What is supernormal conduction?
Electrocardiographic manifestation of “supernormal” conduction is defined as conduction that is more rapid than expected or presence of conduction when block is anticipated. It is not supernormal in the sense or being more rapid than normal.
What is the supernormal period?
THE TERM supernormal phase designates. a short, early, and linmited period of. the cardiac cycle during which a stimulus. elicits either a totally unexpected response. or one that is less abnormal than expected.
How long is the supernormal excitability phase in ventricular cardiomyocytes?
Consequently, the phase of enhanced excitability is between 0.40 and 0.54 seconds after a QRS complex, since only P waves appearing during this phase are conducted to the ventricle.
What is supernormal excitability?
The term supernormal excitability refers to a reduced current requirement to excite a tissue at a specific period of its activity cycle. Periods of supernormal excitability were first described for nerve in 1912 by Adrian and Lucas (4) and for heart muscle in 1938 by Hoff and Nahum (158).
What is the Supranormal refractory period?
supernormal period in electrocardiography, a period at the end of phase 3 of the action potential during which activation can be initiated with a milder stimulus than is required at maximal repolarization, because at this time the cell is excitable and closer to threshold than at maximal diastolic potential.
What is masked by the QRS complex?
The QRS complex is a result of ventricular depolarization and indicates the start of ventricular contraction. The T wave results from ventricular repolarization and signals the beginning of ventricular relaxation. The electrical signal for atrial repolarization is masked by the larger QRS complex.
What are AV nodes?
The atrioventricular (AV) node is a small structure in the heart, located in the Koch triangle,[1] near the coronary sinus on the interatrial septum. In a right-dominant heart, the atrioventricular node is supplied by the right coronary artery. The intrinsic rate of the AV node is 40 to 60 beats per minute (bpm).
What is automaticity of the heart?
Automaticity is the property of cardiac cells to generate spontaneous action potentials. Spontaneous activity is the result of diastolic depolarization caused by a net inward current during phase 4 of the action potential, which progressively brings the membrane potential to threshold.
What is absolute and relative refractory period?
Absolute and relative refractory periods. During the absolute refractory period, a second stimulus (no matter how strong) will not excite the neuron. The period during which a stronger than normal stimulus is needed in order to elicit an action potential is referred to as the relative refractory period (RRP).
