==Change in rhythm==
new atrial fibrillation. Atrial fibrillation occurs in ten percent of elderly people (>70 year) without clinical symptoms. Therefore atrial fibrillation in acute dyspneic patients does not prove atrial fibrillation-induced cardiac decompensation. Also other causes (e.g. cardiac ischemia, pneumonia) should be considered. Previous ECGs could provide additional information.
bradycardia. New sinus bradycardia of 50 beats per minute (bpm) may cause dizziness; however, long-existing bradycardias are often without symptoms. Therefore it is important to know the patient's normal frequency.