Left ventricular extracellular volume fraction and atrioventricular interaction in hypertension
Left atrial enlargement (LAE) predicts cardiovascular morbidity and mortality. Impaired LA function also confers poor prognosis. This study aimed to determine whether left ventricular (LV) interstitial fibrosis is associated with LAE and LA impairment in systemic hypertension.
Following informed written consent, a prospective observational study of 86 hypertensive patients (49 ± 15 years, 53% male, office SBP 168 ± 30 mmHg, office DBP 97 ± 4 mmHg) and 20 normotensive controls (48 ± 13 years, 55% male, office SBP 130 ± 13 mmHg, office DBP 80 ± 11 mmHg) at 1.5-T cardiovascular magnetic resonance was conducted. Extracellular volume fraction (ECV) was calculated by T1-mapping. LA volume (LAV) was measured with biplane area-length method. LA reservoir, conduit and pump function were calculated with the phasic volumetric method.
Indexed LAV correlated with indexed LV mass (R = 0.376, p < 0.0001) and ECV (R = 0.359, p = 0.001). However, ECV was the strongest significant predictor of LAE in multivariate regression analysis (odds ratio [95th confidence interval] 1.24 [1.04–1.48], p = 0.017). Indexed myocardial interstitial volume was associated with significant reductions in LA reservoir (R = -0.437, p < 0.0001) and conduit (R = -0.316, p = 0.003) but not pump (R = -0.167, p = 0.125) function. Multiple linear regression, correcting for age, gender, BMI, BP and diabetes, showed an independent decrease of 3.5% LA total emptying fraction for each 10 ml/m2 increase in myocardial interstitial volume (standard β coefficient -3.54, p = 0.002).
LV extracellular expansion is associated with LAE and impaired LA reservoir and conduit function. Future studies should identify if targeting diffuse LV fibrosis is beneficial in reverse remodelling of LA structural and functional pathological abnormalities in hypertension.
• Left atrial enlargement (LAE) and impairment are markers of adverse prognosis in systemic hypertension but their pathophysiology is poorly understood.
• Left ventricular extracellular volume fraction was the strongest independent multivariate predictor of LAE and was associated with impaired left atrial reservoir and conduit function.
• LV interstitial expansion may play a central role in the pathophysiology of adverse atrioventricular interaction in systemic hypertension.
KeywordsCardiac imaging techniques Magnetic resonance imaging Hypertension Fibrosis Strain
Analysis of ariance
Body mass index
Cardiovascular magnetic resonance
Diastolic blood pressure
Extracellular volume fraction
European Society of Cardiology
Left atrial enlargement
Left atrial volume
Maximal left atrial volume
Minimal left atrial volume
Left atrial volume just prior to left atrial contraction
Left ventricular hypertrophy
Left ventricular mass
Region of interest
Systolic blood pressure
Steady state free precession
This work was supported by the Bristol National Institute for Health Research (NIHR) Cardiovascular Biomedical Research Unit at the Bristol Heart Institute. The views expressed are those of the authors and not necessarily those of the National Health Service, NIHR, or Department of Health.
We thank Christopher Lawton, Superintendent Radiographer, and the Bristol Heart Institute CMR radiographers for their expertise in performing the CMRs. JCLR: Clinical Society of Bath Postgraduate Research Bursary 2014 and Royal College of Radiologists Kodak Research Scholarship 2014. ECH and JFRP are funded by the British Heart Foundation.
This study has received funding by The Royal College of Radiologists Kodak Research Scholarship 2014.
Compliance with ethical standards
The scientific guarantor of this publication is Dr Mark Hamilton.
Conflict of interest
The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Written informed consent was obtained from all subjects (patients) in this study.
Institutional review board approval was obtained.
• performed at one institution
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