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Studies on cardiac pacing : emphasis on pacemaker sensors and cardiac resynchronizationtherapy

Yılmaz, A.

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Citation for published version (APA):Yılmaz, A. (2005). Studies on cardiac pacing : emphasis on pacemaker sensors and cardiac resynchronizationtherapy. Amsterdam University Press.

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Download date: 10 Feb 2021

Heartt rate profiles during two types off exercise testing in healthyy individuals

Aytenn Erol-Yilmaz MD. Raymond Tukkie MD PhD and Arthur Wilde MD PhD

Abstract t

Background d

Thee normal values concerning heart rate (HR) profiles during two frequently used

exercisee tests are limited described in literature, especially in elderly healthy

persons.. Data is lacking about which test is better for pacemaker sensor optimiza-

tionn purposes, Therefore, we studied the HR responses of healthy individuals (HI)

off different age categories using the chronotropic assessement exercise protocol

(CAEP)) and the 6- minute hall walk test (6-HWT).

Materiall and methods

HII of different age categories without co-morbidity and medication were included

andd randomized to either CAEP or 6-HWT exercise test. The age categories were 20-

300 years (groupl). 30-40 years (group 2). 40-50 years (group 3). 50-60 years (group 4)

andd > 60 years (group 5). HR at rest, HR at 1 minute of exercise, time to peak HR,

maximall achieved HR, HR at 1,3 and 10 minutes recovery period, exercise duration,

andd METS or achieved distance (meters) were measured.

Results s

Hundred-seventy-fivee HI (87 men, 88 female) were included in the several age

categories.. Ninety-one HI were randomized to the CAEP and 79 HI to the 6-HWT,

Numberr of HI in each categorie were: 30 in group 1 (mean age 25 2 years), 29 in

groupp 2 (mean age 35 3 years), 40 in group 3 (mean age 44 3 years), 41 in group

44 (mean age 55 2 years) and 30 in group 5 (mean age 66 5 years) respectively.

Thee achieved HR at one minute of exercise was significantly higher and the time to

peakk HR significantly shorter during 6-HWT compared to CAEP. although the

achievedd maximal HR was comparable. There are no gender differences in HI

randomizedd to 6-HWTand minimal gender differences in HI randomized to CAEP.

Thee predicted maximal HR according to the Astrand formula (220-age) was not

significantlyy different compared to the achieved maximal HR in both tests.

Conclusions: :

Thee HR rate profiles can be used to further optimization of the pacemaker sensors.

Thee Astrand formula (220-age) can still be used for prediction of the maximal HR.

Thee 6-HWT is preferable for pacemaker sensor optimization.

58 8

Chapterr 3

Background d

Physicianss are accustomed to decision-making on the basis of knowledge of normal

rangess and normal responses to (diagnostic) tests. Several exercise tests are used for

pacemakerr sensor optimization (the chronotropic assessment of exercise protocol

(CAEP),, 6 minute hall walk test (6- HWT), stair climbing, Kaltebach step test, daily

activities).. The normal values concerning heart rate (HR) profiles during two most

frequentlyy used exercise tests are limited described in literature, especially in the

elderlyy healthy persons.1'31

Thee CAEP protocol according to Wilkoff is designed for pacemaker patients and is one

off the most used exercise test in this patient category beside the 6- HWT. ' In

addition,, data is lacking about which test is better for pacemaker sensor optimization

purposes.. Therefore we studied the HR responses of healthy individuals (HI) of

differentt age categories using the CAEP and the 6-HWT exercise test. These data were

laterr used for pacemaker sensor optimization in chapter 4. We also tried to answer

whichh exercise test is the optimal test for pacemaker sensor optimization.

Material ss and methods

Healthyy individuals

Healthyy individuals (HI) of different age categories without co-morbidity and

medicationn were included and randomized to one of the exercise test protocols.

Thee age categories were 20-30 years (groupl), 30-40 years (group 2), 40-50 years

(groupp 3). 50-60 years (group 4) and > 60 years (group 5)- The two exercise tests used

weree the six minute hall walk test (6-HWT), and the chronotropic assessment

exercisee protocol (CAEP) according to Wilkoff.29 The subjects were exercised until

fatigue,, symptomatic or end of the protocol, but no systematic effort was made to

encouragee exercise to exhaustion. Also the HR response to postural change was

measured.. The HI were recruited by advertising in the local newspaper, on the

severall outward-clinics of our hospital.

59 9

Posturee change

Alll HI were examined in the same conditions (before noon, uniform room tempera-

turee and footgear (subject's own shoes)). After instrumentation, subjects rested

supinee on an examination table with one pillow for 5 minutes. They then elevated

too the sitting position and immediately to the standing position.

Exercisee test protocols

ChronotropicChronotropic assessment of exercise protocol

Healthyy individuals randomized to the CAEP according to Wilkoff underwent a

symptomm limited treadmill test,29 One MET equals 3.5 ml oxygen uptake/kg body

weight/min,, representing the approximate metabolic cost to stand quietly. In his

protocol,, oxygen consumption and carbon dioxide production was not measured,

andd thus metabolic workload (METS ) was not directly measured during exercise.

Rather,, metabolic levels during each stage of exercise were estimated using tread-

milll grade and speed.

SixSix minute hall walk test

Afterr 5 minutes of rest, HI were brought to the parcour. A parcour of 100 m was

createdd by attaching stickers each meter in an oval form showing the walk distance.

Normalss were instructed to walk or run for 6 minutes at the parcour after hearing

thee start sign. After the symptom limited 6-HWT, the HI were brought back to the

testt room for a recovery period of 10 minutes.

Measurements s

Beatt to beat HR was recorded during the physical tests with the Polar advantage

systemm using electrodes mounted in a belt (Polar Electro OY. Kempele. Finland). The

firstt 10 HR of each minute were averaged. During the CAEP exercise test, HI were

alsoo continuously monitored by 12-lead electrocardiographic recordings. HR at rest,

HRR at 1 minute of exercise, time to peak HR, maximal achieved HR, HR at 1,3 and 10

60 0

Chapterr 3

minutess recovery period, exercise duration, and METS or achieved distance (meters)

weree measured.

Statistics s

Firstt the Kruskal-Wallis test was used to analyse differences between the different

agee categories. When the Kruskall-Wallis test was significant, the nonparametric

dataa were analyzed using the Mann- Whitney U test and the parametric data were

analyzedd using the paired sample t test. All data are expressed as mean SD. A P

valuee <0.05 is considered statistically significant.

Results s

Normall population

Hundred-seventy-fivee HI (87 men. 88 female) were included in the several age

categories.. Ninety-one HI were randomized to the CAEP (42 men, 49 female) and 79

HII to the 6-HWT (42 men, 37 female). Number of HI in each categorie were: 30 in

group.. 29 in group 2, 40 in group 3, 41 in group 4 and 30 in group 5 respectively. Of

fourr HI 3 in the HWT (66, 63. 32 years) and 1 in the CAEP (28 year) data derived from

thee Polar advantage system could not be analyzed due to technical disturbance of

thee system. One HI in group 5, a 65 year old female, developed atrial fibrillation

duringg the CAEP and stopped the exercise test.

Exercisee tests

ChronotropicChronotropic assessment exercise protocol

Restt rate

Thee resting HR in HI randomized to the CAEP was not significantly different be-

tweenn group I to 5 (see table 1 and figure 1).

61 1

HRR at one minute of exercise

Thee HR at one minute of exercise was not significantly different between group 1 to

55 (see table 1).

Timee to peak HR

Inn each group the time to peak HR increased. The achieved time to peak HR in group

11 was significantly longer compared to group 4 (p= 0,004) and 5 (p<0.001). The

achievedd time to peak HR in group 2 was significantly longer compared to group 4

(p== 0.07) and 5 (p<0.001). The achieved time to peak HR in group 3 and 4 were

significantlyy longer compared to group 5 (p<0.001. see table 1).

Maximall HR

Thee maximal HR diminished in each group with increasing age. The achieved

maximall HR in group 1 was significantly higher compared to group 3. 4 and 5

(p<0.009.. see table 1, figure ), The achieved maximal HR in group 2 was significant-

lyy higher than in the groups 4 and 5 (p = 0.07. p<0.001). The achieved maximal HR

inn group 3 and 4 was significantly higher compared to group 5 (p=0.004. p = 0,03)-

Thee percentage difference between the achieved and predicted maximal HR was the

largestt in group 1 and 5 (184 10 vs. 195 bpm, A in bpm -6% and 144 36 vs, 154.

AA bpm =6% respectively). In group 2, 3 and 4 the percentage difference between the

achievedd and predicted maximal HR differed minimal (181 15 vs. 185 bpm, A in

bpmm = 2%, 172 13 vs. 176 bpm. A in bpm =3%. 167 10 vs. 165, A in bpm = 2%

respectively). .

Recovery y

Thee HR at 1 minutes of recovery was significantly higher in group 1 compared to

groupp 3, 4 and 5 (p-0.06, p = 0.003, p = 0.03). The achieved HR at 10 minutes was

significantlyy higher in group 2 compared to group 4 (p —0.001). The achieved HR at

1,3.. 10 minutes of recovery in group 3 compared to group 5 was significantly

higherr (p< =0.06).

62 2

Chapterr 3

Exercisee duration and METS

Thee exercise duration of the HI in group 1 was significantly longer than in group 3.

44 and 5 (p = 0.05. p = 0.006, p<0.001). The exercise performance of the HI in group 2,

33 and 4 were significantly higher compared to group 5 (p< 0.03. see table 1).

Thee achieved METS were significantly higher in group 1 and 2 compared to group 4

andd 5 (p<0.001). The achieved METS were also higher in group 3 and 4 compared to

55 (<0.001. see figure 3.d).

6-6- minute hall walk test

Restt rate

Thee resting HR in HI randomized to the 6-HWT was not significantly different

betweenn group 1 to 5 except for group 2 compared to 3 (55 12 vs. 64 7 bpm,

pp = 0.02. see table 2. and figure 2).

HRR at one minute of exercise

Inn contrast to the CAEP test, differences existed in the achieved HR at one minute of

exercisee between the groups. The achieved HR at one minute of exercise was

significantlyy higher in the group 1 compared to 4 (p-0.009). The achieved HR at one

minutee of exercise was significantly higher in group 2 compared to 3.4 and 5

(p<0.05).. The achieved HR at one minute of exercise was significantly higher in

groupp 3 compared to 4 (p-0.006, see table 2 and figure 2).

Timee to peak HR

Thee achieved time to peak HR was only significantly longer in group 1 compared to

44 and 5 (p<0.03, table 2).

63 3

Maximall HR

Thee maximal HR diminished with each age category. The achieved maximal HR in

groupp 1. 2 3. 4 was significantly higher than in group 5 (p<0.009, see table 2, figure 2).

Thee percentage difference between the achieved and predicted maximal HR (Astrand

formule== 220-agel is the largest in group 1 and 2 (179 19 vs. 195 bpm. A in bpm

=8%.. 175 7 vs. 154, A bpm =5%)- In group 3. 4 and 5 the percentage difference

betweenn the achieved and predicted maximal HR minimally differed (175 2 vs. 185

Tablee 1. Heart rate during rest, exercise and recovery with CAEP

Age e

(years) )

266 3 igroup D

355 3 (group 2}

455 3 Igroup 3)

555 2 (group 41

677 5 (group5 )

Resrr rate

(hr/min) )

666 10

600 12

677 12

622 10

655 10

HRatt 1 Ibpml l

911 16

866 13

800 11

833 14

900 18

TIPP HR (mini i

21 2

20 3

19 3

188 3

166 3

Exercise e

MHR R (bpm) )

1844 10

1811 15

1722 13

1677 i 10

1444 + 36

Duration n min n

222 2

211 4

200 3

199 3

177 3

METS S iml/'kg'min) )

16.66 3

16.22 2

14.99 i 3

13-55 2

10.33 3

Tablee 1. CAEP = chronotropic assessment exercise protocol HRR = heart rate: TTPHR = timc to peak heart rate; MHR = maximal heart rate; METS= oxygen uptake/kgg body weigh t/min. min = minute: bpm=beats per minute.

Tablee 2. Heart rate during rest, exercise and recovery with 6-HWT

Age e

(years) )

244 2 (group 11

355 2 (group 21

444 3 \group 31

555 3 '(group 4̂

666 5 igroup 5)

Restt rate

(hr/min.) )

611 9

555 12

644 7

644 13

622 10

MRR at 1 (bpm) )

1422 19

1522 12

1411 0

1244 17

1311 10

TTPP HR min n

4.33 1.7

33 1.7

377 1.6

2.88 16

2,99 i 1-3

Exercise e

MHR R (bpm) )

33 79 19

1755 7

1755 12

1688 12

1511 17

Duration n min n

66 0

66 0

66 0

5.88 0.7

5.77 0-7

METS S (ml/'kg/min) )

12366 236

1116.. 278

9833 181

10066 178

7811 281

Tablee 2. 6-HWT = 6 minute hall walk test; HR^heart rate: TIP HR = time to peak heart rate: MHRR = maximal heart rate: bpm = beats per minute; min= minutes: m = meters.

64 4

Chapterr 3

bpm.. A in bpm =0.6%. 168 12 vs. 176 bpm. A in bpm = 2%. 151 17 vs. 165, A in

bpmm =2% respectively.

Recovery y

Thee HR at 3 and 5 minutes of recovery was significantly higher in group 1 compared

too 2 (p < 0,03) The achieved HR at 1 and 3 minutes of recovery was significantly higher

inn group 1 and 3 compared to group 5 (p<0,05). The achieved HR at 3 and 5 minutes

Recovery y

HRR at 1 min HR at 3 min HR at 5 min HR at 10 min (bprrOO (bpm) (bpm) (bpm)

1488 21 105 0 95 16 93 15

1366 6 106 17 97 2 96 9

1311 4 106 22 92 1 89 2

1277 6 98 17 90 4 88 2

1199 6 95 18 89 4 3

Recovery y

HRatt 1 min HR at 3 min HRat 5 min HR at 10 min

(bpm)) (bpm) (bpirO (bpm)

1377 22 108 0 98 13 95 15

1222 8 89 6 86 6 85 10

1355 8 108 15 96 2 93 2

11 104 4 95 2 86 0

1133 2 94 6 92 5 89 6

65 5

CAEP P 200 0

Minute s s

Figuree 1. Changes in heart rate \mean̂ during CAEP of the different age categories \male and female!.

6-HWT T

99 12 Minute s s

Figuree 2. Changes in heart rate imean1 during 6-HWT of the different age categories (malee and female)

wass significantly higher in group 2 compared to 3 (p<0.05). The achieved HRat 1

minutess of recovery was significantly higher in group 4 compared to 5 (p=0.05).

Exercisee duration and distance

Alll HI exercised for 6 minutes except one HI in group 4 and one in group 5. they

stoppedd before the end of the test due to fatigue. The achieved distance was signifi-

ed d

Chapterr 3

cantlyy longer in group 1 compared to 3. 4 and 5 (p<0.01) and also the achieved

distancee was significantly longer in group 2 and 3 compared to 5 (p<0.04).

Genderr differences

HII randomized to 6-HWT showed no differences between females compared to

maless in the different age categories. Females compared to males in group 2 rand-

omizedd to CAEP showed significant differences in resting HR (52 9 vs.68 9 bpm,

p=0.09).. achieved maximal HR (178 4 vs. 182 8 bpm. p=0.025). exercise

durationn (20 2 vs. 21 4 min. p = 0.046) and achieved METS (14 2 vs. 17.2 1.8

METS,, p = 0.028). Within group 3 and 4, the achieved METS significantly differed

(12.55 1 vs. 17.6 1.8. p=0.001 vs. 12.6 1.8 vs. 14.7 2 METS. p=0.03). In group

5.. achieved maximal HR (134 41 vs. 162 16 bpm, p = 0.035), HR at 3 minutes of

recoveryy {88 14 vs. 106 18 bpm, p = 0.042), HR at 5 minutes of recovery (84 4

vs.. 97 12 bpm, p=0.036) and HR at 10 minutes of recovery (82 13 vs. 93 10

bpm,, p=0.066) were significantly different between men and women.

CAEPP vs. 6-HWT

Thee achieved HR at 1 minute of exercise and the achieved time to peak HR were

significantlyy different between CAEP and 6-HWT for all age categories (86 5 vs. 138

5 bpm. p<0.001 and 18.8 0.9 vs. 3-3 0.3 min, p<0.01). The rest rate, maximal

HRR and HR at 1, 3. 5 and 10 minutes of recovery were not significantly different.

Discussion n

Optimall programming of pacing variables is important in rate adaptive pacemakers

too improve exercise capacity and reduce symptoms. Individual programming should

bee adapted to the age of patients and to associated medical conditions, as well as to

overalll functional capacity. For pacemaker optimization, tests are in use with largely

isotonicc (dynamic or locomotory) exercise. These exercise tests can be divided in:

in-hospitall and out-of hospital exercise tests. From the in-hospital tests, the CAEP

exercisee test according to Wilkof f and the 6-minute walk test are frequently

67 7

used.266 ,2° However, recent data are lacking concerning normal values of HR respons-

ess in different age categories with CAEP and 6-HWT. In addition, data are lacking if

duee to the increasing height and weight during the last century, the HR response is

changedd in HI and whether the Astrand formula (220-age) for prediction of the

maximall HR can still be used. We therefore describe the HR response of 170 HI

withoutt apparent disease and medication during CAEP and 6HWT.

Thee disadvantages of in-hospital testing with standardized tests such as treadmill

andd bicycle ergometry is that these tests are time consuming and not always feasi-

blee in patients with pacemakers (as they are often elderly persons, with physical

limitations)) and the tests poorly represent daily activities.32 Especially the treadmill

testt is not an ideal exercise test for pacemaker patients, because in pacemaker

patients,, exercise is often limited by loss of muscle strength and mass rather than

cardiopulmonaryy capacity. This loss of muscle strength is particularly apparent

whenn exercise testing is performed on a bicycle or treadmill. The CAEP exercise test

hass non-linear characteristics. The first 10 minutes requires low metabolic work-

load,, beyond which the workload abruptly increases. Patients with preserved

functionall capacity, capable of exercising for more than 10 minutes, may quit before

reachingg maximal 02 uptake, mainly because of excessive increments in workload

nearr the end of the test, thus, being limited by mechanical rather than metabolic

barriers.. Caution is needed in the application of the CAEP protocol which is also

illustratedd by Freedman et al.32 They showed that failure in attaining maximum

exercisee could create the appearance of sub-optimal pacemaker performance.

Onee of the first studies which performed an in-hospital walk test was done in

patientss with chronic obstuctive pulmonary disease.7 The in-hospital HWT is

describedd in pacemaker patients with different duration (2. 6. 12 minutes) and most

off them used brisk walking, which is in contrast to our study. In our study the HI

weree allowed to run and they stopped because of maximal exhaustion, with symp-

tomss or end of the protocol. Therefore it is difficult to compare the HR response of

HII to the limited existing literature. Provenier et al. validated the six- minute walk

testt in rate response pacemakers. In his study, the six-minute walk test was per-

formedd in a corridor 45 m long with 1 (m) and 5 (m) marks on the floor.2

Thee 13 HI in his study the achieved a maximal rate of 73% of the predicted maximal

HR,, corrected for age (220-age). The HI in our study achieved almost their predicted

maximall HR, The HWT has several advantages when compared to the CAEP. The

08 8

Chapterr 3

HWTT is short, cheap, has a better practicability and uses a natural way of moving

duringg the walk with good correlation to other types of exercise at home,i q

Inn our study, the achieved HR at one minute of exercise was significantly higher and

thee time to peak HR significantly shorter during 6-HWT compared to CAEP, al-

thoughh the achieved maximal HR was comparable. We therefore think, considering

thee advantages of the 6-HWT that the 6-HWT is the prefered test for pacemaker

sensorr optimization.

Thee difference in body mass index of our HI compared to other studies is minimal

(0-11 kg/m2). even when we compared with the dated studies, which can be explained

duee to the increased height together with the increased weight. '-0'10 1213.15.20.24.27.28

Thereforee the achieved peak HR, which is correlated the body mass index, is not

significantlyy different compared to the dated literature, ^ó-1012^-^.20.24.27.2s

Thee estimation of the maximal HR has been largely based on the Astrand formula

(maximumm HR=220-age). In 13-507 healthy men from several studies, the predicted

maximall HR differed only 4.3 beats per minute compared to the achieved maximal

HRR in our study. 1-6.10.12.13,15.20.24.27.28 Considering the many factors which can

influencee the achieved maximal HR, careful programming of the maximal HR is

needed.333 It bears repeating that this is only an estimate of an individual patient's

maximumm HR. Better methods need to be developed to estimate especially the HR

responsess at sub maximal levels because patients needing a pacemaker are of an age

groupp where they may have disabilities limiting their physical work capacity.

Inn a meta-analysis, Londeree and Moeschberger showed that although 73% of the

variabilityy of the peak HR response could be attributed to age. and 5% to some other

factorss that were examined, the remaining variability could not be accounted for. 23

Thee other minor variables, which have been shown to have some influence on the

maximall HR include: gender, fitness and cardiac illness.18 Fitness and training cause

somee slowing of HR for a given external workload,115

Inn our study there were surprisingly no gender differences in HI randomized to the

6-HWT.. HI randomized to the CAEP had minimal gender differences in the groups 2

too 5. This is in contrast to the studies described before, which showed that females

hadd a higher HR at all levels of exercise. J'

InIn chapter 4. we showed that pacemaker sensor optimization improved exercise

capacityy (METS). However, the HI in this study achieved higher HR than patients

despitee individual optimization, probably because current sensors are still hypo-

69 9

chonotropicc and physicians need to program conservative due to concomitant heart

disease.. The elderly patients in the pacemaker sensor optimization study achieved

muchh lower METS (7.6 vs. 10.3) compared to the elderly HI from this study. These

dataa underline that exercise capacity can be improved in pacemaker patients by

pacemakerr sensor optimization, although other factors such as co-morbidity and

fitnesss also plays a major role. The HI were more active and had no co-morbidity

comparedd to the patients in our study.

Conclusions s

Wee describe the heart rate profiles during two types of exercise testing in 170

healthyy individuals. Only the heart rate at 1 minute of exercise and time to peak

heartt rate are significantly different when these two tests are compared. Surprising-

ly,, there are no gender differences in healhy controls randomized to 6-minute hall

testt and minimal gender differences in healthy individuals randomized to the CAEP.

Inn addition, the body mass index is not significantly changed during the last

century,, The Astrand formula (220-age) can still be used for prediction of the

maximall heart rate, however precaution is needed in the elderly pacemaker patients

withh co-morbidity. Furthermore, our data confirm that the 6-minute hall walk test is

preferablee for pacemaker sensor optimization because of the ease of implementa-

tionn and the natural way of moving during the walk with good correlation to other

typess of exercise at home. These heart rate profiles can be used to further optimize

thee pacemaker sensor.

70 0

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Chapterr 3

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71 1

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