Arrhythmias - Pathophysiology, Presentation and Investigation

Question 1

Describe the clinical presentation of AF

Answer 1

• Asymptomatic
• Palipitations, dyspnoea, chest pain, fatigue
• Embolism

Question 2

Explain 1st, 2nd and 3rd degree heart block

Answer 2

1st - abnormally long PR interval

2nd - some of the atrial depolarisation fails to be transmitted at all;
- Mobitz I/Weckenbach phenomenon: PR interval gets progressively longer until there is a failure of transmission then the cycle repeats, defect in AV node
- Mobitz II - no progressive lengthening of PR interval, only failure of transmission, defect in the fast conducting system
Both types are treated differently.

3rd - No atrial depolarisation is transmitted

Question 3

Describe the investigation of AF

Answer 3

• Document on ECG: 12 leads, 24 hour recording, event recorder
• Blood tests: esp. TFT
• Echocardiogram

Question 4

Define event recorder

Answer 4

• Similar to an ECG

- Wear monitor for 14 to 30 days to monitor daily activity

Question 5

Describe Wolff-Parkinson-White Syndrome

Answer 5

• In addition to AV node, there is another conducting pathway between atria and ventricles
• Travels faster than Av node so results in short PR and different shaped QRS
• May result in periodically high HR

Question 6

Explain sinus arrest

Answer 6

SA node fails to initiate for a period of time

Question 7

Explain sinus arrest

Answer 7

• SA node fails to initiate for a period of time

- If rhythm is taken over by a slower pacemaker elsewhere = escape rhythm

Question 8

Understand the difference between atrial and ventricular ectopic beats

Answer 8

• Arise from myocardial cells in atria or ventricles
• Atrial: distorted P wave
• Ventricular: no P wave, abnormal QRS and T wave

Question 9

Describe AF and flutter

Answer 9

• AF: atria beat irregularly

- Flutter: beat regularly but faster e.g. 4 atrial beats to 1 ventricular beat

Question 10

Describe the clinical presentation of ventricular tachycardia and fibrillation

Answer 10

• Palpitations, CP, dyspnoea, dizziness, syncope
• Usually structural heart disease
• Syncope, poor LV function indicated need for ICD

Question 11

Recognise the medical treatment of AF

Answer 11

• Anticoagulation
• Rate control: 1 - BB, Ca antagonist, 2 - digoxin
• Rhythm control: DC cardioversion