBBB) after heart transplantation (HTX) is a common finding, but its impact on post‐transplant survival remains uncertain. This study investigated the post‐transplant outcomes of patients with complete RBBB (cRBBB) ≤ 30 days after HTX.

Methods

This registry study analysed 639 patients receiving HTX at Heidelberg Heart Center between 1989 and 2019. Patients were stratified by diagnosis of cRBBB ≤ 30 days after HTX. Analysis included recipient and donor data, medication, echocardiographic features, graft rejections, atrial fibrillation, heart rates, permanent pacemaker implantation and mortality after HTX including causes of death.

Results

One hundred thirty‐nine patients showed cRBBB ≤ 30 days after HTX (21.8%), 20 patients with pre‐existing cRBBB in the donor heart (3.2%) and 119 patients with newly acquired cRBBB (18.6%). Patients with newly acquired cRBBB had a worse 1‐year post‐transplant survival (36.1%, P < 0.01) compared with patients with pre‐existing cRBBB (85.0%) or without cRBBB (86.4%), along with a higher percentage of death due to graft failure (P < 0.01). Multivariate analysis indicated cRBBB ≤ 30 days after HTX as significant risk factor for 1‐year mortality after HTX (HR: 2.20; 95% CI: 1.68–2.87; P < 0.01). Secondary outcomes showed a higher rate of an enlarged right atrium (P = 0.01), enlarged right ventricle (P < 0.01), reduced right ventricular function (P < 0.01), 30‐day atrial fibrillation (P < 0.01) and 1‐year permanent pacemaker implantation (P = 0.02) in patients with cRBBB after HTX.

Conclusions

Newly acquired cRBBB early after HTX is associated with increased post‐transplant mortality.

Impact of baseline conduction abnormalities on outcomes after transcatheter aortic valve replacement with SAPIEN-3

BACKGROUND

Baseline conduction abnormalities are known risk factors for permanent pacemaker (PPM) implantation after transcatheter aortic valve replacement (TAVR). We sought to determine the impact of baseline right bundle branch block (RBBB), left bundle branch block (LBBB), left anterior hemiblock (LAHB), first-degree atrioventricular block (AVB) and atrial fibrillation/flutter (AF) on TAVR outcomes.

METHODS

Consecutive patients who underwent transfemoral TAVR with SAPIEN-3 (S3) were included. We excluded patients with prior PPM, nontransfemoral access or valve-in-valve.

RESULTS

Among 886 patients, baseline RBBB was seen in 15.9%, LBBB in 6.3%, LAHB in 6.2%, first-degree AVB in 26.3% and AF in 37.5%. The rate of 30-day PPM was 10.1%. Baseline RBBB (OR 4.005; 95% CI 2.386-6.723; p < .001) and first-degree AVB (OR 1.847; 95% CI 1.133-3.009; p = .014) were independent predictors of 30 day PPM. LAHB also resulted in higher PPM rates but only in unadjusted analysis (21.8% vs. 9.4%; p = .003). Baseline LBBB and AF were associated with lower left ventricular ejection fraction (LVEF) at both baseline and 1 year after TAVR. However, Δ LVEF over time were noted to be similar with baseline LBBB (1.8% vs. 1.4%; p = .809) and AF (1.1% vs. 1.7%; p = .458). Moreover, baseline AF was also associated with higher stroke/transient ischemic attack (TIA) at 1 year (4.4% vs. 1.8%; p = .019), 1-year major adverse cardiac and cerebrovascular events (MACCE) (19.5% vs. 13.3%; p = .012) and 2 year mortality (23.5% vs. 15.2%; p = .016). None of the other baseline conduction defects affected long-term mortality or MACCE.

CONCLUSION

In our S3 TAVR population, baseline RBBB and first-degree AVB predicted higher PPM risk. Prior LBBB and AF were associated with lower LVEF at both baseline and 1 year. Lastly, preexisting AF was associated with higher rates of mortality, stroke/TIA, and MACCE.

Mechanisms of left ventricular dyssynchrony: A multinational SPECT study of patients with bundle branch block

BACKGROUND

To better understand the mechanisms of left ventricular (LV) mechanical dyssynchrony (LVMD), we explored the relative contributions of QRS duration (QRSd), LV ejection fraction (EF), volumes and scar to LVMD measured by gated single-photon emission tomography in a population of consecutive patients with left bundle branch block (LBBB) and right bundle branch block (RBBB) compared to controls.

METHODS

Myocardial perfusion imaging studies of 275 LBBB and 83 RBBB patients from three centers were analyzed. LVMD was defined as an abnormal phase bandwidth or phase standard deviation. Hospital and gender-specific normal values were obtained from 172 controls.

RESULTS

The prevalence of LVMD was 85 and 40% in LBBB and RBBB, respectively. Ejection fraction, scar severity, and LBBB morphology independently explained 70% of variance seen in PhaseBW. Ejection fraction had the highest area under the curve (AUC 0.918) in the receiver operating characteristics analysis of LVMD with an optimal cut-off of 47% (sensitivity 73% and specificity 98%). Notably, QRSd was not predictive.

CONCLUSION

LV mechanical dysfunction plays a greater role than conduction abnormality in the genesis of LVMD, a finding that is intriguing in the context of contemporary literature which suggests that QRSd is the parameter that is most predictive of CRT response.

Late arrhythmias in patients with new-onset persistent left bundle branch block after transcatheter aortic valve replacement using a balloon-expandable valve

BACKGROUND

The arrhythmic burden after discharge in patients with new-onset left bundle branch block (LBBB) undergoing transcatheter aortic valve replacement (TAVR) with the balloon-expandable SAPIEN 3 (S3) valve remains largely unknown.

OBJECTIVE

The purpose of this study was to determine the incidence of late arrhythmias in patients with new-onset LBBB undergoing TAVR with the balloon-expandable S3 valve.

METHODS

This was a multicenter, prospective study that included 104 consecutive TAVR patients with new-onset persistent LBBB following TAVR with the S3 valve. An implantable cardiac monitor (Reveal XT, Reveal LINQ) was implanted before discharge. The primary endpoint was the incidence of high-degree atrioventricular block or complete heart block (HAVB/CHB).

RESULTS

A total of 40 patients (38.5%) had at least 1 significant arrhythmic event, leading to a treatment change in 17 (42.5%). Significant bradyarrhythmias occurred in 20 of 104 patients (19.2%) (34 HAVB/CHB episodes, 252 severe bradycardia episodes), with 10 of 20 patients (50%) exhibiting at least 1 episode of HAVB/CHB. Most HAVB/CHB episodes (60%) occurred within 4 weeks after discharge. Nine patients (8.7%) underwent permanent pacemaker implantation at 12 months based on the Reveal findings (6 HAVB/CHB, 3 severe bradycardia).

CONCLUSION

S3 valve recipients with new-onset LBBB have a high arrhythmic burden, with more than one-third of patients exhibiting at least 1 significant arrhythmic episode within 12 months (HAVB/CHB in 10% of patients). About one-half of bradyarrhythmic events occurred within 4 weeks after discharge. These results should inform future strategies on the use of continuous electrocardiographic monitoring in TAVR S3 patients with new conduction disturbances following the procedure.

Cardiovascular risk assessment and association with novel biomarkers in patients with Type 2 diabetes mellitus

Aim: To investigate the association between cardiovascular risk and biomarkers in patients with Type 2 diabetes (T2DM). Methods: Cross-sectional study, with evaluation of traditional and new biomarkers (serum FGF-23, Syndecan-1 [Sdc-1] and vascular cell adhesion molecule-1 [VCAM-1] and urinary VEGF and kidney injury molecule-1 [KIM-1]) and risk scores (Framingham-FRS and UK Prospective Diabetes Study [UKPDS]). Results: 128 diabetics were included, with predominance of high risk by FRS and low risk by UKPDS. There was an independent association of VCAM-1 and VEGF with higher risk by FRS-lipids and UKPDS. Conclusion: There was an independent association of VCAM-1 and VEGF with higher cardiovascular risk, showing a subclinical endothelial dysfunction in T2DM. The inclusion of novel biomarkers to risk scores may increase accuracy when assessing cardiovascular risk of diabetic individuals.

The precordial R' wave: A novel discriminator between cardiac sarcoidosis and arrhythmogenic right ventricular cardiomyopathy in patients presenting with ventricular tachycardia

BACKGROUND

Cardiac sarcoidosis (CS) with right ventricular (RV) involvement can mimic arrhythmogenic right ventricular cardiomyopathy (ARVC). Histopathological differences may result in disease-specific RV activation patterns detectable on the 12-lead electrocardiogram. Dominant subepicardial scar in ARVC leads to delayed activation of areas with reduced voltages, translating into terminal activation delay and occasionally (epsilon) waves with a small amplitude. Conversely, patchy transmural RV scar in CS may lead to conduction block and therefore late activated areas with preserved voltages reflected as preserved R' waves.

OBJECTIVE

The purpose of this study was to evaluate the distinct terminal activation patterns in precordial leads V₁ through V₃ as a discriminator between CS and ARVC.

METHODS

Thirteen patients with CS affecting the RV and 23 patients with gene-positive ARVC referred for ventricular tachycardia ablation were retrospectively included in a multicenter approach. A non-ventricular-paced 12-lead surface electrocardiogram was analyzed for the presence and the surface area of the R' wave (any positive deflection from baseline after an S wave) in leads V₁ through V₃.

RESULTS

An R' wave in leads V₁ through V₃ was present in all patients with CS compared to 11 (48%) patients with ARVC (P = .002). An algorithm including a PR interval of ≥220 ms, the presence of an R' wave, and the surface area of the maximum R' wave in leads V₁ through V₃ of ≥1.65 mm² had 85% sensitivity and 96% specificity for diagnosing CS, validated in a second cohort (18 CS and 40 ARVC) with 83% sensitivity and 88% specificity.

CONCLUSION

An easily applicable algorithm including PR prolongation and the surface area of the maximum R' wave in leads V₁ through V₃ of ≥1.65 mm² distinguishes CS from ARVC. This QRS terminal activation in precordial leads V₁ through V₃ may reflect disease-specific scar patterns.

Electrocardiogram Criteria to Diagnose Cardiac Amyloidosis in Men With a Bundle Branch Block

Diagnosing cardiac amyloidosis is challenging and requires a high index of suspicion in patients with an increased left ventricular wall thickness (LVWT). Low QRS voltage on electrocardiogram (ECG) has been regarded as the hallmark ECG finding in cardiac amyloidosis; however, the presence of low voltage can range from 20-74% and the voltage/mass ratio carries a greater diagnostic accuracy than QRS voltage alone. Patients with cardiac amyloidosis can have conduction system infiltration and this may result in a BBB. Therefore, the ECG or mass/voltage criteria established for patients with a narrow QRS in the diagnosis of cardiac amyloidosis may not be applicable in patients with a BBB. We sought to identify criteria to aid in the diagnosis of cardiac amyloidosis in patients with increased LVWT on echocardiogram and with a BBB on ECG. We calculated the total QRS score/LVWT, limb lead QRS score/LVWT, R in lead aVL/LVWT, R in lead I/LVWT, and Sokolow index/LVWT. In patients with an increase in LVWT and BBB, total QRS voltage that is indexed to wall thickness can help distinguish between patients with increased wall thickness who have cardiac amyloidosis from those who have LVH related to a pressure overload state. A unique index of Total QRS Score/LVWT is the best predictor of cardiac amyloidosis with a cutoff value of 92.5 mV/cm which is 100% sensitive and 83% specific for the diagnosis of cardiac amyloidosis. This may be a useful screening tool in patients with an increased wall thickness to raise diagnostic suspicion for cardiac amyloidosis.

Wide QRS Complex and Lateral ST-T Segment Abnormality Are Associated With Worse Clinical Outcomes in COVID-19 Patients

BACKGROUND

The information on electrocardiographic features of patients with coronavirus disease 2019 (COVID-19) is limited. Our aim was to determine if baseline electrocardiographic features of hospitalized COVID-19 patients are associated with markers of myocardial injury and clinical outcomes.

METHODS

In this retrospective, single center cohort study, we included 223 hospitalized patients with laboratory-confirmed COVID-19. Clinical, electrocardiographic and laboratory data were collected and analyzed. Primary composite endpoint of mortality, need for invasive mechanical ventilation, or admission to the intensive care unit was assessed.

RESULTS

Forty patients (17.9%) reached the primary composite endpoint. Patients with the primary composite endpoint were more likely to have wide QRS complex (>120 ms) and lateral ST-T segment abnormality. The multivariable Cox regression showed increasing odds of the primary composite endpoint associated with acute respiratory distress syndrome (odds ratio 7.76, 95% CI 2.67-22.59; p < 0.001), acute cardiac injury (odds ratio 3.14, 95% CI 1.26-7.99; p = 0.016), high flow oxygen therapy (odds ratio 2.43, 95% CI 1.05-5.62; p = 0.037) and QRS duration longer than >120 ms (odds ratio 3.62, 95% CI 1.39-9.380; p = 0.008) Patients with a wide QRS complex (>120 ms) had significantly higher median level of troponin T and pro-BNP than those without it. Patients with abnormality of lateral ST-T segment had significantly higher median level of troponin T and pro-BNP than patients without.

CONCLUSIONS

The presence of QRS duration longer than 120 ms and lateral ST-T segment abnormality were associated with worse clinical outcomes and higher levels of myocardial injury biomarkers.

Relationship Between Procedural Right Bundle Branch Block and 1-Year Outcome After Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy - A Retrospective Study

BACKGROUND

Alcohol septal ablation (ASA) is a treatment option in patients with drug-refractory symptomatic hypertrophic obstructive cardiomyopathy (HOCM). In many patients, right bundle branch block (RBBB) develops during ASA because septal branches supply the right bundle branch. However, the clinical significance of procedural RBBB is uncertain.Methods and Results:We retrospectively reviewed 184 consecutive patients with HOCM who underwent ASA. We excluded 40 patients with pre-existing RBBB (n=10), prior pacemaker implantation (n=15), mid-ventricular obstruction type (n=10), and those lost to follow-up (n=5), leaving 144 patients for analysis. Patients were divided into 2 groups according to the development (n=95) or not (n=49) of procedural RBBB. ASA conferred significant decreases in the left ventricular pressure gradient (LVPG) in both the RBBB and no-RBBB group (from 74±48 to 27±27 mmHg [P<0.001] and from 75±45 to 31±33 mmHg [P<0.001], respectively). None of the RBBB patients developed further conduction system disturbances. The percentage reduction in LVPG at 1 year after the procedure was significantly greater in the RBBB than no-RBBB group (66±24% vs. 49±45%; P=0.035). Procedural RBBB was not associated with pacemaker implantation after ASA, but was associated with reduction in repeat ASA (odds ratio 0.34; 95% confidence interval 0.13-0.92; P=0.045).

CONCLUSIONS

Although RBBB frequently occurs during the ASA procedure, it does not adversely affect clinical outcomes.

Right Bundle Branch Block: Current Considerations

RBBB, a pattern seen on the 12-lead ECG, results when normal electrical activity in the His-Purkinje system is interrupted for some reason. The normal sequence of activation is altered in RBBB, with a resultant characteristic appearance on the ECG manifest by a widened QRS complex and changes in the directional vectors of the R and S waves. This ECG pattern is often seen in clinical practice and generally regarded as benign. The anatomy, epidemiology, causes, symptoms, ECG findings and diagnosis, differential diagnosis in ECG, treatment, complications, prognosis, with respect to RBBB are outlined here, demonstrating some typical ECGs of RBBB.

Valve Academic Research Consortium 3: updated endpoint definitions for aortic valve clinical research

Aims 

The Valve Academic Research Consortium (VARC), founded in 2010, was intended to (i) identify appropriate clinical endpoints and (ii) standardize definitions of these endpoints for transcatheter and surgical aortic valve clinical trials. Rapid evolution of the field, including the emergence of new complications, expanding clinical indications, and novel therapy strategies have mandated further refinement and expansion of these definitions to ensure clinical relevance. This document provides an update of the most appropriate clinical endpoint definitions to be used in the conduct of transcatheter and surgical aortic valve clinical research.

Methods and results 

Several years after the publication of the VARC-2 manuscript, an in-person meeting was held involving over 50 independent clinical experts representing several professional societies, academic research organizations, the US Food and Drug Administration (FDA), and industry representatives to (i) evaluate utilization of VARC endpoint definitions in clinical research, (ii) discuss the scope of this focused update, and (iii) review and revise specific clinical endpoint definitions. A writing committee of independent experts was convened and subsequently met to further address outstanding issues. There were ongoing discussions with FDA and many experts to develop a new classification schema for bioprosthetic valve dysfunction and failure. Overall, this multi-disciplinary process has resulted in important recommendations for data reporting, clinical research methods, and updated endpoint definitions. New definitions or modifications of existing definitions are being proposed for repeat hospitalizations, access site-related complications, bleeding events, conduction disturbances, cardiac structural complications, and bioprosthetic valve dysfunction and failure (including valve leaflet thickening and thrombosis). A more granular 5-class grading scheme for paravalvular regurgitation (PVR) is being proposed to help refine the assessment of PVR. Finally, more specific recommendations on quality-of-life assessments have been included, which have been targeted to specific clinical study designs.

Conclusions 

Acknowledging the dynamic and evolving nature of less-invasive aortic valve therapies, further refinements of clinical research processes are required. The adoption of these updated and newly proposed VARC-3 endpoints and definitions will ensure homogenous event reporting, accurate adjudication, and appropriate comparisons of clinical research studies involving devices and new therapeutic strategies.

Valve Academic Research Consortium 3: Updated Endpoint Definitions for Aortic Valve Clinical Research

AIMS

The Valve Academic Research Consortium (VARC), founded in 2010, was intended to (i) identify appropriate clinical endpoints and (ii) standardize definitions of these endpoints for transcatheter and surgical aortic valve clinical trials. Rapid evolution of the field, including the emergence of new complications, expanding clinical indications, and novel therapy strategies have mandated further refinement and expansion of these definitions to ensure clinical relevance. This document provides an update of the most appropriate clinical endpoint definitions to be used in the conduct of transcatheter and surgical aortic valve clinical research.

METHODS AND RESULTS

Several years after the publication of the VARC-2 manuscript, an in-person meeting was held involving over 50 independent clinical experts representing several professional societies, academic research organizations, the US Food and Drug Administration (FDA), and industry representatives to (i) evaluate utilization of VARC endpoint definitions in clinical research, (ii) discuss the scope of this focused update, and (iii) review and revise specific clinical endpoint definitions. A writing committee of independent experts was convened and subsequently met to further address outstanding issues. There were ongoing discussions with FDA and many experts to develop a new classification schema for bioprosthetic valve dysfunction and failure. Overall, this multi-disciplinary process has resulted in important recommendations for data reporting, clinical research methods, and updated endpoint definitions. New definitions or modifications of existing definitions are being proposed for repeat hospitalizations, access site-related complications, bleeding events, conduction disturbances, cardiac structural complications, and bioprosthetic valve dysfunction and failure (including valve leaflet thickening and thrombosis). A more granular 5-class grading scheme for paravalvular regurgitation (PVR) is being proposed to help refine the assessment of PVR. Finally, more specific recommendations on quality-of-life assessments have been included, which have been targeted to specific clinical study designs.

CONCLUSIONS

Acknowledging the dynamic and evolving nature of less-invasive aortic valve therapies, further refinements of clinical research processes are required. The adoption of these updated and newly proposed VARC-3 endpoints and definitions will ensure homogenous event reporting, accurate adjudication, and appropriate comparisons of clinical research studies involving devices and new therapeutic strategies.

Relationships between left ventricular mass and QRS duration in diverse types of left ventricular hypertrophy

AIMS

Hypertrophic cardiomyopathy (HCM) may be associated with very narrow QRS, while left ventricular hypertrophy (LVH) may increase QRS duration. We investigated the relationships between QRS duration and LV mass (LVM) in subtypes of abnormal LV wall thickness.

METHODS AND RESULTS

Automated measurement of LVM on MRI was correlated to automated measurement of QRS duration on ECG in HCM, left ventricular non compaction (LVNC), left ventricular hypertrophy (LVH), and controls with healthy hearts. Uni and multivariate analyses were performed between groups including explanatory variables expected to influence LVM and QRS duration. The relationships between QRS duration and LVM were further studied within each group. Two hundred and twenty-one HCM, 28 LVNC, 16 LVH, and 40 controls were retrospectively included. Mean QRS duration was 92 ms for HCM, 104 for LVNC, 110 for LVH, and 92 for controls (P < 0.01). Mean LVM was 100, 90, 108, and 68 g/m2 (P < 0.01). QRS duration, LVM, hypertension, maximal wall thickness, and late gadolinium enhancement were significantly linked to HCM in multivariate analysis (w/wo bundle branch block). An independent negative correlation was found between LVM and QRS duration in the HCM group, while the relationship was reverse in LVNC, LVH, and controls.

CONCLUSION

QRS duration increases with LVM in LVNC, LVH, or in healthy hearts, while reverse relationship is present in HCM. These relationships were independent from other parameters. These results warrant additional investigations for refining diagnosis criteria for HCM in the future.

Gender- and age-related differences in distinct phenotypes of hypertrophic cardiomyopathy-associated mutation MYBPC3-E334K

The mutation MYBPC3-E334K is a culprit mutation of hypertrophic cardiomyopathy (HCM). The pathogenicity of MYBPC3-E334K is conflicting in ClinVar because of the limited segregation data and the relatively high frequency in gnomAD (0.03% overall, with 0.3% in East Asians and 0.8% in Japanese). The main aim is to clarify the clinical importance and phenotype-genotype correlations in subjects with or without MYBPC3-E334K alone. The prevalence of MYBPC3-E334K was sequenced in 1017 HCM unrelated probands. The clinical features, morphology phenotypes, and electrical phenotypes were further analyzed according to the phenotype and genotype status in families with single-mutation MYBPC3-E334K. Nine of 1017 (0.88%) unrelated HCM probands were detected harboring MYBPC3-E334K, and three of them harbored a second variant in sarcomere protein gene. Family study and co-segregation analyses indicated that patients with single-mutation MYBPC3-E334K showed autosomal dominant mode of inheritance with incomplete penetrance. The overall disease penetrance was 52.6%, and the disease penetrance was higher in males than in females (100% in men vs 25% in women, p = 0.003). The mean age at diagnosis of males was approximately 25 years younger than females (36.57 ± 18.65 vs 62.33 ± 12.10, p = 0.062). The variant MYBPC3-E334K was classified as a likely pathogenic variant, and a second sarcomere variant did not reveal obvious cumulative effects. The patients harboring single-mutation MYBPC3-E334K had incomplete penetrance, and males demonstrated higher penetrance and early onset HCM than females. A second sarcomere variant did not reveal obvious cumulative effects.

Presence of contractile impairment appears crucial for structural remodeling in idiopathic left bundle-branch block

BACKGROUND

To differentiate effects of ventricular asynchrony from an underlying hypocontractile cardiomyopathy this study aimed to enhance the understanding of functional impairment and structural remodeling in idiopathic left bundle-branch block (LBBB). We hypothesize, that functional asynchrony with septal flash volume effects alone might not entirely explain the degree of functional impairment. Hence, we suggest the presence of a superimposed contractile cardiomyopathy.

METHODS

In this retrospective study, 53 patients with idiopathic LBBB were identified and matched to controls with and without cardiovascular risk factors. Cardiovascular magnetic resonance (CMR) was used to evaluate cardiac function, volumes and myocardial fibrosis using native T1 mapping and late gadolinium enhancement (LGE). Septal flash volume was assessed by CMR volumetric measurements and allowed to stratify patients with systolic dysfunction solely due to isolated ventricular asynchrony or superimposed contractile impairment.

RESULTS

Reduced systolic LV-function, increased LV-volumes and septal myocardial fibrosis were found in patients with idiopathic LBBB compared to healthy controls. LV-volumes increased and systolic LV-function declined with prolonged QRS duration. Fibrosis was typically located at the right ventricular insertion points. Subgroups with superimposed contractile impairment appeared with pronounced LV dilation and increased fibrotic remodeling compared to individuals with isolated ventricular asynchrony.

CONCLUSIONS

The presence of superimposed contractile impairment in idiopathic LBBB is crucial to identify patients with enhanced structural remodeling. This finding suggests an underlying cardiomyopathy. Future studies are needed to assess a possible prognostic impact of this entity and the development of heart failure.

TRIAL REGISTRATION

This study was retrospectively registered.

Unity Is Intelligence: A Collective Intelligence Experiment on ECG Reading to Improve Diagnostic Performance in Cardiology

Medical errors have a huge impact on clinical practice in terms of economic and human costs. As a result, technology-based solutions, such as those grounded in artificial intelligence (AI) or collective intelligence (CI), have attracted increasing interest as a means of reducing error rates and their impacts. Previous studies have shown that a combination of individual opinions based on rules, weighting mechanisms, or other CI solutions could improve diagnostic accuracy with respect to individual doctors. We conducted a study to investigate the potential of this approach in cardiology and, more precisely, in electrocardiogram (ECG) reading. To achieve this aim, we designed and conducted an experiment involving medical students, recent graduates, and residents, who were asked to annotate a collection of 10 ECGs of various complexity and difficulty. For each ECG, we considered groups of increasing size (from three to 30 members) and applied three different CI protocols. In all cases, the results showed a statistically significant improvement (ranging from 9% to 88%) in terms of diagnostic accuracy when compared to the performance of individual readers; this difference held for not only large groups, but also smaller ones. In light of these results, we conclude that CI approaches can support the tasks mentioned above, and possibly other similar ones as well. We discuss the implications of applying CI solutions to clinical settings, such as cases of augmented ‘second opinions’ and decision-making.

A Normal Electrocardiogram Does Not Exclude Infra-Hisian Conduction Disease in Patients With Myotonic Dystrophy Type 1

OBJECTIVES

This study aimed to identify electrocardiographic (ECG) predictors of a prolonged His-ventricular (HV) interval in patients with type 1 myotonic dystrophy (DM1).

BACKGROUND

Patients with DM1 have an increased risk of sudden cardiac death. The presence of His-Purkinje system disease/prolonged HV interval (≥70 ms) is associated with a higher risk of potentially life-threatening bradyarrhythmic events.

METHODS

Electrophysiology studies (EPSs) were performed in all DM1 patients referred to 2 tertiary centers for routine cardiac assessment. In a subgroup of patients, the EPS was repeated at varying intervals.

RESULTS

A total of 154 patients (mean age: 43.7 ± 13.3; 58.1% male) underwent 202 diagnostic EPSs. HV ≥70 ms was found on 58 EPSs (28.7%); 9 of 59 patients (15.2%) with PR <200 ms and QRS interval <110 ms on baseline ECG had an HV ≥70 ms on EPS. Among those with PR ≥200 ms and/or QRS interval ≥100 ms, only 33.9% had an HV ≥70 ms on EPS. There were 38 patients who underwent repeated EPS, in which 28.8% demonstrated a prolongation of the HV interval overall compared with baseline. QRS duration demonstrated the most powerful discriminative capacity for HV ≥70 ms (area under the receiver operating characteristic curve: 0.76; 95% confidence interval [CI]: 0.68 to 0.84; p < 0.001). On multivariate analysis, QRS interval ≥112 ms had the highest predictive value for HV ≥70 ms (odds ratio: 7.94; 95% CI: 3.85 to 16.37.

CONCLUSIONS

ECG parameters have a poor predictive value for infra-Hisian conduction block in DM1 patients. QRS and PR intervals are normal in up to 15.2% of DM1 patients with prolonged HV, and 66.1% of those with PR ≥200 ms and/or QRS ≥100 ms do not have advanced His-Purkinje conduction system disease on EPS. Electrophysiology testing should be a mandatory part of screening for all patients to guide prophylactic pacemaker implantation.

Evolution of high-grade atrioventricular conduction disorders after transcatheter aortic valve implantation in patients who underwent implantation of a pacemaker with specific mode-that minimizes ventricular pacing-activated

INTRODUCTION

The evolution of atrioventricular conduction disorders after transcatheter aortic valve implantation (TAVI) remains poorly understood. We sought to identify factors associated with late (occurring ≥7 days after the procedure) high-grade atrioventricular blocks after TAVI, based on specific pacemaker memory data.

METHODS AND RESULTS

STIM-TAVI (NCT03338582) was a prospective, multicentre, observational study that enrolled all patients (from November 2015 to January 2017) implanted with a specific dual chamber pacemaker after TAVI, with the SafeR algorithm activated, allowing continuous monitoring of atrioventricular conduction. The primary endpoint was the occurrence of centrally adjudicated late high-grade atrioventricular blocks during the year after TAVI. Among 197 patients, 138 (70.1%) had ≥1 late high-grade atrioventricular block. Whereas oversizing (p = .005), high-grade atrioventricular block during TAVI (p < .001), and early (within 6 days) high-grade atrioventricular block (p < .001) were associated with occurrence of late high-grade atrioventricular block, self-expanding prothesis (p = .88), prior right bundle branch block (p = .45), low implantation (p = .06), and new or wider left bundle branch block and lengthening of PR interval (p = .24) were not. In multivariable analysis, only post-TAVI early high-grade atrioventricular block remained associated with late high-grade atrioventricular blocks (Days 0-1: odds ratio [OR], 3.25; 95% confidence interval [CI], 1.57-6.74; p = .001; Days 2-6: OR, 4.13; 95% CI, 2.06-8.31; p < .001), whereas other conventionally used predictors were not.

CONCLUSION

One-third of pacemaker-implanted patients do not experience late high-grade atrioventricular block. Our findings suggest that post-TAVI early high-grade atrioventricular block is the main factor associated with occurrence of late high-grade atrioventricular blocks.

Electrocardiographic features of immune checkpoint inhibitor associated myocarditis

BACKGROUND

Myocarditis is a highly morbid complication of immune checkpoint inhibitor (ICI) use that remains inadequately characterized. The QRS duration and the QTc interval are standardized electrocardiographic measures that are prolonged in other cardiac conditions; however, there are no data on their utility in ICI myocarditis.

METHODS

From an international registry, ECG parameters were compared between 140 myocarditis cases and 179 controls across multiple time points (pre-ICI, on ICI prior to myocarditis, and at the time of myocarditis). The association between ECG values and major adverse cardiac events (MACE) was also tested.

RESULTS

Both the QRS duration and QTc interval were similar between cases and controls prior to myocarditis. When compared with controls on an ICI (93±19 ms) or to baseline prior to myocarditis (97±19 ms), the QRS duration prolonged with myocarditis (110±22 ms, p<0.001 and p=0.009, respectively). In contrast, the QTc interval at the time of myocarditis (435±39 ms) was not increased compared with pre-myocarditis baseline (422±27 ms, p=0.42). A prolonged QRS duration conferred an increased risk of subsequent MACE (HR 3.28, 95% CI 1.98 to 5.62, p<0.001). After adjustment, each 10 ms increase in the QRS duration conferred a 1.3-fold increase in the odds of MACE (95% CI 1.07 to 1.61, p=0.011). Conversely, there was no association between the QTc interval and MACE among men (HR 1.33, 95% CI 0.70 to 2.53, p=0.38) or women (HR 1.48, 95% CI 0.61 to 3.58, p=0.39).

CONCLUSIONS

The QRS duration is increased in ICI myocarditis and is associated with increased MACE risk. Use of this widely available ECG parameter may aid in ICI myocarditis diagnosis and risk-stratification.

His-Optimized Cardiac Resynchronization Therapy With Ventricular Fusion Pacing for Electrical Resynchronization in Heart Failure

OBJECTIVES

This study sought to evaluate the effectiveness of His-optimized cardiac resynchronization therapy (HOT-CRT) for reducing left ventricular activation time (LVAT) compared to His bundle pacing (HBP) and biventricular (BiV) pacing (including multipoint pacing [MPP]), using electrocardiographic (ECG) imaging.

BACKGROUND

HBP may correct bundle branch block (BBB) and has shown encouraging results for providing CRT. However, HBP does not correct BBB in all patients and may be combined with univentricular or BiV fusion pacing to deliver HOT-CRT to maximize resynchronization.

METHODS

Nineteen patients with a standard indication for CRT, implanted with HBP without correction of BBB and BiV (n = 14) or right ventricular (n = 5) leads, were prospectively enrolled. Patients underwent ECG imaging while pacing in different configurations using different LV electrodes and at different HBP ventricular pacing (VP) delays. The primary endpoint was reduction in LVAT with HOT-CRT, and the secondary endpoints included various other dys-synchrony measurements including right ventricular activation time (RVAT).

RESULTS

Compared to HBP, HOT-CRT reduced LVAT by 21% (-17 ms [95% confidence interval [CI]: -25 to -9 ms]; p < 0.001) and outperformed BiV by 24% (-22 ms [95% CI: -33 to -10 ms]; p = 0.002) and MPP by 13% (-11 ms [95% CI: -21 to -1 ms]; p = 0.035). Relative to HBP, HOT-CRT also reduced RVAT by 7% (-5 ms [95% CI: -9 to -1 ms; p = 0.035) in patients with right BBB, whereas RVAT was increased by BiV. The other electrical dyssynchrony measurements also improved with HOT-CRT.

CONCLUSIONS

HOT-CRT acutely improves ventricular electrical synchrony beyond BiV and MPP. The impact of this finding needs to be evaluated further in studies with clinical follow-up. (Electrical Resynchronization and Acute Hemodynamic Effects of Direct His Bundle Pacing Compared to Biventricular Pacing; NCT03452462).

The change of cardiac axis deviation in catheter ablation of verapamil-sensitive idiopathic left ventricular tachycardia

BACKGROUND

The underlying mechanism of verapamil-sensitive idiopathic left ventricular tachycardia (ILVT) has been postulated to be reentrant activation in the Purkinje fiber network of the left posterior fascicle or the left anterior fascicle (LAF). However, changing of cardiac axis deviation in sinus rhythm (SR) or during ILVT after radiofrequency catheter ablation (RFCA) has been rarely analyzed.

METHODS

Of the 232 patients with sustained ILVT induced and surface electrocardiogram (ECG) in SR recorded before and after RFCA, the changes of ECG morphology in SR and during ILVT were analyzed.

RESULTS

The surface ECG in SR changed in 114 (49.1%) patients after RFCA. ILVT could still be induced in 27 (23.7%) patients. In comparison with the original ILVT, three forms of ECG morphology were observed. In eight patients, the ILVT morphology was unchanged. In the 13 patients with ILVT axis deviation conversion after ablation, the successful target was more proximal. In the six patients with ILVT morphology change but without axis deviation conversion after ablation, the successful ablation site was more distal. Among 15 patients with recurrent ILVT during follow-up, seven patients had previous axis deviation changes in SR after RFCA, the changes maintained in four patients and recovered in three patients.

CONCLUSIONS

The morphology changes on surface ECG in SR after RFCA would not be a necessary prerequisite or a good endpoint for ILVT ablation. To analyze ILVT morphology changes after ablation would help to further clarify an appropriate approach for catheter ablation of ILVT.

Electrocardiographic predictors of successful resynchronization of left bundle branch block by His bundle pacing

BACKGROUND

His bundle pacing (HBP) is an alternative to biventricular pacing (BVP) for delivering cardiac resynchronization therapy (CRT) in patients with heart failure and left bundle branch block (LBBB). It is not known whether ventricular activation times and patterns achieved by HBP are equivalent to intact conduction systems and not all patients with LBBB are resynchronized by HBP.

OBJECTIVE

To compare activation times and patterns of His-CRT with BVP-CRT, LBBB and intact conduction systems.

METHODS

In patients with LBBB, noninvasive epicardial mapping (ECG imaging) was performed during BVP and temporary HBP. Intrinsic activation was mapped in all subjects. Left ventricular activation times (LVAT) were measured and epicardial propagation mapping (EPM) was performed, to visualize epicardial wavefronts. Normal activation pattern and a normal LVAT range were determined from normal subjects.

RESULTS

Forty-five patients were included, 24 with LBBB and LV impairment, and 21 with normal 12-lead ECG and LV function. In 87.5% of patients with LBBB, His-CRT successfully shortened LVAT by ≥10 ms. In 33.3%, His-CRT resulted in complete ventricular resynchronization, with activation times and patterns indistinguishable from normal subjects. EPM identified propagation discontinuity artifacts in 83% of patients with LBBB. This was the best predictor of whether successful resynchronization was achieved by HBP (logarithmic odds ratio, 2.19; 95% confidence interval, 0.07-4.31; p = .04).

CONCLUSION

Noninvasive electrocardiographic mapping appears to identify patients whose LBBB can be resynchronized by HBP. In contrast to BVP, His-CRT may deliver the maximum potential ventricular resynchronization, returning activation times, and patterns to those seen in normal hearts.

Intramuscular midazolam, olanzapine, or haloperidol for the management of acute agitation: A multi-centre, double-blind, randomised clinical trial

BACKGROUND

The safety and effectiveness of intramuscular olanzapine or haloperidol compared to midazolam as the initial pharmacological treatment for acute agitation in emergency departments (EDs) has not been evaluated.

METHODS

A pragmatic, randomised, double-blind, active-controlled trial was conducted from December 2014 to September 2019, in six Hong Kong EDs. Patients (aged 18-75 years) with undifferentiated acute agitation requiring parenteral sedation were randomised to 5 mg intramuscular midazolam (n = 56), olanzapine (n = 54), or haloperidol (n = 57). Primary outcomes were time to adequate sedation and proportion of patients who achieved adequate sedation at each follow-up interval. Sedation levels were measured on a 6-level validated scale (ClinicalTrials.gov Identifier: NCT02380118).

FINDINGS

Of 206 patients randomised, 167 (mean age, 42 years; 98 [58·7%] male) were analysed. Median time to sedation for IM midazolam, olanzapine, and haloperidol was 8·5 (IQR 8·0), 11·5 (IQR 30·0), and 23·0 (IQR 21·0) min, respectively. At 60 min, similar proportions of patients were adequately sedated (98%, 87%, and 97%). There were statistically significant differences for time to sedation with midazolam compared to olanzapine (p = 0·03) and haloperidol (p = 0·002). Adverse event rates were similar across the three arms. Dystonia (n = 1) and cardiac arrest (n = 1) were reported in the haloperidol group.

INTERPRETATION

Midazolam resulted in faster sedation in patients with undifferentiated agitation in the emergency setting compared to olanzapine and haloperidol. Midazolam and olanzapine are preferred over haloperidol's slower time to sedation and potential for cardiovascular and extrapyramidal side effects.

FUNDING

Research Grants Council, Hong Kong.

Left ventricular end-systolic contractile entropy can predict cardiac prognosis in patients with complete left bundle branch block

BACKGROUND

Several patients with complete left bundle branch block (CLBBB) show left ventricular (LV) dyssynchrony and poor cardiac prognosis. However, the prognostic value of LV end-systolic contractile entropy which was measured by single-photon emission computer tomography (SPECT) has not been elucidated in patients with CLBBB.

METHODS AND RESULTS

We recruited consecutive 115 sinus-rhythm patients with CLBBB who underwent ECG-gated 201TlCl-SPECT. After 30 days of observation, finally 102 patients (75.2 ± 9.5 years, 62 male) were enrolled and observed retrospectively for a median of 671 days. Twenty-five patients fell into major cardiac events. Multivariate Cox regression analysis showed estimated glomerular filtration rate (eGFR) ≤ 39.35 mL/min and entropy ≥ 79% were significant and independent predictors for major cardiac events (hazard ratio: 4.256 and 7.587, P value = 0.006 and < 0.001, respectively). Machine learning (Random Forest method) revealed eGFR and entropy had higher feature importance than other predictors (0.140 and 0.138, respectively). Kaplan-Meyer curve analysis demonstrated that the group with entropy ≥ 79% and eGFR ≤ 39.36 mL/min had the worst cardiac prognosis (Logrank: P = 0.002).

CONCLUSIONS

Left ventricular end-systolic contractile entropy predicts poor cardiac prognosis in patients with CLBBB, which may be more valuable than the other parameters of SPECT.

The electrocardiogram: Still a useful marker for LV fibrosis in aortic stenosis

Left ventricular (LV) strain on the electrocardiogram (ECG) (down-sloping, convex ST-segment depression with asymmetric T-wave inversion in leads V5 and V6) reflects fibrosis as a result of subendocardial ischemia. It is associated with a significantly increased risk of cardiovascular events independent of the presence of LV hypertrophy on the echocardiogram or cardiac magnetic resonance (CMR) scan. Ongoing studies of early aortic valve replacement in asymptomatic patients with severe aortic stenosis are using ECG changes as a marker of possible fibrosis shown by midwall late gadolinium enhancement on CMR. However, until these studies report, it is still reasonable to respond to LV strain on the ECG by tightening control of systemic hypertension and consider intervention in cases where indications are otherwise in borderline.

Recovery of conduction disorders after sutureless aortic valve replacement

OBJECTIVES

Conduction disorders and the need for permanent pacemaker (PPM) implantation after surgical aortic valve replacement are well-recognized complications. However, in the case of sutureless valve prostheses, it remains unknown whether pacemaker (PM) dependency and conduction disturbances resolve over time. Our aim was to evaluate whether conduction disorders after Perceval sutureless valve implantation recover during follow-up.

METHODS

Patients undergoing isolated surgical aortic valve replacement or concomitant aortic valve replacement with coronary artery bypass surgery using the Perceval sutureless valve, between January 2010 and July 2018, were included. Postoperative electrocardiogram findings were analysed to determine the incidence of new-onset left bundle branch blocks (LBBBs) and the requirement for PPM implantation. During a postoperative period of 6-18 months, electrocardiogram findings during PM checks were analysed to determine PM dependency and LBBB persistence.

RESULTS

Out of 184 patients who received a Perceval prosthesis during the study period, 39 (21.2%) patients developed new-onset LBBB and 10 patients (5.4%) received a PPM postoperatively. The occurrence of conduction disorders was not associated with valve size. Follow-up was completed in 176 (95.7%) patients. In patients with a new-onset LBBB, 35.9% recovered during follow-up (P = 0.001). Seven out of 10 (70%) patients remained PM dependent.

CONCLUSIONS

After Perceval aortic valve implantation, new-onset LBBB recovers in more than one-third of patients during follow-up. In patients who needed a postoperative PPM, the majority remained PM dependent.

Clinical and prognostic implications of phenomapping in patients with heart failure receiving cardiac resynchronization therapy

BACKGROUND

Despite having an indication for cardiac resynchronization therapy according to current guidelines, patients with heart failure with reduced ejection fraction who receive cardiac resynchronization therapy do not consistently derive benefit from it.

AIM

To determine whether unsupervised clustering analysis (phenomapping) can identify distinct phenogroups of patients with differential outcomes among cardiac resynchronization therapy recipients from routine clinical practice.

METHODS

We used unsupervised hierarchical cluster analysis of phenotypic data after data reduction (55 clinical, biological and echocardiographic variables) to define new phenogroups among 328 patients with heart failure with reduced ejection fraction from routine clinical practice enrolled before cardiac resynchronization therapy. Clinical outcomes and cardiac resynchronization therapy response rate were studied according to phenogroups.

RESULTS

Although all patients met the recommended criteria for cardiac resynchronization therapy implantation, phenomapping analysis classified study participants into four phenogroups that differed distinctively in clinical, biological, electrocardiographic and echocardiographic characteristics and outcomes. Patients from phenogroups 1 and 2 had the most improved outcome in terms of mortality, associated with cardiac resynchronization therapy response rates of 81% and 78%, respectively. In contrast, patients from phenogroups 3 and 4 had cardiac resynchronization therapy response rates of 39% and 59%, respectively, and the worst outcome, with a considerably increased risk of mortality compared with patients from phenogroup 1 (hazard ratio 3.23, 95% confidence interval 1.9-5.5 and hazard ratio 2.49, 95% confidence interval 1.38-4.50, respectively).

CONCLUSIONS

Among patients with heart failure with reduced ejection fraction with an indication for cardiac resynchronization therapy from routine clinical practice, phenomapping identifies subgroups of patients with differential clinical, biological and echocardiographic features strongly linked to divergent outcomes and responses to cardiac resynchronization therapy. This approach may help to identify patients who will derive most benefit from cardiac resynchronization therapy in "individualized" clinical practice.

Long-term outcomes after radiofrequency catheter ablation of the atrioventricular node: The experience of a Portuguese tertiary center

INTRODUCTION

In patients with supraventricular arrhythmias and high ventricular rate, unresponsive to rate and rhythm control therapy or catheter ablation, atrioventricular (AV) node ablation may be performed.

OBJECTIVES

To assess long-term outcomes after AV node ablation and to analyze predictors of adverse events.

METHODS

We performed a detailed retrospective analysis of all patients who underwent AV node ablation between February 1997 and February 2019, in a single Portuguese tertiary center.

RESULTS

A total of 123 patients, mean age 69±9 years and 52% male, underwent AV node ablation. Most of them presented atrial fibrillation at baseline (65%). During a median follow-up of 8.5 years (interquartile range 3.8-11.8), patients improved heart failure (HF) functional class (NYHA class III-IV 46% versus 13%, p=0.001), and there were reductions in hospitalizations due to HF (0.98±1.3 versus 0.28±0.8, p=0.001) and emergency department (ED) visits (1.1±1 versus 0.17±0.7, p=0.0001). There were no device-related complications. Despite permanent pacemaker stimulation, left ventricular ejection fraction did not worsen (47±13% vs. 47%±12, p=0.63). Twenty-eight patients died (23%). The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome (OR 1.8, 95% CI 1.24-2.61, p=0.002).

CONCLUSIONS

Despite pacemaker dependency, the clinical benefit of AV node ablation persisted at long-term follow-up. The number of ED visits due to HF before AV node ablation was an independent predictor of the composite adverse outcome. AV node ablation should probably be considered earlier in the treatment of patients with supraventricular arrhythmias and HF, especially in cases that are unsuitable for selective ablation of the specific arrhythmia.

Cardiovascular Consequences of Excessive Alcohol Drinking via Electrocardiogram: A Systematic Review

ABSTRACT

There is a link between excessive alcohol drinking and an increased risk to develop cardiovascular disease, including alcoholic cardiomyopathy. This association warrants further research on the potential utility for the electrocardiogram (ECG) in the participatory management of the chronic consequences of alcohol use disorder (AUD). Our goal is to enhance understanding about the pernicious role alcohol plays on cardiac health using the ECG, an accessible, cost-effective, validated tool to inform novel targeted treatments for AUD. In this systematic review of human studies, we examine the relationship between abnormal clinically significant changes to ECG variables and excessive alcohol drinking with the goal of identifying key patterns specific to quantity of alcohol consumed. Three independent reviewers and one consensus reviewer, adhering to the PRISMA guidelines, conducted an initial review on studies published from database inception to April 19, 2019, using PubMed, Embase, CINAHL and COCHRANE databases. The initial search generated 2,225 articles. The final selected number included 153 original articles. This systematic review provides evidence of patterns of clinically significant changes to ECG variables as a consequence of excessive alcohol consumption. Future directions include investigating whether a real-time assessment, such as the ECG, in conjunction with other key behavioral and cardiac measures, can help clinicians and patients realize the progressive and insidious cardiac damage because of excessive alcohol consumption. This theory-guided nurse science review supports the development of personalized symptom monitoring to deliver tailored feedback that illuminate risk factors as a potentially transformative approach in the management of AUD.

Impact of Prone Position on 12-Lead Electrocardiogram in Healthy Adults: A Comparison Study with Standard Electrocardiogram

BACKGROUND

The standard electrocardiogram (ECG) is commonly performed in the supine posture. It may be difficult to report ECG in a supine posture for those who are unable to adopt the supine posture because of certain circumstances such as acute respiratory distress syndrome-patients who are placed in a prone position for long periods to improve oxygenation. Few data are available on the impact of the prone position on the ECG recording with electrodes on the posterior chest. Examining and analyzing the type and extent of changes observed in the prone ECG in healthy adults have become vitally valuable.

METHODS

A cross-sectional observational study enrolled forty healthy adults (24 males and 16 females) aged between 18 and 40 years. The ECG was performed in two different body positions, supine and prone. Influence of prone position on the heart rate, mean QRS axis, amplitude, morphology, duration, mean T wave axis and polarity, mean P wave axis, PR, and mean QTc duration was evaluated.

RESULTS

The mean heart rate was higher in the prone position (73.2 ± 12.4 bpm) compared with the supine position (69.5 ± 11.5 bpm, p = 0.03). The QRS duration decreased considerably from supine (92.8 ± 12.6 ms) to prone (84.9 ± 11.9 ms, p < 0.001). The mean QRS axis moved to the left in the prone posture (40.5° ± 32°) relative to the supine (49° ± 28°, p=0.015). The QRS amplitude in the precordial leads was significantly decreased from supine (7.42 ± 3.1 mV) to prone (3.68 ± 1.7 mV, p < 0.001). In addition, changes in the QRS morphology in leads V1-V3 with the appearance of new Q waves were noted. A notable variation in the mean corrected QT (QTc) period with decrease in duration in prone posture ECG (385 ± 64.8) relative to supine (406 ± 18.8, p=0.05).

CONCLUSIONS

Prone position ECG resulted in significant changes in healthy adults that should be aware of this as this can affect diagnosis and management strategies. Further studies are needed to investigate the impact of prone position on ECG recording in patients with cardiovascular diseases.

Conduction Disorders: The Value of Surface ECG

PURPOSE OF REVIEW

The purpose of the current mini-review is to describe the importance of surface ECG for the diagnosis of conduction disorder.

METHODS

The MEDLINE/PubMed database was used, with the keywords "ECG" and "conduction disorders"; over the past 10 years. Other documents were included because of their relevance.

MAIN FINDINGS

Data on the anatomy and function of the cardiac electrical system have been described. Conduction disorders including sinus node dysfunction, atrioventricular blocks, intraventricular conduction disorders are exposed as to their epidemiology, etiology, presentation, anatomical site of impaired conduction of the electrical stimulus. The importance of ECG in patients with a cardiac implantable electronic device was also discussed, in addition to future perspectives.

CONCLUSION

Surface ECG allows the diagnosis of atrioventricular and intraventricular conduction disorder and its anatomical block site most of the time, without the need for invasive tests such as electrophysiological study. Dysfunctions of cardiac implantable electronic devices can be diagnosed by ECG, as well as the prediction of response to cardiac resynchronization therapy.

Predicting the Development of Reduced Left Ventricular Ejection Fraction in Patients With Left Bundle Branch Block

Left bundle branch block (LBBB) increases the likelihood of developing reduced left ventricular (LV) ejection fraction (EF) but predicting which patients with LBBB and normal LVEF will develop decreased LVEF remains challenging. Fifty patients with LBBB and normal LVEF were retrospectively identified. Clinical, electrocardiographic, and echocardiographic variables were compared between patients who developed a decreased LVEF and those who did not. A total of 16 of 50 patients developed reduced LVEF after 4.3 (SD = 2.8) years of follow-up. Baseline patient and electrocardiographic variables were similar between patients who did and did not develop decreased LVEF. Baseline LVEF was lower in patients who developed decreased LVEF than in those who did not (51.9% [SD = 2.2%] vs 54.9% [SD = 4.4%], p <0.01). Diastolic filling time (DFT) accounted for a significantly smaller percentage of the cardiac cycle in patients who developed decreased LVEF than in those who did not (35.9%, [SD = 6.9%] vs 44.4% [SD = 4.5%] p <0.01). In univariable logistic regression, DFT had a C-statistic of 0.86 (p <0.0001) for prediction of development of decreased LVEF. In conclusion, patients in whom DFT accounted for <38% of the cardiac cycle had a relative risk of developing decreased LVEF of 7.0 (95% confidence interval 3.0 to 16.0) compared to patients with DFT accounting for ≥38% of the cardiac cycle.

Prognostic effects of longitudinal changes in left ventricular ejection fraction with cardiac resynchronization therapy

Aims

Left ventricular ejection fraction (LVEF) is considered an indicator of cardiac resynchronization therapy (CRT). Longitudinal studies on the predictive value of LVEF are scarce. We aimed to comprehensively evaluate the prognostic role of LVEF in the outcomes of Chinese patients with CRT.

Methods and results

Three hundred ninety‐two patients were divided into three tertiles of LVEF: ≤25%, 25–30%, and 30–35%, and four groups by LVEF changes: <0% (negative response); ≥0% and ≤5% (non‐response); >5% and ≤15% (response); and >15% (super‐response). One hundred six patients were super‐responders. During a median follow‐up of 3.6 years, 141 reached the composite endpoint. Odds ratios (ORs) for super‐response depicted a reversed U‐shaped relationship for baseline LVEF with a peak at 25–30%. Independent predictors of super‐response were smaller left atrial diameter [odds ratio 0.897, 95% confidence interval (CI) 0.844–0.955, P = 0.001], smaller left ventricular end‐diastolic diameter (OR 0.937, 95% CI 0.889–0.989, P = 0.018), and higher estimated glomerular filtration rate (OR 1.018, 95% CI 1.001–1.035, P = 0.042) in Tertile 1; atrial fibrillation (OR 0.278, 95% CI 0.086–0.901, P = 0.033), left bundle branch block (OR 4.096, 95% CI 1.046–16.037, P = 0.043), and left ventricular end‐diastolic diameter (OR 0.929, 95% CI 0.876–0.986, P = 0.016) in Tertile 2; while female sex (OR 2.778, 95% CI 1.082–7.132, P = 0.034) and higher systolic blood pressure (OR 1.045, 95% CI 1.013–1.079, P = 0.006) in Tertile 3. An inverse association with the composite endpoint was found in Tertile 1 vs. Tertile 2 (hazard ratio 1.934, 95% CI 1.248–2.996, P = 0.003). The prognostic effects of CRT response in Tertile 3 and Tertile 1 varied significantly (P for trend = 0.017 and <0.001). Among three tertiles in super‐responders, event‐free survival was similar (P for trend = 0.143).

Conclusions

Left ventricular ejection fraction of 25–30% is associated with a better prognosis of super‐response. Predictors of super‐response are different for LVEF tertiles. CRT responses would have better prognostic performance than LVEF tertiles at baseline, which should be considered when clinicians screening eligible patients for CRT.

Left posterior fascicular ventricular tachycardia in a young infant with a structurally normal heart: Clinical course and caveats to electrocardiographic diagnosis

In this illustrative case report, we describe a rare case of left posterior fascicular ventricular tachycardia (LPFVT) in a 2 month-old infant with emphasis on electrocardiographic caveats to diagnosis. The clinical course, treatment, and eventual resolution of the VT over a 2 year follow-up is comprehensively compared and contrasted to a modicum of individual such case reports of infants. The corpus of each such case of infantile LPVT is systematically reviewed and succinctly summarized in a tabular compendium. The collective knowledge compiled here should allow for a refined approach to diagnosis and management of this unusual arrhythmia.

Fusion pacing in patients with right bundle branch block who undergo cardiac resynchronization therapy

PURPOSE

Patients with right bundle branch block (RBBB) are less likely to respond to cardiac resynchronization therapy (CRT). We aimed to assess whether patients with RBBB respond to CRT with biventricular fusion pacing.

METHODS

Consecutive patients with RBBB at a single tertiary care center, who were implanted with a CRT device capable of biventricular fusion pacing using SyncAV programming, were assessed and compared to a historical cohort of CRT patients with RBBB. QRSd was measured and compared during intrinsic conduction, nominal CRT pacing and manual electrocardiogram-based optimized SyncAV programming. Left ventricular ejection fraction (LVEF) was also compared before and 6 months after CRT.

RESULTS

We included 8 consecutive patients with RBBB (group 1) who were able to undergo SyncAV programming and 16 patients with RBBB (group 2) from a historical cohort. In group 1, compared to mean intrinsic conduction QRSd (155 ± 13 ms), mean nominally-paced QRSd was 156 ± 15 ms (ΔQRSd 1.3 ± 11.6; p = 0.77) and SyncAV-optimized paced QRSd was 135 ± 14 ms (ΔQRSd -20.0 ± 20.4; p = 0.03 and ΔQRSd -21.3 ± 16.3; p = 0.008; compared to intrinsic conduction and nominal pacing respectively). In group 2, mean QRSd with nominal pacing was 160 ± 24 ms (ΔQRSd 3.8 ± 33.4; p = 0.66 compared to intrinsic conduction). In group 1, baseline LVEF was 22.1 ± 11.5 and after 6 months of follow-up was 27.8 ± 8.6 (p = 0.047). In group 2, the baseline LVEF was 27.2 ± 10.6 and after 6 months of follow-up was 25.0 ± 10.0 (p = 0.45).

CONCLUSIONS

CRT programed to allow biventricular fusion pacing significantly improved electrical synchrony and LVEF in patients with RBBB. Larger studies are required to confirm these findings.

R-peak time in clinically healthy dogs with different thoracic conformations

R-peak time (RPT) is an electrocardiographic parameter that represents the time taken for electrical activation to spread from the endocardium to the epicardium. In human medicine, right ventricular RPT is measured from lead V₁ to lead V₂, and left ventricular RPT from lead V₅ to lead V₆. The aim of the present study was to define RPT duration in a group of clinically healthy dogs with different thoracic conformations. Sixty clinically healthy dogs underwent a 12-lead electrocardiogram recorded using a previously described precordial system. The dogs were allocated into three morphologic groups. In the brachymorphic group, the median and 25th-75th percentiles for RPT in V₁ were 10.5 ms (10-12 ms); V₂, 18 ms (16.5-20 ms); V₃, 19 ms (18-22 ms); V₄, 20 ms (17-23.5 ms); V₅, 21 ms (18.5-24 ms); and V₆: 22 ms (18.5-25.5 ms). In the mesomorphic group, RPT in V₁ was 16 ms (14-18 ms); V₂, 22 ms (20-24 ms); V₃, 23 ms (21-25 ms); V₄, 23 ms (22-25 ms); V₅, 25 ms (23-27 ms); and V₆, 28 ms (25-30 ms). In the dolichomorphic group, RPT in V₁ was 15 ms (13-17 ms); V₂, 29 ms (26-32.5 ms); V₃, 30 ms (27-33.5 ms); V₄, 29.5 ms (26-35 ms); V₅, 30 ms (28-34 ms); and V₆, 31.5 ms (28-35 ms). RPT in V₁ was significantly shorter than RPT in V₂ to V₆ in all morphotypes (P < 0.05). In all precordial leads, RPT was significantly different between morphotypes (P < 0.05). These results are in agreement with previous findings in humans and with the observation that V₁ reads the right ventricle and V₂ to V₆ read the left ventricle. These preliminary data provide RPT ranges in clinically healthy dogs of different morphotypes.

Prevalence of abnormalities in electrocardiogram conduction in dialysis patients: a comparative study

ABSTRACT Background: The electrocardiogram (ECG) can aid in identification of chronic kidney disease (CKD) patients at high risk for cardiovascular diseases. Cohort studies describe ECG abnormalities in patients on hemodialysis (HD), but we did not find data comparing ECG abnormalities among patients with normal kidney function or peritoneal dialysis (PD) to those on hemodialysis. We hypothesized that ECG conduction abnormalities would be more common, and cardiac conduction interval times longer, among patients on hemodialysis vs. those on peritoneal dialysis and CKD 1 or 2. Methods: Retrospective review of adult inpatients’ charts, comparing those with billing codes for “Hemodialysis” vs. inpatients without those charges, and an outpatient peritoneal dialysis cohort. Patients with CKD 3 or 4 were excluded. Results: One hundred and sixty-seven charts were reviewed. ECG conduction intervals were consistently and statistically longer among hemodialysis patients (n=88) vs. peritoneal dialysis (n=22) and CKD stage 1 and 2 (n=57): PR (175±35 vs 160±44 vs 157±22 msec) (p=0.009), QRS (115±32 vs. 111±31 vs 91±18 msec) (p=0.001), QT (411±71 vs. 403±46 vs 374±55 msec) (p=0.006), QTc (487±49 vs. 464±38 vs 452±52 msec) (p=0.0001). The only significantly different conduction abnormality was prevalence of left bundle branch block: 13.6% among HD patients, 5% in PD, and 2% in CKD 1 and 2 (p=0.03). Conclusion: To our knowledge, this is the first study to report that ECG conduction intervals are significantly longer as one progresses from CKD Stage 1 and 2, to PD, to HD. These and other data support the need for future research to utilize ECG conduction times to identify dialysis patients who could potentially benefit from proactive cardiac evaluations and risk reduction.

Electrocardiogram analysis of patients with different types of COVID-19

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 causes acute myocardial damage and arrhythmia in coronavirus disease 2019 (COVID-19) patients. Studying the changes of electrocardiogram is of great significance for the diagnosis of patients with COVID-19.

METHODS

A retrospective analysis method was adopted to compare the electrocardiogram changes between COVID-19 critically severe and severe patients. Univariate and multivariate logistic regression were used to analyze the correlation of the levels of serum indexes and past medical history with ST-T changes and atrial fibrillation. And the correlation of ECG parameters with in-hospital death and ventilator use were investigated by using the same methods.

RESULTS

The incidence of male, stroke, elevated cardiac troponin I (cTnI), N-terminal of the prohormone brain natriuretic peptide (NT-proBNP), d-dimer, high-sensitivity C-reactive protein (hs-CRP), hyperkalemia, and hypocalcemia in the critically ill patients was higher than that in severe patients. There were differences in ST-T changes, sinus tachycardia, atrial fibrillation, and atrial tachycardia between the two groups. Multivariate logistic regression analysis showed that elevated cTnI and NT-proBNP were the independent risk factors of ST-T changes. Elevated NT-proBNP and age were the independent risk factors of atrial fibrillation. Sinus tachycardia and atrial fibrillation were the independent risk factors of in-hospital death and ventilator use.

CONCLUSION

ST-T changes, sinus tachycardia, and atrial fibrillation are with great significance in the diagnosis of the severity, myocardia injury, and cardiac insufficiency of COVID-19 patients. Sinus tachycardia and atrial fibrillation could be used as independent variables predicting in-hospital death and ventilator use.

Conduction disorders after aortic valve replacement with rapid-deployment bioprostheses: early occurrence and one-year evolution

Background

Rapid-deployment bioprostheses represent one of the newest aortic valve substitutes introduced into clinical practice. The aim of this retrospective single-center study was to evaluate the occurrence of conduction disorders (CDs) after rapid-deployment aortic valve implantation at discharge and at 1-year follow-up, and to identify risk factors for CDs and permanent pacemaker implantation (PPI).

Methods

All patients who reached 1-year follow-up after isolated or combined aortic valve replacement (AVR) with rapid-deployment bioprostheses (Intuity Elite, Edwards Lifesciences, Irvine, CA) at our institution were included in this study. Standard 12-lead electrocardiograms (ECGs) were recorded before the procedure (within 24 hours), after the procedure as soon as the patient was moved to the intensive care unit (ICU), every day during in-hospital stay and at 1-year follow-up. The primary endpoint was the incidence of postoperative CDs at discharge and at 1-year follow up. Patients were divided in two groups: those who developed the primary endpoint (Group CD) and those who didn't (Group Non-CD).

Results

A total of 98 consecutive patients were included in the study. At discharge, the primary endpoint occurred in 40 patients (40.8%). In particular, new CDs and PPI occurred in 33 (33.7%) and in 7 (7.1%) patients, respectively. Valve size was the only independent predictor of primary endpoint at discharge. At 1-year, 30 patients (31.3%) presented with CDs or pacemaker-induced rhythm. In particular, in 25 patients of Group CD (64.1%), 1-year follow-up ECG revealed the persistence of the same CD as at discharge or pacemaker-induced rhythm, while 14 patients (35.9%) showed recovery of their CD. Age and prosthesis size were identified as independent predictors of CDs/pacemaker-induced rhythm at 1-year follow-up.

Conclusions

According to our data, nearly 40% of patients develop a new CD after rapid-deployment aortic valve implantation. Of these, one third recover after one year. Bioprosthesis size and age were identified as independent risk factors for occurrence of CD after surgery.

Quantification of Resting-State Ballistocardiogram Difference Between Clinical and Non-Clinical Populations for Ambient Monitoring of Heart Failure

A ballistocardiogram (BCG) is a versatile bio-signal that enables ambient remote monitoring of heart failure (HF) patients in a home setting, achieved through embedded sensors in the surrounding environment. Numerous methods of analysis are available for extracting physiological information using the BCG; however, most have been developed based on non-clinical subjects. While the difference between clinical and non-clinical populations are expected, quantification of the difference may serve as a useful tool. In this work, the differences in resting-state BCGs of the two cohorts in a sitting posture were quantified. An instrumented chair was used to collect the BCG from 29 healthy adults and 26 NYHA HF class I and II patients while seated without any stress test for five minutes. Five 20-second epochs per subject were used to calculate the waveform fluctuation metric at rest (WFMR). The WFMR was obtained in two steps. The ensemble average of the segmented BCG heartbeats within an epoch were calculated first. Mean square errors (MSE) between different ensemble average pairs were then retrieved. The MSEs were averaged to produce the WFMR. The comparison showed that the clinical cohort had higher fluctuation than the non-clinical population and had at least 82.2% separation, suggesting that greater errors may result when existing algorithms were used. The WFMR acts as a bridge that may enable important features, including the addition of error margins in parameter estimation and ways to devise a calibration strategy when resting-state BCG is unstable.

Determinants and prognostic implications of left ventricular mechanical dispersion in aortic stenosis

AIMS

The present study aimed at investigating the association between left ventricular (LV) mechanical dispersion measured with speckle tracking echocardiography and severity of aortic stenosis (AS) and its impact on prognosis.

METHODS AND RESULTS

This retrospective study included 630 patients [age 72 (62-78) years, 61.4% men] with various grades of AS (mild AS, 19.8%; moderate AS, 37.0%; severe AS, 43.2%). LV mechanical dispersion (defined as standard deviation of time from Q/R on electrocardiogram to peak longitudinal strain in 17 LV segments) was assessed by speckle tracking echocardiography. Clinical, electrocardiographic, and echocardiographic determinants of increased LV mechanical dispersion were evaluated. During a follow-up of 107 (43-133) months, the independent association between LV mechanical dispersion and all-cause mortality (n = 302, 48%) was evaluated including aortic valve replacement as time-dependent co-variate. LV mechanical dispersion increased significantly with increasing severity of AS (mild AS, 54.5 ± 17.2 ms; moderate AS, 56.7 ± 19.3 ms; severe AS, 70.9 ± 24.3 ms; P < 0.001). Independent determinants of increased mechanical dispersion included older age (β = 0.28; P = 0.003), lower LV ejection fraction (β = -0.24; P = 0.020), smaller aortic valve area (β = -8.55; P = 0.001), larger LV mass index (β = 0.20; P < 0.001), and longer QRS duration (β = 1.12 per each 10 ms increase; P = 0.012). LV mechanical dispersion showed incremental prognostic value for all-cause mortality (hazard ratio 1.10 per each 10 ms increase, 95% confidence interval 1.04-1.15; P < 0.001).

CONCLUSION

LV mechanical dispersion assessed by speckle tracking echocardiography increases significantly with severity of AS and is significantly associated with all-cause mortality.