Arrhythmias Flashcards
what are the ECG changes for sinus tachycardia
increased P wave in II, decreased P wave in QvR
How do you treat sinus tachycardia
treat underlying cause
what causes sinus tachycardia
increased automaticity via increased SNS tone by hypovolemia, hypoxia, cocain, meth, drugs for increasing HR, pain and anxiety and increased metabolic activity by hyperthryoidism and fever
what causes sinus bradycardia
decreased automaticity via increased vagal tone eg sleeping, athletes, inferior wall MI, slow AV conduction, decreased metabolic activity- hypothermia, hypothyroidism, increased potassium, increased intracranial pressure
normal QRS width
approx 0.12s
when does conduction block occur
if right coronary artery is occluded and causes an inferior wall MI, fibrosis of AV node, increased potassium, drugs like BB or CCB, infiltrative disease eg sarcoidosis and amyloidosis, lymes disease
ECG changes for Atrial flutter
saw tooth waves in II, III, V1 QvF. should be a 2:1 ratio of saw tooth and normal
how do you treat atrial flutter
treat by vagal manoeuvre, then adenosine (blocks AV node), give beta blocker or CCB, then cardioversion
Long term- ablation of abnormal tissue
what happens in atrial flutter
electrical conduction goes around the atrium extra fast
torsades de pointes is caused by
triggered activity when the myocardial cells are irritated during the plateau phase (early after depolarisations) due to decreased potassium, decreased calcium and some drugs. follows prolonged QT syndrome. occurs in ventricles
sick sinus syndrome shows a
mix of tachycardia and bradycardia
AVRT and AVNRT ECG changes
no visible P waves, retrograde P wave in II, III and QvF
atrial fibrillation ECG changes
fibrillation waves, V1, irregularly irregular rhythm
how to tell whether irregular or regular
measure R to R interval using piece of marked paper
V tach ECG changes
width of QRS greater than 0.14s, still have p waves, extreme right axis deviation
how to treat V tach
amiodarone, procainamide then if dont work put pads on and cardiovert, ablation and look for underlying cause, may need AICD
polymorphic ventricular tachycardia with increased QT interval treatment
can lead to torsades de pointes if QT greater than 500ms. give magnesium sulphate, replete potassium, discontinue offensive meds, overdrive pacing to increase heart rate and reduce QT interval
polymorphic ventricular tachycardia with normal QT treatment
amiodarone or procainamide, cardiovert if doesnt work or defib
bradycardia- if PR interval greater than 200ms
first degree HB- delayed atrioventricular conduction
bradycardia- if PR interval increases each time and drops a QRS
2nd degree mobitz 1- wenckebacks phenomenon
bradycardia- if PR interval normal and drop QRS randomly
2nd degree mobitz 2- intermitted Av conduction interruption
bradycardia- if PR normal, drop QRS, wide QRS
3rd degree heart block- dissociation between atria and ventricles
what bradycardias are benign
1st degree HB and 2nd degree heart block mobitz 1
treatment for bradycardia
atropine, if no improvement then epinephrine, then transcutaneous cardiac pacemaker and then if high risk of asystole- temporary transvenous cardiac pacemaker, eventual permanent cardiac implantable pacemaker
underlying causes of bradycardia
inferior wall MI, increased potassium, too much BB, CCB, digoxin, lymes disease, hypothermia, hypothyroidism
