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32 Cards in this Set
- Front
- Back
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What are the currents involved in generating the cardiac action potential? (3)
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* Na: fast inward, rapid depolarization
* Ca: slow inward, long plateau of AP, contributes to excitation of muscle * K: repolarization |
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How do β1 receptors increase contractility & HR?
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* ↑inward Ca current
* ↑Ca uptake & speed of uptake by SR --> ↑intracellular Ca |
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How do cardiac glycosides increase contractility?
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* Inhibit NaKATPase pump
--> ↑ intracellular Na --> ↓ Na-Ca exchange --> ↑ intracellular Ca |
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Which is the only heart valve that is bicuspid?
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Mitral valve
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Which chemotherapy drug can cause heart failure?
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Adriamycin
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What is the most common cause of restrictive cardiomyopathy in Australia?
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Amyloidosis
(presents mainly in older women) |
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What are the clinical features of acute rheumatic fever?
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* Carditis
* Polyarthritis * Subcutaneous nodules * Erythema marginatum * Sydenham's chorea |
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What is the main effect of progesterone in pregnancy on the cardiovascular system?
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Vasodilation
↓ BP (maximal in 2nd trimester) (but partly compensated by ↑ plasma volume, ↑ HR, ↑ SV) |
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What are risk factors for ischaemic heart disease?
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* Smoking
* Hypertension * Cholesterol * Diabetes * Sedentary lifestyle * FHx * Obesity * ↑ age * Male |
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Which cytokines are important in the development of athersclerosis?
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* VCAM-1 (endothelial adhesion molecule)
* Integrins (monocyte ligand molecules) * PDGF (induce change in SMCs from contractile to synthetic) |
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What is the primary cause of the pain in late-stage peripheral vascular disease?
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Ischaemia of peripheral nerves
(May also --> parasthesia) |
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What is the linkage of "Type A" and "Type D" (distressed) personality with coronary heart disease?
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* No association b/w CHD and Type A personality
* Type D individuals more vulnerable to CHD |
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What does post-MI cardiac remodelling consist of?
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* Infarct expansion
* Stretching & thinning of ventricular wall, due to rearrangement of myoctyes (cell slippage) |
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Which calcium channel blockers cause vasodilation with only minimal heart rate & myocardial effects?
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* The long-acting dihydropyradines:
- Nifedipine - Amlodipine |
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Which calcium channel blockers cause ↓HR and ↓conduction velocity?
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* Verapamil
* Diltiazem |
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Aside from nitrates, beta-blockers, and calcium channel blockers, what other drugs can be used for treatment of angina? (2)
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* Perhexiline (↓ myocardial requirement for aerobic metabolism)
* Ivabradine (↓ HR without beta blockade) |
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What are the possible outcomes when one normal parent and one parent with a translocation have a child?
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* 1/6 normal
* 1/6 balanced carrier (no excess or deficit of genetic material) * 1/3 trisomy * 1/3 monosomy |
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What is the most common congenital cardiac deformity?
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High ventricular septal defect (usually in membranous part of septum)
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What are the four features of tetralogy of Fallot?
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* Aorta overlying L & R ventricles
* VSD * Stenosed pulmonary trunk * RV hypertrophy |
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What are the 3 shunts in foetal circulation?
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* Ductus venosus (umbilical v. --> IVC, bypassing liver)
* Foramen ovale (RA --> LA) * Ductus arteriosus (pulmonary trunk --> aorta) |
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How does pulmonary vascular resistance vary with respiration?
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* Arterioles run with small airways, so inspiration --> ↑radial traction --> ↑vessel diameter --> ↓resistance
* Capillaries run inside alveolar walls, so inspiration --> compression of vessels --> ↑resistance |
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What features are commonly seen in newborns with Down syndrome?
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* Hypotonia
* ↑skin folds at back of neck * Maxillary underdevelopment * In curving & hypoplasia of middle pharanx of little finger * Sandal gap * Epicanthic folds (@ inner canthi of eyes) * Single transverse palmar crease |
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What is the standard content of oxygen in systemic arterial blood?
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20 mL / dL
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How low does blood oxygen have to fall for central cyanosis to be detected?
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* Deoxyhaemaglobin > 50 g/L
* In normal subjects, corresponds to: - O2 sat < 67% - PaO2 < 35 mmHg (even lower PaO2 in anaemic subjects) |
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What is the most significant cause of obesity-related hypertension?
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↑sympathetic activity
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What are the pathological features of hypertensive nephrosclerosis?
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* Narrowed afferent arterioles
* Obsolete glomeruli + atrophy of associated tubules * Cortex replaced with fibrous tissue |
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Aside from baroreceptors, what other receptors provide reflex short-term control of BP?
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* Peripheral chemoreceptors in carotid bodies & aortic arch (sense pO2)
* Atrial receptors (sense change in or redistribution of blood volume) |
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What 2 conditions are required for a re-entry arrhythmia to develop?
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1. Unidirectional block
2. Slowed conduction through the loop of tissue (LVH predisposes to re-entry arrhythmia) |
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What efect does vagal stimulation have on pulse pressure?
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PP ↑ due to ↓ HR (greater time for blood to run off nto capillaries)
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Which adrenoreceptors are not stimulated by noradrenaline?
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β2 receptors
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Which receptors are most sensitive to low doses of NA and Adr respectively?
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NA: α receptors
Adr: β2 receptors |
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What is vasovagal syndrome?
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* Vagally-mediated cardiac slowing
* Peripheral vasodilation (due to inhibition of SYMP activity) |
