Determinants of QRS duration in a diverse cardiomyopathy population of the Western Cape : implications for eligibility for cardiac resynchronization therapy
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Abstract
Background
Cardiac resynchronization therapy (CRT) improves quality of life in heart failure patients
who have a QRS duration ≥120 ms. Relatively few patients presenting with heart failure
to the Division of Cardiology at Tygerberg Hospital are candidates for CRT, mainly
because of a QRS duration <120 ms.
Objectives
The objectives of this study were to determine the QRS duration in a diverse
cardiomyopathy population served by Tygerberg Hospital and to identify possible
determinants of QRS duration in this cardiomyopathy population.
Method
Approval for this study was obtained from Stellenbosch University Health Research
Ethical Committee and Tygerberg Hospital and all patients signed informed consent.
Patients with a left ventricular systolic function (LVEF) <35% were recruited prospectively
from the cardiac clinic. LVEF was determined by echocardiography using Simpson’s
biplane method. QRS duration was measured on a standard 12 lead ECG.
Results
Two hundred patients were included. The mean age was 52 years (range 18-84). Self identified ethnicity revealed 63% coloured, 22% black and 15% white patients. The mean
QRS width was 105 ms. On univariate analysis, parameters associated with a QRS width
≥120 ms included: ethnicity (White >Coloured >Black) (p = 0.01), ischaemic heart disease (<0.01), age (<0.01), left ventricular size (p = 0.03) and male gender (p = 0.05). After
correcting for covariates in a multivariate analysis, ethnicity and sex were no longer
predictive of a broad QRS.
Conclusion
Although it appeared on first evaluation that there was a gender and ethnic disparity in
candidates for CRT, multivariate analysis revealed that this is more likely due to
differences in age, ischaemic aetiology and LV size.
Description
Submitted in partial fulfilment of the requirements for the Master of Health Sciences: Clinical Technology (Cardiology) at the Durban University of Technology, Durban, South Africa, 2023.
Citation
DOI
https://doi.org/10.51415/10321/4979