Part 7
- Created by: amiedesancha_
- Created on: 16-12-18 13:09
I and T
Which troponin have specific cardiac types
MI
Site - diffuse ant chest, left arm and neck
Character - Tight, pressure, weight, constriction, dull
Triggers - exercise, cold, meals, psychological stress
Relief - rest, GTN (if anginga)
Duration - >30mins
STEMI
Most common type of MI
Prevention of an MI
Lower cholesterol
Lower BP
ACE inhibitor
Aspirin
Statins
Beta blockers
Life style (smoking and diabetes)
Atherosclerosis
Progressive disease affecting the intima of elastic and muscular arteries.
Characterised by focal atheroma's
Lipid core covered by fibrous cap
Monckeberg's medial sclerosis
Calcification in the media of muscular arteries
Arteriosclerosis
Proliferation or thickening of hyaline in the wall of small arteries and arterioles
Stages of plaque development
Type 1 = lipid present in macrophages in intima, take up LDL
Type 2 = Lipid present in both macrophages and SM cells - start producing collagen that goes on to form the fibrous cap
Type 3 = Fibrous plaque
Type 4 = Complex plaque (fibrous cap over a lipid core)
Transmural (STEMI)
Commonest
Regional infarct
Ischaemic necrosis that involves the full or nearly full thickness of the ventricle wall in distribution of a single coronary artery.
Associated with coronary artherosclerosis -> plaque rupture -> superimposed thrombus
Subendocardial (NSTEMI)
Inner one third or at most half of the ventricle wall
Diffuse stenosing coronary atherosclerosis and global reduction of coronary flow (shock)
But no plaque rupture or thrombus
Early Post MI complications
Further arrhythmias and subsequent heart failure
Pericarditis
Papillary muscle dysfunction (mitral valve complication)
Mural thrombosis in ventricle
Ventricular rupture
Papillary muscle rupture
Late post MI complications
Ventricular aneurysm
Post MI sundrome
Ischaemia
Reinfarction
Cardiac rupture
1-5% of cases
Commenest 4-7 days post infarct
Ventricular free wall
Haemopericardium
Cardiac tamponade
Rupture of intraventricular septm
Left to right shunt
Rupture of papillary muscles -> severe acute mitral incompetence
Pericarditis
2nd or 3rd day
Fibrinous or fibrinohaemorrhagic
Usually localised to region overlying necrotic area
Embolism
Transfer of abnormal material via bloodstream and impaction in vessel
Different types of emboli
Fragment of thrombus
Material from ulcerating atheromatous plaques (commonest in distal leg A)
Septic emboli
Fragment of tumour growing into a vein
Fat globules (following fractures)
Air emboli (300ml enough to make heart stop)
Parenchymal cells
10th
Day post an operation, most common to suffer from a PE
Acute heart failure
Inability to provide adequate CO to support the needs of tissues - or to do so at the expense of raised filling pressure
Right sided heart failure
Impaired pumping causing reduced CO in both ventricles
Systemic venous pressure rises as RV EDP rises
Circulatory reflexes keep PAP, PVP, LV EDP and aortic pressure constant
Left sided heart failure
Both Ventricle CO falls
Pulmonary venous pressure rises as LV EDP rises
Increased PVP transmitted leading to raised PAP
Aortic pressure and systemic remain constant
Congestive heart failure
Most patients
Heart failure due to LV failure in turn affecting the RV
Fall in CO
Significant rise in PVP as LV EDP rises
Modest elevation in PAP
Rise in SVP
Reflexes keep aortic constant
Causes of heart failure
Pressure overload (HTN, aortic stenosis)
Volume overload (Valve regurgitation)
Contractile dysfunction (ischaemic heart disease, congenital cardiomyopathies)
SNS
Peripheral vasoconstriction
Increased HR
Contractility
All returning BP to normal
Ang II
Vasconstriction at tissues
Stimulates aldosterone release
Types of angina
Stable
Mixed
Unpredictable
Vasospastic
Microvascular - syndrome X
Unstable
Anti-anginal drugs
B-blockers
Ivabradine
Ranolazine
CCB
K+ channel activators
Nitrates
Arrhythmia
Disturbance of the normal rhythmic beating of the heart - ectopic pacemaker
3rd degree heart block (complete heart block)
Causes - idiopathic bundle branch fibrosis, atherosclerotic CHD, dilated cardiomyopathy
Effect on cardiac rhythm - slow HR (degree depends on location of block)
Heart rhythm is driven by escape beats, originating from the distal pacemaker just below the block
Symptoms - temporary syncope followed by recovery with breathlessness, fatigue and possible chest pain
Prognosis - 2 mo without treatment
Treatment - implantation of a permanent pacemaker.
QRS dissociation from P wave as atria and ventricle beat independently
Tachyarrhythmia
Rapid heart rate caused by re-entry
Occurs when adjacent areas of myocardium have different conduction rates and refractoriness (ischaemia, myocardial scarring and certain congenital conditions)
Atrial fibrillation
Chaotic atrial rhythm with rapid irregular ventricular rhythm
Causes - ectopic focus or reentrant pathway in heart muscle surrounding PV or in the atrium
Risk factors - dilation, HF, HTN, overactive thyroid, XS alcohol, old age
Ventricular excitation occurs with atrial depolarisation sufficient to be conducted through AVN
Symptoms - palpitations, breathlessness, dizziness, syncope
Paroxysmal -> persistent -> permanent
Major risk factor for stroke due to stasis of blood
Treat with class 1-4 anti-arrhythmatic drugs, radio catheter ablation, anticoagulants or LA appendage closure
ECG - lack of p wave, irregularly irregular QRS, time smaller f waves
Na+CB, suppressing conduction (flecainide)
Class 1 anti-arrhythmic drug
Beta blockers, inhibit AVN conduction
Class 2 anti-arrhythmic drug
Drugs which prolong AP and refractory period (amio
Class 3 anti-arrhythmic drugs
CCB - inhibit AVN conduction (verapamil)
Class 4 anti-arrhythmatic drugs
Class 2, 4, adenosine and digoxin
Rate control drugs
Class 1 and 3
Rhythm control drugs
VT
Rapid (120-200bpm) successive ventricular beats
Most often due to cardiac scarring post MI or dilated cardiomyopathy, Can be congenital (LQT syndrome, brugada syndrome). Almost always due to re-entry
Regular (monomorphic) or irregular (polymorphic)
Symptoms - chest pain, SOB, syncope
Implant cardioverter Defib
Class 1,2,3 drugs and radio-catheter ablation
Implantable defib
A connect electrode to RV and SVC
Senses arrhytmias by rate and location
Delivers an appropriate shock causing cardioversion (return to sinus rhythm)
Sometimes combined with drugs to reduced freq.
VF
Chaotic disorganised electrical activity
Caused by MI, ischaemia, cardiomyopathy but sometimes idiopathic
No organised ventricular beat therefore no CO
Asystole, PEA
The two non-shockable rhythms (defib)
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