# Normal Frequencies in Heart

I am trying to visualise possible ranges of frequencies from different structures of heart:

• different valves and their possible frequencies
• heart sounds I - IV and their normal frequencties
• what can frequencies be in healthy situation for adult
• what can frequencies be in healthy situation for children 4-9 years old

I searched meta-analysis, clinical trials and reviews in PubMed unsuccessfully.

Is there any review article or book about the frequencies from different structures of heart?

Search terms used

• frequency heart
• frequency heart valve
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frequency as in the electromagnetic frequencies I presume? – The Last Word Jun 13 '14 at 5:35
Yes. Electromagnetic frequencies. – Masi Jun 13 '14 at 5:44

This is a part answer (as this is outside of my field), but the article Self Regulation of the Heart: Natural Frequency and Damping of the Heart Contractions (Bahramali et al. 2009) imply that 'normal' frequencies may not be possible to precisely define, due to:

ECG frequency analysis is complicated by the fact that ECG signals are non-stationary, that is, their activity patterns change slowly or intermittently as a result of variations in a number of physiological and physical influences.

The article extensively reviews the general frequency analysis, divided into P, Q, R, S and T components. However, they define 'optimal conditions' (i.e. 'normal and healthy) as:

optimal conditions of the heart contraction as those under which the dynamics of contraction shows the best agreement with underdamped harmonic oscillation

An example of this is visualised in the diagram below:

this example is provided on the University of Pennsylvania tutorial site ECG Tutorial

In the article Comparison of Power Spectral Density (PSD) of Normal and Abnormal ECGs (Das and Chakraborty, 2011), note comprisons for the QRS component, as

QRS complexes are chosen because it shows distinct differences for different heart diseases

In other words, distinguishing healthy from not-so-healthy.

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Thank you for your review! Those mathematical methods used in those publications are insufficient. Data is lost when filtering is used. Power spectrum vs frequencies can NEVER reveal the exact energy patterns of the cardiac frequencies in time. – Masi Sep 28 '14 at 11:39