Cardiac Cath Hemodynamics

Wiggers Diagram

A diagram of volumes, pressures, electrical activity, and heart sounds. Used to illustrate the relationship between different aspects of cardiac physiology and the sequence of events in the cardiac cycle

Electrical activity that leads atrial contraction

Atrial contraction

Detected via atrial pressure monitoring

Electrical activity that leads ventricular contraction

Heart sound: closure of mitral valve

Ventricular contraction

The large pressure increase that occurs in the ventricle with contraction causes the closed tricuspid valve to bulge into the atrial space, raising atrial pressure

Not always seen

Heart sound: closure of the aortic valve

Isovolumic contraction

Ejection

Isovolumic relaxation

Rapid inflow

Diastasis

Atrial Systole

The blood that is ejected from the left ventricle into the aorta over 1 minute

CO= HR x SV

4-8 L/min

Compares cardiac output to the size of the body

CI= CO/body surface area

2.5-4 L/min/m^2

Percentage of the left ventricular end diastolic volume ejected in systole

EF= (SV/end diastolic volume) x 100%

60%-80%

The sum of the forces resisting blood flow through the systemic circulation

[(mean aortic pressure - right atrial pressure)/CO] x 80

900-1400 dynes/sec/cm^-5

The sum of the forces resisting blood flow through the pulmonary circulation

PVR= [(mean pulmonary artery pressure - pulmonary capillary wedge pressure)/cardiac output] x 80

30-100 dynes/sec/cm^2

Aortic valve opens

Aortic valve closes

Mitral valve closes

Mitral valve opens

Systole

Diastole

Systole

Phonocardiogram

Aortic pressue

Ventricular pressure

Atrial pressure

Ventricular volume

Electrocardiogram

2-8 mmHg

Systolic: 15-30 mmHg

Diastolic: 1-8 mmHg

Systolic: 15-30 mmHg

Diastolic: 4-12 mmHg

2-10 mmHg

2-10 mmHg

Systolic: 100-140 mmHg

Diastolic: 4-12 mmHg

70 +/-5%

70 +/-5%

70 +/-5%

70 +/-5%

70 +/-5%

95 +/-5%

95 +/-5%

95 +/-5%

Pressures on the right side of the heart and the pulmonary circulation

Enters through the femoral, subclavian, internal jugular, or brachiocephalic vein > superior vena cava > R atrium > tricuspid valve > R ventricle > pulmonic valve > pulmonary artery > wedged into a smaller vessel in the pulmonary circulation

Pressure on the left side of the heart

Through measurement of a pulmonary capillary wedge pressure, which is indicative of the pressure in the left atrium

Pulmonary artery catheter

Proximal port

Port to Thermistor

Port to balloon

Distal Port

Superior Vena Cava

Right Atrium

Right ventricle

The tip of the catheter, where the bulk of measurements are taken. Communicates to the distal port

Yellow

30cm mark

Blue

- Central venous pressures or right atrial pressures, depending on the position of the catheter

- Cardiac output

Thermodilution technique

A known volume of injectate (typically 10ml D5W), at a known temperature (room temperature), is injected into the right atrium through the proximal port. Blood temperature is measured at the distal end of the pulmonary artery catheter and injectate temperature is measured as it enters the right atrial lumen. Cardiac output is determined by the change in blood temperature over time

Red

A syringe is attached for the inflation and deflation of the balloon, which sits at the end of the catheter.

Many models include an infusion port for medications, through which vasopressors or other meds may be given

An electronic plug that connects to the thermistor

Measuring the temperature change at the distal portion of the catheter during the measurement of cardiac output when using the thermodilution technique

The device which converts pressure exerted upon it into an electrical signal, generating the waveforms observed during cardiac catheterization

Phlebostatic axis

The intersection of the mid-axillary line and the fourth intercostal space

The level of the atrium

A leveling device

Falsely elevated

Falsely lowered

- level and zero transducer

- ensure connections are not loose or leaking

- remove all bubbles from the circuit

- assess the pressure waves and EKG for correlation

- Take measurements at the appropriate time in the respiratory cycle

Represents right atrial passive filling

The opening of the tricuspid valve

A wave

C wave

V wave

Electrical activity precedes changes in pressure

Right Atrium

It fills passively from venous return

Right ventricular systole

The tricuspid valve is open during ventricular diastole

Dicrotic notch

The notch in the downslope of the pulmonary artery pressure wave, caused by the closure of the pulmonic valve

Pulmonary wedge pressure represents pressures in the left side of the heart, which is a higher pressure area

The p wave should be found on the ECG and correlated to the waveform that immediately follows it

Stenosis of the tricuspid valve

The force of the atrial contraction must be stronger than usual to open a stenotic valve

There would be no a wave

Occurs at the end of ventricular systole, after the T wave on the ECG

Represents left atrial filling against a closed mitral valve

The V wave will be seen just after the pulse is felt

Dehydration or hypovolemia

- Heart failure

- Fluid volume overload

- Tricuspid valve disease

- Atrial septal defect

As the catheter bumps into the walls of the ventricle, it can cause PVCs/vtach

The catheter may need to be pulled back slightly

In some cases, cardioversion may be required

Contraction of the R ventricle

- pulmonic stenosis

- pulmonary hypertension

At the end of diastole, just before systole

- General health of R ventricle

- Ventricular preload

- Right ventricular myocardial infarction

- Untreated pulmonary stenosis

- Untreated pulmonary hypertension

Pulmonary artery

The pulmonic valve is smaller than the tricuspid valve, so some manipulation may be required

A distinct increase in pressures

The disappearance of the atrial kick

Right ventricular systole

Right ventricular diastole

Dicrotic notch

Transient pressure increase related to pulmonic valve closure

- COPD

- pulmonary hypertension

- pulmonary embolus

- left-to-right shunting

- left sided heart failure

- hypoxemia

- valve disease

The inflated balloon is advanced until it "wedges" in a smaller vessel in the pulmonary circulation. The balloon creates a seal against the walls of the vessel, isolating the tip of the catheter from pressure changes behind the balloon

1.5mL

No longer than 15 seconds, or about two respiratory cycles

The balloon is blocking blood flow through the blood vessel, essentially acting as a pulmonary embolus

Near the end of expiration

Endothoracic pressure fluctuates with breathing, causing wedge pressure measurements to vary. Inhalation causes negative endothoracic pressures

Heavily sedated patients may exhibit long, snoring respiratory patterns. This may make measurements less accurate

The balloon may be overinflated,or the vessel may be too small.

The balloon may need to be deflated and the catheter repositioned

- Left ventricular overload

- COPD

- Mitral regurgitation

- Mitral stenosis

- Myocardial infarction affecting the left ventricle

- Heart failure

- Aortic stenosis

- Aortic regurgitation

A wave

Represents left atrial contraction

C wave

Represents bulging of the mitral valve during ventricular systole

Atrial relaxation and the downward movement of the mitral valve

V wave

Represents passive filling of the left atrium

The opening of the mitral valve and ventricular filling

- Mitral stenosis

- Mitral regurgitation

- Left ventricular infarction

- CHF

- Aortic stenosis

- Aortic regurgitation

Just before systole

- volume overload

- valve disease

- diastolic dysfunction

- cardiomyopathy

Left heart catheterization

A large v wave on a left heart pressure waveform

Mitral stenosis

Normally, the left atrial diastolic pressure will be close to the left ventricular end diastolic pressure. In this diagram, the left atrial pressures are high because the stenotic valve is not allowing normal emptying of the left atrium into the left ventricle. This blood, retained in the atrium, results in higher atrial pressures

- rheumatic fever

- drug abuse

- advanced age

- congenital defects

Aortic valve stenosis

Normally, the gradient between LV pressures and aortic pressures is very small, with systolic pressure in the ventricle being slightly higher than aortic systolic pressure.

Here, high left ventricular pressures with significantly lower aortic pressures can be seen. This is because the left ventricle must generate a large amount of pressure to force blood through the narrowed valve. The lower aortic systolic pressure is the result of a lower volume of blood entering the aorta

Aortic valve pullback technique, showing aortic valve stenosis

A technique in which the catheter is advanced through the aortic value into the left ventricle, then pulled back into the aorta.

LV and AO pressures are measured on two sequential beats, evaluating for pressure differences that would indicate aortic stenosis

Right ventricular systolic pressure is high, with low pulmonary artery systolic pressure

By the width of the gradient between right ventricle systolic pressure and pulmonary artery systolic pressure

The saturations in the right atrium would be much higher than those found in the inferior and superior vena cava

This is due to the oxygenated blood crossing from the left atrium to the right atrium through the septal defect

It is possible but much rarer due to the typically higher pressures on the left side of the heart

A sharp decrease in blood oxygen saturation at any point other than the tissues, or a sharp increase in blood oxygen saturation anywhere other than the lungs

Heart failure

Surgery or cardiac catheterization

Saturation in the right ventricle that are higher than that in the right atrium

This is due to oxygenated blood flowing from left ventricle into the right ventricle through the septal defect

Right atrium and right ventricle would have a similar saturation

Left ventricular and aortal saturations would be decreased compared to the left atrium and pulmonary vein

Pulmonic stenosis

Dextroposition of the aorta (aka overriding aorta)

Ventricular septal defect

Thickened right ventricle

Heart murmur

Intermittent cyanosis

Squatting

Severe, continuous cyanosis

heart murmur

Boot-shaped appearance of the heart on radiographs

Fainting spells ("tet spells)

These positions increase vascular resistance, allowing a transient reversal of a portion of the shunting

Shunts blood from the pulmonary artery to the aorta in fetal circulation

Typically closes within a week of birth

Depending on the pressures involved, there is either left to right or right to left shunting (most frequently from the aorta into the pulmonary circulation, raising pressures in the pulmonary circulation

Hypoxemia

SOB

Widening of pulse pressure

Ligation of the vessel

Indomethacin

Helps constrict the ductus arteriosus by inhibiting prostaglandin E2 synthesis