Left ventricular pressure tracings

PRESSURE TRACING OF
LEFT VENTRICLE
By
Gopal C Ghosh

History of cardiac catheterisation
“The cardiac catheter was......the key in the
lock”-Andre Cournand (1956)
Cardiac catheterization was first performed by
Claude Bernard in 1844(horse)
Stephen Hales – as first to do cardiac
catheterisation in animals(1711 on horse)
Mueller RL et al. Am Heart J 1995;129:146.

Cardiac catheterisation in human
• Werner Theodor Otto Forssmann( August
1904 – June 1979)
• First to do cardiac catheterisation in human
heart
• Retrograde left heart catheterization was
first reported by Zimmerman, Scott &
Becker and Limon-Lason and Bouchard in
1950.
Zimmerman HA, Scott RW, Becker ND. Catheterization of the left side of the
heart in man. Circulation 1950;1:357.

Dynamic pressure monitoring
• Dynamic blood pressure has been of interest to
physiologists and physicians
• 1732- Stephen Hales measured the blood
pressure of a horse by using a vertical glass
tube

Fluid-filled standard catheter system
• Proper equipments for high quality catheterisation
recordings
• Coronary angiography: smallest-bore catheters, 5F
& even 4F
• Complex hemodynamic catheterization is optimally
performed with larger-bore catheters that yield
high-quality hemodynamic data. To obtain proper
hemodynamic tracings, 6F or even 7F catheters
may be required

Fluid-filled catheter is attached by means of a manifold to a small-volume-
displacement strain gauge type pressure transducer
Wheatstone bridge

Pressure Measurement
Terminology
• Natural frequency
– Frequency at which fluid oscillates in a catheter when it is tapped
– Frequency of an input pressure wave at which the ratio of output/input
amplitude of an undamaged system is maximal
Grossman W. Cardiac Catheterization, Angiography, and Intervention. 5th
Edition. Baltimore: Williams and Wilkins, 1996.
Shorter catheter
Larger catheter lumen
Lighter fluid
Higher natural frequency

Damping
• Dissipation of the energy of oscillation of a
pressure management system, due to friction
Greater fluid viscosity
Smaller catheter radius
Less dense fluid
Greater damping

Damped natural frequency
• Frequency oscillations in the catheter when friction
losses are taken into account
Natural frequency = Damping  System critically damped
Natural frequency < Damping  OVERdamped
Natural frequency > Damping  UNDERdamped

Less damping  greater
artifactual recorded pressure
overshoot above true pressure
when pressure changes
suddenly
More damping 
less responsive to
rapid alterations in
pressure

Sensitivity
• Ratio of amplitude of the recorded
signal to the amplitude of the input
signal

Optimal damping can maintain frequency response flat (output/input ratio = 1) to
88% of the natural frequency of the system

Frequency response
• Ratio of output amplitude to input
amplitude over a range of frequencies of the
input pressure wave
• Frequency response of a catheter system is
dependent on catheter’s natural frequency
and amount of damping
• The higher the natural frequency of the system,
the more accurate the pressure measurement
at lower physiologic frequencies
Grossman W. Cardiac Catheterization, Angiography, and Intervention.
7th Edition.

What is the optimal frequency
response?
• The essential physiologic information is
contained within the first 10 harmonics of the
pressure wave's Fourier series
• The useful frequency response range of
commonly used pressure measurement
systems is usually <20 Hz
• Frequency response was flat to <10 Hz with
small-bore (6F) catheters

Reflected waves
• Both pressure and flow at any given location
are the geometric sum of the forward and
backward waves

FACTORS THAT INFLUENCE THE
MAGNITUDE OF REFLECTED WAVES

Sources of Error
• Tachycardia
 If pulse is too fast for natural frequency of system, the fidelity of
the recording will drop.
 Pulse = 120  10th harmonic = 20 Hz  Damped natural
frequency should be at least 60 Hz
• Sudden changes in pressure
• Deterioration in frequency response
• Catheter whip artifact
• End-pressure artifact
• Catheter impact artifact
• Systolic pressure amplification in the periphery
• Errors in zero level, balancing, calibration

Sources of Error
• Tachycardia
 Peak LV systole, trough early diastole, catheter bumping against
wall of valve
 Artifact seen due to under damping

Sources of Error
• Tachycardia
 Introduction of air or stopcocks permits damping and reduces
natural frequency by serving as added compliance
 When natural frequency of pressure system and low frequency
components falls, high frequency components of the pressure
waveform (intraventricular pressure rise and fall) may set the
system into oscillation, producing “pressure overshoots” in early
systole & diastole

Sources of Error
• Tachycardia
 Motion of the catheter within heart or large vessels accelerates fluid in
catheter and produces superimposed waves of  10 mm Hg
 Common in pulmonary arteries & unavoidable

Sources of Error
• Tachycardia
 Pressure from endhole catheter pointing upstream is artifactually
elevated. When blood flow is halted at tip of catheter, kinetic
energy is converted in part to pressure. Added pressure may range
2-10 mm Hg.
 When endhole catheter is oriented into the stream of flow, the
“suction” can lower pressure by up to 5%

Sources of Error
• Tachycardia
 Pressure transient produced by impact on the fluid-filled catheter
by an adjacent structure (i.e. heart valve)
 Any frequency component of this transient that coincides with the
natural frequency of the catheter manometer system will cause a
superimposed oscillation on the recorded pressure wave
 Common with pigtail catheters in the left ventricular chamber,
where the terminal pigtail may be hit by the mitral valve leaflets as
they open

Sources of Error
• Tachycardia
• Systolic pressure amplification in the
periphery
 Consequence of reflected wave
 Peripheral arterial systolic pressure commonly 20 mm Hg higher than
central aortic pressure (mean pressure same or slightly lower)
 Masks pressure gradients in LV or across aortic valve
 Use of a double-lumen catheter (e.g., double-lumen pigtail) or
trans-septal technique with a second catheter in the central aorta
can be helpful

Sources of Error
• Tachycardia
 Zero level must be at mid chest level
 All manometers must be zeroed at same point
 Zero reference point must be changed if patient repositioned
 Transducers should be calibrated against standard mercury
reference (rather than electrical calibration signal) and linearity of
response should be verified using 25, 50, and 100 mm Hg

Intracardiac micromanometers
(Catheter-tip pressure manometer)
• High fidelity transducer catheter with
miniaturized transducer placed at tip (Millar
Instruments)
• Improved frequency response characteristics
and reduced artifact
• Measurement of myocardial mechanics
(dP/dt of LV)

• Systolic ejection phase - QT interval on the
ECG
• LV systolic pressure is measured at the peak
pressure of the ejection phase

Left ventricular end diastolic pressure
• End Diastolic pressure can be measured on the
R wave of the ECG, which will coincide just
after the ‘a’ wave on the LV trace. This is
called the post ‘a’ wave measurement of EDP
• To be measured at end expiration

Anachrotic Notch
• During the first phase of ventricular systole
(isovolumetric contraction), a presystolic rise
may be seen
• Occurs before the opening of the aortic valve

Dichrotic notch
• Blood flow attempts to equalize by flowing
backwards - results in closure of the aortic
valve
• This event marks the end of systole and the
start of diastole

Pulse Pressure
• The difference between the systolic and
diastolic pressure
• Factors Factors that affect pulse pressure
pressure
– changes in stroke volume
– aortic regurgitation
– changes in vascular compliance

Common cardiological conditions
Needs invasive monitoring

Aortic Stenosis(severity)
• Discrepancy between the physical examination
and the elements of the Doppler echocardiogram
• Optimal technique: record simultaneously
obtained left ventricular and ascending aortic
pressures
• Mean gradient differences not the peak to
peak gradient (peak left ventricular pressure
does not occur simultaneously with the peak
aortic pressure)

• Pullback traces with a single catheter from the
left ventricle to the aorta can be helpful, but
only if the patient is in normal sinus rhythm
with a regular rate
• Carabello sign:
Critical aortic stenosis
Catheter across the valve itself will cause
further obstruction to outflow
This sign occurs in valve areas 0.6 cm2 or less
& when 7F or 8F catheters are used to cross
the valve

Use side hole catheters. Aortic pressure damping
can occure with end hole catheters

Dont use femoral arterial pressure:
1. Peripheral amplification of arterial wave-decrease the
gradient falsely
2. PAD-increase gradient falsely

Evaluation of low flow low gradient
aortic stenosis(LVEF<40%)
• Gradient (<30 mm Hg) and a low output,
resulting in a small calculated valve
area(<1cm2)
• These patients with low-flow/low-gradient AS
(LF/LGAS) may truly have severe AS with
resultant myocardial failure (true AS) or may
have more moderate degrees of AS and
unrelated myocardial dysfunction (pseudo-
AS)

• True AS: increased flow across a fixed valve
orifice results in increased transvalvular flow
velocity and gradients, without a change in
calculated valve area.
• Pseudo-AS: augmented flow results in only a
mild increase in transvalvular gradient and
an increase in valve area by ≥0.2 cm2

Dynamic LVOT obstruction
• Visual assessment:
Aortic stenosis:
• Delay(tardus) and reduction (parvus) in the
upstroke of the central aortic pressure
Dynamic LVOT obstruction:
• Spike-and-dome pattern with an initial rapid
upstroke
• Late peaking left ventricular pressure

Braunwald-
Brockenborough
sign

Mitral Stenosis
• Continuous-wave Doppler echocardiography is
highly accurate
• Noninvasive estimations are inconsistent &
pulmonary hypertension out of proportion to
the apparent severity of the mitral valve
disease
• Simultaneous pulmonary artery wedge
pressure and left ventricular pressure

Evaluation of valvular regurgitation
• left ventriculography and aortic
angiography are the modalities most often
used to assess the severity of valve
regurgitation
• When there is a discrepency between clinical
assessment and dopplar echocardiographic
measurement
• Sellar criteria used

Precautions
• Large-bore catheters and a large amount of
contrast to completely opacify the cardiac
chambers(small amount underestimate)
• Avoidance of ventricular ectopy and entrapment
of the mitral valve apparatus by the catheter
• High right anterior oblique views for left
ventriculograms may be necessary to avoid the
retrograde contrast from being superimposed on
the spine or descending aorta

Evaluation of aortic regurgitation
• Grade 1: a small amount of contrast material enters the
left ventricle in diastole; it is essentially cleared with
each beat and never fills the ventricular chamber
• Grade 2: More contrast material enters with each
diastole and faint opacification of the entire chamber
occurs
• Grade 3: the LV chamber is well opacified and equal in
density with the ascending aorta
• Grade 4: complete, dense opacification of the LV
chamber in one beat, and the left ventricle appears more
densely opacified than the ascending aorta

Part of the angiographic assessment of aortic
regurgitation involves assessment of (LAO
view):
1. Aortic valve leaflets (mobility, calcification,
number of leaflets)
2. Ascending aorta (extent and type of
dilatation)
3. Possible associated abnormalities (e.g.,
coronary lesions, sinus of Valsalva aneurysm,
dissecting aneurysm of the aorta, and
ventricular septal defect)

Constrictive Pericarditis Versus
Restrictive Cardiomyopathy
CCP RCM
1. Ventricular
interdependence
Present Absent
2. Pulmonary arterial systolic
pressure> 55-60 mm hg
No Yes
3. Equalisation of Right &
Left ventricular EDP
Yes No
4. Dip and platue pattern of
left ventricular end diastolic
pressure
Yes No
5. RVEDP/RVSP> 1/3 Yes No

David G Hurrell et al. Circulation 1996

Ventricular interdependence
• Highly sensitive & specific
• Also seen in cardiac tamponade, acute right
ventricular infarction, subacute tricuspid
regurgitation
• Inspiratory decrease in pulmonary venous and
intrathoracic pressure is not transmitted into
the cardiac chambers
Hatle et al. Circulation.1989;79:357-370.

Irina Kozarez et al.
Grand Rounds Vol
11 pages 111–114

Hypertrophic Cardiomyopathy
• There is frequently a dynamic left ventricular
outflow tract obstruction that is highly
dependent on loading conditions and the
contractile state of the ventricle

Indication for septal ablation
• Suitable anatomy
• Severe symptoms unresponsive to medical
management
• Documented left ventricular outflow gradient
of 50 mm Hg either at rest or during
provocation
2011 ACCF/AHA Guideline for the Diagnosis and Treatment of
Hypertrophic Cardiomyopathy: Executive Summary

• If there is a gradient 50 mm Hg at rest,
provocative maneuvers such as the Valsalva
maneuver or induction of a premature
ventricular contraction should be performed
• However, if a gradient is not provoked with
these maneuvers, infusion of isoproterenol is
helpful because direct stimulation of the beta 1
and beta 2 receptors simulates exercise and
may uncover a labile outflow tract gradient

• The left ventricular outflow tract gradient is
dynamic and can change significantly during a
single diagnostic catheterization
• It is recommended that catheters such as a
multipurpose or Rodriquez catheter with side
holes at the distal portion of the catheter
should be used to determine the exact location
of obstruction (pigtail with multiple side holes
to be avoided & single end hole catheters to be
avoided)
Nishimura et al. Circulation 2012

Brockenbrough-Braunwald sign
• The decrease in pulse pressure after a
premature ventricular contraction is due to
reduced stroke volume caused by increased
dynamic obstruction

HCM: Typical midcavitary
obstruction
Fernando Pivatto et al. Rev Bras Cardiol Invasiva. 2014

Apical HCM
C.-C. Chen et al: Clin. Cardiol. 34, 4, 233–238 (2011)

Takotsubo cardiomyopathy
• Apical ballooning with basal hyperkinesis on
the left ventriculogram.

Golabchi A et al. J Res Med Sci. 2011 Mar;16(3):340-5.

Left ventricular pressure tracings

Left ventricular pressure tracings

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