Bigeminy is an abnormal heart rhythm where every other beat is abnormal. This can be an abnormal atrial beat (atrial bigeminy), a beat arising from the AV junction or bundle of His (junctional bigeminy), or a ventricular beat (ventricular bigeminy). The pattern is as such: Normal beat... abnormal beat... normal beat.... abnormal beat... normal beat... abnormal beat... repeat.
The absence of a P wave on an EKG could indicate an issue with the electrical impulse formation in the atria of the heart, such as in atrial fibrillation where the atria are not depolarizing in a coordinated manner. Other possible causes include atrial flutter, junctional rhythm, or ectopic atrial beats. Further evaluation by a healthcare professional is necessary to determine the underlying cause.
P waves occur from the sinoatrial node and indicate the atrial component of a heart rate. Junctional rhythms occur when the AV node (below the sinoatrial node) takes over. Therefore, in most junctional rhythms there are no p waves.
An accelerated junctional rhythm has a heart rate between 60 and 100. Meanwhile, a junctional tachycardia has a heart rate >100.
Sinus Bradycardia Sinus Tachycardia Sinus Dysrhythmia Sinus Arrest Wondering Pacemaker Premature Atrial Complex Paroxysmal Supraventricular Tachycardia Atrial Flutter Atrial Fibrillation Premature Junctional Complex Junctional Escape Complexes or Rhythms Accelerated Junctional Rhythm Ventricular Escape Complexes or Rhythms Premature Ventricular Complex Ventricular Tachycardia (VT) Ventricular Fibrillation (VF) Asystole Artificial Pacemaker Rhythms First Degree AV Block Second Degree AV Block Type 1 (Wenckebach) Second Degree AV Block Type 2 Third Degree AV Block Disturbances of Ventricular Conduction Pulseless Electrical Activity (PEA) Preexcitation Syndrome: Wolff-Parkinson-White Syndrome Broad complex tachycardia Narrow complex tachycardia
A supraventricular tachycardia is tachycardia (heart rate > 100) that originates above the AV node, in the atria. There are several different forms of supraventricular tachycardia, including sinus tachycardia, atrial fibrillation, atrial flutter, atrial tachycardia, multifocal atrial tachycardia, and a nebulous condition called paroxysmal supraventricular tachycardia (PSVT). Many people also consider junctional tachycardia a supraventricular tachycardia.
The junctional epithelium attaches to enamel by means of internal basal lamina .
The genetic mutations for junctional EB are found in the genes responsible for producing the protein Laminin-5.
The P wave is the first wave in an ECG complex, and it results from the atria depolarizing. It may not be present in arrhythmias where the atria do not necessarily depolarize, such as junctional or ventricular escape rhythms, and at times when the atria are depolarizing abnormally this will be reflected in the P wave's replacement by abnormal waves, such as the low-amplitude "squiggle" seen in atrial fibrillation, or the "sawtooth" pattern seen in atrial flutter.
On the Net, you can find different things being said about the cardiac "junctional fibers". I am going to offer what I understand makes the most sense. The junctional fibers are cardiac muscle cells which are specialized for slowing down the cardiac impulse just before it goes into the atrioventricular node. This delay gives the atria time to empty their blood into the ventricles before the cardiac impulse goes on to stimulate the ventricles to contract. Notes: (1) These junctional fibers are not nerve cells, but are muscle cells which are specialized for conducting the cardiac impulse. You may know how more-narrow nerve axons are slower at passing on an action potential, while wider axons can pass on an action potential faster. Well, these junctional fibers are like nerve fibers, in this way > because these junctional fibers are very narrow, they can slow down the cardiac impulse. (2) So, where do you think these narrow junctional fibers need to be, in order to slow down the cardiac impulse at the right place and time? If the cardiac impulse were to go from the atria right on to to the ventricles, then the ventricles would be stimulated to contract while the atria were still trying to empty blood into the ventricles. And so, the ventricular blood pressure would be pushing back against the blood that was trying to get from the atria into the ventricles. This would not be good. So . . . the heart needs to slow that impulse, just after it leaves the atria . . . slowing it long enough so the ventricles stay relaxed while they receive blood from the atria. (3) And, lo and behold . . . the junctional fibers are located right after the atria; and they receive the impulse which comes from the atrial muscles; then it delays the impulse before letting it go into the atrioventricular node. This slow-down gives the atrial muscles just enough time to finish contracting before the atrioventricular node sends on the cardiac impulse to stimulate the ventricles to contract. (4) You might notice on an EKG how there is the P wave showing atrial depolarization. Then the line goes flat for a little bit before the QRS complex. At the beginning of that flat time at the end of the atrial depolarization, this is where the junctional fibers are slowing down the cardiac impulse before it shows as the QRS which shows the impulse being fired by the atrioventricular node to the ventricles, I understand.
Junctional, confrontational, instructional
Can I drop derty for atrial