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Original Contribution
Electrophysiological Evaluation of Atrioventricular Conduction
Disturbances in Transcatheter Aortic Valve Implantation With
Edwards SAPIEN Prosthesis
Abdurrahman Eksik, MD1, Mehmet Gul, MD1, Huseyin Uyarel, MD2, Ozgur Surgit, MD1, Aydin Yildirim, MD1,
Nevzat Uslu, MD1, Huseyin Aksu, MD1, Selahattin Turen, MD1, Fazih Uzun, MD1, Hulusi Satılmısoglu, MD1,
Mustafa Kemal Erol, MD1, Ihsan Bakir, MD3
valve replacement. Not surprisingly, AV conduction disturbance
can also occur with TAVI, presumably as a consequence of the
pressure applied on the conducting tissues located subendocardially in the left ventricular (LV) outflow tract and interventricular
septum.4 Some clinical and electrocardiographic (ECG) predictors of AV block have already been reported. It’s well known that
AV conduction disturbances and permanent pacemaker (PPM)
requirement are more frequent after CoreValve versus Edwards
SAPIEN implantation. There are a lot of studies about the electrophysiological changes of AV conduction in CoreValve prosthesis.5,6 However, there is no available information regarding
EPS changes on AV conduction with the Edwards SAPIEN prosthesis. The aim of this study was to analyze the effects of Edwards
SAPIEN implantation on AV conduction.
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Abstract: Aims. Permanent pacemaker requirement is a known
complication after transcatheter aortic valve implantation (TAVI). The
aim of the present study was to analyze the effects of Edwards SAPIEN
prosthesis implantation on atrioventricular conduction. Methods. The
study included 28 patients who underwent TAVI due to severe aortic
valve stenosis. An electrophysiological study was performed in the catheterization room immediately before the initial balloon valvuloplasty
and immediately after Edwards SAPIEN prosthesis implantation. Results. His-ventricle interval was significantly prolonged postprocedure
(55.9 ± 11.5 ms) vs preprocedure (47.3 ± 7.8 ms) (P<.001). The antegrade Wenckebach point was observed to be significantly prolonged
postprocedure (354.4 ± 41.3 ms) vs preprocedure (333.7 ± 45.4 ms)
(P=.001). Despite atrial-His interval prolongation, it was not statistically
significant. After the procedure, we observed significant conduction disturbances in 3 patients (10.7%). These conduction problems recovered
before discharge. One of the patients (3.6%) with right bundle branch
block + left anterior fascicular block required permanent pacemaker
implantation. At postprocedure electrocardiogram, QRS duration increased, QRS axis shifted to the left, and both of the values became
normal before discharge. The patient’s echocardiographic and clinical
parameters were improved during follow-up. Conclusion. The effect of
Edwards SAPIEN on the conduction system was mostly infranodal and
temporary. The physical properties of the Edwards SAPIEN prosthesis
may explain this observation. This complication may be lessened if the
frame height characteristics can be improved.
J INVASIVE CARDIOL 2013;25(6):305-309
Key words: electrophysiological study, conduction disturbances,
TAVI, Edwards SAPIEN prosthesis
Transcatheter aortic valve implantation (TAVI) has become
an alternative therapy for patients who have severe aortic stenosis (AS) and are at high risk for surgery.1 Despite continuous improvements in operator expertise and device technology,
complications associated with TAVI are common.2,3 Atrioventricular (AV) block is a known complication of surgical aortic
From the 1Istanbul Mehmet Akif Ersoy Thoracic – Cardiovascular Surgery Training
and Research Hospital Cardiology Department, Istanbul, Turkey, 2Bezmialem Vakif
University, School Of Medicine, Cardiology Department, Istanbul, Turkey, and 3Istanbul Mehmet Akif Ersoy Thoracic – Cardiovascular Surgery Training and Research
Hospital Cardiovascular Surgery Department, Istanbul, Turkey.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest
regarding the content herein.
Manuscript submitted December 26, 2012, provisional acceptance given January 2,
2013, final version accepted February 6, 2013.
Address for correspondence: Mehmet Gul, MD, Istanbul Mehmet Akif Ersoy Hastanesi, Istasyon Mah.Turgut Ozal Bulvarı No:11, Kucukcekmece-Istanbul 34303. Email:
[email protected]
Vol. 25, No. 6, June 2013
Methods
This study included 28 patients (11 males, 17 females; mean
age, 77.5 ± 4.8 years) undergoing TAVI between October 2010
and February 2012. Patients received new-generation balloonexpandable Edwards SAPIEN XT by the transfemoral (n =
27) and transapical (n = 1) approaches. After TAVI, the mean
follow-up time was 9.9 months. All patients had severe AS and
New York Heart Association (NYHA) class III or IV symptoms
and were at high risk for surgery due to comorbidities such as
chronic obstructive pulmonary disease, pulmonary hypertension, peripheral artery disease, and low ejection fraction. The
decision to do TAVI was rendered by a consensus at the heart
team meeting. Preoperative risk was assessed on the basis of
either the European System for Cardiac Operative Risk Evaluation (EuroSCORE) or the Society of Thoracic Surgeons (STS)
risk calculator system.7,8 In the absence of other contraindications to surgical valve replacement, high-risk status was defined
as a logistic EuroSCORE of >20% or an STS score of >10%.
Hypertension was defined as the use of antihypertensive
medications, or the detection of systolic blood pressure >140
mm Hg, or diastolic blood pressure >90 mm Hg in at least
two separate measurements. Diabetes mellitus was defined
based on a previous diagnosis requiring the use of diet or antidiabetic drugs, or by a fasting venous blood glucose level of
126 mg/dL on two occasions in previously untreated patients.
Body mass index was calculated as weight in kilograms divided
by the square of the height in meters. Contrast-induced nephropathy was defined as an increase in serum creatinine level
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EKSIK, et al.
system (CardioTek) was utilized for the procedure, and 1-quadripole catheters were placed across the tricuspid annulus to record His bundle activation. Atrial-His (AH) and His-ventricle
(HV) were measured on records before balloon valvuloplasty
from intracardiac catheter in His region and after placement
of the valve. Antegrade AV node function was assessed with
atrial pacing and extra stimuli. The following parameters were
considered to be normal: an AH interval of <125 ms; an HV
interval of ≤55 ms; and a Wenckebach AV block point of <450
ms. All patients were followed for at least 2 days with temporary transvenous pacemakers.
Statistical analysis. Statistical analysis was performed using the statistical software SPSS 17.0 for Windows (SSPS Inc).
Data were expressed as mean ± standard deviation for continuous variables, and as numbers with corresponding percentages
for categorical variables. The paired sample test was used to
compare the pre- and postprocedural results. A P-value <.05
was considered significant.
Results
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≥0.5 mg/dL or ≥25% from baseline (admission) within 72
hours of radiocontrast administration.
Exclusion criteria were as follows: a narrow or too wide annulus of the aortic valve (≤18 mm or ≥25 mm) on echocardiography, an aortic valve area of more than 0.8 cm2, a short
distance between the main coronary artery and aortic valve (for
Edwards SAPIEN prosthesis <8 mm), severe left ventricular
systolic dysfunction (ejection fraction <20%), acute coronary
syndrome, a history of renal or liver disease, malignancy, hematologic disorders, acute or chronic infection, and a life expectancy of <12 months due to non-cardiac causes. The study was
approved by the local ethics committee, and all patients gave
informed consent.
Severity of AS, aortic valve structure, and the aortic root
were evaluated by transthoracic and transesophageal echocardiography (General Electric Vivid 7 GE Vingmed Ultrasound
AS). Echocardiographic measurements were performed in the
left lateral decubitus position according to the criteria of the
American Society of Echocardiography.9 Multislice computed
tomography and angiography were performed to assess the aortic root-arch calcification, diameters of the femoral and iliac
arteries, and calcifications and tortuosities. The procedure was
accomplished under general anesthesia in 17 patients and under mild sedation in 11 patients. Access was gained by a surgical cutdown in 16 patients, and a percutaneous closure device
(Prostar XL) was used in 12 patients.
Procedure. The TAVI procedure was performed in a sterile
environment (catheterization laboratory) under general or local
anesthesia. The femoral artery with a greater diameter and less
tortuosity was selected. Two sheaths were placed in the contralateral femoral artery and femoral vein for placement of a pigtail
catheter in the aorta and a pacemaker lead in the right ventricle,
respectively. Balloon predilation was performed in all of the patients. For a proper procedure, the balloon was predilated after
passing the native valve with a straight-tip guidewire and an Amplatzer left guide catheter. During balloon predilatation, ventricular tachycardia was induced by rapid ventricular pacing, providing an optimal reduction in cardiac output by creating a transient
cardiac standstill. This was usually achieved at a heart rate of 200
bpm. The Edwards SAPIEN prosthesis was then passed through
the delivery systems and expanded at the level of the native valve.
Rapid ventricular pacing was repeated at that stage in patients
receiving the prosthesis. The aortic root and peripheral arteries
were evaluated after the intervention by contrast injection into
the aortic root and by peripheral angiography.
Electrophysiological study. A 7 Fr sheath was placed into
the femoral vein for electrophysiological study (EPS), which
was implemented in the catheterization room immediately before the initial balloon valvuloplasty and immediately after Edwards SAPIEN prosthesis implantation. Atrial and ventricular
refractory periods were not measured because of the risk for arrhythmia induction, nor did we appraise sinus node functions
in order not to prolong the procedure. No patients received
medications likely to have potential effect on the conduction
system. The patients were hemodynamically stable before and
after the procedure and during the measurements, and no patients took positive inotropic agent. The portable EP Tracer
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Baseline demographic and clinical parameters are given in
Table 1. The mean age was 77.5 ± 4.8 years, and 17 patients
(60.7%) were female. Procedural complications of the patients
are given in Table 2. All devices were properly positioned and
valves were found to be properly functioning on postprocedural angiographic and echocardiographic evaluations. PPM
implantation was required in 1 patient due to atrioventricular
conduction abnormalities. Peripheral arterial injuries occurred
in 4 patients. Coronary artery occlusion occurred in 1 patient.
No paravalvular aortic regurgitation of greater than grade +3-4
was observed. Five patients developed contrast nephropathy.
One patient developed a clinical stroke. At the 1-month echocardiographic follow-up, both the aortic valve area and the left
ventricular ejection fraction significantly increased, with significant decreases in the transvalvular (peak systolic and mean)
gradients. At the 4-month follow-up, the overall mean NYHA
functional class score decreased significantly.
EPS study parameters before and after the procedure are
given in Table 3. The HV interval significantly increased after the procedure (55.9 ± 11.5 ms) compared to the interval
before the procedure (47.3 ± 7.8 ms; P<.001). The antegrade
Wenckebach point was also observed to be significantly more
elongated after the procedure (354.4 ± 41.3 ms) than before
(333.7 ± 45.4 ms; P=.001). We were unable to measure the
AH interval in 5 of our patients because they had atrial fibrillation. We performed statistical analysis of the AH interval in
the remaining 23 patients. AH interval was prolonged, but it
was not statistically significant. AH interval, HV interval, and
antegrade Wenckebach points of patients before and after the
procedure are illustrated explicitly in Figures 1, 2, and 3.
The baseline ECG cardiac conduction parameters of the
28 patients and the postprocedural changes in cardiac conduction following the procedure and at discharge are shown
in Table 4. Preprocedurally, 5 patients were in atrial fibrillation. Eleven patients had one or more AV conduction disturbances, with left bundle branch block (LBBB; 3 patients) and
right bundle branch block (RBBB; 4 patients) being the most
The Journal of Invasive Cardiology®
Edwards SAPIEN Prosthesis and Conduction Disturbances
Table 1. Demographic and clinical parameters of the patients
at baseline (n = 28).
Age (years)
77.5 ± 4.8
Gender (female)
17 (60.7%)
Body mass index (kg/m2)
27.1 ± 5.3
Logistic EuroSCORE (%)
21.9 ± 5.9
Contrast (mL)
209.8 ± 45.9
Fluoroscopy time (minutes)
23.3 ± 5.6
Length of stay in intensive care (hours)
60.8 ± 26.1
Anesthesia (local)
11 (39.3%)
Arterial hemostasis (percutaneous: prostar XL)
12 (42.9%)
Previous cardiac surgery (aortocoronary bypass graft)
10 (35.7%)
Peripheral vascular disease
13 (46.4%)
Diabetes mellitus
11 (39.3%)
21 (75%)
Stroke history
1 (3.6%)
Coronary artery disease
Atrial fibrillation
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Chronic pulmonary disease
Pulmonary hypertension
Postprocedure permanent pacemaker implantation
1 (3.6%)
Contrast-induced nephropathy
5 (17.9%)
Procedure stroke
1 (3.6%)
Postprocedural renal failure requiring dialysis
22 (78.6%)
4 (14.3%)
Procedure coronary obstruction
1 (3.6%)
Follow-up mortality
2 (7.1%)
Postprocedural paravalvular aortic regurgitation
0
7 (25%)
+1
18 (64.3%)
+2
3 (10.7%)
+3-4
Table 3. Electrophysiological study parameters before and
after procedure.
5 (17.9%)
819.8 ± 113.4
.88
119.1 ± 32.9
.25
47.3 ± 7.8
55.9 ± 11.5
<.001
333.7 ± 45.4
354.4 ± 41.3
.001
Mitral regurgitation ≥ 3, 4
4 (14%)
HV (ms)
GFR (MDRD) <60 mL/min/1.73 m2
12 (42.9%)
NYHA functional class 3
17 (60.7%)
Follow-up period (months)
11 (39.3%)
9.9 ± 5.05
Data are given as mean ± standard deviation or as number (%).
EuroSCORE = European for cardiac operative risk evaluation; NYHA =
New York Heart Association; GFR = glomular filtration rate; MDRD =
modification of diet in renal disease.
frequent conduction problem, followed by first-degree AV block
(2 patients), left anterior fascicular block (LAFB; 1 patient), and
RBBB + LAFB (1 patient). Three patients (10.7%) had conduction problems; 1 third-degree AV block, 1 second-degree AV
block, and 1 intraventricular conduction defect were identified.
These conduction problems recovered before discharge. One patient with RBBB + LAFB required PPM implantation because
of symptomatic bradycardia. Immediately after the procedure,
QRS duration increased, and the QRS axis shifted to the left;
both of the values normalized before discharge.
Discussion
This is the first study to examine EPS and ECG changes in
TAVI procedures with the Edwards SAPIEN prosthesis. Despite the conduction disturbances observed in EPS and ECG
immediately after the procedure (10.7%), patients recovered
before discharge. Moreover, the conduction defects were
chiefly infranodal and temporary. Only 1 patient required
PPM implantation (3.6%).
Vol. 25, No. 6, June 2013
PValue
81.8 ± 16.9
4 (14%)
8 (28.6%)
After
TAVI
817.9 ± 106
Left ventricular ejection fraction <40%
Prior to and during the PCI on TAVI
Before
TAVI
BCL (ms)
AH interval (ms)
NYHA functional class 4
0 (0%)
Data are given as mean ± standard deviation or as number (%).
19 (67.9%)
13 (46.4%)
0 (0%)
Procedure vascular complications (access side)
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Hypertension
Table 2. Procedural complications of the patients (n = 28).
Antegrade Wenckebach
points (ms)
BCL = basal cycle length; AH = atrial-His interval; HV = His-ventricle interval.
There are currently two percutaneous heart valves in clinical
trials: the balloon-expandable Cribier-Edwards and Edwards
SAPIEN prosthesis (Edwards Lifesciences), and the self-expanding CoreValve (Medtronic). PPM implantation has been
reported in 3%-9% of patients undergoing surgical aortic valve
replacement.10-12 PPM implantation among patients undergoing TAVI is not uncommon. Previous studies have reported
PPM implantation rates ranging from 5%-43%, with an increased incidence among patients receiving the CoreValve prosthesis (18%-43%), as compared with patients treated with the
Edwards SAPIEN prosthesis (5%-22%).13-19 At our center, we
determined that the patients with CoreValve prostheses more
frequently required PPM implantation.20
The atrioventricular conduction system passes superficially
through the interventricular septum immediately below the aortic valve. Injury during valve implantation may result in partial
or complete AV heart block. Several predictors of AV conduction disturbances necessitating PPM implantation after TAVI
have been described, including advanced age, RBBB at baseline,
prosthesis oversizing, increased septal wall thickness, deep valve
implantation (>6 mm below the annular plane), non-coronary
cusp thickness, and the degree of calcification.13,21,22
In our study, 1 patient with RBBB + LAFB required PPM implantation. Similar to our study, Rubin et al evaluated EPS and
ECG findings before and after TAVI in 18 patients who received
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Figure 1. Atrial-His (AH) intervals of 23 patients without atrial fibrillation pre- and postprocedure indicated as preAH and postAH. There was no
statistically significant difference between mean AH intervals pre- and postprocedure (81.8 ± 16.9 ms and 119.1 ± 32.9 ms, respectively; P=.25).
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CoreValve prosthesis implantation. They evaluated AH and HV
intervals from EPS and QRS, and PR intervals and the QRS axis
from ECG. They found significantly prolonged AH, HV, QRS,
and PR intervals, and the QRS axis shifted to the left. Following the procedure, 78% of patients had conduction problems and
most of them were permanent. CoreValve implantation worsens
AV conduction in most patients, either transiently or permanently.
This is the result of direct damage either to the His bundle or the
AV node. In their study, no differences were found in hemodynamic parameters, such as arterial pressure and heart rate before and
after the procedure, or in sinus function parameters. Therefore, an
autonomic effect is unlikely to be responsible for the changes. The
QRS axis shift was thought to be associated with edema and the
implanted valve’s proximity to the left conduction system.
In our study, mean HV intervals were 47.3 ± 7.8 ms and
55.9 ± 11.5 ms (P<.001) before and after the procedure, respectively. HV interval was significantly prolonged after the
procedure. The PPM implanted patients had a significantly
prolonged HV interval (from 45 ms to 75 ms). At ECG after
the procedure, a significantly prolonged QRS interval and a
QRS axis shift to the left were noted. Despite prolongation
of AH, there was no significant difference noted in the PR
interval. The 3 patients (10.7%) with conduction defects regressed during follow-up. Our study revealed that Edwards
SAPIEN prosthesis had less effect on conduction system than
the CoreValve. These effects on the conduction system as a
result of Edwards SAPIEN prosthesis may be due to indirect
mechanisms such as edema or local inflammation, rather than
direct pressure (as in the case of the CoreValve). The mean
length of the CoreValve was 53-55 mm; however, the mean
Edwards SAPIEN length was 15-17 mm. Differences in device design may explain this finding, as deeper extension of
the tent frame in the left ventricular outflow tract and the
self-expanding properties of the CoreValve prosthesis lead to
the maintenance of a steady radial force on the annular and
subendocardial tissue.23 Most changes occur as direct effects
on the infra-Hisian conduction system, probably caused by
direct pressure on the lower area of the prosthesis on the basal
portion of the ventricular septum and the area involving the
His bundle. The procedure also affects the compact AV node,
probably due to the length of the prosthesis, which is consistent with the lower rate of AV block in the shorter Edwards
SAPIEN prosthesis. AV blocks typically manifest immediately
after valvuloplasty or valve implantation; therefore, placement
of a temporary pacemaker is desirable during the procedure.
There are different heterogenous implantation techniques for
the TAVI procedure, which may influence the PPM implantation ratio.24,25 In the TAVI procedure, PPM requirements may
be lowered by decreasing the frame height.
Study limitations. This is a single-center study with a
small sample size. TAVI is a complex and time-consuming procedure. Because of this, we did not assess sinus node functions.
Other studies have revealed that there was no change in sinus
node functions.5 Predictors of AV conduction problems cannot be analyzed because of the small sample size and low PPM
ratio. We need further studies comparing Edwards SAPIEN
and CoreValve implantation procedures
Figure 2. His-ventricle (HV) intervals of all patients pre- and postprocedure indicated as preHV and postHV. The HV interval was significantly prolonged postprocedure (55.9 ± 11.5 ms) compared to preprocedure (47.3 ± 7.8 ms; P<.001).
Figure 3. Antegrade Wenckebach point intervals of 23 patients without
atrial fibrillation pre- and postprocedure indicated as preWB vs postWB.
Mean antegrade Wenckebach point was significantly prolonged postprocedure compared to preprocedure (354.4 ± 41.3 ms and 333.7 ± 45.4
ms, respectively; P=.001).
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The Journal of Invasive Cardiology®
Edwards SAPIEN Prosthesis and Conduction Disturbances
Table 4. Electrocardiogram parameters before and after the procedure.
PR interval (ms)
Before Procedure
After Procedure
Discharge
P1
P2
162 ± 33.4
180.6 ± 53.7
165.9 ± 31.4
.08
.41
QRS duration (ms)
108.9 ± 26.9
117.1 ± 29.5
109.6 ± 27.9
.007
.36
QRS axis (degree)
17.6 ± 42.6
4.7 ± 16.1
9.4 ± 42.4
.064
.13
Normal conduction
17 (60.7%)
15 (53.6%)
18 (64.3%)
0 (0%)
1 (3.6%)
0 (0%)
1st atrioventricular block
2 (7.1%)
2 (7.1%)
1 (3.6%)
2nd atrioventricular block
0 (0%)
1 (3.6%)
0 (0%)
3rd atrioventricular block
0 (0%)
1 (3.6%)
0 (0%)
Left bundle branch block
3 (10.7%)
3 (10.7%)
3 (10.7%)
LAFB
1 (3.6%)
1 (3.6%)
1 (3.6%)
Right bundle branch block
4 (14.3%)
3 (10.7%)
4 (14.3%)
Right bundle branch block + LAFB
1 (3.6%)
1 (3.6%)
1 (3.6%)
Intraventricular conduction defect
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Data are given as mean ± standard deviation or as number (%); LAFB= left anterior fascicular block.
P1 = comparison of preprocedural and postprocedural values; P2 = comparison of preprocedural values with those at discharge.
In this study, EPS and ECG findings during the procedure
revealed fewer conduction problems with Edwards SAPIEN
prosthesis compared to CoreValve prosthesis similar to previous studies. In addition, the effect of Edwards SAPIEN on the
conduction system was mostly temporary and infranodal. The
physical properties of the Edwards SAPIEN prosthesis may explain this observation. This complication may be lessened if the
frame height characteristics can be improved.
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