Heart failure can be a consequence of untreated high blood pressure, a heart attack, heart muscle disease, valvular heart disease or continual cardiac arrhythmia. Heart failure leads to reduced performance in daily life, a shortage of breath and peripheral edema. Cardiac insufficiency can be detected and graded using an echocardiogram. A cardiac catheterization test will check the blood circulation in the coronary vessels. The first stage in treating heart failure is always with medication. Great importance is attached to the specific course of therapy for the underlying disease. Under certain conditions it is beneficial in the recovery from cardiac insufficiency to implant a special defibrillator or pacemaker (cardiac resynchronization therapy, or CRT).