Cardiology Flashcards
What does a sarcomere consist of?
Actin and myosin
Contractions depend on
Calcium and ATP
How does the cross bridge form?
Calcium binds to troponin, cause the tropomyosin complex to move and unblock cross-bridge site on actin
Myosin then can bind to actin
Stroke volume is what?
Volume per beat
EDV-ESV
What is the main principle of FS curve?
Greater EDV, greater SV
CO =
SVxHR
Ionic channels in pacemaker
Phase 4
Phase 0
Phase 3
HCN (funny current), T-calcium
L-calcium
K voltage gated
S1 is due to
AV valves closing = systole
S2 is due to
Semilunar valves closing = diastole
What is a dicrotic notch?
Vibration when valve is closing
Diastolic lasts for
Systolic lasts for
- 5s
0. 3s
ECHO is diagnostic test for
Murmur, endocarditis
1st degree heart block
PR > 0.2
Angina is caused by
Restricted blood flow due to atherosclerosis
Unstable vs stable angina
Unstable - pain at rest
Stable - pain on exertion
Treatment of angina
GTN –> prophylaxis (BB, ivabradine, CCB) –> surgery
How is MI diagnosed?
Troponin and ECG
Troponin detects what?
Myocardial necrosis
Treat MI
MONA+C Morphine Oxygen Nitrates (GTN) Aspirin Clopidegrol
What is Dressler’s syndrome?
ECG feature?
Post-MI pericarditis
Saddle shaped ST elevation
Left heart failure is due to
Low CO from left side of heart
Diagnosis of LVF
NP test, echo, ecg
Treat LVF long term
Lifestyle, loop, ACEi, BB
Acute LVF treatment
Sit up, oxygen, IV loop, IV morphine
Dilated cardiomyopathy is caused by
Alcohol, chemo, infection
HCM looks like what?
Big solid heart
Inherited and sudden death
Restrictive cardiomyopathy appears what?
What is the problem?
Why?
Normal
Can’t fill up during diastole
Deposition of amyloid, sarcoid, fibrosis following radiation
IV drug users get endocarditis in _______ valve
Tricuspid
Treat prosthetic valve endocarditis
IV vancomycin, rifampicin, gentamicin
Treat aortic stenosis
Valve replacement
How can you treat mitral valve stenosis and regurgitation?
Diuretics, digoxin, ACEi (in regurgitation)/ BB (in stenosis), warfarin, valve replacement
Collapsing pulse indicates
Aortic regurgitation
Early diastolic murmur is where and with what?
Left sternal edge
Aortic regurgitation
MDM localized to apex
Mitral stenosis
Autorhythmicity meaning
Heart beats without external stimuli
Heart controlled by ___ is in sinus rhythm
SA node
SA generates a ________ pacemaker potential
Spontaneous
What is the funny current?
Na+ and K+
Threshold in pacemaker cells
-40
Bundle of His and Purkinje allow _____ spread of action potentials to ventricle
RAPID
Plateau phase channel
L-type calcium
Sympathetic vs parasympathetic in heart
Sympathetic - NA on B1
Parasympathetic - ACh M2
Vagal tone is what?
Parasympathetic dominance of heart at rest
Bradycardia
<60
Tachycardia
> 100
What increases gradient of pacemaker potential?
Sympathetic activity
What is atropine?
Antagonist of ACh in heart
What develops due to HCN channels?
Cation conductance, in response to hyper polarization triggering funny current
Na inwards !
Desmosomes are where?
Within intercalated discs
Adhesion between cardiac muscles
Calcium needed for contraction/relaxation/both
ATP needed for contraction/relaxation/both
Contraction
Both
How is SV regulated? (2)
Intrinsic and extrinsic mechanisms
Give examples of intrinsic mechanisms
Preload: venous return
Afterload
What does FS curve show?
Maximum force generated at optimal fibre length
Stretch increases affinity of what for calcium?
Troponin
Name some extrinsic mechanisms for monitoring SV
Nerves
Hormones
Sympathetic has a inotropic/chronotropic effect?
Both!
Inotropic
Force of contraction
Chronotropic
HR
Force of contraction is _______ mediated
cAMP
Sympathetic stimulation shifts FS to the _____
left
Parasympathetic has inotropic/chronotropic
Only chronotropic
When does the atrium contract?
Between P and QRS
Where are valves approximately on chest?
2nd ICS right: aortic
2nd ICS left: pulmonary
4th ICS left: tricuspid
5th ICS mid clavicular: mitral
