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The 3-dimensional spatial and 2-dimensional frontal QRS-T angles are measures derived from the vectorcardiogram. They are independent risk predictors for arrhythmia, but the underlying biology is unknown. Using multi-ancestry genome-wide association studies we identify 61 (58 previously unreported) loci for the spatial QRS-T angle (N = 118,780) and 11 for the frontal QRS-T angle (N = 159,715). Seven out of the 61 spatial QRS-T angle loci have not been reported for other electrocardiographic measures. Enrichments are observed in pathways related to cardiac and vascular development, muscle contraction, and hypertrophy. Pairwise genome-wide association studies with classical ECG traits identify shared genetic influences with PR interval and QRS duration. Phenome-wide scanning indicate associations with atrial fibrillation, atrioventricular block and arterial embolism and genetically determined QRS-T angle measures are associated with fascicular and bundle branch block (and also atrioventricular block for the frontal QRS-T angle). We identify potential biology involved in the QRS-T angle and their genetic relationships with cardiovascular traits and diseases, may inform future research and risk prediction.

Study objectivesPatients with end-stage kidney disease commonly experience sleep disturbances. Sleep disturbance has been inconsistently associated with mortality risk in patients on hemodialysis, but the burden of symptoms from sleep disturbances has emerged as a marker that may shed light on these discrepancies and guide treatment decisions. This study examines whether functional outcomes of sleep are associated with increased risk of intermediary cardiovascular outcomes or mortality among adults initiating hemodialysis.MethodsIn 228 participants enrolled in the Predictors of Arrhythmic and Cardiovascular Risk in End-Stage Renal Disease study, the Functional Outcomes of Sleep Questionnaire-10 (FOSQ-10), which assesses functional outcomes of daytime sleepiness, was administered within 6 months of enrollment. Intermediary cardiovascular outcomes included QT correction (ms), heart rate variance (ms2), left ventricular mass index (g/m2), and left ventricular hypertrophy. The association of FOSQ-10 score with all-cause mortality was examined using proportional hazards regression.ResultsMean age was 55 years, and median body mass index was 28 kg/m2 (interquartile range, 24, 33), with 70% of patients being African Americans. Median FOSQ-10 score was 19.7 (interquartile range, 17.1, 20.0). A 10% lower FOSQ-10 score was associated with increased mortality risk (hazard ratio, 1.09; 95% confidence interval, 1.01-1.18). Lower FOSQ-10 scores were associated with longer QT correction duration and lower heart rate variance but not left ventricular mass index or left ventricular mass index.ConclusionsIn adults initiating dialysis, sleep-related functional impairment is common and is associated with intermediary cardiovascular disease measures and increased mortality risk. Future studies should assess the impact of screening for sleep disturbances in patients with end-stage kidney disease to identify individuals at increased risk for cardiovascular complications and death.CitationFitzpatrick J, Kerns ES, Kim ED, et al. Functional outcomes of sleep predict cardiovascular intermediary outcomes and all-cause mortality in patients on incident hemodialysis. J Clin Sleep Med. 2021;17(8):1707-1715.

BackgroundThe risk of cardiovascular mortality is high among adults with end-stage renal disease (ESRD) undergoing hemodialysis. Waist-to-hip ratio (WHR), a metric of abdominal adiposity, is a predictor of cardiovascular disease (CVD) and mortality in the general population; however, no studies have examined the association with CVD mortality, particularly sudden cardiac death (SCD), in incident hemodialysis.MethodsAmong 379 participants incident (< 6 months) to hemodialysis enrolled in the Predictors of Arrhythmic and Cardiovascular Risk in ESRD study, we evaluated associations between WHR and risk of CVD mortality, SCD, and non-CVD mortality in Cox proportional hazards regression models.ResultsAt study enrollment, mean age was 55 years with 41% females, 73% African Americans, and 57% diabetics. Mean body mass index was 29.3 kg/m2, and mean WHR was 0.95. During a median follow-up time of 2.5 years, there were 35 CVD deaths, 15 SCDs, and 48 non-CVD deaths. Every 0.1 increase in WHR was associated with higher risk (hazard ratio [95% CI]) of CVD mortality (1.75 [1.06-2.86]) and SCD (2.45 [1.20-5.02]), but not non-CVD mortality (0.93 [0.59-1.45]), independently of demographics, body mass index, comorbidities, inflammation, and traditional CVD risk factors.ConclusionsWHR is significantly associated with CVD mortality including SCD, independently of other CVD risk factors in incident hemodialysis. This simple, easily obtained bedside metric may be useful in dialysis patients for CVD risk stratification.

Several reports have demonstrated that prolongation of the QT interval is associated with sudden cardiac death (SCD). However, it is unknown whether any of the components within the QT interval are responsible for its association with SCD. We examined the association of the individual QT-interval components (R-wave onset to R-peak, R-peak to R-wave end, ST-segment, T-wave onset to T-peak, and T-peak to T-wave end) with SCD in 12 241 participants (54±5.7 years; 26% black; 55% women) from the ARIC study (Atherosclerosis Risk in Communities). The QT interval and its components were measured at baseline (1987-1989) from 12-lead ECGs. SCD cases were adjudicated by a group of physicians through December 31, 2012. During a median follow-up of 23.6 years, a total of 346 cases of SCD were identified. Although prolongation of the QT interval was associated with a 49% increased risk of SCD (hazard ratio, 1.49; 95% confidence interval, 1.01-2.18), only the T-wave onset to T-peak component (per 1-SD increase: hazard ratio, 1.19; 95% confidence interval, 1.06-1.34) was associated with SCD and not any of the other components in separate models. When all of the QT-interval components were included in the same model, T-wave onset to T-peak remained the strongest predictor of SCD (per 1-SD increase: hazard ratio, 1.21; 95% confidence interval, 1.06-1.37). The risk of SCD with the QT interval is driven by prolongation of the T-wave onset to T-peak component. This suggests that shifting the focus from the overall QT interval to its individual components will refine SCD prediction in the community.

Aims Ablation of monomorphic ventricular tachycardia (MMVT) has been shown to reduce shock frequency and improve survival. We aimed to compare cause-specific risk factors for MMVT and polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) and to develop predictive models. Methods and results The multicentre retrospective cohort study included 2668 patients (age 63.1 ± 13.0 years; 23% female; 78% white; 43% non-ischaemic cardiomyopathy; left ventricular ejection fraction 28.2 ± 11.1%). Cox models were adjusted for demographic characteristics, heart failure severity and treatment, device programming, and electrocardiogram metrics. Global electrical heterogeneity was measured by spatial QRS-T angle (QRSTa), spatial ventricular gradient elevation (SVGel), azimuth, magnitude (SVGmag), and sum absolute QRST integral (SAIQRST). We compared the out-of-sample performance of the lasso and elastic net for Cox proportional hazards and the Fine–Gray competing risk model. During a median follow-up of 4 years, 359 patients experienced their first sustained MMVT with appropriate implantable cardioverter–defibrillator (ICD) therapy, and 129 patients had their first PVT/VF with appropriate ICD shock. The risk of MMVT was associated with wider QRSTa [hazard ratio (HR) 1.16; 95% confidence interval (CI) 1.01–1.34], larger SVGel (HR 1.17; 95% CI 1.05–1.30), and smaller SVGmag (HR 0.74; 95% CI 0.63–0.86) and SAIQRST (HR 0.84; 95% CI 0.71–0.99). The best-performing 3-year competing risk Fine–Gray model for MMVT [time-dependent area under the receiver operating characteristic curve (ROC(t)AUC) 0.728; 95% CI 0.668–0.788] identified high-risk (> 50%) patients with 75% sensitivity and 65% specificity, and PVT/VF prediction model had ROC(t)AUC 0.915 (95% CI 0.868–0.962), both satisfactory calibration. Conclusion We developed and validated models to predict the competing risks of MMVT or PVT/VF that could inform procedural planning and future randomized controlled trials of prophylactic ventricular tachycardia ablation. Clinical Trial Registration URL: www.clinicaltrials.gov Unique identifier:NCT03210883. [ABSTRACT FROM AUTHOR]

Background and Aims: In transcatheter aortic valve replacement (TAVR) recipients, the optimal management of concomitant chronic obstructive coronary artery disease (CAD) remains unknown. Some advocate for pre-TAVR percutaneous coronary intervention, while others manage it expectantly. The aim of this study was to assess the impact of varying degrees and extent of untreated chronic obstructive CAD on TAVR and longer-term outcomes. Methods: The authors conducted a retrospective cohort study of TAVR recipients from January 2015 to November 2021, separating patients into stable non-obstructive or varying degrees of obstructive CAD. The major outcomes of interest were procedural all-cause mortality and complications, major adverse cardiovascular events, and post-TAVR unplanned coronary revascularization. Results: Of the 1911 patients meeting inclusion, 75%, 6%, 10%, and 9% had non-obstructive, intermediate-risk, high-risk, and extreme-risk CAD, respectively. Procedural complication rates overall were low (death 0.4%, shock 0.1%, extracorporeal membrane oxygenation 0.1%), with no difference across groups. At a median follow-up of 21 months, rates of acute coronary syndrome and unplanned coronary revascularization were 0.7% and 0.5%, respectively, in the non-obstructive population, rising in incidence with increasing severity of CAD (P <.001 for acute coronary syndrome/unplanned coronary revascularization). Multivariable analysis did not yield a significantly greater risk of all-cause mortality or major adverse cardiovascular events across groups. One-year acute coronary syndrome and unplanned coronary revascularization rates in time-to-event analyses were significantly greater in the non-obstructive (98%) vs. obstructive (94%) subsets (Plog-rank<.001). Conclusions: Transcatheter aortic valve replacement can be performed safely in patients with untreated chronic obstructive CAD, without portending higher procedural complication rates and with relatively low rates of unplanned coronary revascularization and acute coronary syndrome at 1 year. Structured Graphical Abstract (A) Definitions for the four categories of coronary artery disease (CAD) studied alongside the breakdown of transcatheter aortic valve replacement (TAVR) valve type with 91% balloon-expandable valves (BEV) and 9% self-expanding valves (SEV). Procedural complication rates were minimal across the 1911 patients studied. (B) Cumulative incidence curve of major adverse cardiovascular events (MACE) [acute coronary syndrome (ACS), stroke, or heart failure hospitalizations] demonstrating no significant difference between obstructive and non-obstructive groups (P =.609) (C) Cumulative incidence curve of unplanned coronary revascularization showing a significant difference between obstructive and non-obstructive groups (P =.006). (D) Multivariable analyses for all-cause mortality and MACE. CI, confidence interval; ECMO, extracorporeal membrane oxygenation; HR, hazard ratio; LAD, left anterior descending artery; LCX, left circumflex artery; LM, left main; N/A, not available; RCA, right coronary artery. [ABSTRACT FROM AUTHOR]

We examined whether there is a relationship between repolarization abnormalities on electrocardiography (EKG) and deformation abnormalities by echocardiography. Analysis of baseline EKGs and mechanical (echo-based deformation) changes was performed in 128 patients with a clinical diagnosis of hypertrophic cardiomyopathy (HCM). Patients with left ventricular hypertrophy (LVH) or repolarization abnormalities had higher septal thickness when compared to patients with normal EKG. Patients with EKG evidence of LVH or QTc prolongation had lower systolic velocity, systolic strain, systolic strain rate, late diastolic velocity, and late diastolic strain rate than patients with a normal EKG. Patients with strain pattern or ST depression/T-wave inversion had lower systolic velocity, systolic strain, systolic strain rate, early diastolic velocity, and late diastolic velocity when compared to patients with normal EKGs. LVH and repolarization abnormalities on surface EKG are markers of impaired systolic and diastolic mechanics in HCM.

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria. The classical paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces, reflected in the augmented QRS amplitude. However, the low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm. The theoretical background for voltage measured at the body surface is defined by the solid angle theorem, which relates the measured voltage to spatial and non‐spatial determinants. The spatial determinants are represented by the extent of the activation front and the distance of the recording electrodes. The non‐spatial determinants comprise electrical characteristics of the myocardium, which are comparatively neglected in the interpretation of the QRS patterns. Various clinical conditions are associated with LVH. These conditions produce considerable diversity of electrical properties alterations thereby modifying the resultant QRS patterns. The spectrum of QRS patterns observed in LVH patients is quite broad, including also left axis deviation, left anterior fascicular block, incomplete and complete left bundle branch blocks, Q waves, and fragmented QRS. Importantly, the QRS complex can be within normal limits. The new paradigm stresses the electrophysiological background in interpreting QRS changes, i.e., the effect of the non‐spatial determinants. This postulates that the role of ECG is not to estimate LV size in LVH, but to understand and decode the underlying electrical processes, which are crucial in relation to cardiovascular risk assessment. [ABSTRACT FROM AUTHOR]