Incomplete–1st degree, 2nd degree
Complete — 3rd degree
Characterized pr interval greater than 0.20 sec. Junctional tissue delays impulse longer than normal.
Every atrial impulse no conducted through to the ventricles — PR interval may be normal, shortened, or prolonged, but there are more P waves than QRS’s.
(2) Mobitz II–PR interval remains constant but there are occasional to frequently blocked beats.
Complete heart block–no atrial impulses reach ventricles–cause mechanical atrial-ventricular dissociation–P waves and QRS’s do no correlate. Slow ventricular rate.
Nodal and Ventricular Escape Rhythms
- Safety mechanism of heart to provide more heart beats when it becomes too slow.
- Nodal escape–if SA node fails, AV node nest most likely pacemaker. NO P waves, just normal QRS’s.
- Ventricular escape–rhythm of ventricular complexes when higher pacemakers fail.
- Escape beats–occur when brady occurs (ventricular).