It’s very common to feel heart rhythms skipping, going unusually fast, or slow, or strange rhythms.
These are called palpitations. Sometimes they are caused by cardiac arrhythmias, but alot of the time, your heartbeat is measurably normal, yet by the time your brain processes the waves coming from your heart nerves and then the spinal cord, normal heartbeats are not what you experience.
Noone in science or medicine understands this discrepancy between bodily experience and physiological measurement.
I have some good news for some of you reading: if you’re young and basically healthy, without a diagnosis of cardiac rhythms disorders, it’s quite unlikely that when you feel weird heartbeats, it’s due to an actual cardiac rhythm disorder. It’s probably due to emotional or “psychosomatic” factors like anxiety or stress or depression, somehow transforming a normal signal from the heart into something worrisome.
Here is a healthy heart, with normal rhythm, from Wikimedia Commons:
How do I know that most young healthy people without a cardiac rhythm problem are experiencing palpitations due to psychological and emotional and psychosomatic reasons? I researched this for years, and wrote a dissertation on it while finishing my PhD at the University of Texas, with a Program of Work in Medical Cognitive Science:  (For what it’s worth, my supervisor was Gerhard Werner, MD, a pioneering neuroscientist and former Dean of the Medical School at the University of Pittsburgh, and he said at my dissertation defense that this was a new area for science)
Maybe someday we can measure how a normal heartbeat’s signal, which activates cardiac nerves, then the spinal cord, then is processed by the brainstem, thalamus, the insular cortex and other cortical regions, gets experienced by people as weird and unpleasant palpitations. Below, the spinal cord is shown at the bottom, and the insular cortex highlighted, then other cortical regions shown last and on top
There should be some neural mechanisms that explain the mismatch between cognition and body phenomenology vs physiology. After good measurements, maybe we can hypothesize a mechanism. This seems like a good opportunity to leverage the work on embodied cognition and neural oscillations by Varela (1999), who wrote:
“Hypothesis I: For every cognitive act. there is a singular, speciﬁc neural
assembly that underlies its emergence and operation.
According to this hypothesis, the emergence of any cognitive act requires the rapid coordination of many different capacities (attention, perception, memory, motivation, and so on) and the widely distributed neural systems subserving them. The neurophysiological substrate for this large-scale coordination is assumed to be a neural assembly, which can be deﬁned as a distributed subset of neurons with strong reciprocal connections.
In the context of large-scale integration, a dynamic neural assembly engages vast and disparate regions of the brain. There are reciprocal connections within the same cortical area or between areas at the same level of the network; there are also reciprocal connections that link different levels in different brain regions. Because of these strong interconnections across widely distributed areas, a large-scale neural assembly can be activated or ignited from any of its smaller subsets,whether sensorimotor or internal. These assemblies have a transient, dynamic existence that spans the time required to accomplish an elementary cognitive act and for neural activity to propagate through the assembly.”
Perhaps these approaches from theoretical cognitive neuroscience point us in the right direction, or not. The mismatch between what rhythms people feel their hearts doing, vs what can be measured as normal rhythms, seems a very hard problem, but perhaps tractable, even solvable in my lifetime, or yours. Message me if you think you know how this might work, or want to help solve these problems.