The ECG finding in sinus arrest is a transient absence of P waves lasting from 2 seconds to several minutes (see Figure 3.2). There is an alteration of impulses generated by the SA node pacemaker cells. If the SA node does not generate an impulse, the failsafe mechanism is activated via escape beats from the pacemaker cells of the AV junction that take over for the SA node.

Related Video – ECG Rhythm Review – Sinus Arrest

Figure 3.2. Prolonged Sinus Arrest

Prolonged Sinus Arrest ECG

Pauses lasting < 2 seconds may occur in the normal heart. Longer pauses, such as those seen in sick sinus syndrome, often cause dizziness, presyncope, syncope, and, rarely, death.