ECG3 Flipped class room.pptx study health

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1. Electrocardiogram (ECG-iii) Arrhythmias/ ( SGD)

2. A 57-year-old man presents to Pakistan Railway Hospital's emergency department with complaints of shortness of breath and chest pain radiating to the left arm and jaw for the past 2 hours. On physical examination, he appears to be in mild distress and tachycardia with a heart rate of 170bpm and a blood pressure of 105/70mmHg. An electrocardiogram (ECG) shows a  sinus tachycardia  with an elevation of the ST segment, and T waves represent ventricular polarization. and diagnosed as an acute myocardial infarction. Case Scenario

3. By the end of this Lecture, all First year MBBS students would be able to : Correlate the vectorial analysis with recording of electrocardiogram. Enumerate abnormal sinus rhythms LEARNING OBJECTIVES

4. Why would this patient have tachycardia? What is approximate normal heart rate in Ventricular arrhythmias? What are the most common ECG changes in Sinus arrhythmias ? What would the ST segment of this ECG look like? What does the T wave represent? Questions

5. Arrhythmia refers to irregular heartbeat or disturbance in the rhythm of heart. Arrhythmias are any deviations from the normal sinus rhythm Arrhythmias

6. In arrhythmia, SA node may or may not be the pacemaker. If SA node is not the pacemaker, any other part of the heart such as atrial muscle, AV node and ventricular muscle becomes the pacemaker . Because of this, arrhythmia is classified into two types: A . Normotopic arrhythmia B . Ectopic arrhythmia. Classification

7. SA NODE

8. Normotopic arrhythmia is the irregular heartbeat, in which SA node is the pacemaker. Normotopic arrhythmia is of three types: Normotopic Arrhythmias

9. Sinus arrhythmias

10. ECG Changes: ECG is normal during sinus arrhythmia. Only the duration of R-R interval varies rhythmically according to phases of respiration. It is shortened during inspiration and prolonged during expiration.

11. Normotopic arrhythmia is the irregular heartbeat, in which SA node is the pacemaker. Normotopic arrhythmia is of three types: Normotropic arrhythmia

12. Sinus tachycardia is the increase in discharge of impulses from SA node, resulting in increase in heart rate. T he heart rate increases up to 100-150/minute . Sinus tachycardia

13. ECG is normal in sinus tachycardia, except for short R-R intervals because of increased heart rate. ECG changes

14. Normotopic arrhythmia is the irregular heartbeat, in which SA node is the pacemaker. Normotopic arrhythmia is of three types: Normotropic arrhythmia

15. Sinus bradycardia is the reduction in discharge of impulses from SA node resulting in decrease in heart rate . Heart rate is less than 60/minute. Sinus bradycardia

16. ECG shows prolonged waves and prolonged R-R interval. ECG changes

17. Any circulatory reflex that stimulates the vagus nerves causes release of Acetylcholine at the vagal endings in the heart, thus giving a parasympathetic effect . The most striking example of this occurs in patients with carotid sinus syndrome . Vagal Stimulation as a Cause of Bradycardia

18. Ectopic arrhythmia is the abnormal heartbeat, in which one of the structures of heart other than SA node becomes the pacemaker. Impulses produced by these structures are called ectopic foci. Ectopic arrhythmias

19. Heart block is the blockage of impulses generated by SA node in the conductive system. Based on the area affected, the heart block is classified into two types. 1 . Sinoatrial block 2 . Atrioventricular block Heart block

20. Blockage of impulse from the SA node before it enters into the atrial muscle. It is also known as sinus block . Occur due to defect in internodal fibers . Sinoatrial Block – AV Nodal Rhythm

21. Standstill of atria (no P wave) → AV node start generating the impulses(become pacemaker )→ Ventricles pick up a new rhythm and heart start beating with the decrease rate of 40 to 60/minute. ( rate of ventricular QRS complex is slow, otherwise not altered). Sinoatrial Block – AV Nodal Rhythm

22. No P wave. Slow rate of ventricular QRS complex. ECG changes

23. In this condition, impulses cannot pass from atria into the ventricles through AV bundles (bundle of His ). Causes: Condition in which there is decrease rate of conduction or blockage of conduction occur is as follows; Ischemia of AV-node/AV bundles Compression of AV bundles by the scar or calcified tissues Inflammation of AV node ( diphtheria, rheumatic fever) Extreme Stimulation of heart by 10 th nerve Atrioventricular Block

24. Atrioventricular block is of two categories: 1. Incomplete heart block 2. Complete heart block . Types of AV block

25. Atrial flutter is an arrhythmia characterized by rapid ineffective atrial contractions, caused by ectopic foci originating from atrial musculature. Both the atria beats rapidly like the wings of a bird, hence the name atrial flutter originate. Atrial Flutter

26. Atrial rate is about 250 to 350/minute . Atrial flutter is common in patients suffering from cardiovascular diseases . Initially , it is marked by palpitations that are unnoticed. However , prolonged atrial flutter may lead to atrial fibrillation or heart failure . Atrial Flutter

27. ECG changes

28. Atrial fibrillation is the type of arrhythmia characterized by rapid and irregular atrial contractions at the rate of 300 to 400 beats/minute . Atrial fibrillation is common in old people and patients with heart diseases. Atrial fibrillation

29. P wave is absent in ECG . QRS complex normal ECG changes

30. Ventricular fibrillation is the most dangerous cardiac arrhythmia, characterized by rapid and irregular twitching of ventricles . Ventricles beat very rapidly and irregularly. The rate reaches to 400 to 500/minute . Ventricular Fibrillation

31. Cardiac impulses within the ventricular muscle mass first stimulate one portion of the ventricular muscle, then another portion, then another, and eventually feeding back onto itself to re-excite the same ventricular muscle over and over—never stopping. When this happens, many small portions of the ventricular muscle will be contracting at the same time, while other portions will be relaxing. Mechanism

32. The ventricular chambers neither enlarge nor contract but remain in an indeterminate stage of partial contraction, pumping either no blood or negligible amounts- Unconsciousness occurs within 4 to 5 seconds for lack of blood flow to the brain, and irretrievable death of tissues begins to occur throughout the body within a few minutes.