Card Set Information
ECG cardiology lipids MI
ECG, cardiology, lipids, MI
Outline the approach to interpreting an ECG
"An ECG does Not Really Require A Woman's Input"
What are the common ECG findings in an acute MI?
ST segment elevation (>80ms)
Prominent, symmetrical, pointed T waves
How is heart axis determined on an ECG?
Examine lead I and II
If the QRS complex of both are mostly positive = normal axis
If I-QRS positive and II-QRS negative, then posterior deviation
If opposite; I-negative, II positive then anterior deviation
What are the ECG findings of 1st and 3rd degree heart block?
: Prolonged PR interval (>0.2 secs); delayed conduction from atria-ventricles
: No relation between P and QRS; complete block of conduction
How are the waves of an ECG examined?
: One per QRS, no bifidity [except v1]
: Inversion in V3-6 or I/II?
How is the heart rate measured and rhythm determined using an ECG?
300 divided by the number of large boxes between each R spike. (0.6-1.2 seconds)
Mark a strip of paper at every R spike; abnormal/repetitive pattern?
What are the important intervals to note when examining an ECG?
: 1/2 - 1 full large box
: 1/2 a large box
: 2 large boxes in II
What is the relation between cholesterol levels and CVD risk?
High total cholesterol
: CVD risk
High LDL:HDL ratio
: CVD risk
High total triglyceride
: Diabetes risk
Briefly describe the normal metabolism of cholesterols
Absorbed in GI, enter lymph as chylomicrons
In liver, converted to cholesterol then either bile, vLDL or LDL
Transported to tissues, which can return it as HDL
What are the normal plasma concentrations of total cholesterol, HDLs and TAGs?
Outline the pathogenesis of atheroma
LDL enters sub-endothelial space
Macrophages oxidise and consume the LDL
Toxic products are released, causing CAM expression and monocyte infiltration
Macrophages saturate and apoptose = LDL deposition
Thickness of endothelium related to stable/unstable plaque due to collagen exposure
What are the roles of HDLs in preventing atheroma?
Removes cholesterol from muscle/fat for bile acid conversion
Inhibit monocyte adhesion
Antioxidant, preventing LDL oxidation
What are some risk factors for CHD?
Outline the mechanism of action of statins
Inhibit HMG-CoA reductase; prevent cholesterol production from acetyl CoA
To maintain bile acid production, cholesterol removed from tissue by increased HDL ratio
Why would a patient on statins need their plasma CK monitored?
Muscle pain a common adverse effect, related to myopathy and rhabdomyolysis
If it occurs, monitoring required due to CK release; risk of renal impairement
What is ezetimibe used for?
Prevents cholesterol absorption in the brush border of the small intestine
Describe the course of the coronary arteries
What are the common acute coronary syndromes?
: Angina caused by atherosclerotic plaque disruption and so thombosis/embolism. Acute, severe, wave-like pain at rest
What are the recommendations for reperfusion after MI?
Treated <90 minutes after diagnosis if possible
Primary PCI; angioplasty, where stent inflated and plaque 'crushed' against walls
Thrombolysis given until PCI available
Abciximab; Ig which antagonises platelet activation
Briefly outline the pathogenesis of heart failure
Failure of the heart to pump blood sufficiently to supply tissue's demands
Characterised by typical haemodynamic changes, e.g. systemic vasoconstriction and neuro-humoral activation
Causes include MI, hypertension, valve disease
What are the common clinical featuers of heart failure?
Breathlessness, crackles, orthopnoea, PND, cough
Effort intolerance, muscle fatigue
Fluid retention and oedema
Elevated JVP and displaced apex beat
What investigations are performed in suspected HF?
Biochemistry; U+Es, cr, urea, LFTs, urate
What pharmacological interventions are used in HF?
ACE/ARB and beta blockers the cornerstone of acute therapy
Many treatments depend on cause; kidney failure/LV remodelling can make HF refractory
What is cardiac resynchronization therapy?
Pacemaker controlled right and left ventricle
Used in patients with ventricular fibrillation in severe HF
Only really used in patients with LBBB
Define infective endocarditis
Infection of the endocardium (inner heart lining)
Results in valve damage
In what order are the valves most frequently damage in IE?
Pulmonary (very rare)
What are some of the acute clinical features of IE?
Sepsis; hypotension, tachycardia
What clinical features suggest IE?
Fever and heart murmur
: embolism = splinter haemorrhage, petichae, renal infarction
: septic pulmonary emboli
What circumstances should instigate investiation for IE?
Established Staph Aureus infection
IVDU with positive blood culture
Prosthetic valve patient with positive blood culture
Sepsis of unknown origin
What investigations are performed to diagnose IE?
: Multiple focal infiltrates and calficiations
: Ischaemia, conduction delay or arrhythmia
: Take 3 before antibiotics; bacteraemia
CMRI and CTA
How many of the duke criteria must be met to establish IE?
Two major criteria
One major, three minor
What are the major criteria in the Duke diagnosis of IE?
Causative organism in 2 separate cultures
Positive echo OR new valve regurgitation detected in auscultation
What are the minor criteria in the Duke diagnosis of IE?
Predisposing factor, e.g. IVDU, cardiac lesion
Evidence of embolism
Positive blood culture with inconsistent organism
Serological evidence of consistent organism infection
What are the common causes of IE in:
- The general populace
Strep Viridance (or enterococci)
Coagulase negative staph
What is rheumatic fever, and how does it cause IE?
Strep pyogenes infection
Bacteria or exotoxin have 'molecular mimicry'
Antibodies cause autoimmunity against cardiac valves and kidneys
Stenosis and regurgitation occur
Outline the antibiotics used in IE
: Benzylpenicillin and gentamicin
: Benzyl and gentamicin
: Amoxicillin and vanco/gentamicin
: Vancomycin and rifampicin
What are some important complications of acute MI
Congestive heart failure
Describe the long term care of patients after an MI
: diet, alcohol/smoking, physical activity, weight
: Educational/exercise/supportive role
: ACE, aspirin, B1 and statin