A. Intrinsic Cardiac Disease

1. Idiopathic
2. Hypertension
3. Cardiomyopathy
   1. Dilated
   2. Hypertrophic
   3. Restrictive
4. Pericarditis, particularly constrictive
5. Myocardial Ischemia, Myocardial Valve Disease
6. Atrial Myxoma
7. Hyper-vagal tone - young persons with Atrial Fibrillation and low heart rates

B. Non-Cardiac Disease

1. "Holiday Heart" (overindulgence)
   1. Food (usually with salt) intake
   2. Alcohol
   3. Caffeine
2. Medications
   1. Theophylline
   2. ß-adrenergic agonists
   3. Stimulants
3. Pulmonary Disease
   1. Chronic obstructive pulmonary disease (COPD)
   2. Pneumonia
   3. Pleural effusion
4. Hyperthyroidism
5. Hyperadrenalism
   1. Cushing's Syndrome
   2. Cushing's Disease
6. Pheochromocytoma