Journal of the American College of Cardiology
© 2004 by the American College of Cardiology Foundation
Published by Elsevier Inc.
Vol. 43, No. 9, 2004
ISSN 0735-1097/04/$30.00
doi:10.1016/j.jacc.2003.11.055
Left Ventricular Assist Device
Malfunction: A Systematic Approach to Diagnosis
Steven C. Horton, MD, FACC,†‡ Reza Khodaverdian, MD,* Amanda Powers, BS,†
James Revenaugh, MD, FACC,†‡ Dale G. Renlund, MD, FACC,†‡ Stephanie A. Moore, MD, FACC,*†
Brad Rasmusson, MD, Karl E. Nelson, BS, MBA,† James W. Long, MD, PHD*‡
Salt Lake City, Utah
A protocol was designed to diagnose the common malfunctions of a left ventricular assist
device (LVAD).
BACKGROUND Mechanical circulatory support, primarily with an LVAD, is increasingly used for treatment
of advanced heart failure (HF). Left ventricular assist device dysfunction is a recognized
complication; but heretofore, a systematic method to accurately diagnose LVAD dysfunction
has not been thoroughly described.
METHODS
We developed a catheter-based protocol designed to characterize a normally functioning
LVAD and diagnose multiple types of dysfunction. A total of 15 studies of 10 patients
supported with an LVAD were reviewed. All patients had been evaluated due to concerns
regarding LVAD dysfunction.
RESULTS
Of 15 examinations performed, 11 documented severe LVAD inflow valve regurgitation. One
of these cases proved to have coexistent severe mitral valve regurgitation. One case was
diagnosed with distortion of the LVAD outflow graft. One case of suspected embolization
from the pumping chamber excluded the outflow graft as the source of emboli. One study had
aortic insufficiency.
CONCLUSIONS As LVAD use for treatment of end-stage HF becomes widespread and durations of support
are extended, dysfunction will be increasingly prevalent. This catheter-based protocol
provided a practical method to diagnose multiple causes of LVAD dysfunction. (J Am Coll
Cardiol 2004;43:1574 – 83) © 2004 by the American College of Cardiology Foundation
OBJECTIVES
Mechanical circulatory support, primarily with a left ventricular assist device (LVAD), is increasingly used to treat
advanced heart failure (HF). Short-term LVADs are highly
successful in bridging patients with end-stage HF to transplantation (1,2). Additionally, the Randomized Evaluation
of Mechanical Assistance for the Treatment of Congestive
Heart Failure (REMATCH) trial showed that patients
with New York Heart Association functional class IV
congestive HF, who were ineligible for heart transplantation, received a longer-term survival benefit from the
LVAD than from optimal medical therapy (3). Thus,
LVAD technology has also been proven to be effective for
long-term HF treatment, frequently referred to as “destination therapy.” Given the substantial number of patients with
end-stage HF, as well as the potential benefits offered by
mechanical circulatory support, it seems likely that LVAD
use will become a more widespread, mainstream treatment.
As LVAD use becomes more commonplace, the care of
LVAD patients will gradually shift away from surgeons
toward cardiologists. This follows the pattern that emerged
as heart transplantation became widely accepted and as
surgical complications were minimized. While the initial
surgery remains under the proper purview of surgeons, ever
more cardiologists are asked to manage patients who have
LVADs. These cardiologists and others who treat these
From the *Division of Utah Artificial Heart Program; †Department of Cardiology,
LDS Hospital; and the ‡University of Utah School of Medicine, Salt Lake City,
Utah.
Manuscript received April 10, 2003; revised manuscript received November 18,
2003, accepted November 24, 2003.
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patients must, therefore, also deal with the inherent risks in
LVAD use, sometimes complications beyond their immediate expertise. One primary concern is LVAD device
failure, the second leading cause of death in the REMATCH study (3).
We sought to better understand the normal physiology of
LVADs, troubleshoot dysfunctional devices, and diagnose
the most common modes of dysfunction. To date, only a
few catheter-based case reports have been published (4,5).
Using a systematized approach based on cardiac catheterization, we evaluated patients with the HeartMate LVAD
(Thoratec Corp., Pleasanton, California), used either as
bridge to transplant or as destination therapy. The protocol
we developed helped characterize a normally functioning
LVAD and diagnosed multiple types of dysfunction, including LVAD inflow valve regurgitation (IVR), outflow
graft distortion, aortic insufficiency, and possible sources of
device-associated embolization. The protocol offers a useful
tool for cardiologists and others in managing LVAD patients.
METHODS
Our pool of patients were all those who had received the
HeartMate VE or XVE LVAD since September 1999.
Demographic details of those studied are summarized Table
1. Of these, six had received the LVAD as a bridge to
transplant; four had received the LVAD as destination
therapy. All evaluations occurred between June 2000 and
July 2002.
Horton et al.
Diagnosis of LVAD Dysfunction
JACC Vol. 43, No. 9, 2004
May 5, 2004:1574–83
Abbreviations and Acronyms
HF
⫽ heart failure
IVR
⫽ inflow valve regurgitation
LV
⫽ left ventricle/ventricular
LVAD
⫽ left ventricular assist device
PCWP
⫽ pulmonary capillary wedge pressure
REMATCH ⫽ Randomized Evaluation of Mechanical
Assistance for the Treatment of
Congestive Heart Failure
2)
3)
Overall, 15 studies using 10 patients on HeartMate
LVADs were reviewed. All patients were evaluated for
suspected LVAD dysfunction. The function of each LVAD
was tested according to our catheterization laboratory protocol for assessing LVAD function, combining catheterization data with angiography. The protocol is summarized in
Table 2.
All patients were simultaneously evaluated by echocardiography (6).
Statistical methods. Evaluation of patient differences for
cardiac output, LVAD flow, and related factors are presented for patients with and without IVR. Values are
presented as means with standard deviation, and Student t
test was used to evaluate the significance of differences
between inflow valve groups, with two-tailed p values and
0.05 considered nominally significant.
RESULTS
After compiling the assessments, we were able to define a
normally functioning LVAD, depicted in Figure 1. Any
normally functioning LVAD in the auto mode (rate automatically adapted by the device according to the blood
volume available) has all of the following seven characteristics:
1) Pulmonary capillary wedge pressure (PCWP) is normal.
The right heart pressures reflect a well-decompressed left
4)
5)
6)
7)
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ventricle (LV). For the PCWP to be considered normal,
it must be normal in the auto mode or, after being
converted from the “fixed-rate” mode, the PCWP must
normalize within 5 min after conversion.
Cardiac output as indicated in the LVAD monitor is
approximately the same as the thermodilution-derived
cardiac output as long as no native LV ejection is
occurring through the aortic valve.
Aortic blood tracings do not display any significant
beat-to-beat variability. In the absence of a native LV
contribution, aortic pressure is purely mechanical. It
should, therefore, be “clockwork regular.”
There is no pressure gradient within the LVAD outflow
graft; there is no significant systolic gradient across the
LVAD outflow valve. These correspond to the pressures
measured in condition 2, 3, 4, and 5 checked in the
catheterization laboratory protocol (Table 2).
The outflow graft appears smooth without distortion
(Fig. 2).
There is no regurgitation of the LVAD outflow valve on
angiography.
Left ventricular pressures typically remain less than
aortic pressures. The LV pressures vary related to their
timing with the LVAD cardiac cycle. Hemodynamic
parameters from a normal study are shown in Table 3.
Using this definition of normal function as a baseline, we
sought to diagnose several types of LVAD dysfunction:
LVAD IVR, outflow graft distortion, embolization from
LVAD pumping chamber, and acquired aortic valve disease.
Our findings with respect to each type of malfunction are
discussed in detail in the following text.
LVAD inflow valve regurgitation. Inflow valve regurgitation causes ineffective decompression of the LV, and a
volume overloaded state, which eventually renders the
LVAD unable to completely decompress the LV. Inflow
valve regurgitation can be caused by a torn cusp or commisure dehiscence of the prosthetic valve. This can be the
Table 1. Patient Demographics
No.
1
2
3
3
4
4
5
5
6
7
7
8
9
10
10
Age
Gender
Etiology
22
51
78
78
57
57
63
63
30
36
36
48
65
64
64
M
M
M
M
M
M
M
M
F
F
F
M
F
M
M
IDCM
ICM
ICM
ICM
ICM
ICM
ICM
ICM
IDCM
IDCM
IDCM
ICM
ICM
ICM
ICM
Indication for Study
Hemolysis
Runaway VAD
Runaway VAD
Pump failure
Runaway VAD
Pump failure
Pump failure
Embolization
Runaway VAD
Runaway VAD
Runaway VAD
Runaway VAD
Runaway VAD
Runaway VAD
Pump failure
Days From
Implant
Findings at Study
Documentation
156
521
155
345
278
699
402
650
339
396
564
346
507
447
463
Kink in the outflow graft
IVR, severe
IVR, mod-severe
IVR, severe
IVR, mod-severe
IVR, severe
Normal angio study
Normal angio study
IVR, mod-severe
IVR, mod-severe
IVR, mod-severe
IVR, minimal
IVR, mod-severe
IVR, mild-mod
IVR, mod-severe
Surgery, kink in the outflow graft
IV deformation @ explantation
Not obtained
IV deformation @ explantation
Not obtained
IV deformation @ explantation
Not obtained
Normal valves
IV deformation @ explantation
Not obtained
IV deformation @ explantation
IV deformation @ explantation
IV deformation @ explantation
Not obtained
IV deformation @ explantation
ICM ⫽ ischemic cardiomyopathy; IDCM ⫽ idiopathic dilated cardiomyopathy; IV ⫽ inflow valve; IVR ⫽ left ventricular assist device inflow valve regurgitation; VAD ⫽ left
ventricular assist device.
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Diagnosis of LVAD Dysfunction
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May 5, 2004:1574–83
Table 2. Catheterization Laboratory Protocol for Assessing LVAD Function
Prior to Procedure
1.
2.
3.
4.
5.
6.
The hand pump should be readily available throughout the test.
Prep the field allowing for easy access to the driveline without breaking the sterile field.
VE system monitor is needed for comparing LVAD flows with simultaneous thermodilution cardiac outputs.
Pneumatic pumping (IP) is used for the remainder of the test. IP lowers the risk of catheter entrapment.
TURN OFF ICDs: ICDs will be triggered by electrical artifact occurring when guidewires are placed in the inflow cannula.
Catheters: 7-F arterial sheaths, 6-F angled pigtail catheter, 6-F multipurpose catheter, Swan-Ganz type balloon-tipped catheter, 0.034-inch
guidewire and 0.034-inch exchange-length guidewire.
Procedure
1. Place a Swan-Ganz catheter and measure pressures in the standard manner. Obtain cardiac outputs by thermodilution or Fick Method. Measure
cardiac output initially in fixed mode, followed by 5 min later in “auto” mode. Record simultaneous LVAD flows from the VE system monitor.
Normally, due to contribution of native heart contraction, Swan-Ganz catheter reading is slightly higher than pump output. Discrepancies higher
than 20% are considered significant.
2. Change from electrical to IP for the subsequent portions of the test. Record pressures and wave forms in each condition. It is important to record
about 40 to 50 cardiac cycles for conditions 4 to 10.
3. Place a 6-F angled pigtail catheter into the ascending aorta. Measure simultaneous ascending aortic and femoral artery pressures. Record condition 1.
4. Enter the efferent limb of the outflow graft at 30° LAO. The efferent limb attaches to the aorta just above the RCA. Record condition 2.
5. Advance the catheter down the graft until it is quite near the outflow valve. Record condition 3.
6. Inject 30 cc of contrast (14 cc/s) in 10° LAO position @ 30 frames/s. Recorded images should view the outflow valve and the conduit beneath it
to assess valvular regurgitation.
7. Inject 30 cc of contrast (14 cc/s) in 10° LAO position @ 30 frames/s. Recorded images should concentrate on the outflow graft, its anastamosis
with the aorta and on the ascending aorta. Aortic insufficiency can usually be seen during the latter portion of this angiogram, if it is present.
8. Advance the pigtail catheter across the outflow valve. Record conditions 4 and 5.
9. Advance the pigtail catheter across the aortic valve. Record conditions 6, 7, 8, and 9.
10. Exchange the pigtail catheter for a built-purpose catheter and advance this catheter across the inflow valve. It is usually difficult to directly place a
multi-purpose catheter into the conduit. If so, using an exchange wire, place a Swan-Ganz catheter into the LV, and with the balloon inflated,
the conduit can be more easily entered. To perform angiography, exchange over-the-wire for the multi-purpose catheter. Do not use a pigtail
catheter. The proximal holes will inject dye proximal to the inflow valve. Record condition 10.
11. Inject 40 cc of contrast (14 cc/s) in 40° LAO @ 30 frames/s. Panning should be toward the LV to assess inflow valve regurgitation.
12. Record condition 11 as the multi-purpose catheter is withdrawn back into the LV.
Conditions
1. Femoral artery ⫹ ascending aorta. The two pressures should be very close to the same. Discrepancies typically indicate the presence of peripheral
vascular disease or a need to rebalance transducers.
2. Femoral artery ⫹ distal outflow graft. A systolic increase of 10 mm Hg would suggest a narrowing of the anastamosis.
3. Femoral artery ⫹ proximal outflow graft (close to outflow valve). This condition is to check the efferent limb (outflow graft) for severe bends or
stenosis. A systolic gradient of ⬎10 mm Hg indicates an abnormality.
4. Femoral artery ⫹ LVAD outflow (pigtail across outflow valve). A systolic gradient indicates stenosis of the outflow valve.
5. Pigtail pullback (record pressure across outflow valve). This is a confirmatory measurement to assess outflow graft stenosis.
6. Femoral artery ⫹ LV (record LV pressure). LV pressures reflect the state of decompression and should rarely reach femoral artery systolic pressure.
7. LV ⫹ PA (record LV and PA pressure).
8. LV ⫹ PCW position (record LV and PCW pressure). Assesses the integrity of the mitral valve for the presence of mitral regurgitation and mitral
stenosis.
9. Femoral artery ⫹ LVAD inflow near inflow valve.
10. Femoral artery ⫹ LVAD inflow conduit across the inflow valve. Pressures are measured before angiography. These should be identical to condition 4.
11. Femoral artery ⫹ pigtail pullback (record pressure across inflow valve).
ICD ⫽ implantable cardiac defibrillators; IP ⫽ pneumatic driver; LAO ⫽ left anterior oblique coronary artery; LV ⫽ left ventricle; LVAD ⫽ left ventricular assist device; PA
⫽ pulmonary artery; PCW ⫽ pulmonary capillary wedge; RCA ⫽ right coronary artery; VE ⫽ vented electric.
result of high pump chamber pressure. Conditions that can
more rapidly lead to this IVR include significant hypertension and outflow graft twisting or distortion (7).
Clinically, these patients typically presented with prolonged, excessively fast LVAD rates (115 to 120 beats/min)
when placed in the auto mode. This produces the condition
colloquially known as “runaway VAD.” Of 31 VE-LVAD
patients implanted between 1999 and 2001, we diagnosed
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11 with significant IVR (32%). The average time from
implantation to first onset was six months. The earliest
onset was 2 months after implantation; the latest onset was
15 months after surgery.
Of our 15 angiographic examinations, 11 were diagnosed
with severe IVR. One experienced coexistent severe mitral
valve regurgitation. At angiography, the LV became opaque
when radiocontrast dye was regurgitated into the LV after
Horton et al.
Diagnosis of LVAD Dysfunction
JACC Vol. 43, No. 9, 2004
May 5, 2004:1574–83
Figure 1. Normal HeartMate left ventricular assist device (LVAD) physiology. The Thoratec HeartMate LVAD commences support at the left
ventricular apex where a cannula allows blood to flow across a 25-mm
Medtronic pig valve into the LVAD pumping chamber. An electric motor
moves a cam 360°, which engages and raises a pusher plate. This movement
ejects a systolic volume of 80 cc. Blood is ejected across a second 25-mm
Medtronic pig valve through an outflow graft that has an anastamosis in
the proximal ascending aorta. Synchronous pumping means LVAD systole
occurs simultaneously with native left ventricular systole. Asynchronous
pumping indicates the LVAD ejects during native left ventricular diastole.
injection into the LVAD beyond the inflow valve. This
correlated well with observations made simultaneously with
echo-Doppler studies (8). Hemodynamically, patients with
IVR differed from normal in the following ways:
1) Right heart pressures reflect a non-decompressed LV.
The PCWP is elevated in the fixed mode and rarely
returns to normal in the auto mode. This is observed
upon insertion of the thermodilution catheter and in
conditions 7 and 8 of our protocol.
2) The actual cardiac output, as measured by thermodilution or Fick methods, is significantly less than those
displayed on the LVAD system monitor, indicative of
the degree of ineffective cycling of blood.
3) The LVAD rate accelerates and remains at maximal
rates in the auto mode.
4) Aortic blood pressures may vary significantly over many
consecutive beats and follow a periodic pattern. Examples of this variability are shown in Figure 3.
5) Simultaneous LV and aortic pressure tracings reveal
elevated aortic pressures when left ventricular systole and
LVAD systole occur synchronously. When the systoles
occur non-synchronously, the aortic pressures are decreased (Figs. 3 and 4).
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Figure 2. Angiography of the outflow graft.
6) Because of the regurgitant volume, LV diastolic pressures (IVR wave) are more elevated during asynchronous
periods of LVAD pumping. Figure 4 illustrates this
wave pattern.
7) Angiography reveals regurgitation of radiocontrast dye
into the LV with injection beyond the LVAD inflow
valve.
8) In patients with coexistent mitral regurgitation, significant v waves are present in the PCWP tracing.
Figure 5A illustrates the LV opacification and the hemodynamic data (Fig. 5B) of a typical case of IVR. Figure 5C
shows the appearance of the inflow valve at the time of
surgical removal.
In patients without IVR, cardiac output exceeded LVAD
flow by an average of 11% (range, 0% to 11.4%). In patients
with LVAD IVR, the mean LVAD flow was, on average,
32.6% higher (range, 16.3% to 38.9%). When compared with
patients without IVR, patients with IVR showed significantly
lower cardiac output, higher LVAD flows and rates, and a
greater difference between cardiac output and pump flow (p ⬍
0.001). This data is summarized in Table 4.
Two other conditions that could lead to discrepancies
between measured cardiac output and LVAD flow rates are
Table 3. An Example of a Normal Study
Mode
Ao
RA
PA
PCW
CO
(Thermodilution)
LVAD Flow
(l/min)
Heart Rate
(ECG)
LVAD
Rate
Stroke
Volume
Fixed
Auto
100/70
100/70
10
8
50/25
35/16
25
15
6.1 l/min
7.2 l/min
5.6 l/min
7.2 l/min
100 beats/min
100 beats/min
70 beats/min
100 beats/min
80 cc
80 cc
Ao ⫽ aorta; CO ⫽ cardiac output; LVAD ⫽ left ventricular assist device; PA ⫽ pulmonary artery; PCW ⫽ pulmonary capillary wedge; RA ⫽ right atrial pressure.
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Figure 3. Aortic blood pressure variability with simultaneous left ventricle (LV) tracing in a patient with left ventricular assist device (LVAD) inflow valve
regurgitation. ART ⫽ arterial pressure.
Figure 4. Inflow valve regurgitation (IVR) waveforms. Pressure tracing taken from the left ventricle (LV) in the presence of severe IVR during periods of
asynchronous and synchronous pumping. Arrows indicate IVR waves associated with regurgitation from the left ventricular assist device (LVAD) into the
LV when the LVAD ejects. Other abbreviations same as in Figure 3.
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Figure 5. Examples of inflow valve regurgitation. (A) Left ventricular opacification. (B) Hemodynamic data. Ao ⫽ aorta; CO ⫽ cardiac output; ECG ⫽
electrocardiogram; LVAD ⫽ left ventricular assist device; PA ⫽ pulmonary artery; PCW ⫽ pulmonary capillary wedge; RA ⫽ right atrial pressure. (C)
Appearance of inflow valve at time of surgery.
aortic insufficiency and LVAD outflow valve insufficiency.
We did not detect any cases with these problems.
This protocol was not designed for detection of inflow
valve obstructions that could occur in the setting of hypertrophic cardiomyopathy, vegetations, or other impingements of the inflow cannula. Detection of that would
require introduction of two pressure catheters, one in the
LV and one in the body of the LVAD, with simultaneous
pressure measurements.
Outflow graft distortion. One of our patients was diagnosed with distortion of the LVAD outflow graft resulting
from LVAD displacement in a morbidly obese patient.
Clinically, this patient presented with hemolytic anemia.
His alarms indicated his LVAD was pumping against high
pressures. Systolic pressure obtained within the LVAD
pumping chamber (condition 10) was 324 mm Hg. At
angiography, the outflow graft demonstrated an acute angle
bend, making it impossible for a guide wire to pass beyond
the kinked graft. This distortion was confirmed at the time
of surgery.
Figure 6A shows condition 10 pressures, and a still frame
of how the graft appeared at angiography (Fig. 6B).
LVAD-associated thrombembolization. One of our patients was diagnosed with embolization from the pumping
chamber of a failed LVAD as a diagnosis of exclusion. He
presented with acute bilateral leg pain. Angiography revealed a
clot at the aortoiliac bifurcation. Because angiography of the
outflow graft excluded the graft as the source of the thrombus,
we were able to choose an abdominal approach to replace only
the LVAD pump. After explant, we confirmed that a thrombus was within the LVAD chamber. On review, this patient
had been exposed, without anticoagulation, to a long period of
sub-optimal flow dynamics with inadequate filling and emptying while his LVAD was activated pneumatically.
Acquired aortic valve disease. Both acquired aortic stenosis and insufficiency are known to develop during LVAD
Table 4. Comparison of CO and LVAD Flows in Normal and IVR Patients (LVAD Patients
Are in Auto Mode)
Mean
(SD)
CO
(l/min)
LVAD Flow
(l/min)
LVAD Rate
(beats/min)
Flow Minus
CO (l/min)
Without IVR
With IVR
5.7 ⫾ 1.4
4.5 ⫾ 1.1
5.1 ⫾ 1.1
6.7 ⫾ 0.9
66 ⫾ 14
90 ⫾ 13
0.7 ⫾ 0.8
2.2 ⫾ 1.5
CO ⫽ cardiac output; IVR ⫽ inflow valve regurgitation; LVAD ⫽ left ventricular assist device.
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Figure 6. Examples of a kinked outflow graft. (A) High pressures measured within the left ventricular assist device pumping chamber, with simultaneous
aortic pressures. (B) Angiographic appearance.
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Figure 7. Example of normal aortic pressure with left ventricular assist device support during ventricular fibrillation. AO ⫽ aorta.
therapy (9,10). One of our patients had minimal, asymptomatic aortic insufficiency. Angiography performed in
condition 3 of the protocol offers adequate opacification of
the ascending aorta to test for this condition. If high-grade
aortic stenosis was suspected, then detection would be
improved by dropping LVAD rates to low levels in order to
adequately detect a gradient, because gradients are directly
proportional to native ventricular outflow across the native
valve. However, detection of aortic stenosis is not usually
clinically necessary because an LVAD can function normally
in the setting of aortic stenosis (11). Aortic stenosis would
be very relevant in the setting of LVAD failure, or when the
LVAD is used as a bridge to recovery.
Complications. No serious complications occurred using
our protocol. There were no complications of bleeding,
infection, vascular trauma, or stroke.
Two patients experienced transient arrhythmias. Most
arrhythmias are tolerated with a well-functioning LVAD.
One patient developed ventricular fibrillation during catheterization. The patient remained hemodynamically stable
on LVAD support and was easily cardioverted back into
normal sinus rhythm. This arrhythmia is illustrated in
Figure 7.
A unique rhythm situation arose when exchange guide
wires were used to place a multi-purpose catheter across the
inflow valve within a VE-LVAD. We believe these guide
wires transmitted a small electrical current that was sensed
by the surface electrocardiogram leads. While in normal
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sinus rhythm, one patient’s defibrillator interpreted the
otherwise benign current as ventricular fibrillation and
issued defibrillating shocks. The electrocardiograms that
resulted are depicted in Figure 8. To avoid this situation, the
protocol now calls for defibrillators and pacemakers to be
appropriately reprogrammed during catheterization.
DISCUSSION
Left ventricular assist device malfunction is an important
cause of morbidity and mortality (3). The incidence of
device malfunction will increase in the future as durations of
support exceed the life expectancy of current generation
LVADs. As cardiologists provide care for an increasing
number of LVAD patients, it is particularly important that
they be able to accurately diagnose and successfully troubleshoot a dysfunctional device. This paper presents a catheterbased protocol designed to meet that need. By using this
diagnostic tool, cardiologists and others who care for
LVAD patients should be able to successfully identify most
malfunctions of the LVAD.
Acknowledgments
The authors gratefully appreciate the assistance of Ashley
Renlund and Patricia Horton in preparation of the manuscript, and the care given to our patients by Brandi Porter,
RN.
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Figure 8. (A) Normal sinus rhythm on entry to the catheterization laboratory. (B) Electrocardiogram with electrical artifact with exchange wire across the
inflow valve.
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Horton et al.
Diagnosis of LVAD Dysfunction
JACC Vol. 43, No. 9, 2004
May 5, 2004:1574–83
Reprint requests and correspondence: Dr. Steven C. Horton,
324 10th Avenue, Suite 206, Salt Lake City, Utah 84103. E-mail:
SCHorton@msn.com.
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