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 heartâs electrical activity becomes chaotic, and it canât pump blood to the rest of the body. Conditions that can trigger sudden cardiac arrest include: Coronary artery disease . This is the most common cause of sudden cardiac arrest in people older than 35. Cardiomyopathy . When you have this condition, your heart muscle becomes enlarged or thick, so it's weakened.