Download 24 - Medicina

Predictors of a sustained response to exercise
training in patients with chronic heart failure:
A telemonitoring study
Neil Smart, MS, Brian Haluska, MS, Leanne Jeffriess, BS, and Thomas H. Marwick, MD, PhD, FACC
Brisbane, Australia
Background Exercise training (ExT) improves exercise capacity in chronic heart failure, but the results of home-based
training have been variable. We sought the predictors of favorable outcome using a telemonitoring approach.
Methods
Exercise capacity and quality of life (QOL) were assessed in 30 patients (28 men, age 64 F 8 years) with
symptomatic chronic heart failure and left ventricular ejection fraction V35% (28% F 9%) undergoing 8 months of home ExT.
Patients were provided with heart rate monitors and exercise diaries after undergoing 4 months of hospital-based ExT.
Weekly telephone contact was established and heart rate data were downloaded bimonthly. Changes in peak oxygen
consumption per unit time (V̇o2) and QOL were compared between the 15 most and 15 least adherent patients defined by the
number of hours per week at N60% maximum heart rate, observed during heart-rate monitoring.
Results Peak V̇o2 increased by 26% ( P b .001) after 4 months of hospital ExT, but this increase had fallen to 8% ( P = .07)
at 12 months; only adherent patients (n = 15) showed persistent improvement of peak V̇o2 at 12 months ( P = .02).
Improvement in peak V̇o2 at 12 months was associated with baseline peak V̇o2 (r = 0.61, P b .001) and hours logged
on the heart rate monitor (r = 0.47, P = .01). Quality of life improvements were sustained at 12 months for the Minnesota
Living with Heart Failure Questionnaire and Hare-Davis Depression Questionnaire. Nevertheless, QOL improvements
achieved during the outpatient program were lost or attenuated at 12 months in nonadherent patients but were maintained in
adherent patients.
Conclusions Telemonitoring is feasible for following adherence to home ExT. Ongoing adherence is critical in
obtaining sustained benefit from ExT in heart failure. (Am Heart J 2005;150:1240- 7.)
Exercise training (ExT) for patients with chronic heart
failure (CHF) has beneficial effects on functional
capacity, with a recent meta-analysis reporting a 17%
improvement in measured oxygen consumption per
unit time (V̇o2).1 The most favorable effects have been
obtained with supervised training,2,3 especially high
exercise volume, and hospital-based or residential
programs.4 However, although a hospital-based multidisciplinary approach is safe and effective, it is also
relatively costly and of limited availability. Deconditioning occurs rapidly in the absence of ongoing
From the Depatment of Medicine, University of Queensland, Brisbane, Australia.
Supported in part by an MBF Research Grant Award 2003 (Sydney, Australia) and a
scholarship from the National Heart Foundation of Australia (Melbourne, Australia).
Submitted October 8, 2004; accepted January 13, 2005.
Reprint requests: Thomas H. Marwick, MD, PhD, FACC, Department of Medicine,
Princess Alexandra Hospital, University of Queensland, Ipswich Rd, Brisbane, Qld 4012,
Australia.
E-mail: [email protected]
0002-8703/$ - see front matter
n 2005, Mosby, Inc. All rights reserved.
doi:10.1016/j.ahj.2005.01.035
training, so successful graduation to a home-based
program is critical if the effects of training are to be
maintained.
Unfortunately, unpredictable results have been
reported from unsupervised training,5 -12 with ongoing
adherence to a training regimen posing a significant
problem. The key to optimal home training may be the
identification of strategies that adequately motivate
patients as well as the identification of patients who
are having difficulty with the transition from groupto individual-oriented exercise programs, perhaps
enabling more intensive supervision. Telemonitoring of
an exercise program may address these needs. Home
monitoring has been shown to reduce hospitalization
and readmission rates in patients with CHF,13 but not
including ExT. In this study, we sought whether e-mail,
telephone, exercise diaries, and heart rate monitoring
were practical motivational tools and methods of
accurately gathering exercise adherence data and
whether improved adherence could ensure maintenance of the functional capacity and quality of life
(QOL) benefits obtained from hospital-based training.
American Heart Journal
Volume 150, Number 6
Smart et al 1241
Table I. Baseline characteristics in adherent and
nonadherent patients
Adherent
(n = 15)
Figure 1
Nonadherent
(n = 15)
P
15 men
63.7 F 7.7
86.7 F 15.3
29.1 F 5.3
13 (87%)
.15
.98
.12
.16
b.001
28.3 F 7.4
30.2 F 11.3
.94
.34
11.8 F 4.8
7.2 F 1.6
34.2 F 5.8
.69
.09
.74
14 (94%)
14 (94%)
13 (86%)
.96
.96
.99
0.0
20.0
V̇ E /V̇ co 2 , expired volume per unit time/carbon dioxide production per unit time.
Methods
40.0
HRM hours
Sex
13 men
Age (y)
63.8 F 9.1
Weight (kg)
78.9 F 11.6
Body mass index (kg/m2)
26.9 F 3.1
Ischemic cardiomyopathy
7 (47%)
2-Dimensional echocardiography
LVEF (%)
28.1 F 11
Peak LVEF (%)
33.6 F 7.5
Exercise testing
Peak V̇o2 [mL/(kg min)]
12.5 F 4.9
AT
8.2 F 1.7
V̇ E/V̇co2 slope
33.4 F 6.6
Medications [n (%)]
h-Blocker
15 (100%)
ACE inhibitor
15 (100%)
Diuretic
13 (86%)
60.0
80.0
100.0
120.0
140.0
0
2
4
6
8
10
12
14
No. of Patients
Frequency distribution of adherence among the 30 patients.
Patient selection
Exercise echocardiography
Patients with symptomatic heart failure and a left ventricular
ejection fraction (LVEF) V35% were identified at the time of
presentation for echocardiography and from advertisements in
the local media. Other than the exclusion of patients with severe
valvular heart disease or inability to exercise, inability to attend
the initial hospital-based rehabilitation, lack of stabilization on
appropriate medications at a constant dose for at least 1 month
before study entry, and inability to provide informed consent,
there was no other selection criterion for these patients. Patients
with ischemia were admitted into the study provided that they
were not limited by angina. The study was approved by the
ethics committee of the Princess Alexandra Hospital and all
patients gave written informed consent.
All patients were categorized as either New York Heart
Association class II or New York Heart Association class III.
Patients in class II had mild limitation of activity, comfortable
with rest or with mild exertion. Class III patients exhibited
marked limitation of activity, comfortable only at rest.
Before commencement of the exercise test, 2-dimensional
echocardiography was recorded with commercially available
equipment with the patient in the supine left lateral decubitus
position. Images were obtained using a 3.5-MHz transducer at
16 - cm depth in 5 standard views at rest and immediately after
the exercise test. Resting and peak LVEF were calculated using
Simpson’s biplane method.
Exercise testing
All subjects underwent metabolic exercise testing on a cycle
ergometer using a 10 W/min stepped protocol. The electrocardiogram was continuously monitored for ST-segment
changes and arrhythmias; blood pressure and 12-lead electrocardiograms were recorded before exercise, every 2 minutes
during the test, and during the recovery period after exercise.
Tests were symptom limited, with the usual end points being
dyspnea and leg fatigue, and a few studies were limited by
arrhythmia and decreased or exaggerated blood pressure
response. Measured peak V̇o2 was obtained by breath-bybreath analyses of expired gas (V29C Sensormedics, Yorba
Linda, Calif), averaged over 20-second intervals. Every 3
sequential measurements were averaged and peak V̇o2 was
defined as the greatest mean value during exercise. Anaerobic
threshold (AT) was calculated using the V-slope method.14
Quality of life measures
Three previously validated questionnaires assessing QOL
were completed by all patients at baseline, 8 weeks, and 16
weeks. The Minnesota Living with Heart Failure Questionnaire15
is specific to heart failure; its 21 questions give a total score and a
physical and emotional dimensional score. The Hare-Davis
Cardiac Depression Scale16 is a general tool administered to the
cardiac patient population; as with the Minnesota Living with
Heart Failure questionnaire, lower scores indicate that patients
perceive their health to be improving. We focused on 4 of the
8 dimensions of the SF-36 General Health Questionnaire.17
Emotional role is the extent to which emotional problems
interfere with work or other daily activities, including decreased
time spent on activities, accomplishing less, and not working as
carefully as normal. Reduction of vitality reflects the experience
of lack of energetic feelings. Social functioning corresponds to
the extent to which physical health or emotional problems
interfere with normal social activities. Bodily pain reflects the
intensity of pain and effect of pain on normal work, both inside
and outside the home.
Exercise training
All patients initially undertook 16 weeks of cycle ergometer
ExT at 60 RPM, at a workload (in watts) corresponding to an
initial intensity of 60% to 70% peak oxygen consumption,
3 sessions per week. In addition, during weeks 8 to 16, patients
also performed a series of 5 strength exercises including wall
American Heart Journal
December 2005
1242 Smart et al
Figure 2
4.5
4
3.5
Hours/Week
3
2.5
2
1.5
1
0.5
0
1
2
3
4
5
6 7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Patient Number
Hours recorded (per week) at N60% HRmax (light) and hours reported in patient diaries (dark) in all 30 patients completing the home
exercise program.
Table II. Changes in functional capacity, ejection fraction, and QOL up to 12 months in all 30 patients
Base
Peak V̇o2
AT
V̇ E/V̇co2 slope
Resting EF
Peak EF
QOL
Minnesota Living with Heart Failure
Hare-Davis Cardiac Depression Scale
SF-36 RETS
SF-36 VTS
SF-36 SFTS
16 wk
% change
P
12 mo
% change
P
12.2
7.8
34.1
29
32
F
F
F
F
F
4.8
1.6
6
10
10
15.1
10.4
31.3
32
36.3
5.2
2.9
5.3
10
10.6
23.7
33.3
8.3
10.0
13.4
b.001
b.001
.03
.15
.02
13.2 F 3.8
9.6 F 3.1
31.5 F 6
36.2 F 10
40.8 F 10.6
8.2
23.1
10.2
24.8
27.5
.07
.001
.04
.01
b.001
43.5
94.7
56.7
42.2
67.6
F
F
F
F
F
16.6
17.9
41
19
24.4
31.6 F 18
77.6 F 21.6
77.4 F 34
53.8 F 19.8
70.1 F 20
27.4
18.1
36.0
26.0
3.6
b.001
b.001
.03
.03
.15
34.1
86.3
68.3
47.2
74.2
21.7
8.9
17
10.5
9.1
.013
.04
.05
.32
.006
F
F
F
F
F
F
F
F
F
F
18.7
20.9
29.8
18.1
18.8
Unless % change is preceded by a negative sign, it denotes an improvement.
pushups, alternating leg lunges, tricep dips, bicep curls, and sits
to stands from a chair. Exercise intensity was titrated upward by
2 to 5 W/wk, provided that patients were tolerating the cycle
training. In patients who were paced or experienced frequent
ectopy, rate of perceived exertion (RPE) was also used to guide
exercise intensity, using a target RPE 3 to 5 (moderate to hard)
on the modified Borg scale.18 In patients who were most limited
by shortness of breath, a respiratory rate b30 minutes was used
to monitor intensity.
Home exercise program and telemonitoring
After 16 weeks, hospital-based training patients were then
encouraged to exercise independently. All patients were
provided with a home program consisting of an aerobic and a
strength component using the same exercises as above. The
aerobic program (Appendix A) consisted of a 15-minute stair/
step exercise once weekly, approximately 30 minutes of
repeated 6 -minute walks once weekly, and a 60 -minute walk
weekly, totaling approximately 105 minutes per week. Patients
were told to take rest breaks during their 60 -minute walks,
when required, the goal being not to cover a set distance but
walk for the prescribed duration. The aerobic exercise
intensity was governed by the modified Borg (RPE) scale.
Patients were also provided with an exercise diary and a
Polar s610i Heart Rate Monitor (Polar, Kempele, Finland) for
recording heart rate data in a format that was computer
downloadable. During the last 2 weeks of their hospital-based
exercise program, each patient was given training on how to
American Heart Journal
Volume 150, Number 6
Smart et al 1243
Figure 3
Figure 4
16
14
12
10
VO 2
8
ml/kg/min
6
4
2
0
30.00
25.00
Base
20.00
16 Wks
12 Mths
Peak V̇o2 in adherers (light) and nonadherers (dark) at baseline,
16 weeks, and 12 months.
15.00
Figure 5
12
10.00
10
8
Anaerobic
Threshold 6
ml/kg/min 4
5.00
BASELINE
2
12 MONTHS
0
Baseline and 12-month peak V̇o2 values in all 30 patients
completing the home exercise program.
operate the heart rate monitor and was then required to
demonstrate its correct use. Patients were asked to record the
type, frequency, intensity, and duration of activity undertaken,
body weight, and pulse rate in the exercise diaries and to
comment on their general health. Patients were contacted
weekly by telephone or e-mail for a report on their progress;
heart rate monitors and exercise diaries were returned every
4 to 6 weeks. After comparison of exercise diaries and heart
rate files, feedback was given to each patient about
adherence, exercise intensity, and duration.
Adherence
Adherence to the 35-week home exercise program was
characterized by 2 methods. First, the number of hours logged
at N60% maximum heart rate (HRmax) on the heart rate monitor
was calculated. The group was divided into the 15 most and
15 least adherent patients, with the cutoff defined as N1 h/wk
at N60% HRmax, observed during heart rate monitoring.
The primary source of data was the heart rate monitor, but
exercise diary entries were used to verify exercise duration
when extended or shortened heart rate monitor files had been
created because of incorrect use of the heart rate monitor (eg,
patient had forgotten to start or stop the timing mechanism on
the heart rate watch or the heart rate belt sensor had failed to
receive the heart rate signal). Second, adherence was gauged
by the number of exercise sessions, defined from the diary and
heart rate monitor. Program adherence was measured by
Base
16 Wks
12 Mths
Anaerobic threshold in adherers (light) and nonadherers (dark) at
baseline, 16 weeks, and 12 months.
expressing the number of completed sessions as a percentage
of the 175 sessions (35 weeks 5 per week) required to
constitute a completed program.
Statistical analysis
Results are reported as mean F SD. Correlations with change
in peak V̇o2 were performed with clinical variables, resting and
peak LVEF, contractile reserve, and hemodynamic responses to
stress. Patients were characterized as adherent and nonadherent as described above, and repeated-measures analysis of
variance with Bonferroni correction was used to assess differences in primary end points between adherent patients and
nonadherent patients at various phases of the program.
Statistical analyses were performed with an SPSS version 10.1
(SPSS, Chicago, IL).
Results
Patient characteristics
Patients were approached from the hospital echocardiography laboratory and from advertisements in the
local media. Of 73 patients who were approached, 37
were enrolled, including 2 women (5%); of the 36 who
declined, 7 were women (19%, P = .07). Of the 37
American Heart Journal
December 2005
1244 Smart et al
Table III. Comparison of the primary end points between adherent and nonadherent patients during 3 phases of the exercise program
Characteristic
Group
Minnesota Living with
Heart Failure (QOL)
P
Hare-Davis Cardiac
Depression Scale (QOL)
P
SF-36 social function (QOL)
P
Peak ejection fraction
P
Adherent
Nonadherent
(adherent vs nonadherent)
Adherent
Nonadherent
(adherent vs nonadherent)
Adherent
Nonadherent
(adherent vs nonadherent)
Adherent
Nonadherent
(adherent vs nonadherent)
Baseline
16 wk
45.3 F 17.5
41.7 F 16.1
.49
91.9 F 18.1
97.5 F 17.8
.40
68.3 F 21.6
61.7 F 26.9
.06
33.6 F 7.5
30.2 F 11.3
.34
32.5 F 19.2
30.7 F 17.3
.73
74.9 F 21.3
80.3 F 22.3
.38
74.2 F 19.3
73.8 F 21
.17
39.2 F 9.8
35.7 F 10.6
.32
patients initially embarked upon the ExT phase of the
program, 3 failed to complete 16 weeks of supervised
ExT whereas 4 patients withdrew between the
16th week and the 12th month. All patient withdrawals
were caused by noncardiac reasons—2 caused by time
constraints, 1 because of moving from the locality, and
another because orthopedic surgery prohibited continuation of ExT. There were no significant differences in
the demographics, medications, and baseline metabolic,
echocardiographic, and QOL measures in those who did
and did not complete the program. Most patients were
in functional class III.
Of the 30 patients (28 men, age 64 F 11 years) who
completed the program, heart failure was caused by
coronary artery disease in 20, and the LVEF was 28% F
9%. The baseline characteristics of patients completing
the program are listed in Table I, only ischemic
disease etiology was significantly different between
adherent patients (47%) and nonadherent patients
(100%) ( P b .001).
Patient complications and withdrawals
There were no deaths during exercise testing and
training procedures, although one patient had a nonfatal
myocardial infarction, one had a stroke, and another was
briefly hospitalized because of worsening heart failure.
Nevertheless, these 3 patients all completed 12 months
of ExT after temporary breaks through illness. Of the
37 patients, total adherence in terms of patient number
was 30 (82%) for the hospital phase and 15 (41%) for the
home exercise phase.
Adherence during the hospital exercise program
Hospital program adherence was classified as 3 30 minutes of exercise weekly, at a heart rate z70% of
peak V̇o2. Hospital exercise adherence in all 30 patients
was 84%, with no significant difference between
patients who were adherent and those who were
P (baseline vs
16 wk)
.04
.002
.001
.003
.10
.07
.21
.49
12 mo
30.9 F 17.6
37.0 F 20.1
.37
79.2 F 20.2
93.8 F 19.2
.05
72.5 F 18.4
75.8 F 19.7
.46
44.3 F 9.9
37.4 F 10.5
.06
P (baseline vs
12 mo)
.007
1.00
.005
1.00
.18
.06
.04
.10
nonadherent with subsequent home exercise (87% F
19% vs 82% F 17%, P = .78).
Adherence during the home exercise phase
Home program adherence was characterized by
2 methods. Overall, 36% of the total hours recorded was
logged at N60% HRmax on the heart rate monitor. The
mean number of hours per week recorded at N60%
HRmax was 1.2 F 1.3, and the number of hours of
exercise at N60% HRmax in the 15 adherent and 15
nonadherent patients was 83.1 F 36.4 versus 4.9 F
9.7 hours, respectively ( P b .001) (Figure 1). The
adherent patients also showed a greater completed
proportion of the maximum of 175 exercise sessions
(63.7% F 34.1% vs 5.7% F 13.6%, P b .001). Overall, the
target number of exercise sessions for all 30 patients was
43% from a total of 175 exercise sessions, with 4 patients
achieving 100% exercise session adherence. Figure 2
shows hours recorded at N60% HRmax and hours
reported in patient diaries in all 30 patients completing
the home exercise program. Importantly, patients who
were nonadherent to training were not more sick than
the adherent patients, with similar baseline peak V̇o2
and ejection fraction values.
Effects of ExT change on functional capacity
All patients. The response of exercise capacity in the
overall group is summarized in Table II. Overall, baseline
peak V̇o2 increased from baseline by 21% at 16 weeks
( P b .001) and by 8% at 12 months ( P = .08). Body mass
was essentially unchanged ( P = NS) at 16 weeks in this
patient group and cannot therefore explain improved
peak V̇o2 values. Both AT ( P = .001) and the expired
volume per unit time/carbon dioxide production per
unit time slope ( P = .04) were improved significantly
at 12 months. This improvement was matched by an
increment in workload at 16 weeks ( P b .001) and a
reduction in peak heart rate during exercise at 16 weeks
American Heart Journal
Volume 150, Number 6
( P = .007) but not at 12 months ( P = .42). Improvement
in peak V̇o2 at 12 months was associated with lower
baseline peak V̇o2 (r = 0.41, P = .01) (Figure 3) and hours
logged on the heart rate monitor (r = 0.47, P = .01).
Training adherence and functional capacity.
Peak V̇o2 was significantly changed in both groups
(both P = .01) at 16 weeks, but it only remained
significant at 12 months in adherent patients ( P = .02
vs P = 1.00) (Figure 4). Anaerobic threshold changed
significantly at 16 weeks (adherent patients P = .005,
nonadherent patients P b .001) and 12 months only in
the adherent group ( P = .04 vs P = .07) (Figure 5).
Baseline respiratory exchange ratio (RER) was not
correlated with change in peak V̇o2. h-Blocker dose
was not correlated with change in peak V̇o2 at 16 weeks
or at 12 months or with adherence or hours logged on
the heart rate monitor.
Effects of ExT on QOL
All patients. Significant increments in the 3 QOL
measures are summarized in Table II. The Minnesota
Living with Heart Failure total score and Hare-Davis
Cardiac Depression Scale score both improved at 8 and
16 weeks (all P b .001) and at 12 months. Similarly, the
SF-36 questionnaire dimensions emotional role (RETS)
and vitality (VTS) improved at 16 weeks and the SF-36
dimension social functioning (SFTS) was significantly
improved at 12 months ( P = .006).
Training adherence and QOL. Quality of life
improvements achieved during the outpatient program
were lost at 12 months in the nonadherent patients but
were maintained in the adherent patients (Table III). The
Minnesota Living with Heart Failure and Hare-Davis
Cardiac Depression Scale scores both showed significant
changes in both groups at 16 weeks, but changes were
only maintained in the adherent group at 12 months
(Minnesota Living with Heart Failure P = .007), and this
was also true of the Hare-Davis Cardiac Depression Scale
score ( P = .005).
Effects of ExT on global left ventricular function
All patients. Resting ejection fraction improved at
8 weeks ( P = .01), 16 weeks ( P = .15), and 12 months
( P = .01) (Figure 6). Exercise ejection fraction improved
slightly at 8 weeks ( P = .40) and significantly at 16 weeks
( P = .02) and 12 months ( P b .001) (Table II).
Training adherence and left ventricular function.
When the groups were analyzed separately, neither
resting nor peak LVEF was significantly altered at
16 weeks, although improvements were identified in
adherent patients at 12 months (Table III). Direct
comparison at 12 months showed a trend toward greater
improvement in peak LVEF in adherent patients ( P = .04).
Predictors of change in functional capacity
A univariate, general linear regression model was used
to predict change in functional capacity between
Smart et al 1245
Figure 6
40
35
30
25
LVEF % 20
15
10
5
0
Base
16 Wks
12 Mths
Left ventricular ejection fraction in adherers (light) and nonadherers
(dark) at baseline, 16 weeks, and 12 months.
baseline and 12 months and between 16 weeks and
12 months. Increment in peak V̇o2 between baseline
and 12 months was predicted by baseline resting
ejection fraction (r = 0.26, P = .004). A univariate model
(r = 0.44, P = .001) of increment in peak V̇o2 between
16 weeks and 12 months was predicted by total hours
( P = .02), hours N60% HRmax ( P = .01), and the bodily
pain dimension of the SF-36 ( P = .01).
Discussion
Changes in QOL and peak V̇o2 after 16 weeks of
supervised ExT may be sustained during home-based
ExT, especially in patients adherent to a telemedicinesupervised home exercise program. Monitoring and
careful follow-up of adherence could be used to identify
patients requiring more than an unsupervised homebased exercise program.
Factors influencing sustained improvement
in peak V̇o2
Improvement in peak V̇o2 at 12 months was
associated with baseline peak V̇o2 (r = 0.41, P = .01)
and hours logged on the heart rate monitor (r = 0.47,
P = .01), although baseline peak V̇o2 was not a
univariate predictor of 12-month peak V̇o2 change.
Although an ischemic etiology for heart failure did not
emerge as a reason for a lower level of response to ExT,
contrary to previous studies,19 the amount of bodily
pain experienced at baseline could be used to predict
nonadherent patients. Importantly, however, there was
no evidence that lack of adherence was associated with
a more impaired group at baseline, with greatest
changes in peak V̇o2 at 12 months associated with
lower baseline peak V̇o2, although this trend appeared
to occur in most (21/30) patients (Figure 3). Body mass
was unchanged after ExT; nevertheless, increased lean
body mass may have occurred (unfortunately, body
composition was not measured) and could have
contributed to increased peak V̇o2 values.
American Heart Journal
December 2005
1246 Smart et al
Effects of drug therapy
Although this study did not provide a control group, it
is likely that because improved LVEF was also seen in
nonexercising patients, the changes are probably caused
by prolonged medical therapy rather than ExT. It is
possible that this improvement simply reflects the
longer-term effects of h-blockade. Nevertheless,
h-blocker dose did not appear to affect adherence to the
home exercise program or change in peak V̇o2 at
16 weeks and 12 months.
Strategies for improving exercise adherence
Exercise training in the heart failure population is
resource intensive in terms of both personnel and
equipment. Nonetheless, the improvement in exercise
capacity from this intervention may facilitate ongoing
independence and may translate into avoidance of
hospitalization and even reduce mortality.3 The graduation from a supervised to an unsupervised environment
remains a pivotal event that may be associated with loss
of effectiveness if adherence is poor.
Previous work has highlighted the importance of
patient reporting in optimizing adherence to home ExT
programs in other patient populations.20 In this study, we
provided regular patient contact with an exercise
physiologist, by e-mail or telephone, and the heart rate
monitor provided a method of verification for information
provided by the exercise diaries. Interestingly, although
ongoing adherence was associated with preservation of
the improvement in function derived from supervised
training, only half of the group were unable to make the
transition from group to individual ExT. Reasons for this
may be lack of self-motivation, concerns about safety, or
preference of cycling versus walking exercise.
Table IV demonstrates the total number of exercise
tests eliciting RER values b1.05 at baseline, 16 weeks,
and 12 months. There is no significant difference
between the number of adherers and nonadherers
eliciting RER values b1.05. The RER was not correlated
with change in peak V̇o2 at any test period during the
study. Anaerobic threshold (V̇o2 at AT) (Figure 5) is less
influenced by submaximal exercise tests and confirms
the sustained improvement in exercise capacity among
patients who adhered to training.
A comparison of other home exercise studies5-12
demonstrated that our patients were generally comparable with those enrolled in those studies (predominantly men, aged 60 to 70 years, with LVEF from 25% to
35%). However, the low recruitment of women was less
in this study than the 20% prevalence of women
reported in a meta-analysis of 81 studies of heart failure
ExT.1 This represents both lower response to the
recruitment process (mainly advertisement) as well as a
lower proportion of women who elected to proceed
into the study.
Table IV. Number of patients attaining RER b1.05 values
during metabolic exercise tests
Total
Nonadherers
Adherers
8
8
5
6
6
3
2
2
2
Baseline
16 wk
12 mo
Figure 2 demonstrates a difference in hours recorded at
N60% HRmax and hours reported in patient diaries in all
30 patients completing the home exercise program. The
difference in hours recorded at N60% HRmax and hours
reported in patient diaries may reflect overestimation of
exercise time, the performance of low-level exercise by
some patients, inclusion of rest time, and the possibility of
errors in operation of the heart rate monitors.
Conclusion
The response to a home ExT program for heart failure is
related to compliance. Telephone and e-mail contacts,
combined with exercise diaries and heart rate monitoring, were well accepted by the patients and may prove to
be practical motivational tools for maintaining adherence
with ExT for heart failure on an outpatient basis.
We gratefully acknowledge the assistance of Colin
Case, MS; Jonathon Chan, MD; Chiew Wong, MD;
Dhrubo Rakhit, MD; Philip M. Mottram, MD; Lizelle
Hanekom, MD; Robert Fathi, MD, PhD; W. Stuart
Moir, MD; Carly Jenkins; and Rodel Leano during
exercise testing.
References
1. Smart N, Marwick TH. Exercise training for patients with heart
failure: a systematic review of factors that improve mortality and
morbidity. Am J Med 2004;116:693 - 706.
2. Belardinelli R, Georgiou D, Cianci G, et al. Randomized, controlled
trial of long-term moderate exercise training in chronic heart failure:
effects on functional capacity, quality of life, and clinical outcome.
Circulation 1999;99:1173 - 82.
3. Piepoli MF, Davos C, Francis DP, et al. Exercise training metaanalysis of trials in patients with chronic heart failure (ExTraMATCH). BMJ 2004;328:189.
4. Dubach P, Myers J, Dziekan G, et al. Effect of high intensity exercise
training on central hemodynamic responses to exercise in men with
reduced left ventricular function. J Am Coll Cardiol 1997;29:1591 - 8.
5. Brosseau R, Juneau M, Sirard A, et al. Safety and feasibility of a selfmonitored, home-based phase II exercise program for high risk
patients after cardiac surgery. Can J Cardiol 1995;11:675 - 85.
6. Capomolla S, Ceresa M, Civardi A, et al. Home exercise therapy in
chronic congestive heart failure: observational study of factors
affecting adherence to the program. Ital Heart J 2002;3:1098 - 105.
7. Corvera-Tindel T, Doering LV, Woo MA, et al. Effects of a home
walking exercise program on functional status and symptoms in
heart failure. Am Heart J 2004;147:339 - 46.
American Heart Journal
Volume 150, Number 6
Smart et al 1247
8. Duncan K, Pozehl B. Effects of an exercise adherence intervention
on outcomes in patients with heart failure. Rehabil Nurs 2003;28:
117 - 22.
9. Gielen S, Adams V, Mobius-Winkler S, et al. Anti-inflammatory
effects of exercise training in the skeletal muscle of patients with
chronic heart failure. J Am Coll Cardiol 2003;42:861 - 8.
10. LeMaitre JP, Harris S, Fox KA, et al. Change in circulating cytokines
after 2 forms of exercise training in chronic stable heart failure.
Am Heart J 2004;147:100 - 5.
11. McKelvie RS, Teo KK, Roberts R, et al. Effects of exercise training in
patients with heart failure: the Exercise Rehabilitation Trial (EXERT).
Am Heart J 2002;144:23 - 30.
12. Oka RK, De Marco T, Haskell WL, et al. Impact of a home-based
walking and resistance training program on quality of life in patients
with heart failure. Am J Cardiol 2000;85:365 - 9.
13. Louis AA, Turner T, Gretton M, et al. A systematic review of
telemonitoring for the management of heart failure. Eur J Heart Fail
2003;5:583 - 90.
14. Beaver WL, Wasserman K, Whipp BJ. A new method for detecting
anaerobic threshold by gas exchange. J Appl Physiol 1986;60:2020 - 7.
15. Rector TS, Cohn JN. Assessment of patient outcome with the
Minnesota Living with Heart Failure questionnaire: reliability and
16.
17.
18.
19.
20.
validity during a randomized, double-blind, placebo-controlled trial
of pimobendan. Pimobendan Multicenter Research Group
Am Heart J 1992;124:1017 - 25.
Hare DL, Davis CR. Cardiac Depression Scale: validation of a new
depression scale for cardiac patients. J Psychosom Res 1996;40:
379 - 86.
Brazier JE, Harper R, Jones NM, et al. Validating the SF-36 health
survey questionnaire: new outcome measure for primary care. BMJ
1992;305:160 - 4.
Dunbar CC, Glickman-Weiss EL, Bursztyn DA, et al. A submaximal treadmill test for developing target ratings of perceived
exertion for outpatient cardiac rehabilitation. Percept Mot Skills
1998;87:755 - 9.
Adamapoulos S, Coats AJS, Piepoli M. Experience from controlled
trials of physical training in chronic heart failure. Protocol and
patient factors in effectiveness in the improvement in exercise
tolerance. European Heart Failure Training Group. Eur Heart J
1998;19:466 - 75.
King AC, Taylor CB, Haskell WL, et al. Strategies for increasing
early adherence to and long-term maintenance of home-based
exercise training in healthy middle-aged men and women. Am J
Cardiol 1988;61:628 - 32.
Appendix A
Components of the aerobic home exercise program
Activity
Frequency
Duration
Rest
RPE
Sets
Progress
Stair climb
Once
a week
15 30 s
1 min between sets
Somewhat hard,
RPE 5
10 - 20
6 -Min walks
Once
a week
3-5 6 min
3-5 min between
walks
3-5
Long walk
Once
a week
60 min
As required
Moderate,
RPE 4 (walk as
far as possible
in 6 min)
Easy, RPE 3
Start 10 sets,
add 1 set per week,
decrease rest breaks
Start with 3 repeats,
add 1 every
2 months up to 5
1
Walk faster, up hills,
less rests