Basics of ECG, P wave, QRS complex, T wave, PR, QT interval
#ECG#QRS#PRinterval#QTinterval#howtoreadECG
complexThe human Heart is both electrically and mechanically specialized organ.
At a typical heart rate of 70 beats per minute, the heart beats about 100,000 times per day, or 37 million beats a year.
The heart has its own independent rhythm. When removed from nervous system innervation and transplanted into another body, the heart continues to beat rhythmically.
The heartbeat originates from the S A node, which is also called the pacemaker.
The action potential originated from sinoatrial S A node passes successively through the atrial myocardium to the atrioventricular AV node, bundle of his and to the Purkinje fibers.
Making the conduction system for the action potential.
Let’s see what happens when the action potential propagate through the conduction system of heart.
The cardiac action potential originates from the sinus node, located high in the right atrium. It causes depolarization in atrium.
The contraction of atria forces the blood to the ventricles.
The action potential impulse than reaches the AV node.
The AV nodal tissue conducts the electrical impulses very slowly.
This delay between atrial activation and ventricular activation has functional importance because it allows optimal ventricular filling.
From the AV node, the electrical impulse reaches the His bundle and then Purkinje system spread the action potential in ventricles.
This resulting in a “wringing” contraction of the ventricles that begins at the heart apex and moves toward the atria.
This contraction effectively ejects blood from ventricles into the large arteries leaving the heart.
This cycle is repeated in every 0.8 sec throughout over life.
Now we talk about E C G or Electrocardiograph
When impulses pass through the heart, electrical currents are Generated that spread throughout the body.
These impulses can be detected on the body surface and recorded as an electrocardiograph.
The typical ECG has three recognizable waves.
P wave.