Chest leads
Lead System of the ECG
•
.Ⅱ.ECG EVALUATION
The Standard 12-lead Electrocardiogram
How to measure each wave: amplitude duration
25mm/s
How to calculate the heart rate
• Heart Rate = 60/R-R duration
Mean QRS axis
Cardiac Rotation
.Ⅲ. NORMAL ECG
• ⒈ P Wave • ⒉ P-R Interval • ⒊ QRS complex • ⒋ J point • ⒌ ST Segment • ⒍ T Wave • ⒎ Q-T Interval • ⒏ U Wave
.Ⅲ. NOMAL ECG ——QRS complex
• ⑴duration: 0.06~0.10s. • ⑵form and amplitude. • ⑶R peak time • ⑷Q Wave
.Ⅲ. NOMAL ECG
• J point • ST Segment
• T Wave • Q-T Interval • U Wave
•q
Clinical electrocardiolopy elementary knowledge
• Vector • Resultant vector • Loop
Electrical basis and theory
The Standard 12-lead Electrocardiogram
Atrial and Ventricular hypertrophy
(一） left Ventricular enlargment
• QRS voltage: ① R in V5,6>2.5mV, ②
RV5+SV1>3.5 or 4.0mV, ③ RI>1.5mV, R in aVL>1.2mV, aVF>2.0mV, S in V1 2.4mV, ④ RI+SIII2.5mV.
• left axis deviation • QRS duration>0.09ms. • ST segment and T wave
left Ventricular enlargment
Atrial and Ventricular hypertrophy
(二） Right Ventricular enlargment
• ①V1 lead R/S>1, V5 lead R/S<1, • ②Rv1+Sv5 >1.05mV. • ③right axis deviation>+90°. •④ST-T change
Right Ventricular enlargment
Atrial and Ventricular hypertrophy
• ECG dose not record directly the electrical activity of the heart.
• ECG record the electrical activity of the heart from the body surfECTROCARDIOGRAM
The Standard 12-lead Electrocardiogram
How to measure each wave: amplitude duration
25mm/s
ELECTROCARDIOGRAM
• ECG records the changing potential of the field imparted by the heart.
.Ⅲ. NOMAL ECG ——P Wave
• ⑴form：I、II、avF、V4-6 • ⑵duration：<0.12s • ⑶amplitude: Limb leads <0.25mV, Chest leads <0.20mV.
.Ⅲ. NOMAL ECG ——P-R Interval
• duration：0.12s~0.20s.
The Standard 12-lead Electrocardiogram
——R Wave form
Lead System of the ECG
• Limb leads
Einthoven trigone
Hexaxial system
Lead System of the ECG
• Chest leads
Electrical basis and theory
Electrical basis and theory
• depolarization • dipole • repolarization
Electrical basis and theory
Electrical basis and theory
(三） Biventricular enlargement
• Approximately normal ECG. • Left or Right Ventricular Hypertrophy ECG
• Biventricular Hypertrophy ECG
IV. The Abnormal ECG
Atrial and Ventricular hypertrophy
Atrial and Ventricular hypertrophy (一）atrial enlargment
• Right atrial enlargement: • Left atrial enlargement
• SA node • Bachmann • AV node • His bundle • Left and right
branch of bundle • Pukinje fiber
The Standard 12-lead Electrocardiogram
• P Wave • P-R interval • QRS Complex • ST segment • T Wave • Q-T interval