Diastolic heart failure is defined as heart failure with preserved left ventricular ejection fraction. It accounts for 30-50% of heart failure cases. The main causes are cardiac ischemia, hypertension, aging, obesity, and aortic stenosis. Diagnosis requires clinical signs of heart failure, normal left ventricular ejection fraction, and evidence of left ventricular diastolic dysfunction. Treatment focuses on reducing congestion with diuretics, controlling hypertension and ischemia, and improving left ventricular relaxation.