Cardiology 2 Flashcards
What are the risk factors for infective endocarditis?
Rheumatic valve disease (30%) Prosthetic valves Congenital heart defects Intravenous drug users (IVDUs, e.g. typically causing tricuspid lesion) Others: recent piercings
Which organisms cause infective endocarditis?
Staphylococcus aureus
Streptococcus viridans is the commonest cause in patients from developing countries
S. epidermidis is a more likely causative organism of infective endocarditis if the patient has prosthetic valves
What are the ECG features of hypokalaemia?
U waves small or absent T waves (occasionally inversion) prolong PR interval ST depression long QT
What is B-type natriuretic peptide?
Hormone produced mainly by the left ventricular myocardium in response to strain
Raised levels caused by heart failure, myocardial ischaemia, valvular disease, chronic kidney disease
ACE inhibitors, angiotensin-2 receptor blockers and diuretics reduce BNP
Effects of BNP:
vasodilator
diuretic and natriuretic
suppresses both sympathetic tone and the renin-angiotensin-aldosterone system
What are the features of mitral stenosis?
Caused by rheumatic fever Mid-late diastolic murmur (best heard in expiration) Loud S1, opening snap Low volume pulse Malar flush Atrial fibrillation
What does ABPI suggest?
Below 0.9 is suggestive of arterial disease
Below 0.5 is suggestive of severe arterial disease
What are the symptoms and signs of peripheral arterial disease?
Asymptomatic Claudication (leg cramping relieved at rest) Leg pain at rest Ulceration Gangrene Absent leg and foot pulses Cold white legs Atrophic skin Arterial ulcers Long capillary filling time (over 15s in severe ischemia)
What are the heart sounds?
S1
closure of mitral and tricuspid valves
soft if long PR or mitral regurgitation
loud in mitral stenosis
S2
closure of aortic and pulmonary valves
soft in aortic stenosis
splitting during inspiration is normal
S3 (third heart sound)
caused by diastolic filling of the ventricle
considered normal if < 30 years old (may persist in women up to 50 years old)
heard in left ventricular failure (e.g. dilated cardiomyopathy), constrictive pericarditis (called a pericardial knock) and mitral regurgitation
S4 (fourth heart sound)
may be heard in aortic stenosis, HOCM, hypertension
caused by atrial contraction against a stiff ventricle
therefore coincides with the P wave on ECG
in HOCM a double apical impulse may be felt as a result of a palpable S4
What are the histology finding post MI?
0-24hr post-MI histology findings: early coagulative necrosis, neutrophils, wavy fibres, hypercontraction of myofibrils. High risk of ventricular arrhythmia, HF and cardiogenic shock
1-3 days post-MI histology: Extensive coagulative necrosis, neutrophils (associated with fibrinous pericarditis)
3-14 days post-MI histology: macrophages + granulation tissue at margins. High risk of free wall rupture, papillary muscle rupture and LV pseudoaneurysm
2 weeks to several months post-MI histology: contracted scar complete. Associated with Dressler syndrome, HF, arrhythmias, mural thrombus
What are the features of atrial myxoma?
Most common primary cardiac tumour
systemic: dyspnoea, fatigue, weight loss, pyrexia of unknown origin, clubbing
emboli
atrial fibrillation
mid-diastolic murmur, ‘tumour plop’
echo: pedunculated heterogeneous mass typically attached to the fossa ovalis region of the interatrial septum
More common in females
What are the oxygen saturation levels in the heart?
70%- RA, RV, PA
100%- LA, LV, aorta
What are the coronary territories seen on an ECG?
Anteroseptal- V1-V4- Left anterior descending
Inferior- II, III, aVF- Right coronary
Anterolateral- V4-6, I, aVL- Left anterior descending or left circumflex
Lateral- I, aVL +/- V5-6- Left circumflex
Posterior Tall R waves- V1-2- Usually left circumflex, also right coronary
What are the complications of an MI?
Cardiac arrest (VF) Cardiogenic shock Chronic heart failure Tachyarrhythmias- VF/VT Bradyarrhythmias- atrioventricular block (more common in inferior MIs) Pericarditis- 48 hours post MI, Dressler's syndrome several weeks later (fever, pleuritic pain, pericardial effusion and a raised ESR. It is treated with NSAIDs) Left ventricular aneurysm Left ventricular free wall rupture Ventricular septal defect Acute mitral regurgitation
What are the reversible causes of cardiac arrest?
Hypoxia Hypovolaemia Hyperkalaemia, hypokalaemia, hypoglycaemia, hypocalcaemia, acidaemia and other metabolic disorders Hypothermia Thrombosis (coronary or pulmonary) Tension pneumothorax Tamponade – cardiac Toxins
What is Wolf-Parkinson white syndrome?
Caused by a congenital accessory conducting pathway between the atria and ventricles leading to a atrioventricular re-entry tachycardia (AVRT). As the accessory pathway does not slow conduction AF can degenerate rapidly to VF
short PR interval
wide QRS complexes with a slurred upstroke - ‘delta wave’
left axis deviation if right-sided accessory pathway*
right axis deviation if left-sided accessory pathway*
Associated with:
HOCM
mitral valve prolapse
Ebstein’s anomaly
thyrotoxicosis
secundum ASD
LEFT AXIS DEVIATION
What are Aschoff bodies?
Granulomatous nodules consisting of giant cells around areas of fibrinoid necrosis in the heart of the patient- found in RHEUMATIC heart fever
What is rheumatic fever?
Develops following an immunological reaction to recent (2-6 weeks ago) Streptococcus pyogenes infection.
Diagnosis based on 2 major or 1 major with 2 minor
MAJOR
erythema marginatum
Sydenham’s chorea: this is often a late feature
polyarthritis
carditis and valvulitis (eg, pancarditis)*
subcutaneous nodules
MINOR
raised ESR or CRP
pyrexia
arthralgia (not if arthritis a major criteria)
prolonged PR interval
What are the features of aortic regurgitation?
Early diastolic murmur: intensity of the murmur is increased by the handgrip manoeuvre
Collapsing pulse
Wide pulse pressure
Quinke’s sign (nailbed pulsation)
De Musset’s sign (head bobbing)
Mid-diastolic Austin-Flint murmur in severe AR - due to partial closure of the anterior mitral valve cusps caused by the regurgitation streams
What are the causes of aortic regurgitation?
Valve disease: rheumatic fever infective endocarditis connective tissue diseases e.g. RA/SLE bicuspid aortic valve
Aortic root disease: aortic dissection spondylarthropathies (e.g. ankylosing spondylitis) hypertension syphilis Marfan's, Ehler-Danlos syndrome
What are the features of aortic dissection?
chest pain: typically severe, radiates through to the back and ‘tearing’ in nature
aortic regurgitation
hypertension
No ECG changes or ST-segment elevation may be seen in the inferior leads
Hypovolaemic shock due to bloodless (pale, clammy, cold, tachycardic and hypotensive)
What are the associations of aortic dissection?
Hypertension: the most important risk factor
Trauma
Bicuspid aortic valve
Collagens: Marfan’s syndrome, Ehlers-Danlos syndrome
Turner’s and Noonan’s syndrome
Pregnancy
Syphilis
How is aortic dissection classified?
Stanford classification
type A - ascending aorta, 2/3 of cases
type B - descending aorta, distal to left subclavian origin, 1/3 of cases
DeBakey classification
type I - originates in ascending aorta, propagates to at least the aortic arch and possibly beyond it distally
type II - originates in and is confined to the ascending aorta
type III - originates in descending aorta, rarely extends proximally but will extend distally
