25- Heart catheterization. Hemodynamic evaluation. The heart cycle.

what is heart catheterisation

• passage of a catheter through peripheral arteries and veins into cardiac chambers and coronary arteries

describe the catheterisation procedure

1. wire inserted into L or R side of heart

2. dye is injected → angiogram visualised via x ray imaging

3. number of stenosed vessels indicates what to do next

4. pharmacological treatment is the same after

describe left heart catheterisation

• enter via femoral, radial, brachial artery → aorta/ coronaries, LV and mitral valve

• useful in- coronary a., aortic BP measurement, LV pressure/ function

describe right heart catheterisation

• enter via femoral, subclavian, antecubital vein → RA, tricuspid valve, pulmonary valve and artery

• used in- RA/RV pulmonary artery pressures, pulmonary a. occlusion vascular resistance measurements

what does the number of stenosis indicate

• >3 → CABG

• 1-2 → PCI angioplasty

what are the risks with PCI angioplasty

• risk of stent stenosis

  • drug eluting stents prevent this

• can have increased risk of thrombosis

what is the pharmacoological treatment

• BB

• ACEi

• dual anti platelet therapy- aspirin + clopidogrel

• high potency statins

what are the general uses for cardiac catheterisation

• pressure measurements → fluid column pressure differences, gradients

• flow measurements → coronary flow reserve

• angiocardiography → heart chambers

• coronarography → coronary arteries

• PCI

• biopsy

• intravascular US imaging → estimation of arterial narrowing

• pericardiocentesis → fluid aspiration

wha tare the indications for catheterisation

• CAD investigation → detect stenosis and location of CAD

• valvuloplasty

• congenital HF diagnosis/ treatment

• abnormal stress test

• recurrent chest pain

what techniques are used

• Seldinger in combination with

  • fluoroscopy/ digital or X ray recording → real time images

  • contrast dye injection- heart anatomy + vessel imaging

  • perform angioplasty- stenting + ballooning

  • valvuloplasty

  • cariac biopsies

what are the risks/ complications

• haemorrhage/ false aneurysm → cardiac tamponade

• hypersensititivty reaction to contrast material

• arrhythmias, thrombosis, stroke, AMI, angina, infection

what are the relative contraindications

• renal insufficiency

• coagulopathy

• fever/ systemic infection

• uncontrolled arrhythmia

• decompensated HF

• radiopaque dye allergies

what is haemodynamic evaluation

• blood flow and cardiac performance by measuring blood flow at different points in circulation

• feel pulse → simple information about strength of circulation

how is the BP measured for evaluation

• plethysmograph or cuff connected to a pressure sensor

• most common clinical measure of circulation and provides peak systolic + diastolic pressure

what is Doppler flow measurements

• measure flow at any point in circulation including within heart

• pressure gradients

• pathologic flow

what is arterial pulse pressures

• placing tonometer or pressure sensor on skin surface above artery → continuous pressure trace or pulse pressure waveform

• reflects CV perormance

• invasive → measure intraarterial PP through catheter in artery

what is CO/ SV

• distinguish function of heart and vessels

• allows more understanding and treatment of CV system

• important regarding CO and SV is EF

• EF <40%- HF

what are the phases of the heart cycle

1. atrial depolarisation/ contraction- diastole

2. isovolumetric contraction- systole

3. ejection systole → diastole

4. isovolumetric relaxation diastole

describe phase 1 of the heart cycle

• SA node → depolarises atria⇒ P wave

• atrial contraction → atrial P increases → ventricular filling → increased VV

• atrial + ventricular pressure increases until atrial contraction is over → a P decreases

• Small decrease in aortic pressure= less blood remained to flow away from aorta

describe phase 2 of the heart cycle

• ventricular presure > atrial pressure = AV valve close ⇒1st heart sound

• beginning of systole

• ventricular depolarisation/ contraction → increased ventricular pressure

• AV and semilunar valves are closed= isovolumetric contraction

describe phase 3 of the heart cycle

• ventricular pressure increases → exceeds aortic pressure → semilunar valves open

• blood from ventricle to aorta

• V and aortic pressure decreases when ventricular repolarisation occurs

• end of ejection phase when aortic pressure is > ventricular → semilunar valves close⇒ 2nd heart sound

describe phase 4 of the heart cycle

• ventricular pressure decreases with no change in volume= isovolumetric relaxation

• ventricular pressure a bit> atrial

• atrial contraction increases slowly= increases

• atrial preaaure> ventricular → AV valves open → ventricular filling

• dicrotic notch= closure of semilunar valve → aortic pressure decreases slowl