SUMMARY-ECG EDUCATION-H-EXERCISES-CONTINUED

                                                         

SAMPLE ECGS-2

A.PALPITATIONS DUE TO DISEASES-1.ATRIAL FIBRILLATIONS

Normal Rhythm

Fig-1

The above ECG sample shows a kind of arrhythmia known as atrial fibrillation (atrial palpitation)

Atria are the upper chambers of the heart. We know the pacemaker SA node is situated at the right atrium. When SA node starts the conduction which spread over all the atria and the atria contract. We know the normal atrial contractions are represented in the ECG as P wave.

See the above Fig 1. The P-waves are almost absent. Instead of P-waves (check the Normal Rhythm Image above) there are fibrillatory waves seen in the electrodes II, III, and aVF which view the heart from the bottom. The electrode I which view the atria from the top gives no clear waves at all but records fibrillatory waves. Hence we can conclude this is ATRIAL FIBRILLATION.
In atrial fibrillation the atria are fibrillating instead of contracting and hence no proper filling and emptying of the blood takes place. The ventricular contractions are also independent of atrial fibrillation and AV node. The R-R intervals are also randomly irregular. There is no PR interval as P-wave is absent. Waves are deviating randomly up and down from the baseline.
Atrial fibrillation may cause pulmonary embolism or brain damage such as stroke.
2.ATRIAL FLUTTER

Fig-2

See the above Fig-2 and compare this image with the previous one and observe the difference between the two atrial arrhythmias(Palpitations). The former is atrial fibrillation while the later is atrial flutter. Analyze the sample ECG image in Fig-2.
First analyze the lead II (the hero electrode) which views the heart from bottom left(normal axis).P-wave replaced by snaky spiral waves and the Q-wave is absent. The ST segment is raised above the isoelectric line. The R-waves are there with randomly elongated R-R intervals.
See the lead I which views the heart from the top.No P waves at all and R-R intervals are elongated.Lead-III which views the heart from the bottom right also record no P-wave. But all recordings shows there are no deviations from the baseline. Hence because of defective P-waves in all the leads, and elongated R-R intervals the problem is in the atria, which is known as ATRIAL FLUTTER.
The difference between A.fib and A.flut is that the former is characterized by elevated heartbeats (>180 bpm) with tachycardia (shortened R-R intervals)and random deviations from the baseline while the later is characterized by depressed heartbeats (<50 bpm), with randomly elongated R-R intervals (bradycardia) and no deviations from the baseline.
The condition is not as serious as A.fib, but if left untreated it may lead to serious consequences.
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