When this occurs prior to the AV node recovering (the AV node is still refractory), a non-sinus ... the last normal sinus beat. When every other QRS complex is a PAC, then the rhythm is referred ...

The rhythm is either sinus rhythm or not sinus rhythm. Sinus rhythm refers to the origination of the electrical activity coming from the sinus node — also known as the sinoatrial node ...

Non-respiratory sinus arrhythmia may be associated with ... Sinus arrhythmia is a variation in the heart's natural rhythm, usually caused by changes in the breathing cycle—what's known as ...