Impaired Cardiac Sympathetic Activity Is Associated With Myocardial Remodeling and Established Biomarkers of Heart
Luis M da Silva1, Andréa Coy-Canguçu1, Layde R Paim1
1Faculdade de Ciências Médicas Universidade Estadual de Campinas São Paulo Brazil.
Insights
Cardiac sympathetic function is reduced in heart failure (HF) patients with both preserved and reduced ejection fraction. This dysfunction correlates with increased myocardial fibrosis and diminished exercise capacity.
Area of Science:
- Cardiology
- Nuclear Medicine
- Cardiovascular Imaging
Background:
- 123Iodine-meta-iodobenzylguanidine (MIBG) scintigraphy assesses cardiac autonomic dysfunction and predicts heart failure (HF) outcomes.
- The link between cardiac sympathetic function, myocardial remodeling, and fibrosis in HF is not well understood.
Purpose of the Study:
- To evaluate cardiac sympathetic function in HF patients.
- To investigate the relationship between cardiac sympathetic function, myocardial remodeling (extracellular volume), and exercise capacity in HF.
Main Methods:
- Prospective study of HF patients (NYHA class II-III) with preserved and reduced ejection fraction, and controls.
- Cardiovascular magnetic resonance (CMR) for ventricular morphology/function and extracellular volume (ECV).
- 123Iodine-MIBG scintigraphy for cardiac sympathetic function (heart-to-mediastinum ratio) and cardiopulmonary exercise testing.
Main Results:
- 123Iodine-MIBG heart-to-mediastinum ratio was significantly lower in both HF with preserved LVEF and HF with reduced LVEF groups compared to controls.
- Lower cardiac sympathetic function correlated negatively with increased ECV (diffuse fibrosis).
- Increased ECV was associated with reduced peak oxygen consumption.
Conclusions:
- Patients with HF (preserved and reduced LVEF) exhibit impaired cardiac sympathetic function.
- This sympathetic dysfunction is linked to myocardial extracellular volume expansion and reduced exercise capacity.
Background:
123Iodine-meta-iodobenzylguanidine scintigraphy is useful for assessing cardiac autonomic dysfunction and predict outcomes in heart failure (HF). The relationship of cardiac sympathetic function with myocardial remodeling and diffuse fibrosis remains largely unknown. We aimed to evaluate the cardiac sympathetic function of patients with HF and its relation with myocardial remodeling and exercise capacity.
Methods And Results:
Prospectively enrolled patients with HF (New York Heart Association class II-III) were stratified into HF with preserved left ventricular ejection fraction [LVEF] ≥45%) and reduced LVEF. Ventricular morphology/function and myocardial extracellular volume (ECV) fraction were quantified by cardiovascular magnetic resonance, global longitudinal strain by echocardiography, cardiac sympathetic function by heart-to-mediastinum ratio from 123iodine-meta-iodobenzylguanidine scintigraphy. All participants underwent cardiopulmonary exercise testing. The cohort included 33 patients with HF with preserved LVEF (LVEF, 60±10%; NT-proBNP [N-terminal pro-B-type natriuretic peptide], 248 [interquartile range, 79-574] pg/dL), 28 with HF with reduced LVEF (LVEF, 30±9%; NT-proBNP, 743 [interquartile range, 250-2054] pg/dL) and 20 controls (LVEF, 65±5%; NT-proBNP, 40 [interquartile range, 19-50] pg/dL). Delayed (4 hours) 123iodine-meta-iodobenzylguanidine heart-to-mediastinum ratio was lower in HF with preserved LVEF (1.59±0.25) and HF with reduced LVEF (1.45±0.16) versus controls (1.92±0.24; P<0.001), and correlated negatively with diffuse fibrosis assessed by ECV (R=-0.34, P<0.01). ECV in segments without LGE was increased in HF with preserved ejection fraction (0.32±0.05%) and HF with reduced left ventricular ejection fraction (0.31±0.04%) versus controls (0.28±0.04, P<0.05) and was associated with the age- and sex-adjusted maximum oxygen consumption (peak oxygen consumption); (R=-0.41, P<0.01). Preliminary analysis indicates that cardiac sympathetic function might potentially act as a mediator in the association between ECV and NT-proBNP levels.
Conclusions:
Abnormally low cardiac sympathetic function in patients with HF with reduced and preserved LVEF is associated with extracellular volume expansion and decreased cardiopulmonary functional capacity.
More Related Videos
Related Concept Videos
01:17Pathophysiology of Heart Failure
01:20Blood Studies for Cardiovascular System I: Cardiac Biomarkers
The essential diagnostic tools for detecting myocardial necrosis and monitoring individuals suspected of having acute coronary syndrome (ACS) include:
Troponins
Troponins, particularly cardiac troponins I and T, are the most precise and sensitive markers of myocardial injury. They are detectable within 4-6 hours of myocardial injury and remain...
01:19Blood Studies for Cardiovascular System II: CRP, Hcy, and Cardiac Natriuretic Peptide Markers
These markers indicate stress or strain on the heart muscle:
Natriuretic Peptides (BNP)
Cardiac myocytes produce these hormones in response to ventricular stretching...
01:26Heart Failure Drugs: Inhibitors of Renin-Angiotensin System
01:26Imbalances in Cardiac Output
CHF can occur due to the failure of either side of the heart. Left-side failure leads to pulmonary congestion—the right side continues to send...