# cardiac rythm interpretation.pptx - P-waves P-waves...

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P-wavesP-wavesrepresentatrial depolarizationIn sinus rhythm, there should be aP-wavepreceding eachQRScomplexPR intervalThePR-intervalis fromthe startof theP-wavetothe startof theQ waveItrepresentsthetime takenfor electrical activity to movebetweentheatria and ventriclesQRS complexTheQRS-complexrepresentsdepolarization of the ventriclesIt is seen as 3 closely related waves on the ECG(Q,R & S wave);ST segmentTheST-segment startsat theendof theS-wave&finishesat thestartof theT-waveIt representsventricular repolarizationT-waveTheT-waverepresentsventricular re-polarizationIt is seen as a small waveaftertheQRS complex
T-waveTheT-waverepresentsventricular re-polarisationIt is seen as a small waveaftertheQRS complexRR-intervalTheRR-interval startsat thepeak of one R waveto thepeak of the next R waveItrepresentsthetime between two QRS complexesQT-intervalTheQT-intervalstarts at the beginning of theQRS complexand finishes at the end of theT-waveIt represents the time taken for the ventricles to depolarise & then repolarise
How to read ECG paperThe paper whichECG’sare recorded upon isstandardisedacross allhospitals (usually)Eachsmall squarerepresents0.04 secondsEachlarge squareon the paper represents0.2 seconds5 large squarestherefore =1 second
Calculating the Heart RateThere are several methods for calculating the heart rate.1.Rule of 300: If the rhythm is regular, the heart rate can be"estimated" by using the "Rule of 300". Count the number of largesquares between two R waves and divide this number into 300.( There are 300 boxes, or 1500 tiny boxes, in a one minute strip)2.The Six-Second Method: Count the number of complete R waveswithin a period of 6 seconds and multiply that number by 10. This isthe one minute heart rate. This method can be used when therhythm is "regular or irregular".3.The Three-Second Method: Count the number of complete QRScomplexes in a period of three seconds and multiply that by twenty.This is the one minute heart rate.
4.The Block Method: Find a QRS complex that hits exactly ona vertical line.The next block 300The second block 150The third block 100The fourth block 75The fifth block 60The sixth block 50The seventh block 43The eight block 37The ninth block 30The tenth block prayers are neededAnalyzing a Rhythm Strip Using the Eight Step Approach
Rule of 1500 and 300Heart Rate = 1500 / #sm boxes between 2 QRS comples1500/32=46 bpmHeart Rate = 300 / #lg boxes between 2 QRS complex300/62=48
Analyzing a Rhythm Strip Using theEight Step Approach

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