The challenge of building a clinical neurophenomenology of palpitations and cardiodyamics

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from spiritualnetworks.com

Heart disease is a leading threat to health, and people worry when they feel changes

in their heartbeat. Should clinicians trust descriptions of these palpitations? How should

clinicians and scientists model personal, phenomenological statements about what is

happening inside the body of a subject or patient? In an increasingly standardized,

scientific, and objective world of medicine, what role is there for a doctor’s intuitions and

instincts about a patient’s bodily sensations?

These are not simple questions, as they attempt to straddle a fundamental duality

between patients understood as embodied persons in an existential context of health and

disease, and humans understood as systems, as bio-machines modeled by science.

Clinicians collect measurements and interpret data about that category of object known as

a human body, and must compare this externalized, ostensibly objective, techno-scientific

knowledge to their patients’ description of what their bodies feel like. Like the Roman

god Janus, the healer faces two worlds. As modern medicine becomes more involved

with science, integrating these two domains requires ever-more flexibility,

thoughtfulness, and careful techniques for acquiring and modeling data. As complex as

these practical necessities are, science peers even deeper, into the meaning of the often

enigmatic gap that can exist between patient descriptions of the heart speeding up or

missing beats, and the lack of corresponding measurement of heart electrical output as

measured through electrocardiograms (ECG). Medicine needs good approaches for

distinguishing palpitations of psychosomatic origin from those with cardiac etiology, as

well as general guidelines for the trustworthiness of patient-reported data about their

bodily sensations. Science needs to understand what mechanisms in the brain, body, and

mind explain both accurate and inaccurate palpitations reports.

Knowledge of, and theories about, fluid dynamics, hematology, processing of cardiac

state by the peripheral nervous system, receptor activation, hormone binding, protein

signaling, up-regulation and down-regulation of genes, and models of perfusion support

sophisticated models of cardiodynamics. Yet the heart can be thought of in rather more

intuitive terms, as a pump made of muscle that moves oxygen-poor blood to the lungs,

and newly oxygenated blood to the rest of the body. Electrocardiograms show the

rhythms of this pumping as sometimes more regular and periodic and other times less so.

But how much personal knowledge do patients have about what the heart is doing?

Personal knowledge of the body is a problem for mechanistic science. While cardiac

periodicity is an object of scientific measurement, and therefore clinically and

epistemologically privileged for scientists constructing explanations, the personal

experience and phenomenological knowledge of the body may be considered merely

subjective opinion or anecdotal.

People introspecting about their interior sensations sometimes report to their doctor

that their heart is racing, pounding, or skipping beats. In some instances, such data are

compared to that from publically available sources such as ECG, and a diagnosis of

cardiac etiology is made, but in other cases doctors believe the patient is  psychosomatically

cognizing benign heart rhythms as dangerous. When measurements of cardiodynamics do

not correspond well to unwelcome sensations of altered heartbeats, how should medicine

and science understand the discrepancy? This work addresses this problem directly,

by modeling the probabilities that a patient’s experience corresponds to

a medically important heart rhythm disorder. For the patient, feeling a change in

the rhythm or intensity of this fundamental aspect of ongoing embodied existence can

be very worrisome. When the cause is psychosomatic, medicine categorizes it as unexplained,

and cognitive neuroscience faces an explanatory challenge. Somewhere between the cardiac nerves,

brainstem, thalamus,and cortical regions, normal heart rhythms are processed as abnormal and

threatening, but why?

A true understanding of such a gap between personal bodily feelings and cardiac

measurement requires an implicit or explicit mapping of cardiographic, radiological, and

other data onto a description from the patient about what is going on inside their body, or

vice versa. This is not the sort of problem that cognitive science has heretofore usually

focused on, but the field of medical cognitive science can apply ideas from neuroscience

to come up with an explanation. Current evidence (Damasio, 2010) suggests a role for

multiple areas in the peripheral and central nervous systems that process cardiac rhythm

signals, which are cognized into feelings of skipping beats and other abnormal rhythms

(Barsky, 2000).

Such theoretical problems aside, clinicians must apply complex psychological,

anatomical, neurophysiological, and etiological concepts to interpret their patients’

symptom reports. What patients have to say about what is happening in their bodies must

be taken seriously, but not necessarily believed. Traditionally, a doctor might have had

some intuition about the reliability of a patient’s description of their heart fluttering or

racing and would consider the possibility that emotions, stress, and existential or

psychological issues partially or mostly explain the diagnosis. Yet the demands placed on

modern clinicians increasingly constrict the time they may spend listening to the patient,

making it harder for them to get a rich description of the proper existential context

framing the presenting complaint. As such, the need for quickly ascertaining the

probability that palpitation symptoms have a cardiac or psychosomatic etiology becomes

paramount.

What good is patient phenomenology in this new world of evidence-based medicine?

To determine this, I shall focus in particular on comparing the predictive utility of patient

palpitation reports for cardiac arrhythmias to other clinically predictive measures that do

not depend on introspective data from the patient. This predictivity will support the

differential diagnosis of cardiac-based palpitations against psychosomatic etiology, but

modeling how well symptoms correspond to physiological measurements can also serve

to operationalize what I will term “body cognition” and “body knowledge.” Palpitations

are usually defined as unwelcome awareness of cardiac activity (Barsky, 2000), such as

skipping, racing, or thumping heartbeats. Do people with such presenting complaints

have heart rhythm abnormalities requiring medical attention, benign heart rhythm

fluctuations, or normal heartbeats somehow sensed as strange, unpleasant, and abnormal?

Evidence suggests that patients reporting palpitations who have an anxiety disorder are

less likely to have arrhythmias (Abbott, 2005), but the reasons people with normal heart

rhythms report palpitations must be considered a mystery for science, and a challenge

(Barsky, 2000).

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