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CourageousLimeTree

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Azerbaijan Medical University

Abdulmalik Fawaz Kteil

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arrhythmias heart conditions ecg cardiology

Summary

This presentation covers arrhythmias, explaining different types like sinus tachycardia, bradycardia, and various types of AV blocks. It details the causes, including impaired automatism, excitability, and conduction issues. The presentation also explains different arrhythmias based on whether the problem is related to the SA node or ectopic foci. It includes ECG characteristics of each type and the potential implications for treatment.

Full Transcript

Arrhythmias Abdulmalik Fawaz Kteil 122i-2a 1: The conductive system of the heart As we know, the conductive system of the heart consists of the SA node, AV node, bundle of His and Purkinje fibers. 2: Normal ECG 3: Arrhythmias Any abnormal heart rhythm, whether affecting heart...

Arrhythmias Abdulmalik Fawaz Kteil 122i-2a 1: The conductive system of the heart As we know, the conductive system of the heart consists of the SA node, AV node, bundle of His and Purkinje fibers. 2: Normal ECG 3: Arrhythmias Any abnormal heart rhythm, whether affecting heart rate, rhythm, or both is called an arrhythmia. Arrhythmias happen due to a multitude of reasons: o Impaired heart automatism o Impaired excitability o Impaired conduction o Simultaneous impairment of excitability and conduction o Impaired contractility 4: Arrhythmias due to impaired automatism Nomotopic Heterotopic 5: Nomotopic arrhythmias Develop in the SA node and include: o Sinus tachycardia o Sinus bradycardia o Sinus arrhythmia o Sinus node weakness syndrome 6: Heterotopic arrhythmias Generate from other parts of the conductive system and include: o Slow atrial rhythm o AV (Junctional) rhythm o Idioventricular rhythm 6: Heterotopic arrhythmias Slow atrial rhythm: is when the pacemaker is within the left atrium, and heart beat becomes less than 70. Junctional rhythm: is when the pacemaker is the AV node. Characterized by the alteration of P wave and HR of 40-60. Idioventricular rhythm: is when the pacemaker is the bundle of His or Purkinje fibers. Characterized by the absence of P wave, HR of 20-40 and wide QRS complex. Idioventricular rhythm 7: Arrhythmias due to impaired excitability These arrhythmias are related to ectopic foci, cardiomyocytes generating their own impulses when depolarization exceeds that of the pacemaker. The main cause is ionic changes across membranes, most importantly potassium 8: Potassium ions effect 9: Types of arrhythmias of impaired excitability Extrasystole PSVT 10: Extrasystole Extrasystole are premature contractions that can rise at any point in the heart. Extrasystoles can be: Sinus extrasystole: happens due to a premature excitation in the SA node, shows a shortened TP interval before the extrasystole. Atrial extrasystole: happens due to excitation in atria, showing a low-amplitude P wave. 10: Extrasystole AV extrasystole: the wave of excitation from the AV node passes in an anterograde and retrograde fashion, showing a negative P wave after the QRS complex. Ventricular extrasystole: the contraction develops within the ventricles, and is characterized by a compensatory pause and, sometimes, contraction following the extrasystole. QRS is altered due to the movement of the wave of excitation. 11: PSVT Paroxysmal supraventricular tachycardia: is a sudden, very fast 160-220 bpm arrhythmia that develops due to multiple foci above the ventricles. 12: Arrhythmias due to impaired conduction Blocked Accelerated condu conduction ction 13: Blocked conduction Blocked conduction happens due to morpho-functional changes within the conductive system, causing the impulses to not spread. Blocks can be: o Transverse o Longitudinal o Arborization Blocks can be sinoatrial, interatrial, atrioventricular or intraventricular. 13: Blocked conduction 1. Sinoatrial block: this is when the impulses don't pass from the SA node to the atria, in this case a rhythm falls and RR distance is prolonged. 2. Interatrial block: this is when conductive fibers of atria are blocked, this prolongs the P wave. 13: AV blocks Atrioventricular blocks or transverse blocks happen when the AV node doesn't transmit impulses, and it has 3 degrees, varying in ECG presentation and clinical presentation. AV block of I degree: this is 13: AV when there is a delay in blocks transmission, it shows PQ prolongation but is usually undetected. 13: AV blocks AV block of II degree (Mobitz I): PQ lengthens after each cycle until one QRS falls, this is periodic (Wenckebach period) and the fall of a QRS happens each 5-7 cardiac cycles. This arrhythmia doesn't cause noticeable effects on hemodynamics. AV block of II degree (Mobitz II): PQ do not lengthen and usually two or more QRSs fall. It is much more severe and can cause palpitations, fatigue and chest pain. 13: AV blocks AV block of III degree: this is when there is total mismatch of atrial and ventricular contractions, causing them to contract in an unorganized fashion. The atria beat at 70 bpm and ventricles at 20-40 bpm. This arrhythmia is very severe and requires immediate treatment. 14: Intraventricular block This is when conduction at a branch of the bundle of His or Purkinje fibers stops. This causes the ventricle where the block happens to contract very weakly, leading to asynchronous ventricular contractions which can progress to HF. It presents as prolonged and deformed QRS complex. 15: Accelerated conduction Accelerated conduction happens when new conductive pathways develop apart from the normal conductive system, this leads to tachyarrhythmias. The additional pathways are: o Kent-Paladino bundle: this is when a conductive tissue develops around the AV node and bypasses it. o Mahaim bundle: connects the upper parts of the bundle of His with the ventricles o James bundle: connects the atria with the lower section of AV node or the bundle of His 15: Accelerated conduction Wolff-Parkinson-White syndrome (WPW syndrome): a genetic disease that causes the development of the bundle of Kent, causing the atria and ventricles to contract simultaneously, and extrasystoles to occur. This syndrome can lead to ventricular tachycardia if not managed. It presents on the ECG with a shortened PQ interval, expanded QRS complex, and the formation of delta wave. 15: Accelerated conduction Clerc-levy-Cristesco syndrome (CLC syndrome): a genetic disease that causes the development of the bundle of James, causing shortened PQ intervals, premature ventricular contractions and tachycardia. 16: Arrhythmias due to simultaneous impairment of excitability and conduction Such arrhythmias are based on the phenomenon of reentry, when there is damage to a part of the myocardium where impulses don't pass through, causing impulses from other directions to enter, short-circuit and cause continued contractions, ultimately creating new ectopic foci that can cause the chambers to contract as a whole. 17: Atrial flutter Atrial flutter happens when generated impulses reach 250- 400 bpm. Characterized by loss of P waves and normal QRS complexes, this gives a "sawtooth" appearance. When atrial flutter progresses into 400- 18: Atrial 600 bpm, it is called Atrial fibrillation. It fibrillation shows no P waves, is irregularly irregular and has narrow QRS complexes. 19: Ventricular flutter Happens when ventricles beat at 150-300. It is less common as it quickly progresses into ventricular fibrillation. QRS complexes are so deformed and no wave can be distinguished. 20: Ventricular fibrillation This condition is very dangerous and can lead to death within 3 minutes, it is a code blue. Nothing can be distinguished on ECG.

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