Cardio 7.5 Flashcards
(341 cards)
MoA of loop diuretics?
Inhibit the Na-K-Cl cotransporter (NKCC) in the thick ascending limb of loop of Henle, reducing the absorption of NaCl
(2 variants of NKCC - they act on NKCC2, more prevalent in the kidneys)
Indications for loop diuretics?
Adverse effects?
- heart failure: acute IV, chronic PO
- resistant HTN, esp in pts with renal impairment
- hypotension
- hyponatraemia
- hypokalaemia
- hypochloraemic alkalosis
- hypocalcaemia
- ototoxicity
- renal impairment (dehydration + direct toxic effect)
- gout
- hyperglycaemia (less common than with thiazides)
Associations with aortic dissection?
- trauma
- HTN
- bicuspid aortic valve
- pregnancy
- syphilis
- collagens: Marfans, Ehlers-Danlos
- Turners & Noonans syndromes
Features of aortic dissection?
Stanford classifcation?
DeBakey classification?
- chest pain: severe, radiates through to back & ‘tearing’ in nature
- aortic regurgitation
- HTN
- involvement from specific arteries e.g. coronary -> angina, spinal -> paraplegia, distal aorta -> limb ischaemia
Stanford:
type A = ascending, 2/3
type B = descending distal to left subclavian, 1/3
DeBakey:
type I - originates in ascending aorta, propagates to at least the aortic arch & possibly beyond it distally
type II - originates in & is confined to ascending aorta
type III - originates in descending aorta, rarely extends proximally but will extend distally
Causes of a paroxysmal SVT?
- sudden onset narrow complex tachycardia - typically an AVNRT: AV normal re-entry tachycardia
- other causes include AVRT & junctional tachycardias
Acute Rx of SVT?
- vagal manoeuvres
- IV adenosine 6 -> 12 -> 12mg (C/I in Asthma - consider verapamil instead)
- electrical cardioversion
Prevention of SVT?
- beta-blockers
- radio-frequency ablation
Causes of LQTS/Torsades de Pointes
- Jervell-Lange-Nielsen syndrome, Romano-Ward syndrome
- TCAs, antipsychotics
- amiodarone, sotalol, class 1a antiarrhythmics
- chloroquine
- terfenadine
- erythromycin
- hypothermia
- myocarditis
- SAH
- hypocalcaemia, hypokalaemia, hypomagnesaemia
Rx of Torsades de pointes/LQTS?
IV magnesium sulphate
Causes of LBBB?
- IHD
- HTN
- aortic stenosis
- cardiomyopathy
- rare: idiopathic fibrosis, digoxin toxicity, hyperkalaemia
Non-pulsatile JVP
superior vena cava obstruction
Kussmaul’s sign: paradoxical rise in JVP during inspiration
constrictive pericarditis
What does A wave show in the JVP waveform?
Absent in?
Large if?
Atrial contraction
- absent in AF
- large if atrial person: TS, PS, pulm HTN
Cannon ‘a’ waves
- caused by atrial contractions against a closed tricuspid valve
- e.g. complete heart block, ventricular tachycardia/ectopics, nodal rhythm, single chamber ventricular pacing
What does ‘c’ wave show in JVP?
Closure of tricuspid valve
- not normally visible
What does ‘V’ wave show in JVP?
- due to passive filling of blood into the atrium against a closed tricuspid valve
- giant v waves in tricuspid regurgitation
What does ‘X’ descent show in JVP?
Fall in atrial pressure during ventricular systole
What does ‘Y’ descent show in JVP?
Opening of the tricuspid valve
Drug Rx of Angina:
- what should everyone receive in the absence of C/I?
- what should be used to abort angina attacks?
- what is 1st line?
- 2nd line?
- if monothoerapy inadequate & can’t tolerate dual Rx?
- if on dual Rx and still Sx?
- aspirin + statin
- GTN sublingual prn
Nb always increase to max tolerated dose before stepping up treatment - 1st line = beta-blocker or rate-limiting calcium-channel blocker e.g. verapamil/diltiazem
- 2nd line, combo required of beta-blocker + long-acting dihydropyridine calcium-channel blocker e.g. MR nifedipine
- increase to max tolerated dose
If monoRx inadequate or can’t tolerate dual then consider adding one of:
- long-acting nitrate
- ivabradine
- nicorandil or
- ranolazine
If Sx on dual Rx then:
- only add a 3rd drug whilst a pt is waiting assessment for PCI or CABG
Nitrates in angina - tolerance
- many pts develop tolerance & experience reduced efficacy
- take 2nd dose of ISMN after 8h instead of 12 in pts who develop tolerance, as it allows blood-nitrate levels to fall for 4h & maintains effectiveness
- not seen in pts who take MR ISMN
Ivabradine (used in angina)
- what is the MoA?
- what are the adverse effects?
- acts on If (funny) ion current which is highly expressed in the SAN, reducing cardiac pacemaker activity therefore reduces the heart rate
- visual effects esp luminous phenomena are common
- headache
- bradycardia due to oA
5 ECG features of hypokalaemia?
- they begin when K+ falls below 2.7
- prolonged PR interval
- long QT
- ST depression
- small/absent/inverted T waves
- U waves
What is pre-eclampsia?
When is it seen?
Pregnancy-induced hypertension + proteinuria (>0.3g/24h) +/- oedema
- after 20 weeks gestation
What does pre-eclampsia predispose to?
- fetal: prematurity, IUGR
- eclampsia
- haemorrhage: placental abruption, intra-abdo, intra-cerebral
- cardiac failure
- multi-organ failure