Cardiology Flashcards
what is the most common form of cardiomyopathy?
Dilated cardiomyopathy (DCM) accounting for 90% of cases
what determines timing of aortic stenosis management?
AVR surgical repair if symptomatic, otherwise cut-off is gradient of 40 mmHg
ECG features of wolf parkinsons white
short PR interval
wide QRS complexes with a slurred upstroke - ‘delta wave’
left axis deviation if right-sided accessory pathway
(most commonly causes left axis deviation)
right axis deviation if left-sided accessory pathway
Management WFW
- radioablation of accessory pathwya
- sotalol (but not if in AF as this can trigger VF). Amiodarone or fleccanide
Persistent ST elevation following recent MI, no chest pain
left ventricular aneurysm
Drugs to avoid in HOCM
- nitrates
- ACE-inhibitors
- inotropes
contraindications to thiazide like diuretics
gout
Amiodarone - Mechanism of action
blocks voltage-gated potassium channels which prolongs repolarisation and the action potential duration
Magnesium sulfate toxicity (given to pre-eclampsia/ eclampsia) - signs and treatment
Symptoms of magnesium sulfate toxicity include loss of deep tendon reflexes, respiratory depression, and cardiac arrest.
Calcium gluconate is treatment
Which antiarrhythmic may precipitate ventricular fibrillation (VF) in patients in VT
verapamil
Irregular cannon ‘a’ waves
complete heart block
Indications for a temporary pacemaker
symptomatic/haemodynamically unstable bradycardia, not responding to atropine
type 2 or complete heart block post-ANTERIOR MI
trifascicular block prior to surgery
post-INFERIOR MI complete heart block is common and can be managed conservatively if asymptomatic and haemodynamically stable
where does Furosemide and bumetanide exert its action?
Furosemide and bumetanide are loop diuretics that act by inhibiting the Na-K-Cl cotransporter (NKCC) in the thick ascending limb of the loop of Henle, reducing the absorption of NaCl
what medication to hold when starting course of erythromycin/ clari?
statin
which murmur is associated with dilated cardiomyopathy?
mitral regurg
The most specific ECG finding in acute pericarditis is ?
PR depression
causes of changes to Second heart sound (S2)
Second heart sound (S2)
loud: hypertension
soft: AS
fixed split: ASD
reversed split: LBBB
What normally happens to blood pressure during pregnancy?
Falls in first half of pregnancy before rising to pre-pregnancy levels before term.
Mechanical valves - target INR:
aortic: 3.0
mitral: 3.5
Pulmonary arterial hypertension (PAH) may be defined as …
a resting mean pulmonary artery pressure of >= 25 mmHg.
drug that should not be given in VT
verapamil
what should be prescribed to substitute ACEi like ramipril if patient develops cough?
ARBs eg. candesartan
INR target for recurrent DVT
3.5
patients on warfarin having emergency surgery:
If surgery can wait for 6-8 hours - give 5 mg vitamin K IV
If surgery can’t wait - 25-50 units/kg four-factor prothrombin complex
most accurate non-invasive assessment of coronary artery disease (CAD)
Contrast enhanced cardiac CT
hypercalcaeiuma features on ECG
shortened QT
Management of HOCM
ABCDE
Amiodarone
Beta-blockers or verapamil for symptoms
Cardioverter defibrillator
Dual chamber pacemaker
Endocarditis prophylaxis*
Drugs to avoid:
nitrates
ACE-inhibitors
inotropes
When to avoid rate limiting CCBs?
Rate-limiting calcium channel blockers (diltiazem and verapamil) should be avoided in patients with atrial fibrillation (AF) with heart failure with reduced ejection fraction (HFrEF) due to their negative inotropic effects.
SVT prophylaxis
- Beta blockers
Metoprolol is safest if pregnant - Ablation if accessory pathway
statins monitoring
LFTs at baseline, 3 months and 12 months
what is the only calcium channel blocker licensed for use in heart failure?
amlodipine
management of pulmonary hypertension
1) Acute vasodilator testing with intravenous epoprostenol or inhaled nitric oxide.
If there is a positive response -
oral calcium channel blockers
If there is a negative response to acute vasodilator testing (the vast majority of patients)
a) prostacyclin analogues: treprostinil, iloprost
b) endothelin receptor ANTagonists
non-selective: bosentan
selective antagonist of endothelin receptor A: ambrisentan
c) phosphodiesterase inhibitors: sildenafil
combination therapy often required in negative response
it is important to asymmetically dose which cardiac drug?
isosorbide mononitrate is correct. An asymmetric dosing regimen would involve taking the morning dose as normal, then taking the second dose in the early afternoon. This allows a sufficiently long nitrate-free period and helps reduce tolerance.
J waves on ECG
hypothermia
U waves on ECG
Hypokalaemia -
delta waves on ECG
delta waves are associated with Wolff Parkinson White syndrome.
ECG features of digoxin
down-sloping ST
depression (‘reverse tick’, ‘scooped out’)
flattened/inverted T waves
short QT interval
arrhythmias e.g. AV block,
bradycardia
management of angina
aspiring + statin + GTN spray
- b-blocker or CCB
f a calcium channel blocker is to be used as monotherapy, a rate-limiting one such as verapamil or diltiazem should be selected. - b-clocker AND CCB
- one of the drugs + long acting nitrate or nicorandil or ivabradine or ranolazine
Left ventricular ejection fraction equation
Left ventricular ejection fraction = (stroke volume / end diastolic LV volume ) * 100%
Systemic vascular resistance equation
Systemic vascular resistance = mean arterial pressure / cardiac output
how does digoxin work?
increases the force of cardiac muscle contraction due to inhibition of the Na+/K+ ATPase pump. Also stimulates vagus nerve
most common cardiac defect seen in patients with Down’s syndrome?
Endocardial cushion defects account for about 40%
HTN in pregnancy
1/2 risk factors - start aspirin
Labetalol is first-line for pregnancy-induced hypertension, Nifedipine (e.g. if asthmatic)
women with blood pressure ≥ 160/110 mmHg are likely to be admitted and observed
which electrolyte abnormalities are most associated with long QT?
electrolyte: hypocalcaemia, hypokalaemia, hypomagnesaemia
How do ACEi cause cough?
ACE inhibitors prevent the breakdown of inflammatory peptides such as bradykinin and cough is a frequent side effect.
what is Ebstein’s anomaly
associated with lithium use in pregnancy
congenital heart defect characterised by low insertion of the tricuspid valve resulting in a large atrium and small ventricle.
signs:
- tricuspid regurgitation
pansystolic murmur, worse on inspiration
- right bundle branch block → widely split S1 and S2
- Wolff-Parkinson White syndrome
- associated with atrial septal defects
- right heart failure: hepatomegaly, cyanosis, prominent “a” wave in JVP or giant “v” waves
Syndrome X
Features and management
also called microvascular angina
angina-like chest pain on exertion
ST depression on exercise stress test
but normal coronary arteries on angiography
Management
nitrates may be beneficial
Aortic dissection mx
type A - ascending aorta - control BP (IV labetalol) + surgery
type B - descending aorta - control BP(IV labetalol)
indications for implantable cardiac defibrillators
Indications
long QT syndrome
hypertrophic obstructive cardiomyopathy
previous cardiac arrest due to VT/VF
previous myocardial infarction with non-sustained VT on 24 hr monitoring, inducible VT on electrophysiology testing and ejection fraction < 35%
Brugada syndrome
The most accurate method to determine the left ventricular function?
MUGA (multigated acquisition) scan
Brugada syndrome features
autosomal dominant
mutation in in the SCN5A gene (which encode the myocardial sodium ion channel protein)
ECG changes:
1) convex ST segment elevation > 2mm in > 1 of V1-V3 followed by a negative T wave
2) partial right bundle branch block
3) the ECG changes may be more apparent following the administration of flecainide or ajmaline - this is the investigation of choice in suspected cases of Brugada syndrome
Aschoff bodies
describes the granulomatous nodules found in rheumatic heart fever
PDE 5 inhibitors (e.g. sildenafil) should NOT be given with which drugs?
contraindicated by nitrates and nicorandil
high risk of life threatening hypotension
Atrial myxoma - commonest site =
left atrium
at the fossa ovalis border
feature helps distinguish marfans vs homocisteinuria
Marfans = Mitral valve prolapse may cause a late-systolic murmur
Long QT syndrome is due to loss of what function?
- usually due to loss-of-function/blockage of K+ channels
which antibiotic promotes acquisition of MRSA
Ciprofloxacin
definitive treatment of atrial flutter
radiofrequency ablation of the tricuspid valve isthmus is curative for most patients
cholesterol embolisation signs
cholesterol emboli may break off causing renal disease
the majority of cases are secondary to vascular surgery or angiography. Other causes include severe atherosclerosis, particularly in large arteries such as the aorta
Features
eosinophilia
purpura
renal failure
livedo reticularis
Myopathy is more common with which statins?
in lipophilic statins (simvastatin, atorvastatin) than relatively hydrophilic statins (rosuvastatin, pravastatin, fluvastatin)
warfarin target DVT and AF
venous thromboembolism:
target INR = 2.5, if recurrent 3.5
atrial fibrillation, target INR = 2.5
What is the most common cause of death in patients following a myocardial infarction?
Ventricular fibrillation
how many months after valve replacement does the spectrum of organisms that cause endocarditis return to normal.
2 mo
method to detect mutated oncogenes
Polymerase chain reactions
Complete heart block heart auscultation
causes a variable intensity of S1
all heart failure patients should take what drugs at least
both an ACE-inhibitor and a beta-blocker.
what is Syndrome X?
what are the diagnostic findings
management?
microvascular angina
angina-like chest pain on exertion downsloping
ST depression on exercise stress test
but normal coronary arteries on angiography
Management
nitrates may be beneficial
The most important factor predicting outcomes post-STEMI
new systolic heart failure (low ventricular ejection fraction)
which anti-anginal may be associated with visual disturbances?
Ivabradine use may be associated with visual disturbances including phosphenes and green luminescence
only secreted by the adrenal medulla?
Adrenaline is exclusively secreted by the adrenal medulla
noradrenaline is also excreted
what does troponin I bind to?
actin to hold the troponin-tropomyosin complex in place
upper limb blood pressure is greater than that in the lower limbs
coarctation of the aorta
Cardiac action potential - movement of ions
Phase 0: Rapid depolarisation Rapid sodium influx
Phase 1: Early repolarisation Efflux of potassium
Phase 2: Plateau
Slow influx of calcium
Phase 3: Final repolarisation Efflux of potassium
Phase 4: Restoration of ionic concentrations
Resting potential is restored by Na+/K+ ATPase
There is slow entry of Na+ into the cell decreasing the potential difference until the threshold potential is reached, triggering a new action potential
Pulmonary capillary wedge pressure (PCWP)
measurement obtained through the use of a Swan-Ganz catheter.
It provides an indirect estimation of left atrial pressure, which reflects the pressure in the left side of the heart.
This is important for assessing patients with acute pulmonary oedema, as it helps to determine the cause and guide appropriate treatment.
Patients with MI secondary to cocaine use should be given
IV benzodiazepines as part of acute (ACS) treatment
The administration of adenosine is contraindicated by
her history of asthma. Verapamil should therefore be given.
pulmonary hypertension heart sound
loud S2 (due to a loud P2)
mechanism of action of flecainide
sodium channel blocker.
Atrial fibrillation - pharmacological cardioversion:
amiodarone or flecainide
patent ductus arteriosus - What pulse abnormality?
large volume, bounding, collapsing pulse
which drugs impact adenosine function
Dipyridamole Enhances the action.
Aminophylline Reduces the action
DEAR
effect of amiodarone on the thyroid
amiodarone can cause hypothyroidism due to the high iodine content of amiodarone causing a Wolff-Chaikoff effect*
if patient develops hypothyroidism, continue amiodarone and add levothyroxine
amiodarone can also cause thyrotoxicosis
type 1: excess iodine used to make thyroid hormones. Goitre present.
mx. stop amiodarone, give carbimazole
type 2: Amiodarone-related destructive thyroiditis, no goitre present.
mx. stop amiodarone. give steroids.
In the Vaughan Williams classification of antiarrhythmics lidocaine is an example of a:
Class Ib agent
Complete heart block causes what on auscultation
variable intensity of S1
most common acyanotic and cyanotic heart defects
Acyanotic - most common causes
ventricular septal defects (VSD)
cyanotic - TOF (lifelong), but at birth TGA is most common
septal defects
atrial septal defect –> ejection systolic murmur louder on inspiration
ventricular systolic defect –> pansystolic (‘harsh’ in character)
NYHA Classification of HF
NYHA Class I
no symptoms
no limitation
NYHA Class II
mild symptoms
slight limitation of physical activity: comfortable at rest but ordinary activity results in fatigue, palpitations or dyspnoea
NYHA Class III
moderate symptoms
marked limitation of physical activity: comfortable at rest but less than ordinary activity results in symptoms
NYHA Class IV
severe symptoms
unable to carry out any physical activity without discomfort: symptoms of heart failure are present even at rest with increased discomfort with any physical activity
