ECG and arrhythmia Flashcards
(60 cards)
What are the 3 vectors for ventricular depolarization?
Q Septum
R Apex
S Base
Atrial flutter treatment?
DC synchronized cardioversion
Subendocardial ischaemia: why does repolarization occur in subendocardial cells before non ischaemic tissue?
shorter action potential duration
Define target vessel revascularization
repeat intervention of the same segment
What stimulates the septum?
L bundle branch
Differentiate coarse and fine VF
Coarse = recent onset & readily corrected by defibrillation
Fine = longer period of time since onset
What makes up an unstable plaque?
Fibrous cap and necrotic core
WBCs
Macrophages
Foam cells
What is CO for ventricular fibrillation?
CO = 0
What are 2 categories of tachyarrhythmias?
Supraventricular tachyarrhythmia
Ventricular tachyarrhythmia
What happens with atrial thrombus formation?
LA: PE
RA: Stroke
Why is CO reduced in VT
impaired ventricular relaxation and loss of AV synchrony (electrical coordination) leads to reduced CO
Outline ventricular extrasystole?
Ventricularly triggered extra beat
What is the normal PR interval?
0.12 - 0.2 sec
What is a significant difference between DES and BMS stents?
rate of target vessel revascularization
(BMS»_space; DES)
no difference in rate of death or MI
What are 2 supraventricular tacchyarrhythmias?
Atrial fibrillation
Atrial Tachycardia
What is the normal QRS width?
0.08 - 0.12 sec
Arrhytmia
Basic terms…
Narrow QRS (<0.08) =
Wide QRS = (> 0.12)
Narrow = supraventricular arrhythmia
Wide = ventricular arrhythmia
What is the commonest cause of palpitations in people with structurally normal hearts?
AV nodal reentry tachycardia
What causes involution of the collateral arterioles of the heart?
Decreased pressure gradient between coronary collaterals
e.g. due to percutaneous coronary intervention
Depolarization travels from and to where in myocardium?
inner to outer
List 3 defects causing variant / vasospastic angina?
1 calcium in vascular smooth muscle
2 hyperactive sympathetic nervous system
3 disturbances in production or release of NO
Symptoms and signs of arrhythmias?
SOB
Chest pain (radiating)
Decreased level of consciousness
Low BP
Palpitations
Slow/fast HR
Pre syncope / syncope
Pulmonary oedema
Heart congestion failure
Acute MI
Shock
What is the atrial and ventricular rate approximately in atrial flutter? Why?
Atrial = 250-350 bpm
Ventricular 150bpm
AV node protects ventricles by blocking most of the atrial impulses
Describe ECG of NSTEMI
NSTEMI - sub endocardial infarct (non transmural)
Depolarization travels to electrode (subendocardial infarct to non ischaemic tissue)
Results in baseline elevation and relative ST depression