CLINICAL RESEARCH
Europace (2013) 15, 212–218
doi:10.1093/europace/eus254
Sudden death and ICDs
The implantable defibrillator and return
to operation of vehicles study
Darren Mylotte 1*, Richard G. Sheahan 2, Paul G. Nolan 1, Mary Antoinette Neylon 2,
Brian McArdle 2, Orla Constant 3, Audrey Diffley3, David Keane 3, Patrick J. Nash 1,
James Crowley1, and Kieran Daly 1
1
Department of Clinical Cardiology, University College Hospital Galway, Galway, Republic of Ireland; 2Department of Clinical Cardiology, Beaumont Hospital, Dublin, Republic of
Ireland; and 3Department of Clinical Cardiology, St Vincent’s University Hospital, Dublin, Republic of Ireland
Received 24 April 2012; accepted after revision 18 July 2012; online publish-ahead-of-print 11 September 2012
Aims
We sought to characterise driving habits of contemporary implantable cardioverter defibrillator (ICD) patients.
.....................................................................................................................................................................................
Methods
We performed a multicentre prospective observational study of consecutive ICD recipients. Non-commercial drivers
and results
with a valid licence were eligible. Patient and ICD data were recorded. All patients completed an anonymous questionnaire regarding their driving habits. Among 275 patients, 25 (9.1%) stopped driving permanently after ICD implantation. During a mean follow-up of 26.5 + 4.5 months, 25.3% of patients received an ICD shock (52.5%
appropriate). The median time to first shock was 7.0 (2.5, 17.5) months and was not significantly different
between primary and secondary ICD patients. However, shocks (36.5 vs. 21.3%, P ¼ 0.027) and recurrent shock episodes (17.5 vs. 6.2%, P ¼ 0.011) were more common in secondary ICD patients. Physician-recommended driving
restrictions were not recalled by 37.9% and not followed by 23.0% of patients. Overall, the mean duration of
driving abstinence was 2.2 + 2.9 and 3.6 + 5.3 months for primary and secondary patients, respectively. Notably,
36.5% of secondary patients drove within 1 month. Eight patients (3.3%) received a shock while driving, five of
which resulted in road traffic accidents. The annual risk of a shock while driving was 1.5%.
.....................................................................................................................................................................................
Conclusions
Patient driving behaviour following ICD implantation is variable, with over one-third not remembering and almost
one-quarter not adhering to physician-directed driving restrictions. Over one-third of secondary ICD patients
drive within 1 month despite physician recommendations. Further studies are required to establish the optimal duration of driving restriction in ICD recipients.
----------------------------------------------------------------------------------------------------------------------------------------------------------Keywords
Implantable cardioverter defibrillator † Motor vehicle † Road traffic accident † Shock † Driving restriction †
Driving restriction
Introduction
Implantable cardioverter defibrillators (ICDs) reduce mortality in
survivors of cardiac arrest (secondary prevention),1,2 and in
selected patients at high risk of ventricular arrhythmias (primary
prevention).3 – 5 Recipients of implantable defibrillators are
subject to restrictions when driving automobiles as ICD discharge
could induce driver incapacitation and cause road traffic accidents
(RTAs). Although variable worldwide, ICD patients have been
traditionally restricted from non-commercial driving for 6
months following device implantation or discharge, regardless of
the indication for ICD therapy.6 – 8 More recently, up-to-date
recommendations on driving restriction following ICD implantation have been published by the European Heart Rhythm Association and the American Heart Association/North American
Society of Pacing and Electrophysiology.9,10 While these guidelines
are less restrictive, driving abstinence negatively influences the
quality of life of ICD patients and their families; thus, clear
evidence-based recommendations are required to justify driving
restriction. To date, there remains a paucity of data describing
the characteristics and driving habits of patients who continue to
drive following ICD implantation.
To address this issue, we sought to characterise the driving
habits in an unselected contemporary ICD population.
* Corresponding author. Tel: +353 0872905240; fax: +353 091524220, Email: [email protected]
Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2012. For permissions please email: [email protected].
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Implantable defibrillator and operation of vehicles study
What’s new:
† Compared with previous publications of primarily secondary
ICD recipients, only a small proportion of contemporary
ICD recipients stop driving following device implantation.
† Patient recall of physician-recommended driving restrictions
and adherence to these restrictions is improving, however:
37.9% do not recall the duration of driving restriction
recommended, and 23.0% do not adhere to the restriction.
† Importantly, 36.5% of secondary prevention ICD patients
return to driving within 1 month of device implantation. Furthermore, the mean duration of driving abstinence recommended by physicians for these patients was 4.0 + 5.5
months despite societal guidelines recommending longer
driving abstinence.
† The annual risk of a shock while driving was 1.5%.
mandatory. All patients were requested to complete an anonymous
questionnaire regarding their driving habits 3 months following ICD
implantation.
Patient follow-up
Patients returned for the assessment of wound healing and device interpretation within 6 weeks of device implantation. Thereafter, routine
follow-up was performed every 3 months for the first year and 6
monthly thereafter. Follow-up included clinical assessment and
device interrogation. All therapies delivered by the device were classified as appropriate or inappropriate. Appropriate shocks inferred
device discharge for ventricular arrhythmias, and inappropriate
shocks included discharge for sinus tachycardia, supraventricular
arrhythmias, T-wave oversensing, electrode dysfunction, etc. Where
appropriate, device settings and patient medications were adjusted
during follow-up in an effort to minimize device shocks. ATP alone
was not considered as an endpoint due to the relative infrequency
of incapacitation associated with this therapy.13
Statistical analysis
Methods
Patient population
The study population consisted of consecutive patients due to receive
an ICD for primary or secondary prevention in three tertiary referral
centres in the Republic of Ireland. Baseline patient characteristics, information regarding device implantation, and all follow-up visits were
recorded prospectively. Patients were eligible for study inclusion if
they had an ICD inserted ≥6 months previously, and had driven an
automobile prior to ICD implantation. Eligibility criteria for ICD implantation were based on approved guidelines.11 Commercial drivers
and those without a valid driving license were excluded. All eligible
patients were invited to complete an anonymous questionnaire regarding their driving habits and experiences 6 months after ICD implantation. All patients gave informed consent for study participation and
medical ethics committees at each site approved the study.
Device implantation
All ICD implants were performed transvenously by experienced physicians according to standard protocols. Defibrillator systems from a
variety of manufacturers were used: Boston Scientific [Natick, MA,
USA, formerly CPI, Guidant (St Paul, MN, USA)], St Jude Medical (St
Paul, MN, USA), and Medtronic (Minneapolis, MN, USA). Following implantation, defibrillator programming was performed according to an
agreed protocol. Briefly, all devices had a ventricular arrhythmia
monitor zone between 150 and 188 b.p.m., although no therapies
were programmed in this zone unless arrhythmias were detected at
follow-up. Ventricular arrhythmias faster than 188 b.p.m. were
treated with two bursts of antitachycardia pacing (ATP), and subsequent device shocks in case of ATP failure. Any ventricular arrhythmia
faster than 210 b.p.m. was directly treated with a device shock. Atrial
arrhythmia detection was set at 170 b.p.m. with supraventricular
arrhythmia discriminators enabled.
Driving restriction following implantation
In the Republic of Ireland, no separate national legislation exists regarding driving restriction following ICD implantation.12 As such, implanting
physicians were instructed to recommend driving restrictions outlined
in recent societal guidelines.9,10 Clear communication and documentation of the duration of this restriction prior to patient discharge was
Categorical variables are expressed as frequencies and percentages
and were compared by means of the x2 test or Fisher’s exact test.
Continuous variables were analysed for a normal distribution with
the Kolmogorov – Smirnov test (using P value .0.2 as threshold) and
are presented as mean + standard deviation or median and interquartile range according to distribution. The Student t-test was used to
compare continuous variables when these were normally distributed
and the Mann– Whitney U test when not normally distributed. The cumulative incidences for the first and second shocks were determined
by the Kaplan– Meier method, and compared using the log-rank test.
The nominal level of significance was 5%. Statistical analyses were performed with SPSS (version 17, SPSS Inc., Chicago, IL, USA).
Results
Study population
Between January 2008 and July 2009, 298 patients received an ICD
at the study centres. Among these, 5 commercial drivers and 18
non-drivers were excluded, leaving 275 habitual drivers eligible
for study inclusion. The average age of the study population was
61.7 + 11.8 years. Of these patients, 241 (87.6%) drove after
device implantation, 25 (9.1%) stopped driving permanently, and
9 (3.3%) declined to participate in the study. Patients who permanently stopped driving after ICD implantation were older (66.5 +
10.9 vs. 61.7 + 11.8 years, P ¼ 0.002), more likely to be female
(59.3 vs. 19.5%, P , 0.0001), and more frequently had an ICD
for secondary prevention of sudden cardiac death (60.0 vs.
26.1%, P ¼ 0.0003).
The baseline characteristics of the 241 patients who continued
driving after device implantation are presented in Table 1. The
average of the study population was 61.7 + 11.8 years, the majority
had a history of coronary artery disease, and the mean left ventricular ejection fraction (LVEF) was 31.6 + 14.2%. The most common
pathology leading to ICD implantation was ischaemic heart disease
(56.8%), and 27.0% of patients had a history of atrial fibrillation/
flutter. Patients were treated with appropriate medical therapy,
with 83.8% prescribed an angiotensin-converting enzyme inhibitor
or angiotensin receptor blocker, and 85.5% taking beta-blockers.
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D. Mylotte et al.
Table 1 Patient demographics and clinical characteristics
Variable
All patients (n 5 241)
Primary prevention
(n 5 178)
Secondary prevention
(n 5 63)
P value
...............................................................................................................................................................................
Mean age, (mean + SD), years
Female gender
Cardiovascular risk factors
Hypertension
Hyperlipidaemia
Diabetes mellitus
Current cigarette smokers
Family history of coronary artery disease
Coronary artery disease
Congestive cardiac failure
61.7 + 11.8
61.3 + 12.0
62.6 + 11.2
0.453
47 (19.5)
33 (18.5)
14 (22.2)
0.580
132 (54.8)
100 (56.2)
32 (50.8)
0.466
172 (71.4)
133 (74.7)
39 (61.9)
0.074
50 (20.7)
43 (17.8)
35 (19.7)
32 (18.0)
15 (23.8)
11 (17.5)
0.476
0.999
119 (49.4)
96 (53.9)
23 (36.5)
0.019
146 (60.6)
150 (62.2)
109 (61.2)
111 (62.4)
37 (58.7)
39 (61.9)
0.765
0.999
LVEF (mean + SD), %
31.6 + 14.2
30.3 + 14.1
36.2 + 13.3
0.004
LVEF , 30%
QRS duration (mean + SD), ms
109 (45.2)
127 + 31
88 (49.4)
131 + 33
21 (33.3)
124 + 29
0.028
0.137
137 (56.8)
47 (19.5)
102 (57.3)
30 (16.9)
35 (55.5)
17 (27.0)
0.883
0.096
Cardiac pathology
Ischaemic
Idiopathic
Hypertrophic
33 (13.7)
30 (16.9)
3 (4.8)
0.018
24 (10.0)
65 (27.0)
16 (8.9)
47 (26.4)
8 (12.7)
18 (8.6)
0.463
0.743
Statin
ACE-inhibitor/ARB
158 (65.6)
202 (83.8)
131 (73.6)
152 (85.4)
27 (42.9)
52 (82.5)
,0.0001
0.684
Diuretic
134 (55.6)
102 (57.3)
32 (50.8)
0.380
Beta-blocker
Amiodarone
206 (85.5)
42 (17.4)
150 (84.3)
26 (14.6)
56 (88.8)
16 (25.4)
0.414
0.080
34 (14.1)
22 (12.4)
12 (19.0)
0.209
36 (14.9)
24 (13.5)
12 (19.0)
0.307
142 (58.9)
105 (59.0)
52 (21.6)
36 (20.2)
Other
History of atrial fibrillation/flutter
Medication
Sotalol
Digoxin
Device
Single chamber
Biventricular pacing
37 (59)
16 (25.4)
0.999
0.321
Data presented as number and percentage unless stated. LVEF, left ventricular ejection fraction; ACE, angiotensin-converting enzyme; ARB, angiotensin-receptor blocker.
Patients were divided according to indication for ICD implantation; primary prevention: 178 (73.9%), and secondary prevention:
63 (26.1%). Primary prevention patients were more likely to have
hypertrophic cardiomyopathy (16.9 vs. 4.8%, P ¼ 0.018) and more
severe impairment of LVEF (30 + 14 vs. 36 + 13%, P ¼ 0.028)
compared with secondary prevention patients.
Implantable cardioverter defibrillator
shocks
The mean duration of follow-up was 26.5 + 4.5 months, during
which 61 patients (25.3%) received an ICD shock (Table 2).
Shocks occurred more frequently in the secondary prevention
group compared with the primary prevention group (36.5 vs.
21.3%, P ¼ 0.027; Figure 1). The median time to first shock following ICD implantation was 7.0 (2.5, 17.5) months and was not significantly different between the primary and secondary groups
[5.0 (1.0, 17.3) vs. 9.0 (4.0, 19.0) months, P ¼ 0.427]. Appropriate
shocks accounted for 52.5% of all shocks, and the median time to
first appropriate shock was 7.0 (2.8, 16.0) months. Of the 61
patients who received a shock, 22 (36.0%) received a further
shock. The median duration to a second shock was 2.0 (1.0, 9.0)
months. Multiple shocks were more common in secondary patients
(17.5 vs. 6.2%, P ¼ 0.011), but were not statistically more common
in patients who had an initial appropriate shock compared
with those who had an initial inappropriate shock (50.0 vs. 20.7%,
P ¼ 0.61 Figure 2). In all patients who had more than one inappropriate shock (n ¼ 9), all subsequent inappropriate shocks occurred
within 1 month of the initial shock. In contrast, the median time
to a second appropriate shock was 2.0 (1.0, 9.0) months.
Driving characteristics
All patients who recommenced automobile driving following ICD
implantation completed the anonymous questionnaire on their
driving habits. Driving was described as a necessity of daily living
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Implantable defibrillator and operation of vehicles study
Table 2 Device and shock characteristics
Variable
All patients
(n 5 241)
Primary prevention
(n 5 178)
Secondary prevention
(n 5 63)
P value
0.352
...............................................................................................................................................................................
Duration follow-up (mean + SD), months
26.5 + 4.5
26.2 + 4.7
26.8 + 4.2
ICD shock
61 (25.3)
38 (21.3)
23 (36.5)
0.027
Time to first shock, median, months
Shock ≤3 months after implantation
7.0 (2.5, 17.5)
16 (6.6)
5.0 (1.0, 17.3)
9 (5.1)
9.0 (4.0, 19.0)
7 (11.1)
0.427
0.565
Appropriate shock
32 (52.5)
18 (47.4)
14 (60.9)
0.428
Time to first appropriate shock, median, months
Inappropriate shock
7.0 (2.8, 16.0)
29 (47.5)
5.0 (2.0, 16.0)
20 (52.6)
7.0 (4.0, 16.0)
9 (39.1)
0.664
0.428
Time to first inappropriate shock, median, months
2.0 (1.0, 9.0)
5.0 (1.0, 23.0)
16.0 (4.5, 24.0)
0.421
Multiple shocks
Time to second shock
22 (36.0)
2.0 (1.0, 9.0)
11 (6.2)
3.0 (0.5, 12.0)
11 (17.5)
1.0 (0.8, 2.0)
0.011
0.305
ICD, implantable cardioverter defibrillator.
Figure 1 Time to first implantable cardioverter defibrillator
shock in primary and secondary prevention implantable cardioverter defibrillator patients. Kaplan– Meier curve for the first
shock in primary and secondary prevention implantable cardioverter defibrillator recipients.
by 79.7% of patients (Table 3). Overall, 37.9% of patients did not
correctly recall the duration of driving cessation recommended
by the treating physician. Recall was better in the secondary
group (74.6 vs. 59.0%, P ¼ 0.033). Among patients who did recall
the recommended driving restriction, 23.0% did not adhere to
their physician’s instructions. ‘Necessity’ was the principal reason
given for not adhering to the physician-directed driving restrictions.
The mean duration of driving abstinence recommended by physicians was 2.2 + 2.9 months for the primary group and was
4.0 + 5.5 months for the secondary group. The mean duration of
driving abstinence actually undertaken by patients was 2.2 + 2.9
and 3.6 + 5.3 months for the primary and secondary groups, respectively. One-month post-ICD implantation, 53.3% of primary
and 36.5% of secondary patients had recommenced driving.
Following recommencement of driving, 30.7% of patients limited
their driving to essential travel only, and 25.4% believed that the
Figure 2 Time to a second implantable cardioverter defibrillator shock following an initial appropriate or inappropriate shock.
Kaplan– Meier curve for the second device shock in all patients
with an initial appropriate or inappropriate shock.
ICD negatively impacted on their driving ability. Presyncope
while driving was reported by 9.5% of patients following ICD implantation. During follow-up, a total of 14 motor vehicle accidents
occurred in the entire cohort following ICD implantation, giving
an RTA rate of 2.6%. Eight patients (3.3%) received a shock
while driving at a mean of 5.4 + 3.9 months following implantation.
Of these patients, four had inappropriate shocks that were not
associated with loss of consciousness (two resulted in minor
RTAs), and three of four appropriate shocks reported a loss of
consciousness (three resulted in minor RTAs). No serious injuries
or fatalities resulted from an ICD shock while driving. The annual
risk of a shock while driving was 1.5%.
Discussion
This study of contemporary ICD recipients shows that 9.1% of
patients stopped driving permanently following ICD implantation,
216
D. Mylotte et al.
Table 3 Driving characteristics following implantable cardioverter defibrillator implantation
Variable
All patients
(n 5 241)
Primary prevention
(n 5 178)
Secondary prevention
(n 5 63)
P value
Driving a necessity
192 (79.7)
142 (79.8)
50 (79.4)
0.999
Limited driving
74 (30.7)
52 (29.2)
22 (34.9)
0.429
Recall of medical instructions
Adhered to medical instructions
152 (63.1)
117 (77.0)
105 (59.0)
81 (77.1)
47 (74.6)
36 (76.6)
0.033
0.999
Driving abstinence recommended
(months)
2.9 + 2.3
2.6 + 1.9
4.0 + 5.5
0.022
Recommenced driving (months)
2.6 + 3.7
2.2 + 2.9
3.6 + 5.3
0.01
Number of patients driving at:
1 month
119 (49.4)
96 (53.9)
23 (36.5)
0.019
194 (80.5)
149 (83.7)
45 (71.4)
0.042
6 months
Presyncope while driving
226 (93.8)
23 (9.5)
168 (94.4)
16 (9.0)
58 (92.1)
7 (11.1)
0.547
0.622
Shock while driving
8 (3.3)
5 (2.8)
3 (4.7)
0.434
Annual risk of shock while driving (%)
RTA after ICD
1.5
14 (5.8)
1.3
11 (6.2)
2.2
3 (4.8)
0.999
...............................................................................................................................................................................
3 months
RTA, road traffic accident; ICD, implantable cardioverter defibrillator.
that 37.9% could not recall the duration of driving restriction
advised by their physician, and that 23.0% did not adhere to this
restriction. Over half (53.9%) of primary and a third (36.5%) of secondary ICD patients drove within 1 month of device implantation.
Shocks occurred more frequently and were more likely to occur
on multiple occasions in secondary patients compared with
primary patients.
Motor vehicle driving restrictions for ICD recipients have
remained inconsistent since the introduction of ICD technology
in the early 1980s. While there is general agreement that ICD
patients should not be permitted to drive professionally, the
optimal duration of driving restriction following device implantation
or discharge for private drivers is unclear. Several studies have
investigated the driving characteristics of patients who receive an
ICD for secondary prevention;14 – 18 however, the demographics
of the ICD implant population has changed considerably, as the
proportion of ICD implants for primary prevention has increased.19
Indeed, we observed considerable differences in the driving behaviour of contemporary ICD patients compared with that
reported in the literature. In our study, 9.0% of patients ceased
driving permanently following ICD implantation, a figure that compares favourably to previous estimates (25.5%).20 The reasons for
the lower incidence of permanent driving cessation in the current
study are unclear, but may relate to the specific regulatory environment or population density characteristics in Ireland. The availability of public transport and patient and family attitudes to
enforced driving restriction are also likely to impact on driving
practices. Patients who stopped driving tended to be older,
female, and more frequently had an ICD for secondary prevention.
We speculate that the negative psychological impact of a cardiac
arrest is likely to have played a role in reducing the proportion
of secondary patients that recommence driving.21 Patient recall
and adherence to physician-directed driving restrictions has
traditionally been poor. Lerecouvreux et al. 22 reported that only
28% patients remembered and 13% actually adhered to physicianrecommended driving restrictions. In our study, the majority of our
patients recalled (63.1%) and adhered to the recommended restriction. Nevertheless, the observation that almost a quarter of
all patients (23.0%) did not adhere to the recommended driving
abstinence, and in particular that over one-third (36.5%) of secondary prevention patients recommenced driving within 1 month of
ICD implantation is of concern. Although one could speculate
that the proportion of patients adhering to recommended
driving restrictions might vary geographically and according to specific regulatory environments, it is clear that a considerable number
of patients ignore physician and regulatory directives.
The mean duration of driving restriction recommended by physicians is falling in accordance with recent guidelines.9,10 In the
current study, physicians advised a mean abstinence of 2.6 + 1.9
months for primary patients and 4.0 + 5.5 months for secondary
patients. These figures suggest that physicians remain somewhat
reluctant to allow patients to drive immediately following device
implantation for primary prevention despite societal recommendations. In contrast, physicians do not appear to be advising the full
6-month recommended restriction for secondary ICD recipients.
Thus, a continued focus on both physician and patient education
regarding the requirement for driving restrictions, and an emphasis
on adhering to these restrictions are required.
The reported incidence of ICD shocks while driving is
low.14,17,22,23 In our study, eight patients (3.3%) received an ICD
shock while driving, at a mean 5.4 + 3.9 months following implantation. Four of these episodes were related to inappropriate shocks,
and thus loss of consciousness did not occur in these patients.
Three patients who experienced an appropriate shock while
driving reported significant incapacitation following shock delivery.
It is therefore likely that the risk of an RTA is higher following an
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Implantable defibrillator and operation of vehicles study
appropriate shock than it is with an inappropriate shock. The
annual risk of a shock while driving was 1.5% and, indeed, the
risk of an RTA in our study was low and is consistent with that
of the general population.24
In line with previous studies,25 we observed more frequent ICD
shocks in secondary patients compared with primary patients (36.5
vs. 21.3%, P ¼ 0.027), over a mean follow-up period of 26.5 + 4.5
months. Furthermore, secondary patients were more likely to
receive therapies on multiple occasions compared with primary
patients. Thus, if the risk of an RTA in ICD patients is related to
the probability of ICD shocks, then secondary patients may represent a higher-risk population than primary patients.
Recently, Thijssen et al. 26 assessed the occurrence of ICD
shocks and the annual risk of harm in a large population (n ¼
2786) of ICD patients in the Netherlands. The risk of harm, calculated using the formula developed by the Canadian Cardiovascular
Society Consensus Conference6,27 calculates the yearly risk of
harm to other road users posed by a driver with heart disease.
The authors concluded that no driving restriction was warranted
following ICD implantation for primary prevention, secondary prevention, or following inappropriate device discharge, as the risk of
harm was below the accepted cut-off. In keeping with our data, the
elevated risk of further shocks following appropriate ICD discharge
warranted a driving restriction. Recent societal guidelines recommend ,1-month driving restriction following ICD implantation
for primary prevention; however, a 6-month abstinence is recommended following ICD implantation for secondary prevention or
following appropriate ICD shock.9,10 It is clear that more data
from large prospective studies of ICD patients, and in particular
ICD patients who recommence driving following device implantation, are required to further inform physicians and national regulatory authorities.
Study limitations
This was a prospective observational study of consecutive ICD
patients of limited size. We did not control the duration of
driving restriction for patients as we sought to observe real-world
behaviour and we did not include ATP therapies in the analysis as
the reported incidence of syncope with ATP is low.13 The small
proportion of habitual drivers that declined to participate in the
study (3.3%) could have represented a population of drivers with
specific driving characteristics or attitudes, and may have influenced the results of the study. Importantly, the results of the
current study might only be applicable to the Republic of Ireland
or countries with comparable population density profiles and
similar driving legislation for ICD recipients.
Conclusions
Among contemporary ICD recipients, a small proportion of
patients stop driving permanently, over one-third do not recall
the duration of driving restriction advised by their physician, and
almost one-third do not adhere to this restriction. Over half of
primary and a third of secondary ICD patients drive within 1
month of device implantation. Further studies are required to establish the optimal duration of driving restriction in ICD recipients.
Conflict of interest: none declared.
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EP CASE EXPRESS
doi:10.1093/europace/eus200
Online publish-ahead-of-print 11 July 2012
.............................................................................................................................................................................
Three-dimensional retrograde atrial activation maps obtained during
atrioventricular nodal re-entrant tachycardia provides insights
into the location of nodal inputs
Clarence Khoo and Santabhanu Chakrabarti*
Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
* Corresponding author. Department of Medicine, University of British Columbia, Heart Rhythm Services, St Paul‘s Hospital, 211– 1033 Davie Street, Vancouver, British
Columbia, Canada V6E 1M7. Tel: +1 604 806 9842; fax: +1 604 806 8335, Email: [email protected]
Summary
Three patients who had three-dimensional (3D) atrial
local activation time maps measuring ventriculo-atrial
intervals during atrioventricular node re-entrant tachycardia (AVNRT) were identified. Three-dimensional
mapping of the clinical tachycardia was performed with
the Ensite Nav-X system (St Jude Medical, St Paul, MN,
USA).
Patients 1 and 2 presented with typical slow–fast
AVNRT. Earliest atrial activation (fast pathway) was localized at the left-atrial superior septal position, the rightsided His Bundle, and at the antero-superior aspect of
the coronary sinus (CS) os. Patient 3 presented with
atypical slow–slow AVNRT. Earliest atrial activation
(see figure) was located antero-superiorly to the CS
os. In all patients, successful slow pathway modification
was achieved antero-inferior to the CS os.
Our findings highlight the need to consider non-traditional anatomical sites of atrioventricular node inputs. The earliest atrial
activation site does not correspond well to the successful site of ablation in typical AVNRT. Our inability to localize continuous
atrial activation during AVNRT despite extensive bi-atrial mapping confirms that the majority of the circuit may either be electrically
quiescent or sub-endocardial.
Conflict of interest: none declared.
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Documents/insights-into-location-of-nodal-inputs.pdf
Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2012. For permissions please email: [email protected].