What Causes Inverted Qrs Complex?
What the height of the QRS complex means?
I understend QRS , but what specificly height of QRS means? At rest it is shorter than after exercise , whay?
To start with.....The 'QRS' complex of the ECG represents ventricular depolarization, causing the ventricles to contract. The 'QRS' complex can be used to determine a patient's cardiac rate. The QRS complex tends to look "spiked" rather than rounded due to the increase in "conduction velocity".
The height of the QRS referred to as the AMPLITUDE corresponds with the "VOLTAGE" conducted with every contraction of the ventricles. As why it is shorter at rest than after exercise, obviously because during exercise the heart function is increased which means there is more VOLTAGE upon ventricular contraction.
The height or amplitude of QRS has wide normal limits. An amplitude of 5 mm or less in all three standard leads is considered to be unhealthy often seen in coronary disease, cardiac failure, emphysema, and obesity.
The upper limit is variable from lead to lead, but generally is between 20 and 30 mm. Amplitude are affected by many factors besides the health of the heart. Some of these factors include chest size, chest wall thickness,and emphysema -these factors should always be given consideration before judging the voltage of any complex to be too high or too low.
why is there a delay in the QRS complex and the peak pulse measured in the finger ?
why is there a delay in the QRS complex and the peak pulse measured in the finger ?
because of the millisecond time difference- the QRS electrical impulses travel to the electrodes quicker than the heart actually pumps the blood
When the QRS complex is reduced & when the P wave is reduced, what will happen to the cardiac output and why?
These are 2 questions for the ECG. question 1: when QRS complex is reduced what will happen to cardiac output, why? question 2: when P wave is reduced what will happen to cardiac output, why? can someone give me a simple explanation on both the questions.
The QRS complex corresponds to ventricular depolarisation and depolarisation. The P wave corresponds to atrial depolarisation and depolarisation.
Hopefully that will help you fill in the rest.
Would someone help me find a website that explains how to interpret ECG (EKG) strips?
Would someone please help me find a website that will help me understand how to analyze ECG strips? I have a test on Monday and still don't feel confident about interpreting those! Thank you!
Here's another one, the good ol' wikipedia:
But I can give you some basics:
The first halfcircular wave of the ECG is known as the P wave. During the P wave, the Sinus Node (the normal heartbeat initiator of the heart in the right atrium) fires an impulse which spreads through the atriums activating them making them contract. After the P wave, there's a small pause which is followed by a large spiky wave known as the QRS complex. During the first small downwards pointing spike of the QRS known as the Q wave, the atrioventricular node between the atriums and the ventricles fires to the Bundle of His. During the large upwards pointing spike known as the R wave the Bundle of His fires the impulse forward which then goes to the Purjinke Fibers and then to the ventricles making them contract. The last spike of the QRS known as the S wave represents the activation of the last part of the ventricles. The medium sized halfcircular wave after the QRS Complex is known as the T wave. During the T Wave the ventricles return from a heartbeat (depolarize) causing an electrical impulse.
What heart conditions effect the P wave, QRS complex and T-wave, independently.?
I'm looking for a heart conditions that affects each independently, having some extreme difficulties. Thanks
OK, big question! lol
OK first, in case you didn't know the following cuz it's really hard to explain pathology if you don't get how it's supposed to work, you know?
So - quick conduction lesson: There's an electrical cycle and a mechanical cycle. The p-wave-qrs-t-wave "picture" represents the electrical cycle, or an impluse travelling through the heart. The electrical cycle stimulates mechanical activity, and there are delays between the electrical "picture" and the actual mechanical response, because mechanical is slower (makes sense, right?). You can also have electrical activity without mechanical response, but not the other way around.
The SA node being the primary pacemaker of the heart, a normal cycle represents this: the p wave is atrial depolarization (when the atrial contracts). The PR-interval is the time it takes for the electrical impulse to travel from the SA node, through the AV node, and into the Purkinjie fibers (bundle branches) to depolarize the ventricles (represented by the QRS complex). The t-wave is the electrical representation of re-polarization of the ventricles.
The P-wave: Changes in the shape of the P-wave and PR-interval generally point to conduction problems and origination changes. Inverted or missing P-waves indicate a Junctional rhythm (Conduction impulse originating from the AV node instead of the SA node). P-waves that are upright and present for every QRS complex but have at least 3 different shapes present indicate a wandering atrial pacemaker - meaning the impulse is not originating from the SA node, but from multiple different points around the atria (could be either left or right). That can lead to a multifocal atrial tachycardia - which can be dangerous. These multiple different points the impulse is coming from are also referred to as "ectopic foci". Ectopic impulses can also cause re-entrent pathways, aka the SA node tries to conduct and so does the ectopic foci, and it sort of leads them in a circle - creating "bad" pathways that don't conduct the impulse in the direction it should go, but back into the SA node instead. This can lead to SVTs, which can be dangerous or fatal. This is the basis of Wolfe Parkinson White Syndrome (WPW).
You also need to know that "normalcy" in EKG structures is often based on the time of conduction, calculated on EKG paper by the little boxes. The little boxes are 0.04 ms each.
A normal PR-interval is 0.12-0.20 ms. When the P-wave is upright and normal looking, but there is an extended gap (more than 0.20 ms) between the P-wave and QRS, that is called an AV-block, meaning a conduction "block" or delay in the impulse being transmitted from the SA node through the AV-node. It indicates that communication between the atria and ventricles is impaired or lost. There are varying degrees of AV-blocks, starting at 1st (least serious) and going up to 3rd (most serious, also known as a complete AV Block. In this AVB, the atria and ventricles can't communicate at all and although you might see normal looking p-waves, they do not correspond at all with any QRS. The QRS will also probably look different, most likely wide). Try looking up those for more specific info - it can be complicated and difficult to understand.
QRS morphology (shape) represents ventricular conduction and a normal QRS is 0.04-0.12. When a QRS is "wide" (greater than 0.12), it indicates that the stimulus for the ventricles to contract is coming from the ventricles themselves, instead of the SA or AV node. This is generally considered very pathologic and in need of immediate treatment/correction. The ventricles intrinsically beat at a rate of 20-40 beats/min which is generally too slow to sustain a person's body functions for very long. Ventricular rhythms represented by a "wide" QRS include idioventricular (slow, deadly), agonal (very slow, VERY deadly), V-tach (ventricular tachycardia, an accelerated ventricular rhythm) and V-fib. V-fib, aka ventricular fibrillation, is NOT a wide-rhythm. It is an irregular, chaotic, 300+ bpm (not countable) that is also referred to as "Ventricular standstill." This is cardiac death, and if not immediately reversed leads to asystole, aka "flatline", the abscense of any electrical activity. Basically the ventricle is just vibrating, like jello, not pumping blood, not perfusing the body. Not good. You also will see wide QRS complexes with a complete 3rd degree block with a ventricular response. All that means is, like I said before, the atria and ventricles aren't communicating, but the ventricles are still trying to beat. So you will see p-waves (quite possibly normal shaped) as well as wide-QRS complexes, but they do NOT correlate with each other. When you have a complete/3rd degree block with no ventricular response, you might see asystole or you might see p-waves with no QRS. P-waves with no QRS complexes at all are called "P-wave asystole." Anyway as far as shape goes, any "wide" QRS