Bradycardia
Bradycardia, or persistent slow pulse, is much rarer than the
persistent rapid pulse discussed at the beginning of the chapter on
tachycardia. Cases are, indeed, sufficiently rare to be medical
curiosities. Prof. Clifford Allbutt has called attention to the fact
that the status of bradycardia or brachycardia, as Osler (following
Riegel because of the analogue tachycardia) prefers to call it, is
very different from that
of tachycardia. In the latter, especially, in
the specific sense of the term, the symptoms occur paroxysmically,
endure for a definite length of time and then there is a return to the
normal pulse rate. For this, or at least for the condition known as
essential tachycardia, there is no well-defined cause and no definite
pathological lesion. Bradycardia or brachycardia, however, is usually
present as the result of some known physiologic or pathologic
condition; it endures as long as the cause continues to act and then
ceases, usually not to return unless the same cause gives rise to it
again.
There are some cases, however, of slow pulse that cannot be traced to
any definite lesion and in which the pulse is much slower at certain
times than at others, though without its being possible to trace any
definite immediate cause. These cases seem to be physiological
analogues of tachycardia. In tachycardia there is an irritation of the
accelerator nerves to the heart, in brachycardia of the inhibitory
nerves.
Depressed Mental States.--Occasionally the reason for this can be
found, though it is rather vague. In depressed mental states, for
instance, a pulse between fifty and sixty is common. In people who
suffer from periodic fits of depression it is not unusual to find that
in the early morning the pulse is not more than fifty-five. I have
seen patients who were worrying about their hearts present records of
early morning pulse before they got up that were always below sixty.
This is probably in a certain number of people quite normal. I
remember a series of observations made on the attendants in the
Charite Hospital in Berlin in which it was clear that the normal
German morning temperature at seven a.m. was below 97 F., while the
pulses were always below sixty. A reassurance of this kind is helpful
to patients who have acquired the bad habit of taking their own pulse
and have been disturbed by finding it so much below what they consider
normal.
Illustrative Case.--A number of cases of persistent slow pulse seem to
be congenital or produced by some definite pathological lesion, yet do
not prove serious for the patient. Some years ago I described one of
these cases in a paper read before the Section on Medicine of the New
York Academy of Medicine [Footnote 29] and I have had the opportunity
to follow it for about fifteen years. Though the patient's pulse is
usually below forty and even after a rapid walk does not rise above
fifty, she is in reasonably good health and during those years has
buried two husbands. When I saw her she was compelled to go up and
down stairs frequently and yet did not experience much difficulty.
While patients suffering from palpitation would find it impossible,
because of the discomfort produced, to make the journeys up and down
stairs that she did, she felt only about as much respiratory
discomfort as would come to a woman of her size. Her respirations were
somewhat hurried--22 to 24 to the minute--but her general health was
very good. Her urine was normal, her liver not enlarged, her ordinary
organic functions were not disturbed and there was no sign of arterial
degeneration.
[Footnote 29: The Medical News, November 10, 1900.]
With the pulse rate as low as this one might expect to find the
patient phlegmatic, slow of movement and not readily moved to emotion.
On the contrary, she has always been rather nervous and high-strung
and inclined to be excitable. Her cardiac condition was first noted
just after the first grip epidemic in this country, though her
attention was not called to it during the course of the grip. It seems
probable that the heart condition was acquired as a consequence of
some irritative lesion affecting the inhibitory nerves to the heart
that developed at that time. After her heart condition had been
discovered she was for a time a skirt dancer and frequently danced for
the amusement of her friends. She was always lively and active and
after her first husband's death, when it became necessary for her to
earn her own living, she was on the stage for a time and danced
without any embarrassment of either heart or respiration. As a
consequence of running down in weight and general health, owing to
conditions since her husband's death, she noticed that dancing proved
exhausting to her and she gave it up.
In general, she considered herself quite as capable as any of her
friends for the ordinary duties and amusements of life. When I first
saw her her digestion had been somewhat disturbed by worries and
unsuitable nutrition taken at irregular intervals and this, I think,
accounted much more than her heart for her complaint of tiredness on
exertion. Later, after her second marriage, when she was in better
circumstances, all her symptoms disappeared and even her heart rate
rose so that it was seldom below forty, and after exertion always went
to fifty. What was needed in her case more than anything was a change
of environment, the satisfaction of mind that comes with freedom from
worries and the cares of making her own living, and the improvement in
digestion due to regular meals of good, simple, nutritious food.
Compatibility with Health and Activity.--The above case is interesting
as illustrating mental influence upon such a serious condition as
bradycardia. Most people who suffer from it are likely to be
over-depressed and this reacts to disturb digestion and also further
to disturb the heart itself. What these patients need above all, then,
is reassurance with regard to their condition. There are some striking
examples in history and in medical literature of bradycardia or
persistent slow pulse in persons who are able to accomplish a large
amount of work and whose general health and capacity for
accomplishment were not at all disturbed by this physical condition.
Above all, they were not depressed and did not lack initiative.
Napoleon I, whose pulse is said normally to have been about forty,
rising during the excitement of battle to fifty, is a typical example.
Medical literature records a number of patients with congenital slow
pulse without any discernible heart lesion who lived long and
successful lives. One of these was a very successful English athlete.
The prognosis of these cases is not as bad as it might seem to be and
the mental state of the patient is more important than anything else
in the treatment.