Cardiology Flashcards
MRCP part 1 studying
What is the commonest site for radiofrequency ablation in AF ?
PULMONARY VEINS
Wide circumferential ablation is performed aroud the areas where pulmonary veins join with the atrium - > the goal is to electrically isolate rapid electrical acitivity arising from within the veins, or adjacent to the pulmonary vein ostia, from the rest of the left atrium. (85% success rate)
AF when to consider rythm over rate control in haemodynamically stable patients?
Less than <48h onset :
- Significantly symptomatic patients
- Younger patients / Fewer comorbidities
- Chemical cardioversion prefered over mechanical
What agents can be used to chemically cardiovert stable patients?
- No structural heart disease : Flecanide or propafenone
- Structural heart disease or if uncertain : Amiodarone
Features of CHB on examination?
- Slow regular pulse that doesn’t have exertional variation
- Basal systolic flow murmur - increase cardiac stroke volume ( attempt to compensate), increases turbulance across the aortic valve. ( Functional murmur)
- Irregular Cannon A waves from the heart beating across a closed tricuspid.
What two subtypes do we know of streptococcus viridans ?
S. sanguinis and S.mitis (commonly mentioned )
Echo findings in HOCM?
- Elevated flow velocity across the left ventricular outflow tract.
- Diastolic disfunction with reduced left ventricular compliance
- Systolic anterior motion of the anterior mitral valve leaflet
- Assymetric septal hypertrophy
What causes loud first heart sounds and wide reversly split second heart sound?
( Histroy of palpatations )
- Wolff Parkinson white syndrome type B
Causes of reversed splitting of S2 ?
- Delayed A2 - LBBB, AS ( thickened aortic leaflets close more slowly), HOCM.
- Early P2 - WPW type B where the right sided accessory pathway causes early RV depolarisation
In HOCM what causes worsening of the left ventricular outflow tract ?
Standing / Exericice / ACE
• Reducing preload - decreased venous return leads to a decrease in the left ventricle cavity size, this brings the hypertrophied septum and teh anterior mitral leaflet closer together, which narrows the left ventricular outflow tract.
- Reducing afterload - decreased amount of resistance against which blood is being ejected, means increased velocity of the blood ejected. This leads to the venturi effect ->suction pulling the anterior mitral leaflet towards the hypertrophied septum.
- Increasing contractility - same thing as with preload
What is preload ?
Volume of blood filling the left ventricle during diastole.
What is afterload ?
The force that the left ventricle has to work against to work against to pump blood out during systole.
Paten foramen ovale are the most common congenital cardiac defect, but they are not open all the time, what can cause them to open?
When right sided atrial pressure exceeds left sided atrial pressure, e.g valsalva maneouvre - straining, exercice, diving.
Mechanism of action of Nicorandil
Dual action drug :
1. Activates ATP sensitive potassium channels in vascular smooth muscle causing vasodilation
2. Stimulates guanylate cyclase , causing increased formation of cGMP and as a result vasodilation.
The intensity of what murmur decreases during pregnancy?
Aortic regurgitation - the fall in diastolic BP during pregnancy causes the decrease of the murmur.
Diastolic BP in pregnant patients falls due to vasodilation
Antihypertensive medication in pregnancy, 1st line ?
- Labetolol (contraindication asthma) - beta blocker with alpha blocking properties.
- Nifedipine - non -dihydroperidine calcium channel blocker
- Methyldopa - Alpha 2 agonist - has to be stopped 2 days postpartum as it can cause depression.
What are the ECG changes in WPW ?
- Short PR interval <0.12s
- Widened and slurred (due to delta wave) QRS complex
- Type A - left sided accessory pathway = right sided axis deviation, dominant R wave in V1
- Type B - right sided accessory pathway = left sided axis deviation, no dominant R wave in V1
When is aortic stenosis severe/ critical?
Severe when the valve area orifice is 1cm2 and a mean gradient of greater than 40mmHg, critical when the orrifice is < 0.5cm2
Criteria for starting ivarbadine + ivarbadine’s mechanism of action?
It is an If ( funny) channel inhibitor, predominantly negative choronotropic effect (slows down the heart rate), this is because I(f) are highly expressed in the sino-atrial node. The slowed heart rate improved myocardial perfusion.
3rd line treatment for HF on the conditions that :
- > EF below 35% despite optimisation of 1st and 2nd line
-> HR >75BPM
-> Failed bisoprolol
Indications for aortic valve replacement
Normal QT range?
- Less than 430 in males
- Less than 450 in females
What are the contraindications to percutanous baloon valvotomy?
- Moderate to severe mitral regurgitation
- Left atrial thrombus
- Heavily calcified mitral valve
- Concominant coronary artery or other valvular disease requiring surgery.
The ESC guidelines for diagnosis of acute pericarditis?
Two out of 4 of the following :
1) Pericardititic chest pain
2) Pericardial rub
3) New Whidespread ST elevation or PR depression
4) Pericardial effusion, new or worsening.
Ebstein’s anomaly - deffinition and assosiations ?
- Atrialisation of the right ventricle by low insertion of the tricusspid valve causing large atrium and small ventricle.
- May be caused by lithium in utero
- Assosiated with patent foramen ovale or atrial septal defect in 80% of patients
- Assosiated with WPW
Three good reasons to start a patient with hear failure with reduced ejection fraction on thrombembolic therapy ?
- previous thromboembolic event
- intracardiac thrombus
- left ventricular aneurysm
