Sinus Pause/Sinus Block
Sinus pause describes a condition where the SA node fails to generate an electrical impulse for what is generally a brief period of time. In the above example, the initial rate is 88 beats per minute (the first two beats are normal), then there is a 1.8 second sinus pause before the heart resumes, initially at a somewhat slower rate of 52 beats per minute. A related rhythm is SA block which is often hard to distinguish from a sinus pause. In SA block, the SA node creates an impulse, but it is blocked from leaving the SA node. The differences are beyond the scope of this discussion.
Patients who have sinus pauses may complain of missed or skipped beats, flutters, palpitations, hard beats or may feel faint, dizzy or lightheaded or experience a syncopal episode (passing out). Frequent pauses would heighten these symptoms. This is a result of patients actually missing or dropping beats. Obviously, if the heart misses a beat, blood does not flow during that time period resulting in a lack of oxygen or perfusion throughout the body.
Treatment and prognosis depend on the cause and cardiac status of the patient. This condition may be drug induced or it may be a result of cardiac disease. Treatment may involve the use of medications or the use of a temporary or permanent pacemaker.