Cardio Examination (ECG) FF

when is S3 sound heard

early diastole

when is S4 sound heard

late diastole

conduction system of the heart

1. SA node initiates depolarization (pacemaker)

2. AV node passes depolarization to ventricles

3. APs go through bundle branches to L and R ventricles

4. Purkinje fibers carry out APs

ECG waves meaning

p-wave: atrial depolarization

QRS wave: ventricular depolarization and atrial repolarization

T wave: ventricular repolarization

3 areas to look at for ECG

1. rate - p-wave and QRS complex

2. rhythm (intervals) - for AV blocks

3. axis - for depressions/elevation

6 second method for counting HR

count 30 large boxes (= 6 seconds)

- count the number of R waves and then multiply by 10

1st degree AV nodal block

- PR interval >1 large box (0.2 sec)

- seen in athletes w/ increased vagal tone

- doesn't mean too much

*continue exercise

2nd degree AV block Mobitz I/Wenckebach

PR interval progressively gets longer until finally a QRS is "dropped"

- needs to be predictable

*lower intensity of exercise and monitor

2nd degree AV block Mobitz II

PR intervals are constant and QRS is randomly dropped

- no pattern

- disease of bundle of His and Purkinje

*stop exercise

3rd degree AV block

no relationship of P-R intervals

- constantly changing PR interval and QRS is wide and bizarre

*stop exercise and activate EMS

myocardial ischemia on ECG

ST segment depression (>1 mm)

- T wave may be flattened or inverted

myocardial infarction on ECG

ST segment elevation (>1mm)

- occlusion of blood supply and cell death

supraventricular arrhythmias

atrial rate:

- atrial tachy: 100-250 bpm

- atrial flutter: 250-350 bpm

- atrial fib: 400-600 bpm

NOT 911 emergencies

PVCs

ventricles contract before atria so no P waves

when are PVCs 911

multifocal PVC: 2 do not appear similar in configuration

couplet: 2 PVCs together w/ no beat between them

3+ PVCs in a row: v tach