ECG Flashcards
APB
ATRIAL PREMATURE BEAT (APB)
- Atrial depolarization occurs before next sinus p wave
- QRS complex of APB preceded by P wave that looks different from other P waves on strip
- After APB, slight pause occurs before normal sinus beat resumes
- May reach junction during refractory period and be blocked
JUNCTIONAL Rhythm
- Absent P wave before QRS complex
–> impulse is not being generated from atrial depolarization; being started at level of AV junction
- can spread in BOTH DIRECTIONS (ventricles and atria) so it creates variations in P wave
–> can come after QRS wave becasue depolarization takes longer than ventricles
MULTIFOCAL ATRIAL TACHYCARDIA
- multiple sites of atrial depolarization
- PR interval varies
- 3 or ore consecutive non-sinue P waves with DIFFERENT SHAPES
- ventricular rate is irregular (some beats get through, some do not) and rapid
ATRIAL FIBRILLATION
- fibrillation waves vary in shape and polarity (come from multiple sites throughout atrial muscle)
- irregularly irregular: variable f-f intervals and irregular ventricular (QRS) response
atrial fibrillation vs atrial flutter
FIRST DEGREE AV BLOCK
- P wave (usually sinus) followed by QRS complex
- PR interval is UNIFORMALY PROLONGED
- same number of P waves as QRS
Second degree Type I block
- Intermittently DROPPED QRS complexes (P wave not followed by QRS complex)
- pattern of conducted: dropped beats is regular (3P waves: 2 QRS complexes)
- produces strip with grouped or clustered beats
Second degree type II AV block
- Sudden appearance of single, DROPPED BEATS (P wave not followed by a QRS complex)
–> RANDOM (NOT PROGRESSIVE) lengthened (to infinity) PR INTERVAL
–> Conducted beats have constant PR interval
Third degree AV block
- Complete heart block: no conduction from atria to ventricles; AV DISSOCIATION
- Atria continue to be paced by SA node, regular P waves
–> more P waves than QRS
- Location of ventricular escape rhythm will dictate QRS duration
Right Bundle Branch Block
- Conduction occurs more slowly in the RIGHT VENTRICLE as compared to LEFT, generating a WIDE QRS complex
- LATE QRS forces point toward the right ventricle (positive in V1 and negative in V6
Left bundle branch block
- Conductio occurs much mroe slowly in LEFT VENTRICLE compared to right, generating a WIDE QRS
–> Septal depolarization occurs from RIGHT TO LEFT due to the lag of impulse from left side
–> V1 = wide QS complex (can be notched like an W)
–> V6 wide R wave (can be notched like an M)
UNIFOCAL PREMATURE VENTRICULAR COMPLEX
- PVC have similar appearance in any one lead
- usually precede sinus P wave, sometimes followed by retrograde (non-sinus) P wave
Multifocal premature ventricular complexes
- Multiform ventricular premature beats have different shapes in the same lead
describe Ventricular tachycardia
- 3 or more PVC’s in a row at a rate of 100bpm
- can be result of focal or reentrant mechanisms
- TWO TYPES
–> SUSTAINED = Lasts for more than 30 secs
–> NONSUSTAINED = less tahn 30 secs
- can be monomorphic or polymorphic (with or without QT interval prolongation)
Ventricular fibrillation
- Completely disorganized ventricular rhythm
- NO CARDIAC OUTPUT
- Course or fine nomenclature refers to amplitude of waves
- progresses from COARSE (some amplitude) to FINE (little) to ASYSTOLE (NONE)
RIGHT ATRIAL ABNORMALITY
- Results ina bnormal amplitude of P wave but does not change duration
- sometimes called P PULMONALE due to association with pulmonary disease
LEFT ATRIAL ABNORMALITY
- Rsults in wide, sometimes notched P wave in one or more extremity leads
–> wide biphasic P waves in lead V1
Right ventricular hypertrophy
- Tall RIGHT PRECORDIAL R WAVES
- right axis deviation
- right precordial T WAVE INVERSION
LEFT VENTRICULR HYPERTROPHY
- High voltage (abnormally tall) R waves in left chest leads
- Promient S waves in right chest leads
- OFTEN ACCOMPANIED BY LEFT AXIS DEVIATION
Occurs with pressure overload on the left side of the heart
