Irregular rhythms, AV nodal blocks and ventricular arrythmias Flashcards
Describe a normal sinus rhythm.
Rate of 60-100bpm, regular rhythm.
Describe sinus bradycardia.
Rate of less than 60bpm, regular rhythm.
Describe sinus tachycardia.
Rate of more than 100bpm, regular rhythm.
Describe sinus arrythmia.
Same as a normal sinus rhythm except it is irregular.
Describe sinus arrest.
SA node fails to initiate a pulse, causing a full beat to be missed, resuming after.
Describe premature atrial complex.
P wave appears earlier than the next sinus beat, which can cause the R-R interval to be shortened.
Describe supraventricular tachycardia.
Rate of more than 150bpm, regular rhythm. Increased speed causes P wave being lost in the T wave of the preceding beat.
Describe atrial flutter.
Atria contract at a higher ratio to ventricles (1:1, 1:2, 1:3), creating “F waves” which present as tooth-shaped waves, and can be regular or irregular.
Describe atrial fibrillation.
Irregularly irregular (meaning there is no pattern), P wave is replaced by erratic small waves.
Describe junctional AV rhythm.
Rate of 40-60bpm, regular rhythm, AV node begins the rhythm, causing the P wave to be either hidden behind the QRS complex, presenting after the QRS complex or inverted.
Describe accelerated junctional rhythm
Same presentation as junctional AV rhythm, except the rate is between 60-100bpm.
Describe first degree heart block.
P-R interval is extended, displaying as greater than 5 small squares (0.2 seconds).
Describe second degree heart block Mobitz type 1 (Wenckebach).
Rate of 60-100bpm, P-R interval increases gradually each beat until a beat is dropped.
Describe second degree heart block Mobitz type 2.
Same as Mobitz type 1, except the P-R interval doesn’t increase, meaning that a beat is dropped without a change to the P wave.
Describe third degree heart block.
Generally bradycardic, P wave occurs without a QRS complex at different ratios, meaning that atrial and ventricular rhythms occur independently from each other.
