Cards Flashcards
ECG rate, rhythm, Axis
Causes of sinus bradycardia and sinus tachy cardia
Normal rate: 60-100 bpm, brady to tachy cardia
Sinus brady-Phhysical fitness, sick sinus syndrome, drugs, vasovagal attacks, acute MI increase intracranial pressure
Sinus Tachy- anxietym anemia, pain fever, sepsis, CHF, PE, Hypovolemia, thyrotoxicosis, CO2 retention, and sympathomimetics
Rhythm- sinus rhythm that originates from sinus node, a P wave ( that is upright in 2, 3 and AVF, and inverted in aVR) preceding every QRS and a QRS after every P wave, sinus arrhythmia is common in young adults
Can be determined by examining the QRS in leads 1 2 and aVF
RAD RALPH and the LAD from VILLA hates WOLVES
Right Axis Deviation- right ventricular hypertrophy, Anterolateral MI, LPH (left posterior hemiblock, also PE)
Left axis Deviation- Ventricular tachy Inferior MI, LVH, Left Anterior hemiblock
WOLVES- WPW can cause both
Intervals of ECGs
PR interval: Normally 120-200 msec (3-5 small boxes). Prolonged= delayed AV conduction (1st degree heart block). Short= fast AV conduction down accessory pathway (WPW syndrome)
QRS Interval: normally under 120 (3 sm box) Q wave is <40 and <2mm deep Ventricular conduction defects can cause widened QRS complex (>120 msec)
LBBB- Deep S wave and no R wave in V1 (W shape) LBBB new is pathologic and sign of MI
RBBB- RST complex- rabit ears in V1
QT interval: <440, Long QT syndrome disposes to Vtach acute MI, brady cardia, myocardiits, hypo K, CA, Mg, congenital syndromes, head injury, and drugs
Jervell and Lange-Nielsen Syndrome: long QT syndrome due to a defect in K channel conduction, associated with sensorineural deafness, treat with b-blocker and pacemaker
Ischemia/infarction
Acute- within hours, peaked T waves, and sT segment changes. 24 hours, T wave inversion and ST seg resolution. Within a few days, pathologic Q more than one third height of QRS, Q waves usually persist, but can resolves Q waves signify either acute or prior ischemic events
Non Q wave infarcts- subendocardial infarcts have ST and T changes without Q waves
In a normal ECG R waves increase in size compared to the S waves between leads V1 and V5, Poor r waves progression refers to diminished R waves in these precordial leads and can be a sign of infarction although it is not specific
cardiac phys
21
