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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3597_Библиотеки_им_академика_М_И_Перельмана
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202 4 —
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C
200 mm Hg
Hemodynamic Data
LV
D
Figure 4-12, cont’d
catheterization table. Organization by color coding and coiling to protect
cables against damage is very helpful to achieve optimal catheterization
laboratory operation. D, Lef t, Left ventricle (LV) pressure tracing showing
normal “damping” with viscous contrast media in the fluid path. Right, After
flushing with saline, the tracing now is seen as underdamped with an exag gerated ringing artifact. (A to C, Reprinted with permission from Cath Lab
Digest, copyright HMP Communications.)
quire setting each tracing’s pressure scale on a different value. Rightheart scales range from 0 to 50 mm Hg, whereas typical left-heart
pressure scales range from 0 to 200 mm Hg.
0
C, Picture shows cables hanging on the back of the
For pressure scales, displaying more than one tracing may re-
Hemodynamic Recording
Techniques
Coordination between the recording technician and operators is
required to obtain high-quality hemodynamic recordings. The following are some suggestions that aid in providing consistent, reliable data:
1. At the start of each procedure, enter the patient’s identifiers, the
date, and other key data. Calibrate the transducers and set at zero
at the mid-chest level. Measure the mid-chest point with a ruler and
mark for later reference.
2. Anticipate changes in the recording settings as the catheter is
moved to new positions. Change pressure scales and sweep speeds
as needed.
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Example: For monitoring RA pressure in a patient with pulmonary
hypertension, a full-scale 0 to 50 mm Hg may be appropriate. As the
catheter passes through the tricuspid valve, RV pressure may be
>
50 mm Hg. The technician should observe this, anticipate the change,
and quickly change the scale (e.g., 0- to 100-mm Hg full scale)
accordingly.
4 —
Hemodynamic Data 203
Hemodynamic Data Collection: Points of
Confusion and Frustration
It is frustrating for nurses and technicians to enter a laboratory wherein
all of the cabling connecting the transducers to the table and the table
connectors to the hemodynamic recorder is unplugged and lying all
over the floor (see Fig. 4-12, C). This may be a continuous battle if
cleaning personnel between or after cases unplug the cables for better
cleaning. Numbering or color coding all cables and inputs for easy
match-ups is one way to solve this problem. In addition to clear labeling, cable attachments to the table side with Velcro strips or tapes will
help organization and eliminate confusion and wasted time.
Likewise, during a procedure on the catheterization table, it is
worthwhile to color code the transducers or connecting tubing or to
number them so that communication between the table and the
recording technician can proceed smoothly. For example, “please
zero transducer number 1, pressure is up on number 1” will clarify
recording of FA pressure and not RA pressure.
Hemodynamic Examples
and Artifacts
Artifacts of Hemodynamic Tracings
Pressure Fidelity: Underdamping and Overdamping
Normal pressure waveforms from fluid-filled systems are sharp without
rounded contours. The correct frequency of the system permits some
high-frequency oscillations to be visible at low pressures and maintain
rapid upstrokes without overshoot or hyperoscillation at high pressure. If the transducer is too sensitive, a small pressure wave can cause
a big deflection of the signal. Narrow spikes or exaggerated overshoot
of the ventricular (right and left) pressure suggests underdamping.
Conversely, if the transducer is not sensitive enough, the same pressure wave will not sufficiently deflect the signal, producing a dull or
rounded waveform. This is called an overdamped signal and is usually
produced by a problem in the fluid path to the transducer or a transducer that is not calibrated correctly.
Air Bubbles
An air bubble in a LV pressure line produces a tracing with exaggerated systolic and diastolic overshoot (see Fig. 4-11), demonstrating
underdamping. After the line is flushed and the air bubble eliminated,
the sharp, crisp upstroke of ventricular pressure shows a normal pressure rise. An accurate waveform for a properly flushed fluid-filled
catheter system shows little overshoot during the high-frequency systolic period and at the same time shows mild vibratory waves during
the low-frequency diastolic period. An underdamped tracing can be
corrected by instilling diluted contrast media in the pressure line.
Figure 4-12, D, shows a suitable LV pressure with normal (or only
slightly rounded) waveform after flushing of the line (right side of
tracing). Early diastolic and systolic portions of the pressure wave on
the right show striking overshoot underdamping. Table 4-3 lists
common problems and solutions for hemodynamic waveforms.
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Table 4 -3
Hemodynamic Data
Common Hemodynamic Recording Problems
Problem Possible Cause Solution
Overdamping* Bubble or clot in line or
Underdamping
†
transducer
Small lumen of tubing
system
Soft or compliant tubing Use stiffer tubing
Loose catheter
connection
Kink in catheter Unkink catheter
System tubing too stif f Use sof ter tubing
System tubing too long Shorten tubing
Hyperdynamic state Increase filter on
Reflush system
Increase internal
diameter of tubing
Tighten catheter
amplifier; introduce
small bubble or
Catheter tip in turbulent
Loss of signal Bad transducer Change transducer
Pressures do
not return to
zero
Modified from Tilkian AG , Daily EK: Cardiovascular pro cedures: diag nostic
techniques and therapeutic procedures, S t Louis, 1986, Mosby.
*Overdamping system is not sensitive enough and yields flat or rounded tracings.
†
Underdamping system is too sensitive and produces too much ringing o r over shoot
of tracings.
jet
Bad cable Change cable
Bad amplifier Switch amplifier
Catheter disconnected Check connections
Catheter obstructed/
kinked
Same causes as loss of
signal as above
Reposition catheter
Flush/change catheter
Readjust zero line
Recalibrate
Check zero at mid chest
Underdamping produces a “noisy” PCWP (Fig. 4-13). With instillation
of contrast media into the catheter, underdamping is corrected, yielding a tracing with clearly interpretable waveforms. Figure 4-14 shows
the effect of different timing signals of the transducers for pressure
and ECG.
Catheter Malposition or Movement
A false Ao valve stenosis gradient is shown in Figure 4-15. For measure-
ment of LV and Ao pressures, all side holes of the pigtail catheter must
be under the Ao valve. In Figure 4-15, B, the pigtail catheter is partly
out of the LV. LV pressure is partly contaminated by Ao pressure, which
reduces the LV-Ao gradient. This artifact also is evidenced by the
abnormal diastolic waveform, which shows a continued decline
(downslope) in diastolic pressure (see Fig. 4-15, C). LV diastolic pressure should be lowest in the first part of diastole, with a rising pressure
across the mid and late diastolic period. Figure 4-15, A shows the true
gradient when the pigtail catheter is advanced slightly. This artifact is
important and if unappreciated may lead to a false conclusion of only
minimal Ao valve disease (Fig. 4-16).
Loose Tubing Connections
Loss of pressure may be due to loose connections among the tubing,
catheter, manifold, or transducer (Fig. 4-17). An LV pressure that is
lower than the Ao pressure is due to this problem (unless the Ao pressure is increased by another source, such as heterotopic transplant or
extra cardiac hemodynamic support).
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ECG
40 mm Hg
RA
0
Figure 4-13 Right atrial (RA) pressure tracing showing marked under-
damped ringing artifact. Instillation of viscous contrast media damps the
system, producing excellent waveforms. ECG, Electrocardiogram.
4 —
Hemodynamic Data 205
Figure 4-14 Left ventricular (LV) pressure and electrocardiogram (ECG)
show an artifact of amplifier miscalibration regarding timing between the
two signals. Note that the ECG occurs in the middle of diastole rather than
at the left ventricular end -diastolic pressure (LVEDP) (second red line). Reset
the default time for each amplifier to rectif y this problem. (Reprinted with
permission from the Cath Lab Digest, copyright HMP Communications.)
Normal Right Ventricular and Right Atrial
Pressure Waves
The respiratory influences on RA pressure are shown in Figures 4-18
and 4-19. Simultaneous RV and RA pressures are shown in Figure 4-20.
The atrial filling wave a and ventricular filling wave v correspond to
the RV pressure tracing. Following the a wave is the “x” descent, and
following the v wave is the normal “y” descent. These waveforms may
be altered by specific heart disease or arrhythmias. The notch (Fig.
4-20, left-facing arrow) on the top of the RV tracing is the “ringing”
artifact of an underdamped fluid-filled catheter. This ringing is also
evident on the early diastolic part of the pressure wave (bottom of
same beat, right-facing arrow).
Figure 4-21 shows the continuous pressure on pull back (red
arrow) across the interatrial septum from the LA to the RA of a patient
with Ao stenosis. It also shows the differences between LA and RA a
and v waves. The v waves in the LA pressure wave are prominent with
their corresponding “x” and “y” descents. In the RA, the a and v waves
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ECG
200
mm Hg
FA
LV
0
A
Hemodynamic Data
1 sec
B
40 mm Hg
C
Figure 4-15
fully across the aortic (Ao) valve. B, Falsely low aortic stenosis (AS) gradient
caused by pigtail catheter side holes in the aor ta. C, Abnormal diastolic left
ventricular (LV) pressure wave pattern showing relaxation failure of diastolic
dysfunction. Note that the lowest diastolic pressure occurs in the middle
of diastole, whereas normally the lowest diastolic pressure occurs at the
very beginning of diastole. ECG, Electrocardiogram; FA, femoral artery
pressure.
A, True gradient is seen when the pigtail catheter is advanced
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1 sec
ECG
200 mm Hg
LV
*
Pigtail catheter pull back
Figure 4 -16 A falsely wide aortic (Ao) pulse pressure (*) with the use of
a pigtail catheter is caused by incomplete withdrawal of all side holes
outside the left ventricle (LV). On final catheter positioning (far right), Ao
pressure is normal. ECG, Electrocardiogram.
200
Ao
LV
4 —
Hemodynamic Data 207
LV/FA with bad connection
Figure 4 -17 A loose connection on the left ventricle (LV) catheter to the
pressure manifold causes loss of LV pressure (right side). Few real conditions produce aortic (Ao) pressure higher than LV pressure. FA, Femoral
artery.
ECG
RA
Inspiration
Figure 4-18 Normal decrease in right atrial (RA) pressure during inspira-
tion (scale 0 to 40 mm Hg). Note increase in “y” descent (arrow).
are less striking. In general, RA a waves are larger than v waves. In the
LA, v waves are more prominent than a waves.
Right Atrial Pressure with
Tricuspid Regurgitation
With tricuspid valvular regurgitation, blood is pushed backward into
the RA during systole. In contrast to the normal pattern, RA pressure
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40 mm Hg
Figure 4 -19 Abnormal response of right atrial (RA) pressure to inspiration
in a patient with constrictive physiology or heart failure. Although “y” descent
is exag gerated, no corresponding fall in a or v wave height occurs. ECG,
Electrocardiogram.
Hemodynamic Data
ECG
RA
Inspiration
ECG
40 mm Hg
RV
a v
RA
Figure 4 -20 Right atrial (RA) and right ventricular (RV) tracings in a normal
patient. Left-facing arrow, Notch of ringing or overshoot on RV pressure rise;
right-facing arrow, ringing and overshoot of decline in RV pressure at early
diastole; a, atrial wave; v, ventricular filling wave.
ECG
40 mm Hg
LA
0
v
a
y
x
RA
a'–c
a'
v
x
y
Figure 4-21 Hemodynamic tracing of the left atrium (LA) with catheter pull
back to the right atrium (RA) across the intraatrial septum. See text for
details of waveform analysis. ECG, Electrocardiogram.
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50
RV
25
RA
0
4 5 6 1 2 3 4 5 6
Figure 4 -22 Right atrial (RA) pressure in a patient with severe tricuspid
regurgitation. When R A pressure is paired with simultaneous right ventricular (RV) pressure, tricuspid regurgitation can be seen associated with tricuspid stenosis as the separation (gradient) between the RA and RV pressures
during diastole.
ECG
40 mm Hg
4 —
Hemodynamic Data 209
C
RA
a
a
Figure 4-23 Right atrial (RA) pressure during atrial-ventricular dissocia-
tion. a, Small a wave during synchrony of atrial and ventricular activity; C,
cannon wave; ECG, electrocardiogram. See text for details.
rises throughout RV systole. Figure 4-22 shows an example of a patient
with tricuspid regurgitation. The RA pressure shows striking regurgitant v waves during systole without a gradient during diastole between
RA and RV pressures, indicating no tricuspid stenosis. RV and RA
pressure are elevated (RV systolic, 70 mm Hg; RA mean pressure,
17 mm Hg). A small gradient exists between the RA (higher tracing)
and RV (lower tracing) during diastole because of mild tricuspid stenosis (a narrow and limited opening of the tricuspid valve).
Right Atrial Pressure in a Patient with
Atrioventricular Dissociation
Normal a waves represent the pressure response to atrial contraction
on ventricle pressure. During an AV block, the atria are not contracting
at the proper time (just before ventricular contraction) (Fig. 4-23).
Immediately after the QRS, the ventricles contract and the tricuspid
and mitral valves close. If the P wave (and atrial contraction) occurs
after the tricuspid valve is closed, a giant a, or cannon, wave can be
seen. With return of AV synchrony (normal sequence) on beats 6 and
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ECG
Hemodynamic Data
CARDIAC CATHETERIZATION LAB
50
25
50
25
*
RA
3 1 2 3 4 5 6 1 2 3
4 5 6
Figure 4-24 Right atrial (RA) pressure during and af ter temporary right
ventricular (RV) pacing. Electrocardiogram (ECG) shows large pacer spikes
associated with giant a waves on RA pressure. Fusion beats begin at the
asterisk, and the timing of an atrial contraction begins to precede ventricular
activation, resulting in normal a waves.
II
V
5
6 mm/mV
25 mm/s
200
100
00
HR
71
SA
130/66
(93)
0
Figure 4-25 Aor tic (Ao) pressure changes occur when rhythm changes
from sinus to junctional. HR, Heart rate.
7, a waves return, appropriate for the atrial contraction, emptying
blood before ventricular systole (QRS). Similar findings may be seen
when a pacemaker causes the dissociation; giant a waves occur during
pacing (Fig. 4-24). The atrial contribution may be as much as 25%
to 30% of CO and its effect on systemic pressure can be seen in
Figure 4-25.
Pulmonary Capillary Wedge Pressure and
Left Atrial Pressure with Simultaneous
Trans-septal and Right-Sided Heart
Catheterization
For ever y waveform, the LA pressure rise precedes that of PCWP by
approximately 100 to 150 msec. Figure 4-26 shows simultaneous LA
pressure and PCWP tracings. PCWP is measured through a 7-F fluidfilled, balloon-tipped catheter; LA pressure is measured through a
Brockenbrough catheter. The correspondence of these two pressures
is generally close and permits clinical use of PCWP for most standard
hemodynamic cases.
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ECG
4 —
Hemodynamic Data 211
40 mm Hg
LA
0
Figure 4 -26
(PCW) tracings. ( The patient has aortic stenosis [AS] with high ventricular
filling pressure.) ECG, Electrocardiogram.
Simultaneous left atrial (LA) and pulmonary capillar y wedge
PCW
a
v
v′
a′
Figure 4 -27 Left, Simultaneous aortic (Ao) and left ventricular (LV) pres -
sures recorded from a micromanometer high-fidelity dual transducer cath eter. Note small impulse gradient of a normal lef t ventricular outflow tract
(LVOT). Right, Simultaneous hemodynamic tracings of femoral ar terial (FA)
pressure, taken through the side arm of an 8 -F sheath and central Ao pressures. Ao pressure is obtained through the 7-F pigtail catheter. Overshoot
of FA pressure and the lag in the pressure upstroke are the normal characteristics of femoral tracings. (Reprinted with permission from the Cath Lab
Digest, copyright HMP Communications.)
Normal Femoral Arterial and Central
Aortic Pressures
The femoral arterial (FA) and centrally measured Ao pressures have
a fairly close correspondence. Normally, there is a slight overshoot of
systemic pressures at the peripheral and FA locations. In the example
in Figure 4-27, FA pressure measured through the side arm of the FA
sheath (8 F) is matched against pressure in the pigtail catheter (7 F)
positioned above the Ao valve. By observing the timing of the upstroke
of the pressures, the operator can distinguish the central Ao pressure
(first signal rising). The mean of the two pressures is identical. Figure
4-27 shows the high-fidelity pressure tracings of simultaneous LV and
Ao pressures from a dual high-fidelity catheter.
The contribution of atrial filling to systemic pressure can be seen
in Figure 4-28. The normal sinus beats (1 and 2) with simultaneous Ao
(FA) and LV pressure tracings show a systolic pressure of 175 mm Hg
and Ao diastolic pressure of 70 mm Hg. Atrial contribution is lost
because of a-v dissociation (Fig. 4-28, arrow), and a pacemaker rhythm
takes over. The systolic pressure falls dramatically to 118 mm Hg and
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