From the Guidelines
Ischemic heart disease causes dilated cardiomyopathy through progressive myocardial damage resulting from inadequate blood supply to the heart muscle, leading to ventricular remodeling and eventual heart failure. This process begins when coronary arteries become narrowed or blocked by atherosclerotic plaque, resulting in myocardial ischemia 1. If this ischemia is prolonged or severe, as in myocardial infarction, cardiomyocytes die and are replaced by non-contractile scar tissue. Over time, this loss of functional heart muscle triggers compensatory mechanisms, including ventricular remodeling, where the remaining viable myocardium hypertrophies and the ventricle dilates to maintain cardiac output 1.
The key factors contributing to the development of dilated cardiomyopathy in the context of ischemic heart disease include:
- Myocardial ischemia and infarction leading to cardiomyocyte death
- Ventricular remodeling and dilation as compensatory mechanisms
- Neurohormonal activation contributing to further myocardial damage and fibrosis
- Eventual maladaptive changes leading to progressive ventricular enlargement, thinning of the ventricular walls, and decreased contractility
According to the American Heart Association, treatment should be individualized and target the underlying cause, in addition to standard systolic heart failure therapies 1. In the case of ischemic heart disease causing dilated cardiomyopathy, management focuses on treating the underlying coronary artery disease through revascularization procedures and medications to improve myocardial perfusion and prevent further ischemic damage. The goal is to prevent further myocardial damage, reduce symptoms, and improve quality of life. Recent guidelines emphasize the importance of understanding the specific cause of dilated cardiomyopathy to guide treatment, as outlined in the 2021 ACC/AHA key data elements and definitions for heart failure 1.
From the Research
Ischemic Heart Disease and Dilated Cardiomyopathy
- Ischemic heart disease (IHD) can lead to dilated cardiomyopathy (DCM) through various mechanisms, including coronary artery disease, myocardial ischemia, and microvascular dysfunction 2.
- The pathophysiology of IHD is complex and multifaceted, involving not only atherosclerotic plaque formation but also other factors such as oxidative stress, ion channel dysfunction, and coronary microvascular dysfunction 3.
- Myocardial ischemia, which can result from IHD, can cause damage to the heart muscle, leading to ventricular remodeling and eventually DCM 4.
- The relationship between IHD and DCM is supported by studies showing that patients with IHD are at increased risk of developing DCM, and that the presence of DCM can worsen the prognosis of patients with IHD 5, 2.
Mechanisms of IHD-Induced DCM
- Coronary artery disease, a common cause of IHD, can lead to reduced blood flow to the heart muscle, resulting in ischemia and damage to the heart muscle cells 4.
- Myocardial ischemia can trigger a series of cellular and molecular changes, including oxidative stress, inflammation, and apoptosis, which can contribute to the development of DCM 3.
- Microvascular dysfunction, which can occur in patients with IHD, can also contribute to the development of DCM by reducing blood flow to the heart muscle and promoting ischemia 2.
Clinical Implications
- The diagnosis and treatment of IHD and DCM require a comprehensive approach, taking into account the complex pathophysiology of these conditions 5, 4.
- Management of IHD and DCM may involve lifestyle modifications, pharmacological therapies, and revascularization procedures, such as coronary artery bypass grafting or percutaneous coronary intervention 4, 6.
- Early detection and treatment of IHD and DCM are critical to preventing progression of these conditions and improving patient outcomes 5, 2.