Decreased E to F slope and elevated E/e' ratio is observed in which type of cardiomyopathy?

The correct answer is restrictive cardiomyopathy (CM). In restrictive cardiomyopathy, the heart muscle becomes stiff and does not relax properly, which affects the filling of the ventricles. This can lead to a decreased E to F slope, which refers to the early diastolic filling velocity compared to the late filling wave, indicating impaired relaxation.

Additionally, an elevated E/e' ratio is commonly observed in restrictive cardiomyopathy. This ratio measures the early diastolic mitral inflow velocity (E) compared to the early diastolic tissue velocity (e') and is an important parameter for assessing left ventricular filling pressures. An increased E/e' ratio indicates higher left atrial pressure, which is typical in conditions where ventricular filling is compromised, such as in restrictive cardiomyopathy.

In summary, both the decreased E to F slope and the elevated E/e' ratio reflect the hemodynamic changes associated with restrictive cardiomyopathy, making it the correct option in this scenario.