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.
In summary, inhalation causes the heart rate to be higher and exhalation results in a reduction in heart rate. We see this most readily as a cyclic compression and retraction of the R wave to R wave intervals - i.e. - the R waves are compressed during inhalation and retract during exhalation. B. Sinus Arrest : Sinus arrest is also called sinus pause or sinus block. Sinus arrest occurs when the sinoatrial node stops firing.