What is a dipole in the heart?
What is a dipole in the heart?
The cardiac dipole is a vector which has both a direction (from the most negative to most positive regions of the heart) as well as an amplitude (voltage). Several electrodes are placed on the body to “look” at the cardiac dipole from different points of view.
Which ECG leads make an einthoven’s triangle?
Lead III has the positive electrode on the left leg and the negative electrode on the left arm. These three bipolar limb leads roughly form an equilateral triangle (with the heart at the center) that is called Einthoven’s triangle in honor of Willem Einthoven who developed the electrocardiogram in the early 1900s.
What does einthoven’s triangle represent?
n. An imaginary equilateral triangle having the heart at its center and formed by lines that represent the three standard limb leads of the electrocardiogram.
What causes negative deflection in ECG?
If the waveform travels away from the + electrode towards the – electrode, a negative going deflection will be seen. If the waveform is travelling in a direction perpendicular to the line joining the sites where the two electrodes are placed, no deflection or a biphasic deflection will be produced.
What is a current dipole?
The electrical current dipole can be thought of as an infinitesimally short length of wire which carries a current. The strength of the source is defined by its dipole moment ( ). This leads to an electrical source term of the form: (188) where is the Dirac delta function.
What do the aVR AVL and AVf leads look at?
The information from the limb electrodes is combined to produce the six limb leads (I, II, III, aVR, aVL, and aVF), which view the heart in the vertical plane. The information from these 12 leads is combined to form a standard electrocardiogram.
What is the first downward or negative deflection on an ECG waveform?
The QRS complex represents ventricular depolarization. It consists of three waveforms. The normal complex begins with a downward deflection known as the Q wave, followed by an upward deflection called the R wave. The next downward deflection will be the S wave.
What is a dipole on EEG?
In EEG / MEG this is typically represented by a so-called dipole, or dipole source. A dipole is defined by its location (the dipole position) and a vector that represents the strength and orientation of the flow of electric current (the dipole orientation).
What is permanent dipole?
A permanent dipole is when you have a polar molecule with oppositely charged ends, and these ends attract other polar molecules, bonding them together. The polar molecules will always be slightly negative on one end and slightly positive on the other.
What does polarization of the heart mean?
Heart muscle cells are polarized when at rest. This means that the net charge density of the fluid inside and outside of the cells is different, because ion concentrations are different on either side of the cell membranes.
What causes a positive deflection on ECG?
A wave of depolarization traveling toward a positive electrode results in a positive deflection in the ECG trace. A wave of depolarization traveling away from a positive electrode results in a negative deflection. A wave of repolarization traveling toward a positive electrode results in a negative deflection.
How do you remember telemetry leads?
A little rhyme I use to remember 5-Lead ECG placement is:
- Smoke over fire – (black over red)
- Clouds over grass – (white over green)
- Chocolate on the stomach- (but you must remember that it’s not on the actual stomach but on the right sternal boarder of 4th intercoastal space)
What does it mean if aVR is positive?
In patients with hypertrophic cardiomyopathy, positive QRS wave in aVR is a predictor for inducible ventricular tachycardia (38). These patients are at greater risk for future sudden death. Arrhythmia is also an important problem for patients with tricyclic antidepressant intoxication.