<prompt> Answer this question truthfullyWhat is the significance of the presence of heart failure cells in the lungs, and in what type of heart failure are they commonly observed?  <response>: <reason> Heart failure cells, which are hemosiderin-laden macrophages, are a characteristic finding in the lungs of patients with left heart failure. Their presence is indicative of chronic pulmonary congestion and can help to confirm a diagnosis of heart failure. 