ECG case studies (Proceedings)


ECG case studies (Proceedings)

Nov 01, 2010

Solutions to ECG examples

1. Sinus rhythm with second degree AV block.

2. Sinus rhythm with advanced 2nd degree AV block: P-waves are again present without QRS complexes, all QRS complexes however have a P-wave that is uniformly associated with it. This type of conduction defect will be from AV nodal disease, in dogs pacemakers are recommended.

3. 3rd degree AV block: no association between P-waves or QRS complexes can be seen. Heart rate is slow at around 40 BPM.

4. Hyperkalemia (sinus standstill) in a cat: The rate is slow at 110. P-waves cannot be seen and QRS complexes are wide and bizarre and T-waves are tall and spiked.

5. 3rd degree AV block in a cat: Rate is around 110 BPM. P-waves and QRS complexes are not associated with each other. Unlike dogs, in cats a pacemaker is only needed if clinical signs are noted. Usually also from old age fibrosis.

6. Sinus rhythm with left bundle branch block: it is important to not judge rhythms by shape of the waveforms. Here the QRS is wide and bizarre, but the association between P-wave and QRS is constant, consistent with sinus rhythm.

7. Sinus rhythm with atrial premature contraction: Most complexes have a consistent P-wave to QRS relationship. One premature complex is noted. Since it has the same morphology as the "normal beats" (deep S-wave likely from conduction defect) this argues for a supraventricular origin (atrial premature beat).

8. Atrial fibrillation: Heart rate is >240 BPM. The R to R interval are very irregular. P-waves cannot be seen. This is consistent with atrial fibrillation.

9. Sinus rhythm with paroxysmal ventricular tachycardia: In this ECG there are premature beats present. They differ from the normal QRS complexes and are wide and bizarre, consistent with a ventricular origin.

10. Predominantly ventricular rhythm: Third complex from the right is a sinus beat. The other beats are all ventricular in origin (sometimes P-waves are seen but they are not uniformly associated with a QRS). Heart rate is 240 BPM. Where the heart rate is measured the complexes show R on T where the VPC starts before the VPC before the heart can completely repolarize. This is of great concern, sudden death is possible.

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