Atrial fibrillation is an abnormal heart rhythm that frequently results in a fast heart rate. Although atrial fibrillation itself does not typically cause death, people with atrial fibrillation are at higher risk for stroke. The risk for stroke increases with age and with other medical problems like heart failure, high blood pressure
, diabetes, prior stroke, and coronary artery disease. After consultation with a physician, many patients with atrial fibrillation are placed on a blood thinner such as warfarin to decrease their risk of stroke. It is important for you to consult your doctor
about the specific risks of atrial fibrillation for you and whether anticoagulation
The low heart rate may be a different issue. Is it not uncommon for someone's heart rate to drop this low while asleep. If you are on medications to control your heart rate, such as metoprolol, it is possible you are switching in and out of atrial fibrillation. If this occurs, some people have much higher heart rates while in atrial fibrillation and much lower heart rate when they switch into their normal sinus rhythm. Very low heart rates can cause fatigue, lightheadedness, or loss of consciousness. However, not all people experience this symptoms with a heart rate of 35. It is not possible to determine if this heart rate poses a danger for you, and I strongly advise you to consult your cardiology in person for further evaluation.