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What exactly do your irregular heartbeats feel like?
I experience quite a variety of irregularities in my heartbeat; sometimes I will feel a single extra beat, as if my heart got excited and didn't want to wait enough time between beats, while on other instances I have the impression that my heart stops for a moment before grudgingly deciding to resume its function. Other times (and these are the occasions that really make me scared) I will feel a sort of extended skipped beat. Today it was as if my heart seized up, rose into my throat, gave a few hard fast thumps, and then, just when I was certain it was going to stop for good, sank gracefully back down into its natural position and started back in on its usual rhythm as if it hadn't just misbehaved so inconsiderately! I have heard so many times that skipped beats are not dangerous, and I believe it, but I think am never certain if my type of irregularities are the same as other people's. I bet you all have heard such statements uttered before too; I think a lot of people on here are convinced that they are the exception to the rule. It just seems like my heart irregularities, while perhaps not always as frequent, are much more pronounced than those of other people, and thus much more life-threatening. Am I right?
Hello. I'm sorry.
I'll try to explain.
The area between Q and T on EKG is known as the systolic phase, where the heart contracts. The other part, (the "flatline") is known as diastolic phase, where the heart fills. Some people think that the heart only contracts during the QRS complex (the spike) which is wrong. So when measuring the QT time, you are really measuring the time the heart needs to contract.
During the diastolic phase, premature beats may occur. How benign the premature beats are, depends to a certain degree on when in the diastolic phase the premature beat fires. With PVCs, you have two opposites:
A) A fusion beat, where the PVC is so late that it merges with the NEXT normal sinus beat.
B) An R/T PVC, where the PVC is so early that it merges with the PREVIOUS normal sinus beat. In other words, the heart isn't fully electrical "recharged" when the PVC fires because the T wave represents heart "recharging".
In a healthy heart, the "fire" (depolarization, QRS complex) and "recharge" (repolarization, T wave) happens more or less similar through the heart. In other words, it's unlikely that a PVC will fall on the previous T wave because if one part is repolarized (and able to fire off a PVC), the other parts will be repolarized as well, so the T wave is finished.
In addition, in healthy hearts, early PVCs are often benign even if they occur (due to a phenomenon known as EAD, early afterdepolarization) because the heart cells are stable and not suffering from ischemia.
In people with non-healthy hearts, a variety of things can happen if you get early PVCs, because the repolarization often takes longer time, because the heart now has different types of tissue with different electrical abilities. In HCM, the septum can have other qualities than the rest of the heart, for example. After a heart attack, scar tissue leads electricity poorly. In long QT syndrome, some parts repolarize later than others or the repolarization itself takes too long.
That's the reason why people with old heart attacks can have ventricular tachycardia triggered by an early PVC. The heart muscle, except the area around the heart attack is repolarized and may fire PVCs, but the area around the heart attack is not. When the PVC is conducted there, however, this area has repolarized, so the impulse is moving around the heart attack, and by the time the impulse has passed, the rest of the heart can receive impulses and you get kind of a "ping-pong" effect, where the impulse is travelling back and forth. This is known as "reentry ventricular tachycardia" or "sustained ventricular tachycardia".
The same goes for other "structural heart diseases". Different repolarization and depolarization time is the key. How early the PVC fires, is differing "benign" PVCs from "PVCs that may cause an arrhythmia". If the PVC is late, chance that the entire heart is "recharged" is higher.
People with prolonged QT are vulnerable to early beats, but through another mechanism, and with another arrhythmia triggered.
During an EP study, the doctors are provoking earlier and earlier PVCs to see if something happens. If it does, the test is "positive". If not (no arrhythmia triggered) it's "negative".
I'll try to explain.
The area between Q and T on EKG is known as the systolic phase, where the heart contracts. The other part, (the "flatline") is known as diastolic phase, where the heart fills. Some people think that the heart only contracts during the QRS complex (the spike) which is wrong. So when measuring the QT time, you are really measuring the time the heart needs to contract.
During the diastolic phase, premature beats may occur. How benign the premature beats are, depends to a certain degree on when in the diastolic phase the premature beat fires. With PVCs, you have two opposites:
A) A fusion beat, where the PVC is so late that it merges with the NEXT normal sinus beat.
B) An R/T PVC, where the PVC is so early that it merges with the PREVIOUS normal sinus beat. In other words, the heart isn't fully electrical "recharged" when the PVC fires because the T wave represents heart "recharging".
In a healthy heart, the "fire" (depolarization, QRS complex) and "recharge" (repolarization, T wave) happens more or less similar through the heart. In other words, it's unlikely that a PVC will fall on the previous T wave because if one part is repolarized (and able to fire off a PVC), the other parts will be repolarized as well, so the T wave is finished.
In addition, in healthy hearts, early PVCs are often benign even if they occur (due to a phenomenon known as EAD, early afterdepolarization) because the heart cells are stable and not suffering from ischemia.
In people with non-healthy hearts, a variety of things can happen if you get early PVCs, because the repolarization often takes longer time, because the heart now has different types of tissue with different electrical abilities. In HCM, the septum can have other qualities than the rest of the heart, for example. After a heart attack, scar tissue leads electricity poorly. In long QT syndrome, some parts repolarize later than others or the repolarization itself takes too long.
That's the reason why people with old heart attacks can have ventricular tachycardia triggered by an early PVC. The heart muscle, except the area around the heart attack is repolarized and may fire PVCs, but the area around the heart attack is not. When the PVC is conducted there, however, this area has repolarized, so the impulse is moving around the heart attack, and by the time the impulse has passed, the rest of the heart can receive impulses and you get kind of a "ping-pong" effect, where the impulse is travelling back and forth. This is known as "reentry ventricular tachycardia" or "sustained ventricular tachycardia".
The same goes for other "structural heart diseases". Different repolarization and depolarization time is the key. How early the PVC fires, is differing "benign" PVCs from "PVCs that may cause an arrhythmia". If the PVC is late, chance that the entire heart is "recharged" is higher.
People with prolonged QT are vulnerable to early beats, but through another mechanism, and with another arrhythmia triggered.
During an EP study, the doctors are provoking earlier and earlier PVCs to see if something happens. If it does, the test is "positive". If not (no arrhythmia triggered) it's "negative".
I've learned a lot from is_something_wrong but it is very technical. I'm just not quite as smart about the heart. I found a website that helped me understand it a little more. http://www.mauvila.com/ECG/ecg_premature.htm
thank you =) I was like everyone else before; had palpitations and thumps and pains and really nothing wrong (or so I thought) my ekg and even an echo came out "normal"
then I had a holter monitor and stress test done where they found some inconsistencies and problems...I still have a ton of questions because pvc's/pac;s just don't morph into something dangerous....not that I have found so far.
then I had a holter monitor and stress test done where they found some inconsistencies and problems...I still have a ton of questions because pvc's/pac;s just don't morph into something dangerous....not that I have found so far.
Wow. I'm sorry. Your condition sounds extremely scary. I guess that modern medicine can help with a lot of problems, but not always as much as we would like. I am just glad that you have received some help, and as I say, I will be thinking of you. Take care :)
I wish mine weren't dangerous - I just happen to be one of the ones who really didn't believe I could ever have anything wrong because I didn't feel bad even when I fainted, had 50,000+ pvc's or felt my heart stopping.
I have a malignant form of PVC's they found during my ablation called Polymorphic Ventricular Tachycardia found in 3 separate places in my heart which causes VTach episodes and makes my heart stop.
I had to have an ICD implanted and been shocked many times as recently as June 2011 my heart went whacko and stopped 3 different times.
They think this is due to a genetic condition and at first thought it was ARVD but then diagnosed me with HOCM (Hypertrophic Obstructive Cardiomyopathy) it's a toss up what's really wrong - dr's disagree with each other which is the correct dx.
I don't know all the answers for me because I seem to be a medical mystery to dr's - even ones who teach other world class EP's at the largest university here....he threw his hands up and said what else do you want me to do for you? nothing else can be done medically and told me to go back to my original EP because my case was too complex for him :(
I have a malignant form of PVC's they found during my ablation called Polymorphic Ventricular Tachycardia found in 3 separate places in my heart which causes VTach episodes and makes my heart stop.
I had to have an ICD implanted and been shocked many times as recently as June 2011 my heart went whacko and stopped 3 different times.
They think this is due to a genetic condition and at first thought it was ARVD but then diagnosed me with HOCM (Hypertrophic Obstructive Cardiomyopathy) it's a toss up what's really wrong - dr's disagree with each other which is the correct dx.
I don't know all the answers for me because I seem to be a medical mystery to dr's - even ones who teach other world class EP's at the largest university here....he threw his hands up and said what else do you want me to do for you? nothing else can be done medically and told me to go back to my original EP because my case was too complex for him :(
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