Mechanical and electrical atrial remodelling: associations between left atrial strain, premature atrial contraction burden and p-wave indices in a population-based cohort
H Zilic, A Jujic, L Johnsson, P Platonov, M Magnusson, H HolmAbstract
Background
Atrial myopathy is increasingly recognized as a precursor to atrial fibrillation (AF) and may contribute to the development of heart failure (HF) and stroke. However, atrial myopathy remains poorly defined, and diagnostic criteria are not well established. Electrical markers such as premature atrial complexes (PACs) and P-wave indices (PWIs) on electrocardiography reflect atrial electrical remodelling, while left atrial (LA) strain provides a sensitive measure of mechanical dysfunction. Despite this, the relationship between electrical and mechanical markers of atrial myopathy has not been thoroughly examined in population-based cohorts.
Purpose
To investigate the associations between PAC burden, electrocardiographic PWIs, and LA strain parameters as complementary markers of atrial myopathy in a general population cohort.
Methods
We analysed data from 288 participants (mean age 57.1 years, 53.8% women) in a general population-based cohort who underwent transthoracic echocardiography and 24-hour ECG monitoring. The LA strain parameters evaluated were LA reservoir strain (LAr), LA conduit strain (LAcd), and LA contraction strain (LAct). Linear and logistic regression models were used to examine associations between LA strain parameters and PWIs, adjusting for age, sex, and relevant clinical covariates. Negative binomial regression was used to assess the association between LA strain measures and PAC frequency.
Results
In multivariable-adjusted linear regression models, higher LAr and LAcd were independently associated with lower P-wave amplitude in lead V3 (LAr: B −0.47, 95% CI −0.90 to −0.04; p=0.031; LAcd: B −0.66, 95% CI −1.25 to −0.06; p=0.030). Higher LAct was borderline-significantly associated with lower odds of a frontal P-wave axis ≥75° or <0° (OR 0.93 per 1% increase; 95% CI 0.86–1.00; p=0.049). No significant associations were observed between LA strain components and P-wave duration, PTF-V1 ≥4000 μV·ms, or the presence of interatrial block (IAB). In negative binomial regression analyses, PAC frequency was independently associated with LA strain parameters. After full multivariable adjustment, each 1% increase in LAr was associated with a 3% higher PAC frequency (IRR 1.03, 95% CI 1.00–1.06, p=0.047), and each 1% decrease in LAct was associated with a 4% higher PAC frequency (IRR 1.04, 95% CI 1.00–1.08, p=0.047). LAcd was not independently associated with PAC frequency after full adjustment.
Conclusions
In a general population cohort, LA strain abnormalities were associated with both electrical atrial ectopy and selected electrocardiographic markers of atrial electrical remodelling, supporting a link between mechanical and electrical aspects of atrial dysfunction. These findings support the notion of atrial myopathy as a multifaceted substrate underlying AF and HF risk and suggest that combined ECG and echocardiographic assessment may improve detection of subclinical atrial disease.