The time between heartbeats and what it reveals about cardiac rhythm
The rhythm of the heart is not defined only by how fast it beats, but by how the timing between beats changes over time.
One of the most important ways to observe this timing is through RR intervals. These intervals represent the time between consecutive heartbeats and provide a deeper view of how the heart rhythm behaves.
In Cardiomic, RR intervals are derived from heart sound recordings captured with the smartphone microphone, allowing the rhythm of the heart to be analyzed directly from acoustic signals.
What is an RR interval
An RR interval is the time between two consecutive heartbeats.
The name comes from electrocardiography, where the main peak of the heartbeat signal is called the R wave. The interval between two R waves is therefore called the RR interval.
Even though Cardiomic records heart sounds instead of electrical signals, the same concept can be applied by detecting the timing of each heartbeat in the acoustic signal.
The heart is not perfectly regular
A common misconception is that a healthy heart beats like a metronome with perfectly equal intervals.
In reality, the time between heartbeats naturally fluctuates from moment to moment. These small variations reflect the continuous interaction between the heart and the nervous system.
Because of this, RR intervals constantly change as the body adapts to breathing, movement, and internal physiological regulation.
From RR intervals to heart rhythm insights
Observing RR intervals allows the rhythm of the heart to be analyzed beyond simple heart rate.
Instead of only counting beats per minute, the pattern formed by the intervals reveals how stable, variable, or dynamic the rhythm appears during a recording session.
This information forms the basis for several rhythm metrics used in Cardiomic, including measures of rhythm variability and the Cardiac Progress Score.
Why RR intervals matter
RR intervals provide one of the most fundamental ways to observe the dynamics of heart rhythm.
By studying how these intervals evolve over time, it becomes possible to identify patterns that remain invisible when looking only at average heart rate.
For this reason, RR interval analysis is widely used in physiological research and heart rhythm studies.
Cardiomic brings this concept into an accessible form, allowing users to explore the timing patterns of their own heart rhythm through simple smartphone recordings.