Heart failure is also relatively common in clinical practice, primarily due to dysfunction in the heart's contractile or relaxation capabilities. This leads to ineffective expulsion of venous blood returning to the heart, resulting in venous congestion and a series of symptoms. Patients typically experience varying degrees of breathing difficulty, coughing, expectoration, coughing up pink frothy sputum, as well as gastrointestinal symptoms. Following the onset of heart failure, a patient's heart rate generally increases as a compensatory response to promote increased cardiac output. If a patient enters the terminal stage of heart failure, a decrease in heart rate may occur, and can even lead to death.