Usefulness of left atrial abnormality for predicting left ventricular hypertrophy in the presence of left bundle branch block

Evaluation of electrocardiographic criteria for predicting left ventricular hypertrophy and dilation in presence of left bundle branch block

BACKGROUND

The utility of standard published electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH) in patients with left bundle branch block (LBBB) is not established. We have previously shown that in ECGs demonstrating LBBB, QRS duration outperforms vectorcardiographic X, Y, Z lead and root-mean-squared (3D) amplitudes and voltage-time-integrals in diagnosing LVH and dilation. We sought to evaluate diagnostic yields of published LVH criteria versus QRS duration for ECG based diagnosis of LVH and dilation in presence of LBBB.

METHODS

We included adult patients with typical LBBB having ECG and transthoracic echocardiogram performed within 3 months of each other in 2010-2020. We obtained area under receiver-operator characteristic curve (AUC) for QRS duration and each of the published ECG LVH criteria to predict increased LV mass indexed (↑LVMi, women >95 g/m2, men >115 g/m2) and LV end diastolic volume indexed (↑LVEDVi, women >61 mL/m2, men >74 mL/m2).

RESULTS

Among 413 adults (53 % women, age 73 ± 12 yr) with LBBB, the traditional LVH criteria performed poorly to detect ↑LVMi or ↑LVEDVi. Cornell voltage-duration product had the highest AUCs (↑LVMi 0.634, ↑LVEDVi 0.580). QRS duration had a higher AUC for diagnosing ↑LVMi (women 0.657, men 0.703) and ↑LVEDVi (women 0.668, men 0.699) compared to any other criteria.

CONCLUSIONS

In patients with LBBB, prolonged QRS duration (women ≥150 ms, men ≥160 ms) is a superior predictor of LVH and dilation than traditional ECG-based LVH criteria.

Electrocardiographic prediction of left ventricular hypertrophy in women and men with left bundle branch block - Comparison of QRS duration, amplitude and voltage-time-integral

BACKGROUND

Standard ECG criteria for left ventricular (LV) hypertrophy rely on QRS amplitudes. However, in the setting of left bundle branch block (LBBB), ECG correlates of LV hypertrophy are not well established. We sought to evaluate quantitative ECG predictors of LV hypertrophy in the presence of LBBB.

METHODS

We included adult patients with typical LBBB having ECG and transthoracic echocardiogram performed within 3 months of each other in 2010-2020. Orthogonal X, Y, Z leads were reconstructed from digital 12‑lead ECGs using Kors's matrix. In addition to QRS duration, we evaluated QRS amplitudes and voltage-time-integrals (VTIs) from all 12 leads, X, Y, Z leads and 3D (root-mean-squared) ECG. We used age, sex and BSA-adjusted linear regressions to predict echocardiographic LV calculations (mass, end-diastolic and end-systolic volumes, ejection fraction) from ECG, and separately generated ROC curves for predicting echocardiographic abnormalities.

RESULTS

We included 413 patients (53% women, age 73 ± 12 years). All 4 echocardiographic LV calculations were most strongly correlated with QRS duration (all p < 0.00001). In women, QRS duration ≥ 150 ms had sensitivity/specificity 56.3%/64.4% for increased LV mass and 62.7%/67.8% for increased LV end-diastolic volume. In men, QRS duration ≥ 160 ms had a sensitivity/specificity 63.1%/72.1% for increased LV mass and 58.3%/74.5% for increased LV end-diastolic volume. QRS duration was best able to discriminate eccentric hypertrophy (area under ROC curve 0.701) and increased LV end-diastolic volume (0.681).

CONCLUSIONS

In patients with LBBB, QRS duration (≥ 150 in women and ≥ 160 in men) is a superior predictor of LV remodeling esp. eccentric hypertrophy and dilation.

Left bundle branch block: Epidemiology, etiology, anatomic features, electrovectorcardiography, and classification proposal

In left bundle branch block (LBBB), the ventricles are activated in a sequential manner with alterations in left ventricular mechanics, perfusion, and workload resulting in cardiac remodeling. Underlying molecular, cellular, and interstitial changes manifest clinically as changes in size, mass, geometry, and function of the heart. Cardiac remodeling is associated with progressive ventricular dysfunction, arrhythmias, and impaired prognosis. Clinical and diagnostic notions about LBBB have evolved from a simple electrocardiographic alteration to a critically important finding affecting diagnostic and clinical management of many patients. Advances in cardiac magnetic resonance imaging have significantly improved the assessment of patients with LBBB and provided additional insights into pathophysiological mechanisms of left ventricular remodeling. In this review, we will discuss the epidemiology, etiologies, and electrovectorcardiographic features of LBBB and propose a classification of the conduction disturbance.

Heart ventricular activation in VAT difference maps from children with chronic kidney disease

Children with chronic kidney disease (CKD) are affected by cardiovascular complications, including disturbances in the intraventricular conduction system. Body surface potential mapping (BSPM) is a non-invasive method of assessing the cardioelectrical field. Our aim was to investigate conduction disturbances in young CKD patients using ventricular activation time (VAT) maps. Our study comprised 22 CKD children (mean age: 13.1 ± 2.5 years) treated conservatively and 29 control patients. For each child 12-lead electrocardiogram (ECG) readings were taken, and blood pressure and serum concentrations of iPTH, Pi, t-Ca, creatinine, Fe(+3), ferritin, and Hb, as well as eGFR were measured. All children underwent registration in the 87-lead BSPM system, and group-mean VAT maps and a difference map, which presents statistically significant differences between the groups, were created. The VAT map distribution in CKD patients revealed abnormalities specific to left anterior fascicle block. The difference map displays the areas of intergroup VAT changes, which are of discriminative value in detecting intraventricular conduction disturbances. Intraventricular conduction impairments in the left bundle branch may occur in children with CKD. BSPM enables conduction disturbances in CKD children to be detected earlier than using 12-lead ECG. The difference map derived from the group-mean isochrone maps precisely localizes the sites of disturbed conduction in the heart intraventricular conduction system.

Fine particulate air pollution is associated with higher vulnerability to atrial fibrillation--the APACR study

The acute effects and the time course of fine particulate pollution (PM₂.₅) on atrial fibrillation/flutter (AF) predictors, including P-wave duration, PR interval duration, and P-wave complexity, were investigated in a community-dwelling sample of 106 nonsmokers. Individual-level 24-h beat-to-beat electrocardiogram (ECG) data were visually examined. After identifying and removing artifacts and arrhythmic beats, the 30-min averages of the AF predictors were calculated. A personal PM₂.₅ monitor was used to measure individual-level, real-time PM₂.₅ exposures during the same 24-h period, and corresponding 30-min average PM₂.₅ concentration were calculated. Under a linear mixed-effects modeling framework, distributed lag models were used to estimate regression coefficients (βs) associating PM₂.₅ with AF predictors. Most of the adverse effects on AF predictors occurred within 1.5-2 h after PM₂.₅ exposure. The multivariable adjusted βs per 10-μg/m³ rise in PM₂.₅ at lag 1 and lag 2 were significantly associated with P-wave complexity. PM₂.₅ exposure was also significantly associated with prolonged PR duration at lag 3 and lag 4. Higher PM₂.₅ was found to be associated with increases in P-wave complexity and PR duration. Maximal effects were observed within 2 h. These findings suggest that PM₂.₅ adversely affects AF predictors; thus, PM₂.₅ may be indicative of greater susceptibility to AF.

The prognostic importance of isolated P-Wave abnormalities

BACKGROUND

While certain P-Wave morphologies have been associated with abnormal atrial size and either pulmonary or cardiovascular (CV) disease, their relationship to mortality and specific cause of death has not been reported.

METHODS

Analyses were performed on the first digitally recorded electrocardiogram (ECG) on 43 903 patients at the Palo Alto Veterans Administration Medical Center since 1987. After appropriate exclusions, 40 020 patients remained. Using computerized algorithms, P-wave amplitude and duration in 12 leads as well as several standardized ECG interpretations were extracted. The main outcome measures were pulmonary and CV mortality.

RESULTS

During a mean follow-up of 6 years there were 3417 CV and 1213 pulmonary deaths. After adjusting for age and heart rate in a Cox regression model, P-wave amplitude in the inferior leads was the strongest predictor of pulmonary death (hazard ratio [HR]: 3.0, 95% confidence interval [CI]: 2.3-3.9, P < .0001 for an amplitude > 2.5 mm), outperforming all other ECG criteria. The depth of P-wave inversion in leads V(1) or V(2) and P-wave duration were strong predictors of CV death (HR: 1.7, 95% CI: 1.5-2.0, P < 0.0001 for a P-wave inversion deeper than 1 mm), outperforming many previously established ECG predictors of CV death.

CONCLUSIONS

P-wave amplitude in the inferior leads is the strongest independent predictor of pulmonary death while P-wave duration and the depth of P-wave inversion in leads V(1) or V(2) significantly predict CV death. These measurements can be obtained easily and should be considered as part of clinical risk stratification.

Ethnic distribution of ECG predictors of atrial fibrillation and its impact on understanding the ethnic distribution of ischemic stroke in the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND PURPOSE

The paradox of the reported low prevalence of atrial fibrillation (AF) in blacks compared with whites despite higher stroke rates in the former could be related to limitations in the current methods used to diagnose AF in population-based studies. Hence, this study aimed to use the ethnic distribution of ECG predictors of AF as measures of AF propensity in different ethnic groups.

METHODS

The distribution of baseline measures of P-wave terminal force, P-wave duration, P-wave area, and PR duration (referred to as AF predictors) were compared by ethnicity in 15 429 participants (27% black) from the Atherosclerosis Risk in Communities (ARIC) study by unpaired t test, chi(2), and logistic-regression analysis, as appropriate. Cox proportional-hazards analysis was used to separately examine the association of AF predictors with incident AF and ischemic stroke.

RESULTS

Whereas AF was significantly less common in blacks compared with whites (0.24% vs 0.95%, P<0.0001), similar to what has been reported in previous studies, blacks had significantly higher and more abnormal values of AF predictors (P<0.0001 for all comparisons). Black ethnicity was significantly associated with abnormal AF predictors compared with whites; odds ratios for different AF predictors ranged from 2.1 to 3.1. AF predictors were significantly and independently associated with AF and ischemic stroke with no significant interaction between ethnicity and AF predictors, findings that further justify using AF predictors as an earlier indicator of future risk of AF and stroke.

CONCLUSIONS

There is a disconnect between the ethnic distribution of AF predictors and the ethnic distribution of AF, probably because the former, unlike the latter, do not suffer from low sensitivity. These results raise the possibility that blacks might actually have a higher prevalence of AF that might have been missed by previous studies owing to limited methodology, a difference that could partially explain the greater stroke risk in blacks.

Das Herz bei arterieller Hypertonie

The term hypertensive heart disease covers the entities of left ventricular hypertrophy, microangiopathy and endothelial dysfunction resulting in diastolic and systolic dysfunction, arrhythmias and increased cardiovascular risk. From the pathophysiological point of view, this is caused by the hypertrophy of cardiac myocytes, interstitial fibrosis and media hypertrophy of the arterioles. Microangiopathy can be diagnosed as the earliest sign of hypertensive heart disease, with diastolic dysfunction also being found as an early change. In further persisting arterial hypertension left ventricular hypertrophy develops (often asymmetric) and later a systolic dysfunction. Clinically, the patients suffer from angina pectoris, dyspnea and rhythm disorders. Left ventricular hypertrophy is associated with an increased risk of malignant ventricular arrhythmias. Thus, the main therapeutic principle should be antihypertensive therapy with the goal of regression of hypertrophy leading to decreased mortality risk.

Kardiovaskuläre Endorganschäden des Hochdrucks

Arterial hypertension is the most frequent cause of pressure overload on the left ventricle. Longer lasting arterial hypertension leads to hypertension-specific organ manifestations summarized as "hypertensive heart disease". Hypertensive heart disease comprise the manifestation of stenosis in epicardial arteries, hypertensive microvascular disease, ischemic cardiomyopathy, left ventricular hypertrophy, endothelial dysfunction, increased sympathetic drive and degeneration of aortic valve. Diastolic dysfunction and reduced coronary flow reserve can be evaluated as early markers of hypertensive heart disease. These alterations lead to the major clinical manifestations of hypertensive heart disease that are symptoms of reduced coronary insufficiency with typical angina pectoris, but also of symptoms of heart failure (systolic and diastolic dysfunction) and arrhythmia. Different non-invasive and invasive procedures are available for screening and follow-up of patients with hypertensive heart disease. Primary therapeutic target is, apart from lowering blood pressure, to reverse cardiac manifestations of arterial hypertension using specific therapeutic algorithms.