Cardiac Arrythmias Flashcards
Chronic cardiovascular diseases
What is cardiac arrythmias?
Disorders of heart rate
What is tachy arrythmias? give examples (2)
Fast heart rate- atrial fibrillation and ventricular tachycardia
What is brady arrythmias? Give example
Slow heart rate- heart block
What drugs can induce brady arrythmias?
Beta blockers and digoxin
What is heart block?
Slow/ no conduction through the AV node to ventricles of impulse from S node, prolonged P-Q interval on ECG
How are the different levels of heart block classified?
By length of signal delay- 1st degree, 2nd degree, and 3rd degree/ complete heart block
What is 3rd degree of heart block/ complete heart block?
No impulse passed to the ventricles
How does tachy arrythmias impair cardiac function?
Reduce diastolic filling time- reduced cardiac output leads to heart failure
What is atrial fibrillation?
Rapid atrial impulses conducted to ventricles giving high heart rate. No P waves as disorganised atrial activity. Narrow QRS on ECG and irregular pulse
What is ventricular tachyarrythmia?
Broad QRS on ECG
Which tachy arrythmia can lead to ventricular fibrillation and death?
Ventricular tachyarrythmias
What is used to treat bradyarrythmias?
Cardiac pacemakers
How do cardiac pacemakers treat bradyarrythmias?
Keep heart rate at a minimum level- don’t pace the heart if natural heart rate is above a certain level, have a sensing and pacing circuit, box fitted into chest wall and wires pass through blood vessels into ventricle, some will simulate heart action by pacing atria and ventricles in sequence
Why should we as dentists be careful for patients with pacemakers?
Theoretical risk of electrical interference- dental equipment- pulp tester is okay however avoid induction scalers
What is each stage of the sinus rhythm?
P-atrial depolarisation
QRS complex- ventricular depolarisation
T wave- ventricular repolarisation
