Diagnosis, Testing, and Ruling Out Other Causes

Diagnosing alcoholic cardiomyopathy (ACM) is often a process of elimination. Because the symptoms of ACM—like fatigue and shortness of breath—are identical to those caused by clogged arteries or viral infections, your doctors must work backward to rule out other causes before confirming ACM ^[1]. This process is known as a diagnosis of exclusion ^[2].

Ruling Out Other Causes

To confirm ACM, your care team needs to ensure that your heart muscle weakness isn’t caused by something else. They will typically look for three things:

1. Dilation and Weakness: Evidence that your heart chambers are enlarged and pumping poorly ^[1].
2. Alcohol History: A significant history of alcohol use, often historically defined as more than 80 grams of ethanol (about 5 to 6 drinks) daily for at least five years, though this is a research convention and can vary based on individual sensitivity ^[3][1].
3. No Other Explanation: Ruling out ischemic heart disease (blocked arteries), primary valve disease, active viral myocarditis (inflammation of the heart muscle), tachycardia-mediated cardiomyopathy, uncontrolled hypertension, thyroid or other endocrine disorders, nutritional deficiency, stimulant or chemotherapy exposure, and familial DCM ^[1][4].

Key Diagnostic Tests

Your doctor will use several specialized tests to look at the structure, function, and “scars” of your heart.

• Echocardiogram (Echo): This is usually the first test. It uses sound waves to create a real-time video of your heart. It measures your Ejection Fraction (EF)—the percentage of blood your heart pumps out with each beat—and can detect “subclinical” damage through strain analysis, which looks at how well the heart muscle fibers stretch and contract ^[5][6].
• Cardiac MRI (CMR): This provides the most detailed look at your heart tissue. Doctors look for Late Gadolinium Enhancement (LGE), which identifies areas of fibrosis (scarring) or inflammation ^[5]. In ACM, this scarring is often found in the mid-wall or the septum (the wall between the chambers). This helps distinguish it from a heart attack, where scarring usually starts on the inner lining, though this pattern can overlap with genetic DCM, myocarditis, and sarcoidosis ^[6][7].
• Blood Biomarkers:
  • NT-proBNP: A protein released when the heart is under “stretch” or stress. It helps measure the severity of your heart failure, but it is influenced by age, kidney function, and atrial fibrillation, so there is not one universal treatment target ^[8].
  • Troponins: These are released when heart cells are damaged. High levels might suggest a recent “hit” to the heart or inflammation like myocarditis ^[9].
  • Liver Enzymes: Because alcohol affects the liver, these nonspecific tests help your doctor understand the overall impact of alcohol on your body ^[1].

The Role of Genetic Testing

In the past, ACM was blamed entirely on alcohol. However, we now know that some people with ACM carry a genetic variant—most commonly in the titin (TTN) gene—that makes their heart muscle more vulnerable to toxic substances ^[10][11].

Genetic counseling and a multigene cardiomyopathy panel may be considered, particularly with a family history, young age, unexplained or persistent dysfunction, or features suggesting inherited dilated cardiomyopathy. Identifying a pathogenic variant is important because it may guide how your doctor screens your family members ^[12]. Keep in mind that a Variant of Uncertain Significance (VUS) should not be used to label relatives or direct their care. Pre- and post-test genetic counseling is highly important.

Your Diagnostic Checklist

When you receive your test results, look for these specific measurements, keeping in mind that your clinicians will interpret them based on the whole clinical picture: