British
Heart
Journal,
1976,
38,
465-471.
Incidence
of
arrhythmias
induced
by
isometric
and
dynamic
exercise'
James
M.
Atkins,
Oscar
A.
Matthews,
C.
Gunnar
Blomqvist,
and
Charles
B.
Mullins
From
Parkland
Memorial
Hospital
and
the
Moss
Heart
Center
for Research,
Department
of
Internal
Medicine,
The
University
of
Texas
Health
Science
Center
at
Dallas,
Southwestern
Medical
School,
Dallas,
Texas
75235,
U.S.A.
The
incidence
of
arrhythmias
during
isometric
sustained
handgrip
exercise
and
during
dynamic
graded
bicycle
exercise
was
compared
in
agroup
of
45
patients
with
various
forms
of
heart
disease
on no
antiarrhyth-
mic
therapy.
Atrial
arrhythmias
were
equally
common
during
handgrip
and
bicycle
exercise
but
ventricular
arrhythmias
were
morefrequent
during
handgrip
exercise.
Of
the
45
patients,
38
per
cent
developed
ventricular
arrhythmias
during
isometric
exercise,
with
ventricular
tachycardia
occurring
in
15
per
cent.
During
dynamic
exercise
22
per
cent
of
the
45
patients
developed
ventricular
arrhythmias,
with
ventricular
tachycardia
occurring
in
2
per
cent.
Patients
with
coronary
artery
disease
and/or
depressed
left
ventricular
function
developed
twice
the
incidence
of
ventricular
arrhythmias
with
isometric
than
with
dynamic
exercise
Thus,
isometric
exercise
testing
is
of
more
value
than
dynamic
exercise
testing
in
unmasking
latent
ventricular
arrhythmias
in
patients
with
heart
disease.
The
circulatory
response
to
dynamic
exercise,
pressures,
with
little
or
no
change
in
systemic
exemplified
by
walking
and
running,
has
been
well
vascular
resistance.
characterized
both
in
normal
subjects
and
in
The
use
of
isometric
exercise
as
a
stress
test
for
patients
with
various
forms
of
heart
disease.
How-
evaluation
of
left
ventricular
function
has
recently
ever,
many
activities
during
daily
life
primarily
been
explored
in
this
laboratory
by
Matthews
et
al.
involve
static
or
isometric
exercise,
for
example,
(1974),
Mitchell
and
Wildenthal
(1974),
and
by
lifting,
carrying,
or
pushing
heavy
objects.
The
others
(Helfant,
de
Villa,
and
Meister,
1971;
physiological
aspects
of
isometric
exercise
in
normal
Jacobs
et
al.,
1970;
Kivowitz
et
al.,
1971).
We
were
subjects
have
been
studied
in
detail
by
Lind,
impressed
by
the
frequent
occurrence
of
arrhyth-
McNicol,
and
Donald
(1966)
and
Freyschuss
mias
during
isometric
exercise
performed
in
the
(1970),
while
other
studies
have
been
reported
in
course
of
our
haemodynamic
studies.
The
present
patients
with
heart
disease
(Cohn
et
al.,
1973;
investigation
was
undertaken
to
compare
the
Ewing
et
al.,
1973;
Fisher
et
al.,
1973;
Grossman
incidence
of
arrhythmias
during
and
after
isometric
et
al.,
1973;
Haissly
et
al.,
1974;
Krayenbuehl
et
al.,
and
dynamic
exercise
in
patients
with
heart
disease.
1972;
Ludbrook,
Karliner,
and
O'Rourke,
1974;
Mullins
and
Blomqvist,
1973;
Quinones
et
al.,
Patients
and
methods
1974;
Siegel
et
al.,
1972).
Firty-five
patients
were
continuously
monitored
by
The
principal
circulatory
effects
of
dynamic
and
electrocardiography
during
both
isometric
and
dynamic
isometric
exercise
are
different.
Dynamic
exercise
exercise.
The
group
included
35
men
and
10
women,
causes
an
increase
in
heart
rate
and
cardiac
output,
with
a
mean
age
of
54-5
years
(range
28-78
years).
with
a
small
increase
in
mean
arterial
pressure
and
a
Twenty-three
patients
had
ischaemic
heart
disease,
significant
fall
in
systemic
vascular
resistance.
18
had
valvular
heart
disease,
3
had
primary
myocardial
Isometric
exercise
in
normal
subjects
produces
an
disease,
and
one
patient
had
a
residual
post-traumatic
increase
in
heart
rate
and
cardiac
output
and
a
large
right
bundle-branch
block.
According
to
the
New
York
increase
in
both
systolic
and
diastolic
arterial
Heart
Association
classification,
2
patients
were
in
functional
class
I,
20
in
class
II,
and
23
in
class
III.
Received
8
September
1975.
Thirty-one
patients
underwent
cardiac
catheterizations.
'Supported
by
grants
from
the
US
Public
Health
Service,
No
patient
was
on
antiarrhythmic
therapy
at
the
time
NASA,
and
the
American
Heart
Association,
Texas
Affiliate,
of
study,
and
no
patient
had
ectopic
activity
at
rest
Inc.
during
a
5-minute
control
period.
46"
Atkins,
Matthews,
Blomqvist,
and
Mullins
A.
Isometric
exercise
(handgrip)
non-invasive
isometric
exercise
test.
Indirect
arterial
Isometric
exercise
was
performed
using
a
spring-
blood
pressure
was
recorded
during
the
last
minute
of
loaded
handgrip
dynamometer.L
After
determining
the
exercise
at
each
work
load
as
with
isometric
exercise.
force
of
a
maximal
voluntary
contraction
by
averaging
The
bicycle
test
was
performed
on
a
separate
day
the
results
of
three
different
maximal
efforts,
the
patients
within
one
week
of
the
handgrip
test
in
22
of
the
performed
a
sustained
25
per
cent
mimal
voluntary
patients.
The
two
tests
were
done
on
the
same
day
in
23
contraction
for
3
to
5
minutes,
with
an
average
duration
patients.
Isometric
exercise
always
preceded
dynamic
of
4
minutes.
After
a
5-minute
rest
period,
the
patients
exercise,
with
a
rest
period
of
at
least
one
hour
between
performed
a
50
per
cent
maximal
voluntary
contraction
the
two
tests.
until
fatigue
set
in;
the
average
duration
of
the
50
per
C
Definition
of
arrhythmias
cent
voluntary
contraction
was
1
minute,
with
a
range
of
30
seconds
to
3
minutes.
Care
was
taken
to
prevent
a
Any
patient
with
an
arrhythmia
during
rest
or
control
Valsalva
manoeuvre.
Of
the
45
patients,
23
were
periods
was
eliminated
from
the
study.
Ventricular
examined
by
non-invasive
techniques,
and
22
patients
tachycardia
was
defined
as
3
or
more
successive
pre-
were
examined
during
cardiac
catheterization.
mature
ventricular
contractions.
A
single
premature
The
23
patients
examined
by
non-invasive
techniques
contraction
was
counted
as
an
arrhythmia.
were
monitored
with
continuous
recording
of
the
Frank
lead
electrocardiogram
at
a
paper
speed
of
10
mm/s.
Records
at
paper
speeds
of
25
or
50
mm/s
were
obtained
Results
during
rest,
the
last
minute
of
exercise,
immediately
after
Mean
data
on
work
load,
heart
rate,
and
blood
exercise,
and
3
minutes
after
exercise.
Indirect
brachial
data
o
n
dgrk
ad
heart
rat
e
are
artery
pressure
was
recorded
every
30
seconds
during
pressure
durng
handgrip
and
bicycle
exercise
are
exercise
and
every
minute
during
recovery
with
a
semi-
presented
in
Table
1.
The
mean
peak
heart
rate
±
automatic
device,2
with
the
cuff
placed
on
the
resting
the
standard
error
with
isometric
exercise
was
arm.
86+2
beats/minute
while
it
was
122±4
beats/
Twenty-two
patients
were
examined
during
cardiac
minute
with
dynamic
exercise.
The
mean
peak
catheterization
with
continuous
and
simultaneous
re-
systolic
blood
pressure
was
179
±
6
mm
Hg
(23.8
+
cordings
of
the
electrocardiogram,
brachial
artery
0-8
kPa)
with
isometric
exercise
and
167±5
mmHg
pressure,
and
left
ventricular
pressure
recorded
on
an
(22*2±0-7
kPa)
with
dynamic
exercise.
Electronics
for
Medicine
recorder
at
varying
paper
The
incidence
of
various
arrhythmias
is
presented
speeds
of
10,
25,
and
100
mm/s.
Cardiac
output
was
i
Table
2
and
Fig.
1.
Arrhythmias
were
found
measured
at
rest
and
during
the
last
minute
of
exercise
in
panientsArhyhmgsthe
found
at
each
load
level
by
the
indicator-dilution
method.
All
more
frequently
in
patients
during
the
isometric
cineangiograms
were
performed
after
completion
exercise
test
than
during
the
bicycle
test,
44%
(20
of
the
exercise
study.
The
ejection
fraction
was
de-
of
45)
of
patients
compared
to
24%
(11
of
45)
termined
according
to
the
method
of
Greene
et
al.
(P
<
0'051).
The
number
of
patients
having
arrhyth-
(1967),
from
single
plane
(right
anterior
oblique)
mias
with
handgrip
at
the
25
per
cent
maximal
cineangiograms.
voluntary
contraction
level
was
11
per
cent
(5
of
45).
Premature
atrial
contractions
were
equally
B.
Dynamic
or
bicycle
exercise
common
with
both
types
of
exercise
and
were
seen
The
45
patients
also
performed
dynamic
exercise
at
in 11
per
cent
(5
of
45)
of
the
patients
during
the
progressive
loads
on
a
mechanically-braked
bicycle
handgrip
test
and
in
9 per
cent
(4
of
45)
during
the
ergometer.
The
duration
of
exercise
at
each
load
was
bicycle
test.
The
incidence
of
ventricular
arrhyth-
5
minutes,
with
a
5-minute
rest
period
between
work
loads.
Selection
of
the
initial
work
load
was
based
on
the
mcas
was
higher
during
the
handgrip
test,
38
per
patient's
history.
Patients
in
functional
class
I
and
II
cent
(17
of
45)
compared
with
22
per
cent
(10
of
45),
began
exercise
at
300
kpm/min
and
patients
in
class
III
but
the
difference
was
not
significant.
When
single
at
150
kpm/min
or
at
no
load
except
for
the
internal
premature
ventricular
contractions
were
dis-
resistance
of
the
ergometer.
The
load
was
increased
in
regarded,
31
per
cent
(14
of
45)
of
patients
had
2
steps
of
150
kpm/min.
The
test
was
carried
to
a
or
more
contractions
during
the
handgrip
test
symptom-limited
maximal
load
unless
the
patient
de-
compared
with
20
per
cent
(9
of
45)
during
the
veloped
progressive
horizontal
ST
depression
of
at
least
bicycle
test.
A
striking
difference
was
observed
in
0.1
mV
(1
mm),
or
unless
an
increasing
number
of
the
incidence
of
ventricular
tachycardia,
15
per
cent
premature
ventricular
contractions,
multifocal
prema-
(7
of
45)
during
the
handgrip
test
and
2
per
cent
ture
ventricular
contractions,
or
runs
of
two
or
more
(1
of
45)
during
the
bicycle
test
(P
<
0-05)
(Fig.
1).
occurred.
The
indications
for
discontinuing
exercise
AR
of
who
had
venbicular
05)
(Fig
conformed
to
the
standards
presented
by
Rochmis
and
patients
who
had
ventricular
arrhythmias
during
Blackburn
(1971).
The
technique
for
monitoring
by
the
bicycle
test
also
developed
premature
ventricular
electrocardiogram
was
identical
to
that
used
during
the
contractions
and
ventricular
tachycardia
during
'C.
H.
Stoelting
Company,
Chicago,
Illinois.
the
handgrip
test.
Examples
of
arrhythmias
are
2Narco
Systems,
Inc.,
Houston,
Texas.
8x2.
Isometric
and
dynamic
exercise
arrhythmias
467
TABLE
1
Work
load,
heart
rate,
and
arterial
blood
pressure
at
peak
levels
of
handgrip
and
bicycle
exercise
Blood
pressure
(mmHg)
Work
load*
Heart
rate
Systolic
Diastolic
Handgrip
exercise
35+
6
86+2
179+
6
127+
6
Bicycle
exercise
391+31
122+4
167+
5
94+3
*Work
load
expressed
as
kilopond-metres/minute
for
bicycle
exercise
and
as
force
in
kilograms
for
isometric
exercise.
Mean+
SE,
n=
45.
Conversion
from
Traditional
Units
to
SI
Units:
1
mmHg
0-133
kPa.
TABLE
2
Incidence
of
arrhythmias
with
isometric
exercise
and
dynamic
exercise
Isometric
exercise
Dynamic
exercise
Diagnosis
No.
pts
PAC's
PVC's
VT
PAC's
PVC's
VT
Ischaemic
heart
disease
23
3
8
4
1
5
1
Valvular
heart
disease
18
0
6
1
2
3
0
Primary
myocardial
disease
3
2
2
1
1
2
0
Cardiac
contusion
1
0
1
1
0
0
0
All
diseases
45
5
17
7
4
10
1
(11%)
(38%)
(15%)
(9%)
(22%)
(2%)
Abbreviations:
PAC,
premature
atrial
contractions;
PVC,
premature
ventricular
contractions;
VT,
ventricular
tachycardia.
Four
patients
had
both
PAC's
and
PVC's
or
VT.
Patients
with
VT
are
included
in
the
PVC
column.
illustrated
in
Fig.
2,
3,
and
4.
A
comparison
of
were
matched
with
respect
to
age
and
the
severity
arrhythmias
by
cardiac
diagnoses
during
isometric
of
angina.
Five
of
10
(50%0)
patients
studied
and
dynamic
exercise
is
illustrated
in
Fig.
5.
during
cardiac
catheterization
had
arrhythmias
To
exclude
the
possibility
that
catheter-induced
compared
with
30
per
cent
(4
of
13)
in
the
group
arrhythmias
affected
our
results,
the
incidence
of
studied
by
indirect
techniques.
This
difference
was
arrhythmias
during
handgrip
exercise
in
a
group
not
significant
between
invasive
and
non-invasive
of
patients
with
ischaemic
heart
disease
who
were
techniques
(P
>
0
2).
Four
episodes
of
ventricular
catheterized
was
compared
with
a
group
of
patients
tachycardia
were
seen
in
the
catheterized
patients
examined
by
non-invasive
techniques.
The
patients
and
3
episodes
were
seen
in
the
patients
studied
by
non-invasive
methods.
All
patients
were
excluded
40
who,
during
catheterization,
had
arrhythmias
at
-
c
rest
or
during
control
periods
with
the
catheters
Isometric
exercise
in
place.
30
-
E
Dynamic
exercise
Twenty-one
patients
had
left
ventricular
cine-
angiograms.
Patients
with
ventricular
arrhythmias
had
a
mean
ejection
fraction
of
46
per
cent,
suggest-
0/0
20
*
E
ing
that
arrhythmias
are
more
common
with
deteriorating
left
ventricular
function.
Nine
patients
had
ischaemic
heart
disease
l0
documented
by
coronary
cineangiography.
Ven-
tricular
arrhythmias
occurred
in
3
of
4
patients
with
triple-vessel
disease,
1
of
3
patients
with
2-
o
11
S
11
[
|
2
vessel
disease,
and
1
of
2
patients
with
single-
P\/CX
VT
PA
C
vessel
disease,
suggesting
that
arrhythmias
were
more
common
in
patients
with
more
severe
coronary
F
I
G.
1
Incidence
of
arrhythmias
induced
by
iso-
artery
disease;
however,
the
number
of
patients
is
metric
and
dynamic
exercise
stress
testing
in
45
too
small
for
this
trend
to
be
significant.
patients.
PVC,
premature
ventricular
contraction;
Individual
heart
rate,
blood
pressure,
and
heart
VT,
ventricular
tachycardia;
PAC,
premature
atrial
rate-systolic
blood
pressure
product
data
in
a
sub-
contraction.
group
of
11
patients
with
angina
pectoris
and
ST
468
Atkins,
Matthews,
Blomqvist,
and
Mullins
mm
Hq
Control
depressions
during
bicycle
exercise
are
presented
in
Control
Fig.
6.
Mean
maximal
heart
rate
was
84
during
handgrip
exercise
and
118
during
bicycle
exercise.
IOO
BA
/nv
rf*Cs
au
r
Peak
systolic
blood
pressure
was
slightly
higher
during
handgrip,
188
mmHg
(25.0
kPa),
than
LV
\
\
\
/
\
/
\
during
bicycle
exercise,
175
mmHg
(23-3
kPa).
O
\J
\
'
\~
\
The
heart
rate-systolic
blood
pressure
product/100
509bMVC-
1min
was
higher
during
bicycle
exercise,
207,
compared
mmHg
Mr
with
158
with
isometric
exercise.
Discussion
100
~~~~~~~~~Ventricular
arrhythmias
are
frequently
seen
in
patients
undergoing
exercise
stress
tests
using
O
.LV
dynamic
exercise
methods.
We
found
that
22
per
ECG'
Continuous
tracinq
cent
of
the
patients
with
heart
disease
in
this
study
m20Ho9
developed
arrhythmias,
a
similar
incidence
to
that
2
~~~~~~~~~~~~of
other
reported
series.
BA
Kosowsky
et
al.
(1971)
reported
26
per
cent
ventricular
arrhythmias
during
a
treadmill
test
in
-Jo
patients
who
were
free
from
arrhythmias
at
rest.
Other
investigators
have
reported
ventricular
O
'
I1
s
arrhythmias
in
10
to
39
per
cent
of
cardiac
patients
undergoing
treadmill
or
bicycle
exercise
tests,
but
FIG.
2
An
example
of
ventricular
arrhythmias
quantitative
comparison
between
series
is
difficult
occurring
during
isometric
stress
testing
during
cardiac
because
of
the
differences
with
respect
to
patients,
catheterization.
No
arrhythmia
was
present
before
exercise
test
modes,
monitoring
techniques,
diag-
testing.
The
handgrip
was
released
and
the
patient
nostic
criteria,
and
antiarrhythmic
therapy.
returned
to
normal
sinus
rhythm.
BA,
brachial
artery
Ventricular
arrhythmias
are
rare
among
young
pressure;
LV,
left
ventricular
pressure;
MVC,
maxi-
normal
subjects
during
dynamic
exercise
but
the
mal
voluntary
contraction;
50
per
cent
MVC
1
min,
incidence
increases
sharply
with
increasing
age.
50
per
cent
maximal
voluntary
handgrip
contraction
Strandell
(1963)
found
at
least
occasional
premature
held
for
1
minute.
ventricular
contractions
in
32
per
cent
of
apparent
Control
s%Y*MVC
21
X
z
F
IG.
3
An
example
of
arrhythmias
developing
during
isometric
stress
testing
using
xyz
Frank
lead
system.
Multifocal
ventricular
as
well
as
supraventricular
arrhythmias
are
present.
50
per
cent
MVC
2',
50
per
cent
maximal
voluntary
handgrip
contraction
held
for
2
minutes.
Isometric
and
dynamic
exercise
arrhythmias
469
Control
z
Is
500/oMVC
2
X
Z~~~~~~~~~~~
~
pse?
p
1
r
r
Y
z
FIG.
4
An
example
of
ventricular
tachycardia
occurring
during
isometric
stress
testing.
See
Fig.
3
for
abbreviations.
healthy
men,
age
60
to
83,
who
performed
maximal
400
Heart
rate
x
systolic
blood
or
near-maximal
bicycle
exercise.
Ellestad
et
al.
pressure
(1969)
saw
9
cases
of
ventricular
tachycardia
among
300
1000
asymptomatic
middle-aged
subjects
during
or
/.
after
a
progressive
treadmill
test.
Similar
findings
200
have
also
been
reported
by
Gooch
and
McConnell
The
surprising
finding
in
this
study
was
the
high
100
;
incidence
of
ventricular
arrhythmias
during
iso-
metric
stress
testing.
Thirty-eight
per
cent
of
the
0o
Dn
Isometric
Dynamic
Exercise
25
rIsoerceecs
0.Heart
rate
40.Systolic
blood
Iso
l
u
&)y
metric
exercise
200
Hea
rt
rate
400
1
pressure
Dynamic
exercise
20
IAG.5Comparisonofa
rrhythmias
b50
cardic
r
20
1
100
2
300
-
ASD
shei
er
dsae
H,vlua
maxma
her
rate
-ytlcbodpesr/0
RBB
ih
ude-rnhbokcusdb
ada
lowe
lf-hn
pae
r
lotte
th
aia
er
0
o
10~~~~~~~~~~~~~~~~
S'
~~~~~~~~~~~~~~Isomet'ric
Dynamic-
Isometric
Dy'namic
Exercise
Exerci
se
FIG.
6
Heart
rates
and
systolic
blood
pressures
in
I11
0
AH
VH
PM
RBB
patients
with
angina
pectoris
during
isometric
and
ASHD
VHD
PMD
RBBB
~dynamic
exercise.
The
solid
lines
connecting
dots
F
IG.
5
Comparison
of
arrhythmias
by
cardiac
represent
individual
patients.
The
dashed
lines
are
the
diagnoses
during
isometric
and
dynamic
exercise,
group
means.
In
the
upper
panel
are
plotted
the
A
SHD,
ischaemic
heart
disease;
VHD,
valvular
maximal
heart
rate
x
systolic
blood
pressure/100
heart
disease;
PMD,
primary
myocardial
disease;
during
both
isometric
and
dynamic
exercise.
In
the
RBBB,
right
bundle-branch
block
caused
by
a
cardiac
lower
left-hand
panel
are
plotted
the
maximal
heart
contusion.
rates
during
both
isometric
and
dynamic
exercise.
470
Atkins,
Matthews,
Blomqvist,
and
Mullins
patients
developed
ventricular
arrhythmias,
a
16
during
isometric
exercise
when
compared
with
per
cent
increase
above
the
incidence
with
dynamic
dynamic
exercise
may
be
related
to
a
lower
heart
testing.
Arrhythmias
with
isometric
exercise
in
rate
at
any
given
level
of
cardiac
work
(Fig.
6).
normal
subjects
are
unusual.
We
have
seen
only
a
The
high
incidence
of
serious
ventricular
arrhyth-
single
premature
ventricular
contraction
in
2
of
60
mias
with
isometric
stress
testing
in
this
study
normal
subjects
during
isometric
stress
testing.
suggests
that
stress
tests
based
on
isometric
exercise
Other
reports
(Cohn
et
al.,
1973;
Fisher
et
al.,
should
be
performed
where
facilities
for
monitoring
1973;
Grossman
et
al.,
1973;
Haissly
et
al.,
1974;
and
resuscitation
are
available.
It
also
seems
prudent
Helfant
et
al.,
1971;
Kivowitz
et
al.,
1971;
Krayen-
to
discourage
activities
requiring
heavy
isometric
buehl
et
al.,
1972;
Ludbrook
et
al.,
1974;
Matthews
exercise
in
patients
with
heart
disease
because
of
the
et
al.,
1974;
Mitchell
and
Wildenthal,
1974;
chance
of
sudden
death
induced
by
ventricular
Mullins
and
Blomqvist,
1973;
Prakash
et
al.,
1972;
tachycardia
or
fibrillation.
Quinones
et
al.,
1974;
Siegal
et
al.,
1972)
have
indicated
only
occasional
arrhythmias;
however,
these
studies
were
not
designed
to
look
specifically
References
for
arrhythmias,
and
continuous
electrocardio-
Cohn,
P.
F.,
Horn,
H.
R.,
Teichholz,
L.
E.,
Kreulen,
T.
H.,
graphic
recordings
were
not
always
made.
Further-
Herman,
M.
V.,
and
Gorlin,
R.
(1973).
Effects
of
angio-
more,
no
comments
were
made
regarding
the
use
of
graphic
contrast
medium
on
left
ventricular
function
in
coronary
artery
disease.
American
J'ournal
of
Cardiology,
antiarrhythmic
therapy
before
exercise
testing.
32,21.
In
this
series
all
patients
who
developed
arrhyth-
Ellestad,
M.
H.,
Allen,
W.,
Wan,
M.
C.
K.,
and
Kemp,
G.
L.
mias
did
so
at
50
per
cent
maximal
voluntary
(1969).
Maximal
treadmill
stress
testing
for
cardiovascular
contraction,
a
higher
isometric
stress
than
used
by
evaluation.
Circulation,
39,
517.
contrction
a
hiher
iometic
stess
tan
usd
by
Ewing,
D.
J.,
Irving,
J.
B.,
Kerr,
F.,
and
Kirby,
B.
J.
(1973).
other
investigators.
The
incidence
of
ventricular
Static
exercise
in
untreated
systemic
hypertension.
British
arrhythmias
was
only
11
per
cent
in
this
series
at
Heart
Journal,
35,
413.
25
per
cent
maximal
voluntary
contraction.
Fisher,
M.
L.,
Nutter,
D.
O.,
Jacobs,
W.,
and
Schlant,
R.
C.
The
incidence
of
ventricular
arrhythmias
and
(1973).
Haemodynamic
responses
to
isometric
exercise
(handgrip)
in
patients
with
heart
disease.
British
Heart
especially
ventricular
tachycardia
was
high
in
tjournal,
35,
422.
patients
with
ischaemic
heart
disease
and
in
Freyschuss,
U.
(1970).
Cardiovascular
adjustment
to
somato-
those
with
abnormal
ventricular
function.
Those
motor
activation.
Acta
Physiologica
Scandinavica,
Suppl.
patients
with
depressed
ejection
fraction
and
342.
Gooch,
A.
S.,
and
McConnell,
D.
(1970).
Analysis
of
transient
those
with
severe
coronary
disease
on
coronary
arrhythmias
and
conduction
disturbances
occurring
angiography
had
a
50
per
cent
incidence
of
ven-
during
submaximal
treadmill
exercise
testing.
Progress
tricular
arrhythmias
during
isometric
stress
testing.
in
Cardiovascular
Diseases,
13,
293.
The
reasons
for
the
high
incidence
of
ventricular
Greene,
D.
G.,
Carlisle,
R.,
Grant,
C.,
and
Bunnell,
I.
L.
(1967).
Estimation
of
left
ventricular
volume
by
one-plane
arrhythmias
during
isometric
exercise
in
patients
cineangiography.
Circulation,
35,
61.
with
heart
disease
is
not
clear.
A
more
intense
Grossman,
W.,
McLaurin,
L.
P., Saltz,
S.
B.,
Paraskos,
J.
A.,
sympathetic
drive
during
isometric
than
during
Dalen,
J.
E.,
and
Dexter,
L.
(1973).
Changes
in
the
dynamic
exercise
is
a
possible
but
unlikely
explana-
inotropic
state
of
the
left
ventricle
during
isometric
tion.
Physiological
studies
by
Lind
etIal.
(1966)
exercise.
British
Heart
Journal,
35,
697.
tion
Phyioloicalstudes
b
Lin
et
l.
(966)
Haissly,
J.
C.,
Messin,
R.,
Degre,
S.,
Vandermoten,
P.,
and
by
Freyschuss
(1970)
suggest
that
the
heart
Demaret,
B.,
and
Denolin,
H.
(1974).
Comparative
re-
rate
increase
during
isometric
exercise
is
primarily
sponse
to
isometric
(static)
and
dynamic
exercise
tests
in
mediated
by
vagal
withdrawal.
The
rate
accelera-
coronary
disease.
American
Journal
of
Cardiology,
33,
791.
tiondurig
dyamicexeriseat
lw
wok
lod
leels
Helfant,
R.
H.,
deVilla,
M.
A.,
and
Meister,
S.
G.
(1971).
tion
during
dynamic
exercise
at
low
work
load
levels
Effect
of
sustained
isometric
handgrip
exercise
on
left
is
also
primarily
the
result
of
vagal
withdrawal,
but
ventricular
performance.
Circulation,
44,
982.
sympathetic
stimulation
becomes
increasingly
im-
Jacobs,
W.
F.,
Nutter,
D.
O.,
Siegal,
W.,
Schlant,
R.
C.,
and
portant
at
higher
loads
(Robinson
et
al.,
1966).
Hurst,
J.
W.
(1970).
Hemodynamic
responses
to
isometric
The
arrhythmia-suppressing
effect
of
an
increased
handgrip
in
patients
with
heart
disease
(abstract).
Circula-
The
arhythma-supressig
effet
of
n
inceased
tion,
42,
Suppl
3,
169.
heart
rate
is
well
known,
i.e.
sinus
tachycardia
over-
Kivowitz,
C.,
Parmley,
W.
W.,
Donoso,
R.,
Marcus,
H.,
drive
of
the
ventricular
arrhythmia.
The
occurrence
Ganz,
W.,
and
Swan,
H.
J.
C.
(1971).
Effects
of
isometric
of
chest
pain
and
ischaemic
ST
depressions
more
exercise
on
cardiac
performance:
the
grip
test.
Circulation,
frequenly
durng
dynmic
execise
i
the
ptients
44,
994.
frequently
during
dynamic
exercise
in
the
patients
Kosowsky,
B.
D.,
Lown,
B.,
Whiting,
R.,
and
Guiney,
T.
with
ischaemic
heart
disease
and
the
peak
heart
rates
(1971).
Occurrence
of
ventricular
arrhythmias
with
and
heart
rate-systolic
blood
pressure
products
exercise
as
compared
to
monitoring.
Circulation,
44,
826.
during
exercise
indicate
that
peak
myocardial
Krayenbuehl,
H.
P.,
Rutishauser,
W.,
Schoenbeck,
M.,
and
oxygen
demand
was
higher
during
dynamic
exercise.
Amende,
I.
(1972).
Evaluation
of
left
ventricular
function
oxygen
demand
was
higher
during
dynamic
exercise.
from
isovolumic
pressure
measurements
during
isometric
The
higher
incidence
of
ventricular
arrhythmias
exercise.
American
Journal
of
Cardiology,
29,
323.
Isometric
and
dynamic
exercise
arrhythmias
471
Lind,
A.
R.,
McNicol,
G.
W.,
and
Donald,
K.
W.
(1966).
cular
response
to
isometric
exercise.
American
Heart
Circulatory
adjustments
to
sustained
(static)
muscular
Journal,
88,
29.
activity.
In
Physical
Activity
in
Health
and
Disease,
p.
38.
Robinson,
B.
F.,
Epstein,
S.
E.,
Beiser,
G.
D.,
and
Braunwald,
Ed.
by
K.
Evang
and
K.
L.
Andersen.
Universitats-
E.
(1966).
Control
of
heart
rate
by
the
autonomic
nervous
forlaget,
Oslo.
system:
studies
in
man
on
the
interrelationship
between
Ludbrook,
P.,
Karliner,
J.
S.,
and
O'Rourke,
R.
A.
(1974).
baroreceptor
mechanisms
and
exercise.
Circulation
Effects
of
submaximal
isometric
handgrip
on
left
ventri-
Research,
19,
400.
cular
size
and
wall
motion.
American
Journal
of
Cardiology,
Rochmis,
P.,
and
Blackburn,
H.
(1971).
Exercise
tests:
a
33,
30.
survey
of
procedures,
safety,
and
litigation
experience
in
Matthews,
0.
A.,
Blomqvist,
C.
G.,
Cohen,
L.
S.,
and
approximately
170,000
tests.
Journal
of
the
American
Mullins,
C.
B.
(1974).
Left
ventricular
function
during
Medical
Association,
217,
1061.
isometric
exercise
(handgrip):
significance
of
an
atrial
Siegel,
W.,
Gilbert,
C.
A.,
Nutter,
D.
O.,
Schlant,
R.
C.,
and
gallop
(S4).
American
Heart
Journal,
88,
686.
Hurst,
J.
W.
(1972).
Use
of
isometric
handgrip
for
the
Mitchell,
J.
H.,
and
Wildenthal,
K.
(1974).
Static
(isometric)
indirect
assessment
of
left
ventricular
function
in
patients
exercise
and
the
heart:
physiological
and
clinical
considera-
with
coronary
atherosclerotic
heart
disease.
American
tions.
Annual
Review
of
Medicine,
25,
369.
J7ournal
of
Cardiology,
30,
48.
Mullins,
C.
B.,
and
Blomqvist,
G.
(1973).
Isometric
exercise
Strandell,
T.
(1963).
Electrocardiographic
findings
at
rest,
and
the
cardiac
patient.
Texas
Medicine,
69,
53.
during
and
after
exercise
in
healthy
old
men
compared
Prakash,
R.,
Parmley,
W.
W.,
Dikshit,
K.,
Forrester,
J.,
and
with
young
men.
Acta
Medica
Scandinavica,
174,
479.
Swan,
H.
J.
C.
(1972).
The
effects
of
isometric
handgrip
stress
in
patients
with
acute
myocardial
infarction
(ab-
Requests
for
reprints
to
Dr.
James
M.
Atkins,
Cardio
-
stract).
Clinical
Research,
20,
209.
Quinones,
M.
A.,
Gaasch,
W.
H.,
Waisser,
E.,
Thiel,
H.
G.,
pulmonary
H8-116,
5323
Harry
Hines
BouI2lard
and
Alexander,
J.
K.
(1974).
An
analysis
of
the
left
ventri-
Dallas,
Texas
75235,
U.S.A.
