22.8.2013 Flashcards
Electrical alternans
Beat to beat variation of QRS complexes by 1mm
Tall waves,DD
Chamber enlargement
Young individuals
Thin,Emaciated individuals
Mastectomy pts
Calculation of heart rate,boxes
100 use small boxes
Causes of low voltage QRS complexes
Obesity COPD Pleural or pericardial effusion Generalised Edema Hypothyroidism Amyloidosis
Causes of electrical alternans
Cardiac tamponade
Poor conduction in ventricles alternating with normal conduction
SVT
Severe myocardial ischemia
Normal intrinsicoid deflection in V1 and V2
<0.03S
Normal intrinsicoid deflection in V5 and V6
<0.05S
Components of QRS
Ventricular activation time
Intrinsicoid deflection
Sequence of ventricular activation
- septum
- free wall of both ventricles
- posterobasal wall of septum and left ventricle
Total duration of septal q wave should not exceed
0.03S
Normal sinus rhythm is indicated by
Upright p wave in lead 2
Measurements of inverted portion of p wave
Less than 1mm in depth and duration
ECG of rt atrial enlargement
Tall(>2.5mm) peaked p waves in leads 2,3,avF
Axis of p wave shifted to right of 60’
P3>P1
Normal p wave duration
<110ms
Causes of rt atrial enlargement
Tricuspid or pulmonary valvular disease
Pulmonary hypertension
Acute pulmonary embolism
Right ventricular failure or hypertrophy