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 ...

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 ...

With a sustained block of the SNS, the researchers observed loss of the day-night rhythm in sinus node pacemaking and in pacemaking ion channels. Surprisingly, the heart’s local circadian clock ...