help understanding pr, qrs, qt

I am having a hard time getting this. I think-I found on the internet that normal for pr is .12-.20, normal for qrs is .4-.12, and normal for qt is .42.
Looking over my event report, I have huge variations. My EP never mentioned any of it--so I did not know what normal was or wasnt--but here is what some numbers out of that range were---if anyone can help me please to understand this and its meaning I would be greatful.

PR-.23, .24, .21, .22 ( I am assuming this is due to 1st degree heart block I have?)

QRS-.38, and 1.15- .10 (mostly it was .7or .11)---any idea what this means?

QT-lots of .34, .35, .o7, .40 (seems to vary greatly)--whats this?

[jennyfi1234]

PS, I found another site saying QT norms are .35-.44--so again, if thats true, then wye the .07 and dr. said nothing?

[Brooke_38]

The PR interval begins at the onset of the P wave and ends at the onset of the QRS complex. This interval represents the time the impulse takes to reach the ventricles from the sinus node. It is termed the PR interval because the Q wave is frequently absent. Normal values lie between 0.12 and 0.20 seconds. First degree atrioventricular block is diagnosed if the PR interval is greater than 0.20 seconds.

The PR interval will gradually increase with the Wenckebach phenomenon. Your report may be likely due to 1st degree block. This type of block is usually benign and most often requires no treatment.

The QRS complex begins at the onset of the Q wave and ends at the endpoint of the S wave. It represents the duration of ventricular depolarisation.Normally all QRS complexes look alike. They are still termed QRS complexes even if all three waves are not visible


The Q-T interval represents the time for both ventricular depolarization and repolarization to occur, and therefore roughly estimates the duration of an average ventricular action potential.  This interval can range from 0.2 to 0.4 seconds depending upon heart rate.  At high heart rates, ventricular action potentials shorten in duration, which decreases the Q-T interval.  Because prolonged Q-T intervals can be diagnostic for susceptibility to certain types of tachyarrhythmias, it is important to determine if a given Q-T interval is excessively long.  In practice, the Q-T interval is expressed as a "corrected Q-T (QTc)" by taking the Q-T interval and dividing it by the square root of the R-R interval (interval between ventricular depolarizations).  This allows an assessment of the Q-T interval that is independent of heart rate.  Normal corrected Q-Tc intervals are less than 0.44 seconds

This is alot of information...I hope that it helps you to understand the question you asked. Let me know if you would like further info.

[is_something_wrong]

There are a lot of numbers there, and I think you mix some of the numbers.

The PR time is correctly stated and may indicate a first degree AV block. This is usually not dangerous, as long as the heart rate increases properly with increasing work load. Beta blockers and calcium channel blockers can (and should) increase the PR time. It should decrease with higher parasymp. activity, such as exercise / higher heart rate.

Regarding QRS, it seems you mix in some axis numbers in the list. A QRS axis of 38 degrees is completely normal (even -38 degrees is just a little out of normal range). A QRS duration of .38 seconds is impossible, even with a ventricular rhythm. I believe the axis is 38 degrees, and your QRS duration is 115 msec (.115 sec) and 100 msec (.1 sec). They are both normal, though 115 msec is on the far side of normal. QRS times vary with heart rate, and high heart rate tends to increase it (rapid impulses can cause a little abberancy, the heart is not completely able to receive new impulses).

Your QT times are completely normal. The .07 is possibly what is called QT dispersion, in other words, difference between QT times in different leads of the EKG. A prolonged QT dispersion makes the heart vulnerable to so-called R on T PVCs, but I don't think .07 sec (70 msec) is outside normal range. I'm not completely sure about this one.

Summary: I think your EKG's are normal. But I (of course) can't say for sure because I'm not a doctor.

[jennyfi1234]

Thank you guys!