Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3597_Библиотеки_им_академика_М_И_Перельмана
.pdf
282 6 —
https://t.me/med1917
The Electrophysiology Laboratory and Electrophysiologic Procedures
INTRACARDIAC
EPS
DEFIBRILLATION
Anterior
patch
Figure 6-11 Diagram of intracardiac defibrillation, which may be used
when ventricular fibrillation (VF) is refractor y to multiple transthoracic defibrillations. During the routine electrophysiologic study (EPS), anterior and
posterior skin patches are attached by a connector to a standard defibrillator. When multiple transthoracic high-energy shocks fail to terminate VF, the
anterior patch may be disconnected and the distal pole of the right ventricular (RV) catheter attached to the defibrillator. High-energy shocks are delivered from the RV catheter to the posterior patch. (From Cohen TJ, Scheinman
MM, Pullen BT, et al: Emergency intracardiac defibrillation for refractory
ventricular fibrillation during routine electrophysiologic study. J Am Coll
Cardiol 18:1280 –1284, 1991.)
Posterior
patch
Connector
– +
Defibrillator
Distal pole
RV catheter
Posterior
patch
Connector
– +
Defibrillator
the heart. They are indicated in patients who no longer have the
intrinsic ability to provide adequate electrical stimulation to maintain
a functional HR or complete conduction from the atria to the ventricles. They can be either single or dual chamber devices with a lead
in the atrium, ventricle, or both, depending on the patient, pathology,
and clinical scenario.
Implantable Cardiac Defibrillators
Where pacemakers are used for bradycardic indications, defibrillators
are designed to treat tachyarrhythmias, specifically ventricular tachycardia (VT) and VF. These devices have all of the functions of a
pacemaker; but in addition, they have the ability to defibrillate (shock)
the heart. The primary difference in these devices in comparison to a
pacemaker is the use of a high-voltage lead in the RV with an active
“can” (pulse generator [PG]) to complete the defibrillation circuit. The
lead has at least one shock coil and acts with the PG to provide a
defibrillation wave front across the heart if the need arises. In addition,
all current defibrillators have the ability to rapidly pace the ventricle
(anti-tachycardia pacing [ATP]) in order to attempt to terminate ventricular tachyarr ythmias and prevent the need for a shock.
When a patient with an implantable cardiac defibrillator (ICD)
undergoes a change in his or her antiarrhythmic drug regimen, the
device may need to be tested, because changes in rate of tachycardia
may necessitate reprogramming of the device’s rate detection criteria,
and changes in the defibrillation threshold may be caused by certain
medications.
Primary Prevention of Sudden Death
The survival rate after out-of-hospital cardiac arrest is extremely low,
and attention has been directed at identifying high-risk patients who
https://t.me/med1917
6 —
The Electrophysiology Laboratory and Electrophysiologic Procedures 283
may benefit from prophylactic treatment as a means of primary prevention of sudden cardiac death. Two primar y prevention trials indicated that patients with coronar y disease, significant LV dysfunction
(left ventricular ejection fraction [LVEF] 35% to 40%), spontaneous
nonsustained VT, and inducible sustained ventricular arrhythmia by
EPS experienced a survival benefit from prophylactic ICD implantation. There is no evidence that EPS-guided antiarrhythmic drug therapy
is effective as preventive therapy for sudden cardiac death in high-risk
individuals. A primary prevention trial, which that did not require
spontaneous or induced ventricular arrhythmias as entry criteria, concluded that prophylactic ICD implantation benefited patients with
coronary artery disease and found an LVEF of less than 30%. This
study suggests that poor LV function alone is a strong predictor of
subsequent sudden cardiac death. Indications for implantation of
pacemakers and ICDs are listed in Table 6-1.
Cardiac Resynchronization Therapy
In the mid 1990s, a new tool was developed to assist in the management of patients with systolic heart failure (HF): biventricular pacing
to improve systolic function. Since that time, the use of cardiac resynchronization devices has become a mainstay of an EP practice. These
devices have undergone numerous refinements with time, and as clinical trials have been published, the patient population that can benefit
from such therapy has greatly expanded (Fig. 6-12). This section provides a broad overview of cardiac resynchronization therapy (CRT)
as a common procedure performed in the EP laboratory.
Theory
HF remains an extensive and expensive problem in the United States,
and the majority of HF patients have systolic dysfunction. As systolic
dysfunction becomes progressively worse, both mechanical and electrical remodeling occurs. The electrical component manifests in the
QRS duration. As QRS duration increases, morbidity and mortality
levels from systolic dysfunction significantly increase. The electrical
delay often leads to delayed activation of the LV. Because of this delay
in activation, the septal wall is not held stable by simultaneous contraction of the LVs and RVs, leading to a less efficient contraction. This
has led to the advent of cardiac resynchronization devices to allow for
pacing of both chambers to resynchronize the contraction and stabilize the septum for a more effective LV contraction.
Implantation Procedure
The primary difference in implanting a CRT device compared with
standard pacemakers and defibrillators is in the placement of an LV
lead in a branch of the coronary sinus. This does add an additional
level of complexity to the standard implant procedure, and thus,
knowledge of the coronary sinus anatomy is essential. Given that
cardiac electrophysiologists routinely place catheters in the coronary
sinus for EPSs, they are very experienced in the intricacies of working
in this vessel and are natural implanters for these devices. The coronary sinus is often accessed via the axillary vein and a long sheath is
passed into the coronar y sinus to deliver the lead. LV leads are
designed to be wedged into a branch vessel of the coronary sinus, and
the lead tip usually has a cant or tab to help maintain the location of
the lead (Figs. 6-13, 6-14, and 6-15). Once a lead is advanced and
located in a branch of the coronary sinus, the sheath is split and
removed. The lead is sutured in place and can interface with a CRT
defibrillator (CRT-D) or CRT pacemaker (CRT-P) PG.
284 6 —
https://t.me/med1917
The Electrophysiology Laboratory and Electrophysiologic Procedures
Table 6 -1
Indications for Pacemaker and Implantable Cardiac
Defibrillator Implantation
Pacemaker
SND •
Acquired AV block
in adults
SND with documented symptomatic bradycardia,
including frequent sinus pauses that produce
symptoms (class I, LE C)
• Symptomatic chronotropic incompetence (class I,
LE C)
• Symptomatic sinus brad ycardia that results from
required drug therapy for medical conditions (class I,
LE C)
• Minimally sy mptomatic patients with chronic HR
<40 bpm while awake (class IIb, LE C)
• Not indicated for SND in asymptomatic patients
(class III, LE C)
• Not indicated for SND in patients for whom
symptoms sug gestive of bradycardia have been
clearly documented to occur in the absence of
bradycardia (class III, LE C)
• Not indicated for SND with symptomatic bradycardia
due to nonessential drug therapy (class III, LE C)
Third-degree and advanced second-degree AV block
•
at any anatomic level associated with bradycardia
with symptoms (including HF) or ventricular
arrhy thmias presumed to be due to AV block (class I,
LE C)
• Third- and advanced second- degree AV block at any
anatomic level associated with arrhy thmias and
other medic al conditions requiring drug therapy that
results in symptomatic bradyc ardia (class I, LE C)
• Third- and advanced second- degree AV block at any
anatomic level in awake, symptom -free patients in
sinus rhythm, with documented periods of asystole
≥3.0 sec, any escape rate <40 bpm, or an escape
rhythm that is below the AV node (class I, LE C)
• Third- and advanced second- degree AV block at any
anatomic level after catheter ablation of the AV
junction (class I, LE C)
• Third- and advanced second- degree AV block at any
anatomic level associated with postoperative AV
block that is not expected to resolve after cardiac
surger y (class I, LE C)
• Third- and advanced second- degree AV block at any
anatomic level associated with neuromuscular
diseases with AV block, such as myotonic muscular
dystrophy, Kearns-Sayre syndrome, Erb dystrophy
(limb-girdle muscular d ystrophy), and peroneal
muscular atrophy, with or without symptoms (class I,
LV B)
• Second- degree AV block with associated
symptomatic bradycardia regardless of the type or
site of block (class I, LE B)
• Asymptomatic per sistent third -degree AV block at
any anatomic site with average awake ventricular
rates of 40 bpm or faster if cardiomegaly or LV
dysfunction is present or the site of block is below
the AV node (class I, LE B)
• Second- or third- degree AV block during exercise in
the absence of myocardial ischemia (class I, LE C)
• Persistent third-degree AV block with an escape
rate >40 bpm in asymptomatic adult patients
without cardiomegaly (class IIa, LE C)
• Asymptomatic second- degree AV block at intra- or
infra -His levels found at EPS (class IIa, LE B)
• First- or second- degree AV block with symptoms
similar to those of pacemaker syndrome or
hemodynamic compromise (class IIa, LE B)
https://t.me/med1917
6 —
The Electrophysiology Laboratory and Electrophysiologic Procedures 285
Table 6 -1
Indications for Pacemaker and Implantable Cardiac
Defibrillator Implantation (Cont.)
• Asymptomatic type- II second-degree AV block with a
narrow QRS (class IIa, LE B)
• Neuromuscular diseases, such as myotonic
muscular dystrophy, Erb dystrophy, and peroneal
muscular atrophy with any degree of AV block
(including first-degree AV block), with or without
symptoms, because there may be unpredict able
progression of AV conduction disease (class IIb, LE B)
• AV block in the setting of drug use and/or drug
toxicit y when the block is expected to recur even
after the drug is withdrawn (class IIB, LE B)
• Not indicated for asymptomatic first-degree AV
block (class III, LE B)
• Not indicated for asymptomatic type I second-
degree AV block at the supr a-His (AV node) level or
that which is not known to be intra- or infra -Hisian
(class III, LE C)
• Not indicated for AV block that is exp ected to
resolve and is unlikely to recur (e.g., drug toxicit y,
Lyme disease, or transient increases in vagal tone
or during hypoxia in sleep apnea syndrome in the
absence of symptoms) (class III, LE B)
Chronic
bifascicular
block
After acute phase
of MI
Advanced second-degree AV block or intermittent
•
third-degree AV block (class I, LE B)
• Type II second-degree AV block (class I, LE B)
• Alternating bundle-branch block (class I, LE C)
• Syncope not demonstr ated to be due to AV block
when other likely causes have been excluded,
specifically VT (class IIa, LE B)
• Incidental finding at EPS of a markedly prolonged
H–V inter val (≥100 msec) in asymptomatic patients
(class IIa, LE B)
• Incidental finding at EPS of pacing-induced infra -His
block that is not physiological (class IIa, LE B)
• In the setting of neuromuscular diseases, such as
myotonic muscular dystrophy, Erb dystrophy, and
peroneal muscular atrophy with bifascicular block or
any fascicular block, with or without symptoms
(class IIb, LE C)
• Not indicated for fascicular block without AV block
or sy mptoms (class III, LE B)
• Not indicated for fascicular block with first-degree
AV block without symptoms (class III, LE B)
Persistent second -degree AV block in the His-
•
Purkinje system with alternating bundle- branch
block or third- degree AV block within or below the
His- Purkinje system af ter STEMI (class I, LE B)
• Transient advanced second- or third-degree
infranodal AV block and associated bundle-branch
block. If block site is uncertain, an EPS may be
necessary (class I, LE B)
• Persistent and sy mptomatic second- or third -degree
AV block (class I, LE C)
• Persistent second - or third-degree AV block at the
AV node level, even in the absence of symptoms
(class IIb, LE B)
• Not indicated for transient AV block in the absence
of intraventricular conduction defects (class III, LE B)
• Not indicated for transient AV block in the presence
of isolated left anterior fascicular block (class III, LE B)
• Not indicated in new bundle-branch block or fascicular
block in the absence of AV block (class III, LE B)
• Not indicated for persistent asymptomatic
first- degree AV block in the presence of bundlebranch or fascicular block (class III, LE B)
Continued
286 6 —
https://t.me/med1917
The Electrophysiology Laboratory and Electrophysiologic Procedures
Table 6 -1
Indications for Pacemaker and Implantable Cardiac
Defibrillator Implantation (Cont.)
Hypersensitive
carotid sinus
syndrome and
neurocardiogenic
syncope
After cardiac
transplantation
Recommendations
for permanent
pacemakers that
automatically
detect and pace
to terminate
tachycardias
Pacing to prevent
tachycardia
Pacing to prevent AF•
Recommendations
for pacing in
patients with
HCM
• Recurrent syncop e caused by spontaneously
occurring carotid sinus stimulation and carotid
sinus pressure that induces ventricular asystole of
>3 sec (class I, LE C)
• Syncope without clear, provocative events and with
a hypersensitive cardioinhibitor response of ≥3 sec
(class IIa, LE C)
• Significantly symptomatic neurocardiogenic syncope
associated with bradycardia documented
spontaneously or at the time of tilt-table testing
(class IIb, LE B)
• Not indicated for a hypersensitive cardioinhibitory
response to carotid sinus stimulation without
symptoms or with vague symptoms (class III, LE C)
• Not indicated for situational vasovagal syncope in
which avoidance behavior is ef fective and preferred
(class III, LE C)
Persistent inappropriate or sy mptomatic br adycardia
•
not expected to resolve and for other class I
indications for permanent pacing (class I, LE C)
• When relative bradycardia is prolonged or recurrent,
which limits rehabilitation or discharge af ter
postoperative recovery from cardiac tr ansplantation
(class IIb, LE C)
• Syncope after cardiac transplantation even when
bradyarrhy thmia has not been documented (class
IIb, LE C)
Symptomatic recurrent SVT that is reproducibly
•
terminated by pacing when catheter ablation and/or
drugs fail to control the arrhy thmia or produce
intolerable side effects (class IIa, LE C)
• Not indicated in the presence of an accessory
pathway that has the capacity for rapid anterograde
conduction (class III, LE C)
Sustained pause-dependent VT with or without Q–T
•
prolongation (class I, LE C)
• High -risk patients with congenital LQTS (class IIa,
LE C)
• For prevention of symptomatic, drug-refractory,
recurrent AF in patients with coexisting SND (class
IIb, LE B)
• Not indicated for frequent or complex ventricular
ectopic activity without sustained VT in the absence
of LQTS (class III, LE C)
• Not indicated for torsades de p ointes VT due to
reversible causes (class III, LE A)
Not indicated for the prevention of AF in patients
without any other indication for pacemaker
implant ation (class III, LE B)
SND or AV block in patients with HCM as described
•
previously in guidelines (class I, LE C)
• Medically refrac tory symptomatic patients with HCM
and significant resting or provoked LV outflow tract
obstruction (class IIa, LE A)
• Not indicated for patients who are asymptomatic or
whose symptoms are medically controlled (class III,
LE C)
• Not indicated for symptomatic patients without
evidence of LV out flow tract obstr uction (class III,
LE C)
https://t.me/med1917
6 —
The Electrophysiology Laboratory and Electrophysiologic Procedures 287
Table 6 -1
Indications for Pacemaker and Implantable Cardiac
Defibrillator Implantation (Cont.)
Recommendations
for permanent
pacing in
children,
adolescents, and
patients with
congenital heart
disease
• Advanced second- or third-degree AV block
associated with symptomatic bradycardia,
ventricular dysfunction, or low cardiac output
(class I, LE C)
• SND with correlation of symptoms during age -
inappropriate bradycardia; the definition of
bradycardia varies with patient age and expected
HR (class I, LE B)
• Postoperative advanced second- or third- degree AV
block that is not expected to resolve or that
persists for at least 7 days af ter cardiac surger y
(class I, LE B)
• Congenital third -degree AV block with a wide QRS
escaped rhythm, complex ventricular ectopy, or
ventricular dysfunction (class I, LE B)
• Congenital third -degree AV block in an infant with a
ventricular rate <55 bpm or with congenital heart
disease and a ventricular rate <70 bpm (class I,
LE C)
• Congenital heart disease and sinus bradycardia for
the prevention of recurrent episodes of intraatrial
reentr ant tachycardia; SND may be intrinsic or
secondary to antiarrhythmic treatment (class IIa,
LE C)
• Congenital third -degree AV block beyond the first
year of life with an average HR <50 bpm, abrupt
pauses in ventricular rate that are two or three
times the basic cycle length, or association with
symptoms due to chronotropic incompetence (class
IIa, LE B)
• Sinus bradycardia with complex congenital heart
disease with a resting HR <4 0 bpm or pauses in
ventricular rate >3 sec (class IIa, LE B)
• Congenital heart disease and impaired
hemodynamics due to sinus br adycardia or loss of
AV synchrony (class IIa, LE C)
• Unexplained syncope in the patient with prior
congenital heart surgery complicated by transient
CHB with residual fascicular block after a careful
evaluation to exclude other causes of syncope
(class IIa, LE B)
• Transient postoperative third- degree AV block that
reverts to sinus rhythm with residual bifascicular
block (class IIb, LE C)
• Congenital third -degree AV block in asymptomatic
children or adolescents with an acceptable rate,
narrow QRS complex, and normal ventricular
function (class IIb, LE B)
• Asymptomatic sinus bradycardia af ter biventricular
repair of congenital heart disease with a resting HR
<40 bpm or pauses in ventricular rate >3 sec (class
IIb, LE C)
• Not indicated for transient postoperative AV block
with return of normal AV conduction in an otherwise
asymptomatic patient (class III, LE B)
• Not indicated for asymptomatic bif ascicular block
with or without first- degree AV block after surgery
for congenital heart disease in the absence of prior
transient complete AV block (class III, LE C)
• Not indicated for asymptomatic type I second-
degree AV block (class III, LE C)
• Not indicated for asymptomatic sinus bradycardia
with the longest relative risk interval <3 sec and a
minimum HR >40 bpm (class III, LE C)
Continued
288 6 —
https://t.me/med1917
The Electrophysiology Laboratory and Electrophysiologic Procedures
Table 6 -1
Indications for Pacemaker and Implantable Cardiac
Defibrillator Implantation (Cont.)
Implantable Cardiac Defibrillator
Sur vivors of cardiac arrest due to VF or hemodynamically unstable
•
sustained V T af ter evaluation to define cause of event and exclude any
completely reversible causes (class I, LE A)
• Structural heart disease and spontaneous sustained VT, whether
hemodynamically st able or unstable (class I, LE B)
• Syncope of undetermined origin with clinically relevant, hemodynamically
significant sustained VT or VF induced at EPS (class I, LE B)
• LVEF ≤ 35% due to prior MI, at least 4 0 days postmyocardial infarction,
and NYHA functional class II or III (class I, LE A)
• Nonischemic dilated cardiomyopathy, LVEF ≤ 35%, and N YHA functional
class II or III (class I, LE B)
• LV dysfunction due to prior MI or at least 40 days postmyocardial
infarction, LVEF ≤30%, and NYHA functional class I (class I, LE A)
• Nonsustained VT due to prior MI, LVEF ≤40%, and inducible VF or
sustained V T at EPS (class I, LE B)
• Unexplained syncope, significant LV dysfunction, and nonischemic
dilated cardiomyopathy (class IIA, LE C)
• Sustained VT and normal or near-normal ventricular function (class IIA,
LE C)
• HCM with one or more major risk factors for sudden cardiac death (class
IIA, LE C)
• Prevention of sudden cardiac death, with ARVC or ARVD and one or
more risk factors for sudden cardiac death (class IIA, LE C)
• Reduction of sudden cardiac death, with LQTS, syncope, and/or VT while
receiving β -blockers (class IIa, LE B)
• Nonhospitalized and awaiting transplantation (class IIA, LE C)
• Brugada syndrome and prior syncope (class IIA, LE C)
• Brugada syndrome and documented VT that has not resulted in cardiac
arrest (class IIa, LE C)
• Catecholaminergic polymorphic VT, syncope, and/or documented
sustained V T while receiving β-blockers (class IIa, LE C)
• Cardiac sarcoidosis, giant cell myocarditis, or Chagas disease (class IIa,
LE C)
• Nonischemic hear t disease, LVEF ≤35%, NYHA functional class I (class
IIb, LE C)
• LQTS and risk factors for sudden cardiac death (class IIb, LE B)
• Syncope and advanced structural heart disease with thorough invasive
and noninvasive investigation failing to define cause (class IIb, LE C)
• Familial cardiomyopathy associated with sudden death (class IIb, LE C)
• LV noncompaction (class IIb, LE C)
• Not indicated in those without reasonable exp ectation of sur vival, with
acceptable functional status for at least 1 year even after meeting ICD
implant ation criteria specified in class I, IIa, and IIb recommendations
above (class III, LE C)
• Symptomatic sustained VT in association with congenital hear t disease,
with prior hemod ynamic and EP evaluation; catheter ablation or surgical
repair may offer possible alternatives in carefully selected patients
(class I, LE C)
• Congenital heart disease with recurrent syncope of undetermined origin
in the presence of either ventricular dysfunc tion or inducible ventricular
arrhy thmias at EPS (class IIa, LE B).
• Recurrent syncop e associated with complex congenital hear t disease
and advanced systemic ventricular dysfunction after thorough invasive
and noninvasive investigations have failed to define a cause (class IIb,
LE C)
AF, Atrial fibrillation; AV, atrioventricular; AVRC, arrhy thmogenic right-ventricular
cardiomyopathy; AVRD, arrhy thmo genic right- ventricular dysplasia; bpm, beats per
minute; CHB, complete heart block; EP, electrophysiologic; EPS, elec trophysiologic
study; HCM, hypertrophic cardiomyopathy; HF, heart failure; HR, hear t rate; ICD,
implantable cardiac defibrillator; LE, level of evidence; LQTS , long QT syndrome;
LV, left ventricle; LVEF, left ventricular e jection fraction; MI, myocardial infarction;
NYHA, New York Heart Association; QRS, Q, R, and S waves; SND, sinus node
dysfunction; STEMI, ST-seg ment elevatio n myocardial infar ction; SVT,
supraventricular tachycar dia; VF, ventri cular fibrillat ion; V T, ventricular tachycardia.
although patients may not experience immediate symptomatic benefit, late remodeling
https://t.me/med1917
6 —
The Electrophysiology Laboratory and Electrophysiologic Procedures 289
Patient with cardiomyopathy on GDMT for ≥3 mo or on GDMT and ≥40 d after MI,
or with implantation of pacing or defibrillation device for special indications
LVEF ≤35%
Evaluate general health status
Acceptable noncardiac health
Evaluate NYHA clinical status
NYHA Class I
• LVEF ≤30%
• QRS ≥150 msec
• LBBB pattern
• Ischemic
cardiomyopathy
• QRS ≤150 msec
• Non-LBBB
pattern
NYHA Class II
• LVEF ≤35%
• QRS ≥150 msec
• LBBB pattern
• Sinus rhythm
• LVEF ≤35%
• QRS 120–149
msec
• LBBB pattern
• Sinus rhythm
• LVEF ≤35%
• QRS ≥150 msec
• Non-LBBB
pattern
• Sinus rhythm
• QRS ≤150 msec
• Non-LBBB
pattern
Comorbidities and/or
frailty limit survival
with good functional
capacity to <1 y
NYHA Class III &
Ambulatory
Class IV
• LVEF ≤35%
• QRS ≥150 msec
• LBBB pattern
• Sinus rhythm
• LVEF ≤35%
• QRS 120–149
msec
• LBBB pattern
• Sinus rhythm
• LVEF ≤35%
• QRS ≥150 msec
• Non-LBBB
pattern
• Sinus rhythm
• LVEF ≤35%
• QRS 120–149
msec
• Non-LBBB
pattern
• Sinus rhythm
Continue
GDMT without
implanted
device
Special CRT
Indications
• Anticipated to
require frequent
ventricular
pacing (>40%)
• Atrial fibrillation,
if ventricular
pacing is
required and
rate control will
result in near
100% ventricular
pacing with CRT
Colors correspond to the class of recommendations in the ACCF/AHA Table 1.
Benefit for NYHA class I and II patients has only been shown in CRT-D trials, and
may be avoided along with long-term HF consequences. There are no trials that
support CRT pacing (without ICD) in NYHA class I and II patients. Thus, it is
anticipated that these patients would receive CRT-D unless clinical reasons or
personal wishes make CRT pacing more appropriate. In patients who are NYHA
class III and ambulatory class IV, CRT-D may be chosen, but clinical reasons and
personal wishes may make CRT pacing appropriate to improve symptoms and
quality of life when an ICD is not expected to produce meaningful benefit in survival.
Figure 6-12 Indications for biventricular pacing. ACCF/AHA, American
College of Cardiology Foundation/American Heart Association; CRT, cardiac
resynchronization therapy; CRT-D, cardiac resynchronization therapy defibrillator; GDMT, guideline-determined medical therapy; HF, heart failure;
ICD, implantable cardiac defibrillator, LBBB, left bundle- branch block;
LVEF, left ventricular ejection fraction; MI, myocardial infarction; NYHA, New
York Heart Association. (From Tracy CM, Epstein AE, Darbar D, et al: 2012
ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008
guidelines for device-based therapy of cardiac rhy thm abnormalities: a
repor t of the American College of Cardiology Foundation/American Heart
Association Task Force on Practice Guidelines and the Heart Rhythm
Society. J Am Coll Cardiol 61[3]:e6 –e75, 2013.)
290 6 —
https://t.me/med1917
The Electrophysiology Laboratory and Electrophysiologic Procedures
Medtronic Attain® Left-Heart Leads
Attain Select™ II + SureValve® compatible**
®
™
Performa
Attain
Model 4598
5.3 Fr Offset S
Large Veins Small Tortuous
Attain Select™ II + SureValve
Attain Ability®
Plus Lead
Model 4296
5.3 Fr, dual electrode*
Figure 6-13
Attain Star-
®
Fix
Lead
Model 4195
5 Fr, unipolar
Examples of LV leads. (Reproduced with permission of
Attain Performa
Model 4298
5.3 Fr, dual bend
Attain Ability
Lead
Model 4196
4 Fr, dual electrode*
Attain Performa
Model 4398
5.3 Fr, straight
with tines
®
compatible**
Attain Ability
Straight Lead
Model 4396
4 Fr, dual electrode*
Vessels
* Dual cathode
** Leads ≥ 88 cm length
Medtronic, Inc.)
Figure 6-14 Examples of LV leads. (From Boston Scientific Corporation.)
Not only is it necessary to find a branch vein of the coronary sinus
to accept the lead, location of the lead is also very important. Subgroup analyses of many major trials have investigated the importance
of lead location and found that patients obtain the most benefit from
a basilar location on the posterior or lateral LV. Anterior placement of
the lead does not provide benefit due to the lack of distance between
LV and RV pacing (apical RV) locations, so true resynchronization
does not occur. In addition, an apical placement of the lead has been
shown to be harmful because patients tend to benefit less on subgroup
analyses.
https://t.me/med1917
6 —
The Electrophysiology Laboratory and Electrophysiologic Procedures 291
Figure 6-15 E xample of an LV lead. (EnSite, Velocity, Quartet, SJM Confirm
and St. Jude Medical are trademarks of St. Jude Medical, Inc. or its related
companies. Reprinted with permission of St. Jude Medical, © 2015. All
rights reserved.)
Figure 6-16 Example of an implantable cardiac monitor. (Reproduced with
permission of Medtronic, Inc.)
With the higher complexity of implanting a LV lead comes a
higher level of complications from the procedure. Procedure times
tend to be longer for CRT device implantation when compared with
dual chamber devices. In addition, a third lead increases the risk of
short-term and long-term mechanical problems. Lead dislodgement
occurs at a higher rate due to the passive mechanisms used to retain
the lead in place. Oftentimes, the number of possible branches available is limited in any given patient who can accept a lead, and pacing
thresholds can frequently be elevated compared with acceptable
thresholds for RA and RV leads. Diaphragmatic stimulation can also
be a problem, because branches from the coronary sinus can traverse
very near the phrenic nerve, which can allow stimulation from the LV
lead. However, even with the higher level of complications, the benefit
from such resynchronization therapy can be substantial and in most
patients these additional risks are easily justified.
Implantable Cardiac Monitors
The use of implantable cardiac monitors has recently grown in popularity as the size of devices has been reduced and the implantation
procedure simplified. Implantable cardiac monitors, also known as
loop recorders, can record and store arrhythmias. They are implanted
subcutaneously and generally have a batter y life of approximately 3
years. Such devices can be useful for patients with rare symptoms, in
whom traditional monitoring is unlikely to provide a diagnosis, or with
patients unwilling or unable to wear traditional noninvasive monitors.
A relatively new indication for these monitors has been in the area of
cryptogenic stroke. A significant portion of cr yptogenic strokes is
caused by asymptomatic paroxysmal AF. The implantable cardiac
monitor provides a method to monitor these patients for AF. A diagnosis of this arrhythmia would change therapy for the stroke with the
initiation of anticoagulation (Figs. 6-16 and 6-17).
Соседние файлы в папке Библиотека им академика М.И. Перельмана