Electrocardiogram, analysis of ECG Flashcards
ECG what is it?
Electrical activity of single myocytes (only experimentally). However, the sum of the activities of all fibers can be measured on the surface of the body (ECG).
ECG: what is Einthoven’s Triangle
Einthoven invented a device to detect slight electric changes (mV). Pairs of electrodes are placed around the heart – as dipole – creating the „Einthoven’s Triangle”. Potential differences (U) are measured between the pairs of electrodes.
ECG: what is Einthoven’s Triangle during rest
the sum of the potential differences around the dipole (integral vector) is always zero.
Einthoven’s standard bipolar leads
Lead 1: reference electrode = RA,investigating electrode = LA
Lead 2: reference electrode = RA, investigating electrode = LL
Lead 3: reference electrode = LA, investigating electrode = LL
Analysis of ECG curves: p wave
P-wave: The atrial muscle fibers are being depolarized.
Analysis of ECG curves: PQ segment
PQ-segment: the period of atrioventricular conduction
Analysis of ECG curves:QRS-complex
: depolarization of ventricular fibers & repolarization of the atria.
Analysis of ECG curves: Q-wave:
transmission of the excitation from the bundle of His to the ventricular muscles, downward deflection.
Analysis of ECG curves: R-wave:
ventricles are being depolarized, largest deflection of the ECG curve.
Analysis of ECG curves: S-wave:
right ventricle depolarizes from the endocardium close to the apex towards the epicardial surfaces of the base of the heart.
Analysis of ECG curves:ST-segment:
ST-segment: all ventricular muscle fibers are activated, this causes a shift from the isoelectric line
Analysis of ECG curves: T-wave:
ventricular repolarization
Analysis of ECG curves: TP segment
TP-segment: represents the resting phase after full repolarization.
Types of ECG
Unipolar
His bundle ECG & Esophageal ECG:
Vector cradiography:
Vector loop
ECHO cardiography
Types of ECG: Unipolar
Types of ECG
