The common cold is generally mild and self-limiting with most symptoms generally improving in a week. Half of cases go away in 10 days and 90% in 15 days. Severe complications, if they occur, are usually in the very old, the very young, or those who are immunosuppressed.
Types of sick sinus syndrome and their causes include: 1  Sinoatrial block. Electrical signals move too slowly through the sinus node, causing an abnormally slow heart rate. 2  Sinus arrest. The sinus node activity pauses.  Bradycardia-tachycardia syndrome.
The immediate cause of most sudden cardiac arrests is an abnormal heart rhythm. The heartâs electrical activity becomes chaotic, and it canât pump blood to the rest of the body. Coronary artery disease . This is the most common cause of sudden cardiac arrest in people older than 35.