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High-Risk Cardiac Catheterization
Table 8 -3
Types and Characteristics of Contrast Media
Generic Name U.S. Trade Name
Iodixanol Visipaque 270 290
Iopromide Ultravist 150 328
Ioversol 34% Optiray 160 328
Iodixanol Visipaque 320 290
Iohexol Omnipaque 180 388
Iopamidol 40.8% Isovue 200 413
Iopromide Ultravist 240 483
Ioversol 51% Optiray 240 502
Iohexol 51.8% Omnipaque 240 520
Iopamidol 51% Isovue 250 524
Ioxilan 62.3% Oxilan 300 607
Iopromide Ultravist 300 607
Iopamidol 61.2% Isovue 300 616
Ioversol 64% Optiray 300 651
Iohexol 64.7% Omnipaque 300 672
Ioxilan 72.7% Oxilan 350 695
Ioversol 68% Optiray 320 702
Iopromide Ultravist 370 774
Ioversol 74% Optiray 350 792
Iopamidol 75.5% Isovue 370 796
Iohexol 75.5% Omnipaque 350 844
Osmolality
(mOsm/Kg H20)
Table 8 -4
Risk Factors for Development of Contrast-Induced
Nephropathy
Patient Related Extrinsic Possible
Existing renal
insufficiency
(estimated GFR
<
60/mL/min/1.73 m2)
CHF High-osmolal contrast Diabetes
Diabetes with existing
renal insufficiency
Age >70 years
Volume depletion Multiple contrast
Hypotension Urgent/emergent PCI Female gender
Anemia Multiple myeloma
Hyper tension Cirrhosis
Peripheral vascular
disease
Modified from Klein LW, S heldon MW, Brinker J, et al: The use of r adiogr aphic
contrast media during PCI: a focused review. Catheter Cardiovasc Interv 74:728,
2009.
ACE-I, Angiotensin -converting enzyme inhibitor; ARB, angiotensin receptor blocker;
CHF, congestive hear t failure; GFR, glomerular filtration rate; IABP, intraaortic balloon
pump; PCI, percutaneous coronary inter vention.
Contrast volume
administered
IABP used Impaired glucose
Nephrotoxic drugs Hyperuricemia
administrations
(within 72 hr)
Metabolic sy ndrome
tolerance
ACE-I or ARB
Low-osmolar and nonionic contrast agents are associated with a lower
incidence of bradycardia, hypotension, and myocardial ischemia, and
these agents are now routinely used during cardiac catheterizations
in most labs.
Several risk factors have been identified in patients at higher likeli-
hood of developing CIN (Table 8-4). Unfortunately, many of these
parameters are not modifiable and therefore do not lend themselves
to modifying to avoid CIN. A risk score, devised to identify patients at
higher risk for CIN, is shown in Figure 8-1. Three prophylactic strategies
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High-Risk Cardiac Catheterization 363
Risk Factors
Hypotension
IABP
CHF
Age >75 years
Anemia
Diabetes
Contrast media volume
Serum creatinine >1.5 mg/dl 4
or
eGFR <60 mL/min/1.73 m
eGFR (mL/min/1.73 m2) =
186 x (SCr)
x (0.742 if female) x (1.210 if
African American)
–1.154
Risk
Score
x (age)
Risk of
CIN
Integer Score
1 for each 100 cc
2
0.200
Calculate
Risk of
Dialysis
5
5
5
4
3
3
3
2 for 40–60
4 for 20–40
6 for <20
≤5
7.5% 0.04%
6 to 10 14.0% 0.12%
11 to 16 26.1% 1.09%
≥16
57.3% 12.6%
Figure 8-1 Risk-factor scores developed by Mehran, et al., to predict the
likelihood of contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI). Adding up all of the points for any given patient
calculates the total risk score. Estimated risk for CIN and dialysis. CHF,
Congestive heart failure; eGFR, estimated glomerular filtration rate; IABP,
intraaortic balloon pump. (From Mehran R, Aymong ED, Nikolsky E, et al: A
simple risk score for prediction of contrast-induced nephropathy after percutaneous coronary intervention: development and initial validation. J Am
Coll Cardiol 44:1393–1399, 2004.)
to decrease the risk of CIN center include maintaining adequate intravascular volume, limiting amount of contrast delivered, and avoiding
medications that could exacerbate renal dysfunction.
Many protocols have been published that outline how to ensure
adequate hydration. For high-risk patients, American College of
Cardiology/Society for Cardiovascular Angiography and Interventions
(ACC/SCAI) guidelines currently recommend normal saline or sodium
bicarbonate solution infusion at 1 to 1.5 mL/kg/min for 3 to 12 hours
before and 6 to 12 hours after the procedure. Recent data showed no
benefit for N-acetylcysteine administration, and thus it is not currently
recommended in the guidelines. However, a large-scale clinical trial
(PRESERVE) is underway to investigate the effectiveness of sodium
bicarbonate infusions and N-acetylcysteine administration. Many
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High-Risk Cardiac Catheterization
other pharmacologic treatments (including furosemide, mannitol,
dopamine, and fenoldopam) have not been shown to be effective or
even have caused more harm and should not be used.
To minimize the chance of CIN, use the lowest amount of contrast
necessary to perform the study. Measures such as minimizing contrast
“puffs” (test shots), increasing frame rates to lessen contrast injection,
avoiding ventriculography and aortography, and decreasing the
number of angiograms performed can reduce the amount of contrast
used. Iso-osmolar contrast may be beneficial in high-risk patients,
such as diabetics with renal insufficiency, but its superiority over all
other low-osmolar agents in reducing CIN remains under study.
Medications such as angiotensin receptor blockers (ARBs),
angiotensin-converting enzyme inhibitors (ACE-Is), and nonsteroidal
antiinflammatory drugs (NSAIDs) should be discontinued for 1 to 2
days before catheterization. Withholding them for 3 to 4 days following
the procedure is also common. However, it has never been shown that
the use of ACE-Is or ARBs, in the absence of renal arter y stenosis, truly
increases the risk of renal insufficiency.
Allergic reactions to contrast are discussed in Chapter 1. It is
worth remembering that these reactions are characterized as anaphylactoid, in that they do not require previous exposure to contrast (and,
thus, to circulating reaginic [immunoglobulin E] antibody), but they
do occur as a result of mast cell degranulation. A patient with a history
of multiple food and drug allergies and, of course, those that have had
previous reactions to contrast are at especially high risk. The perception that patients with a seafood or shellfish allergy are also at higher
risk has never been shown to be true and should not be used as criteria
to administer prophylaxis for contrast reactions.
Prophylaxis for patients who are at risk for reactions to contrast media should include prednisone and diphenhydramine
(Fig. 8 -2). Figure 8-3 depicts treatment algorithms for mild and severe
reactions.
Thrombocytopenia
Thrombocytopenia (low platelet count) is a troublesome finding on
preprocedural laboratory work. For elective procedures, thrombocytopenia should be identified and its underlying cause treated before
Recurrent contrast reaction prophylaxis
Preprocedural
recommendations
1. Obtain atopy history,
asthma history
2. Hold β-blockers for 24
hours
3. Diphenhydramine 50 mg
1 hour prior
4. Prednisone 50 mg 13, 7,
and 1 hour prior to
procedure
5. +/– Cimetidine 300 mg
orally or ranitidine 150
mg orally 1 hour prior
Figure 8-2 Treatment paradigm to guide prophylaxis against contrast-
induced allergic reactions. (From Klein LW, Sheldon MW, Brinker J, et al:
The use of radiographic contrast media during PCI: a focused review: a
position statement of the Society of Cardiovascular Angiography and Interventions. Catheter Cardiovasc Interv 74:731, 2009.)
1. Low or iso-osmolar contrast
media
2. Careful attention to
hemodynamic monitoring
3. Equipment and medications
for treatment and
anaphylatoid reaction
prepared
Procedural
recommendations
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High-Risk Cardiac Catheterization 365
by mask,
2
intubate
1. Epinephrine IV
2. Large volume 0.9%
NS (1 to 3 L in the
1. Epinephrine IV
2. Large volume 0.9%
NS (1 to 3 L in the
4. Diphenhydramine
first hour)
3. O
by mask,
2
first hour)
3. O
intubate
4. Diphenhydramine
50 to 100 mg IV
5. Hydrocortisone
400 mg IV
6. Cimetidine 300 mg
IV or ranitidine 50
mg IV over 15 min
7. CVP/Swan-Ganz
50 to 100 mg IV
5. Hydrocortisone
400 mg IV
6. CVP/Swan-Ganz
7. Oximetry/ABGs
8. Oximetry/ABGs
9. Dopamine 2 to 15
mcg/kg/min IV
10. ACLS support
Severe anaphylactoid reaction
Assess airway:
Call anesthesia
Mild Moderate/severe Responsive Unresponsive
Facial and laryngeal edema Hypotension/shock
Assess airway:
Call anesthesia
1. Oxygen face
mask and
pulse oximetry
1. Oxygen face
mask and
pulse oximetry
via mask,
2
O
intubation, or
Epinephrine IV
tracheostomy tray
via mask,
2
O
intubation, or
tracheostomy tray
Epinephrine SubQ
2. Diphenhydra-
mine 50 mg IV
3. Hydrocortisone
200 to 400 mg IV
4. Cimetidine 300
mg IV or
2. Diphenhydra-
mine 50 mg IV
3. Hydrocortisone
200 to 400 mg IV
4. Cimetidine 300
mg IV or
50 mg IV
Diphenhydramine
50 mg IV
Diphenhydramine
ranitidine 50
mg IV over 15
ranitidine 50
mg IV over 15
Cimetidine
Oximetry/ABGs
Cimetidine
Oximetry/ABGs
min
5. Epinephrine IV
10-mcg/min
boluses then
min
5. Epinephrine
SubQ 0.3 cc
of 1:1000 q 15
over 15 min
300 mg IV or
ranitidine 50 mg IV
over 15 min
300 mg IV or
ranitidine 50 mg IV
infusion of 1 to 4
mcg/min;
observe
min up to 1 cc
Mild anaphylactoid reaction
Urticaria and skin itching Bronchospasm
Responsive Mild Moderate SevereUnresponsive
1. Oxygen face
mask and
pulse oximetry
2. Diphenhydra-
mine 50 mg IV
SubQ
q 15 min
Epinephrine
Diphenhy-
up to 1 cc
0.3 cc of 1:1000
comfort
dramine
orally for
25 to 50 mg
3. Hydrocortisone
200 to 400 mg IV
4. Cimetidine 300
mg IV or
ranitidine 50
mg IV over 15
min
+
50 mg IV
300 mg IV
Cimetidine
or ranitidine
over 15 min
5. Albuterol
inhaler 2 puffs
A B
CVP, central venous pressure; IV, intravenously; NS, normal saline; q, every; SubQ, subcutaneously. (From Klein LW, Sheldon MW, Brinker J, et al: The use of radiographic contrast
Figure 8-3 Treatment protocols for allergic reactions to contrast. A, For mild reactions; B, for severe reactions. ABG, Arterial blood gas; ACLS, advanced cardiovascular life support;
media during PCI: a focused review: a position statement of the Society of Cardiovascular Angiography and Interventions. Catheter Cardiovasc Interv 74:731, 2009, fig 1a and b.)
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proceeding. Depending on the etiology of the thrombocytopenia and
platelet count, platelet transfusions may be necessary before and
during the procedure. For patients at high risk of bleeding, one should
consider radial artery access; of course, nonaccess site bleeding risks
remain the same.
High-Risk Cardiac Catheterization
Systemic Hypertension
Poorly controlled hypertension increases risks throughout the procedure. In addition to the increased risk of cerebrovascular accident and
respiratory insufficiency in the presence of diastolic dysfunction, elevated blood pressure increases the risk of vascular access complications. Elective procedures may need to be postponed to allow for
improved blood pressure control for levels >180/100. Closure devices
are relatively contraindicated in patients with significant hypertension.
Attempts should be made to lower the blood pressure safely before
sheath removal. To control blood pressure, the patient can be given
their home medications orally or with intravenous (IV) pushes of
hydralazine, metoprolol, or labetalol. It is important to continue hemodynamic monitoring of the patient postcatheterization, because high
blood pressure–related complications can be detected early with continued reassessment of the patient’s status.
Other Comorbidities
If possible, other comorbidities should be stabilized before the patient
is sent to the catheterization suite. Anemia and bleeding tendencies should be identified and etiologies known before undergoing the
procedure. This is especially true for those patients who require
PCI and may be on multiple anticoagulant and antiplatelet agents.
Patients with decompensated CHF, in whom catheterization can be
delayed, should be diuresed to improve the safety and comfort of the
procedure.
Chronic obstructive pulmonary disease is another illness often
coexisting with cardiovascular disease, and patients who are experiencing acute exacerbations of this problem should have their procedure postponed if possible. An underdiagnosed problem in medicine
is obstructive sleep apnea. These patients often become hypoxic with
sedation and should have their noninvasive ventilation devices (continuous positive airway pressure [CPAP] or bi-level positive airway
pressure [BiPAP]) with them during the procedure to minimize the
risk of worsening their baseline respiratory insufficiency.
Management of Complications During
Cardiac Catheterization
Complications of coronary arteriography in high-risk patients must be
managed at once (Table 8-5).
Vascular Complications
The management of vascular access complications is discussed in
detail in Chapter 2.
Arterial thromboembolism can occur to any vascular bed in the
body manifesting as stroke, TIA, intestinal ischemia, or peripheral
emboli. Treatment options depend on the vascular bed involved and
presence of symptoms. Most concerning is development of neurological symptoms consistent with a stroke following cardiac catheterization. Any patient with these symptoms should receive urgent evaluation
by a stroke team or transfer to a stroke center for evaluation of thrombolytics or mechanical thrombectomy. In patients receiving anticoagulants in the lab, intracranial hemorrhage must be ruled out. Cortical
blindness is a rare event that can be caused by ionic and nonionic
contrast agents. It usually manifests initially as blurry vision and
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High-Risk Cardiac Catheterization 367
Table 8 -5
Management of Complications During Cardiac
Catheterization
Complications and
Precautions Treatment
Ventricular tachycardia,
asystole, or fibrillations
(0.6%)
Air embolism (0.1%) Prevent by careful back-bleeding and flushing
Hematoma in femoral
artery (0.1% major, 1%
to 2% minor)
Retroperitoneal bleeding Avoid high (above IEA) femoral ar tery puncture
ACLS, Advanced c ardiovascular life suppor t; BP, blood pressure; CAD, coronary
artery disease; CPR, cardiop ulmonar y resuscitation; CT, computed tomography;
ECG, electrocardio gram; IEA, inferio r epigastric artery; IV, intravenous;
LV, left ventricle; RV, right ventricle; VF, ventricular fibrillation.
Nonionic contrast agents in high- risk patients
Cough for temporary increase in BP
Remove catheter from RV, LV, or coronary
ostium
Do not wed ge coronary ar tery catheter;
contrast material washout should be brisk;
ECG and BP should be normal before nex t
injection
CPR followed by prompt defibrillation (200 J)
Do not inject when c atheter tip pressure is
damped
Lidocaine (50-mg bolus, 2 to 4 mg/min IV)
Atropine, volume expansion, or infusion
Amiodarone (300- mg bolus) and then
metaraminol (Aramine) for hypotension
Refractory VF usually as a result of extensive
CAD; consider emergency percutaneous
cardiopulmonar y bypass
Limit contrast medium injected into coronary
arteries; avoid prolonged injections
of all connections; ensure that all
connections are tight
100% oxygen, fluids, aspiration, ACLS if
indicated
Puncture below inguinal ligament IEA and
above bifurcation of superficial and
profunda femoral arteries
Evacuation rarely required
Attention to compression
Surgical consult for enlarging hematoma,
compar tment syndrome, or cool extremit y
Prolonged compression if coughing or aor tic
insufficiency, hyper tension, or heparin not
reversed
Vascular closure device
Reverse anticoagulants
Volume replacement
Watch for hypotension, low abdominal or flank
pain within 2 to 12 hours of procedure, low
hematocrit, tachycardia (if not receiving
β- blockers)
Transfusion if hematocrit <25
Contralateral access with angiogram and
possible covered stent
Surgical consultation
Noncontrast CT scan
progresses to total blindness. It is usually transient, resolving in a
couple of days, and requires no definitive treatment.
An air embolus can occur from injection of air through the catheters. To ensure that no air is in the line, vigorous and complete flushing of the catheters should always be performed before injection with
close monitoring. Air embolus to the central nervous system may
cause the patient to show features of acute stroke, such as agitation,
confusion, or aphasia. A small air embolus usually resolves and does
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not often result in permanent damage. Significant air embolus to the
coronary circulation can cause myocardial ischemia and potential
collapse. Although hyperbaric oxygen chambers have been used successfully for treatment, these are not widely available. Patients should
be placed on high flow oxygen and given supportive care.
High-Risk Cardiac Catheterization
Management of Hypotension
Hypotension may occur before, during, and after cardiac catheterization from a variety of conditions. Before cardiac catheterization, hypotension may be caused by hypovolemia induced by fasting before the
procedure (water intake should be allowed) or diuretics.
During the procedure, hypotension may be due to vasovagal reaction. Untreated vasovagal reactions with hypotension can lead to irreversible shock. Vasovagal reactions are often elicited by pain at the
vascular access site. In some elderly patients, a vagal reaction may
occur without bradycardia and appear as unexplained hypotension.
Hypotension that develops after coronary angiography or left ventriculography is generally transient, self-limited, and responds to IV fluids.
Other considerations during the procedure include oversedation, IV
contrast allergy, or vagal reaction from a full bladder.
After the procedure, hypotension may be caused by hypovolemia,
myocardial ischemia, bleeding from the arterial access site, cardiac
tamponade, or retroperitoneal hemorrhage. Any of these can present
with bradycardia and hypotension and initially appear to be a vagal
response.
Hypotension resulting from hypovolemia is treated with IV saline
infusion. Patients often respond acutely to elevation (>30 degrees) of
the legs (increased venous inflow, “internal transfusion”). Generally,
several hundred milliliters of saline is required to restore adequate
blood pressure in patients who have hypotension caused by hypovolemia. Preprocedure prevention of hypovolemia can be avoided by IV
saline (>
administration of blood products is necessary and hemostasis must
be achieved at once. Care should be taken to prevent volume overload
in patients with CHF. If a patient’s volume status cannot be determined
clinically, a pulmonary artery catheter and pulmonary capillary wedge
pressure measurement may be necessary.
emia reaction, pharmacologic therapy may be necessary to restore
adequate blood pressure. Atropine for vasovagal hypotension
(0.5 mg IV every 3 minutes as needed) is used first. IV phenylephrine
(0.1 to 0.3 mg) or an epinephrine bolus (1 mL of 1:10,000-U dilution)
temporarily increases blood pressure to normal range while the staff
member continues to assess the patient and prepare other vasopressors. For patients with prolonged hypotension or hypotension without
hypovolemia, IV infusions of pressors may be initiated and can be
titrated up as needed. Dopamine starting at 5 mcg/kg/min or norepinephrine at 10 mcg/min can be titrated to response.
antagonize, ameliorate, or minimize the actions of the offending agent.
Narcotic-induced hypotension can be treated with administration of
naloxone (Narcan). The initial dose is 0.4 mg (1-mL ampule), which
may be repeated every 2 to 3 minutes as needed. Hypotension (or
hypoventilation) resulting from benzodiazepine administration can be
treated with flumazenil (Romazicon). The initial dose is 0.2 mg (2 mL)
administered over 30 seconds; additional doses of 0.2 mg (up to 1 mg)
can be administered every 1 minute. Due to the sedatives’ longer halflife than that of reversal agents, resedation can occur, and repeat doses
can be given every 20 minutes, with a maximum dose of 3 mg/hr.
chro notropic, and vasodilator actions of calcium channel blockers.
500 mL) for 4 to 6 hours before the start of the procedure.
For patients who have hypovolemia caused by hemorrhage,
For patients with hypotension resulting from vasovagal or isch-
Drug-induced hypotension should be addressed with agents that
Hypotension can result from negative inotropic, negative
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Vasodilator actions can be at least partially reversed by administration of calcium chloride (1 ampule, 13.6 mEq). Administration of glucagon (1 mg) may partially ameliorate the effects of β-blockers. If
nitroglycerin-induced hypotension develops, IV infusion should be
stopped or the nitropaste wiped off.
Hypotension resulting from cardiac tamponade is an emergency
condition that requires immediate pericardiocentesis.
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High-Risk Cardiac Catheterization 369
Management of Refractory Myocardial Ischemia and
Hemodynamic Instability
Transient ischemia and coronary artery occlusion can be caused by
catheter-induced spasm, cannulation of a severely diseased coronary
artery, or a severe ostial lesion. Initial intervention is removal of the
catheter from the coronary ostium. Continued myocardial ischemia
should initially be treated with pharmacologic therapy beginning with
nitrates, either sublingual nitroglycerin (0.4 mg every 5 minutes), or
IV or intracoronary nitroglycerin (100-µg boluses repeated every
5 minutes as necessary). Nitroglycerin can be used, provided that the
patient does not have hypotension. For patients with tachycardia,
negative inotropic therapy with a β-blocker, such as metoprolol
(5 mg IV every 5 minutes), or a calcium channel blocker, such as
verapamil (2.5 to 5 mg IV every 5 minutes), should be considered if
the patient is otherwise hemodynamically stable.
When ischemia persists after optimal medical treatment, or
when it is associated with significant hemodynamic instability including pulmonar y edema or hypotension or both, mechanical
assistance, usually intraaortic balloon pump (IABP) insertion, should
be considered.
Management of Arrhythmias
Serious arrhythmias (including ventricular fibrillation, ventricular
tachycardia, supraventricular tachycardia, asystole, and heart block)
occur in approximately 1% of either right- or left-sided heart catheterizations. In almost all instances, the arrhythmia can be managed
successfully by prompt recognition and treatment. Arrhythmias may
result from intracardiac catheter manipulation, intracoronary contrast
injection, or myocardial ischemia during angioplasty.
For malignant ventricular arrhythmias with hypotension, the most
important determinant of short- and long-term (neurologically intact)
survival of the patient is the interval from the onset of hemodynamic
collapse to the restoration of effective, spontaneous circulatory and
respiratory function. The following section provides suggestions for
optimal treatment. These suggestions do not preclude other measures
that may be indicated on the basis of specific clinical circumstances
of the individual patient.
Primary Prevention of Arrhythmias
Electrocardiographic Monitoring
Continuous electrocardiographic (ECG) monitoring is essential for the
performance of a safe cardiac catheterization. If a problem develops
with ECG leads or equipment during the procedure, the operator must
remedy it before the procedure continues.
Intravenous Access
Before the procedure is begun, a functioning peripheral IV line should
be established in the patient. If peripheral venous access cannot be
obtained, the operator should insert a femoral venous sheath large
enough to accommodate a pacing wire and allow rapid saline
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infusion. A ≥6-F femoral venous sheath should be placed in potentially
unstable or acutely ill patients.
High-Risk Cardiac Catheterization
Standby Transvenous Pacing
The need for a prophylactic temporary transvenous pacemaker is
determined by the patient’s risk of bradyarrhythmia or heart block and
ability to tolerate these arrhythmias should they occur. The use of
flexible, balloon-tipped, flow-directed pacemaker wires provides the
lowest risk for cardiac perforation. Risk factors for bradyarrhythmia
include the following:
1. Preexisting right bundle-branch block during left-sided heart
catheterization
2. Preexisting left bundle-branch block during right-sided heart catheterization, particularly when stiff catheters are used
3. Heart block greater than first degree
4. Marked sinus bradycardia
5. Coronary artery angioplasty involving the (dominant) artery supplying the atrioventricular (AV) node, especially when rotational
atherectomy or thrombus extraction devices are used
Limitation of Cardiac Catheter Manipulations
Catheter passage through the heart should be performed with caution
and a smooth motion. Particular note should be made of ventricular
ectopy during catheter manipulation. Vigorous stretching of the right
atrium may cause atrial arrhythmias (atrial fibrillation, supraventricular tachycardia). Ventricular arrhythmias are associated with stimulation of the right ventricular outflow tract or papillary muscles by
catheter contact. Removing the stimulating catheters usually terminates the arrhythmia.
Occlusive Engagement of Coronary Arteries
Engaged coronary catheter pressure should always be checked before
contrast medium is injected. Figure 8 -4 shows ventricularization and
damping of pressure waveforms with cannulation of coronary vessels.
Injection of contrast with damped or ventricularized waveforms
increases the risk of dissection or arrhythmia.
Limitation of Coronary Artery Contrast
Injections of contrast medium should be sufficient to opacify the arterial tree without excessive volume or rates of injection. Ionic contrast
media predispose a patient to bradycardia and ventricular fibrillation,
especially during injection of the right coronary artery. The operator
should have the patient cough when sustained hypotension is recognized before loss of consciousness (and cardiac arrest). Forceful
coughing can generate sufficient blood flow to the brain to maintain
consciousness until definitive treatment can be initiated.
Defibrillation and Cardioversion
Definitive electrical treatment has the highest priority of any modality. A defibrillator should be located near the patient in each cardiac
catheterization laboratory suite. Before the procedure is begun,
the defibrillator should be turned on with pads easily available
or conductive jelly ready to apply to the defibrillator paddles to avoid
delay in defibrillation. The time to successful defibrillation is the major
determinant of the patient’s survival. If pulseless ventricular tachycardia or ventricular fibrillation is present, defibrillation should
be performed at once. An algorithm for treatment of ventricular
fibrillation with cardiopulmonar y resuscitation (CPR) is provided in
Figure 8-5.
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High-Risk Cardiac Catheterization 371
S
S
100
D
0
A
S
S
D
D
S
D
S
S
S
D
S
S
D
D
S
D
S
D
S
D
S
D
B
Figure 8-4 A, Hemodynamic tracing showing damping of waveform upon
engagement into a coronary ostium. B, Hemodynamic tracing showing
damping with ventricularization of the pressure waveform. Injections with
these waveforms increase the risk of vessel dissection or arrhythmia. D,
Diastolic; S, systolic.
Treatment for Specific Arrhythmias
The following sequences are useful for treating a broad range of
patients with arrhythmias in the catheterization laboratory, but
sequences should be modified as the clinical situation warrants.
Vasovagal reactions, which are often preceded by a slowing of
heart rate before a decrease in blood pressure, respond dramatically to IV atropine (0.5 to 1 mg). Elevation of the patient’s legs and
infusion of saline may increase blood pressure transiently. Early signs
of vasovagal reaction include pallor, nausea, yawning, sneezing, or
coughing.
Bradycardia (ventricular heart rate <60 beats/min [bpm]) may be
caused by autonomic influences (vagal) or intrinsic disease of the
cardiac conducting system (ischemia). Atropine sulfate is the treatment of choice for symptomatic bradycardia, defined as a heart rate
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