Race and Sex Differences in QRS Interval and Associated Outcome Among Patients with Left Ventricular Systolic Dysfunction

Abstract

BackgroundProlonged QRS duration is associated with increased mortality among heart failure patients, but race or sex differences in QRS duration and associated effect on outcomes are unknown.Methods and ResultsWe investigated QRS duration and morphology among 2463 black and white patients with heart failure and left ventricular ejection fraction ≤35% who underwent coronary angiography and 12‐lead electrocardiography at Duke University Hospital from 1995 through 2011. We used multivariable Cox regression models to assess the relationship between QRS duration and all‐cause mortality and investigate race‐QRS and sex‐QRS duration interaction. Median QRS duration was 105 ms (interquartile range [IQR], 92–132) with variation by race and sex (P<0.001). QRS duration was longest in white men (111 ms; IQR, 98–139) followed by white women (108 ms; IQR, 92–140), black men (100 ms; IQR, 91–120), and black women (94 ms; IQR, 86–118). Left bundle branch block was more common in women than men (24% vs 14%) and in white (21%) versus black individuals (12%). In black patients, there was a 16% increase in risk of mortality for every 10 ms increase in QRS duration up to 112 ms (hazard ratio, 1.16; 95% CI, 1.07, 1.25) that was not present among white patients (interaction, P=0.06).ConclusionsBlack individuals with heart failure had a shorter QRS duration and more often had non‐left bundle branch block morphology than white patients. Women had left bundle branch block more commonly than men. Among black patients, modest QRS prolongation was associated with increased mortality.

Women are underrepresented in cardiac resynchronization therapy trials

“…The overall lifetime risk of HF is comparable in both sexes, around 21% for men and 20% for women at 40 years of age according to the Framingham Heart study 4 . In addition, the prevalence of LBBB, an indication for CRT in HF patients and a strong predictor of incident HF 5 is much higher in women compared to men in the general population, in contrast to right bundle branch block which is more prevalent in men 6–8 . However, the representation of women in the RCTs is less than 1/4th of the total study population.…”

“…Significant variations exist in cardiac structure, electrophysiology, and response to cardiovascular therapies based on biological sex. For example, women with HF have a smaller ventricular size, shorter QRS duration and higher rates of nonischemic cardiomyopathy compared to men 6,13,14 . Women under‐representation in trials, thus compromises the generalizability of the evidence.…”

“…4 In addition, the prevalence of LBBB, an indication for CRT in HF patients and a strong predictor of incident HF 5 is much higher in women compared to men in the general population, in contrast to right bundle branch block which is more prevalent in men. [6][7][8] However, the representation of women in the RCTs is less than 1/4th of the total study population. The sex bias in the participation of RCTs is consistent in most cardiology trials.…”

“…For example, women with HF have a smaller ventricular size, shorter QRS duration and higher rates of nonischemic cardiomyopathy compared to men. 6,13,14 Women under-representation in trials, thus compromises the generalizability of the evidence. In addition, limited enrollment of women in CRT trials may skew baseline variables and might limit the ability to concretely assess sex-based differences in the outcomes of CRT.…”

Racial and ethnic disparities in arrhythmia care: A call for action

“…Black individuals with heart failure with reduced ejection fraction and progressive QRS prolongation have increased heart failure hospitalizations, readmission rates, and mortality. 37,38 Similarly, the QT interval has been identified as a risk factor for SCD in Black individuals. Both the ARIC study 39 and Duke Databank for Cardiovascular Disease 40 demonstrated that prolonged QT interval predicted increased risk of silent myocardial infarction and coronary artery disease and was associated with adverse cardiovascular events in both races, but with higher predilection in Black individuals.…”