What is a major sign of cardiomyopathy?

Decreased heart function is indeed a significant indicator of cardiomyopathy. This condition affects the heart muscle itself, impairing its ability to pump blood effectively. When the heart's function is compromised, it can lead to symptoms such as fatigue, shortness of breath, and fluid retention due to reduced cardiac output.

In contrast, normal heart size might suggest the absence of cardiomyopathy, as this condition often leads to either hypertrophy (thickening of the heart muscle) or dilation (enlargement of the heart). Increased blood pressure may occur due to various cardiovascular issues but is not specific to cardiomyopathy itself. Irregular heartbeat patterns can be associated with several heart conditions but are not definitive signs of cardiomyopathy alone. Thus, decreased heart function stands out as a key and specific characteristic of this disorder.