In a quest to find the sound of our heart, in an electromagnetic frequency sense I got in contact with two cardiologists through a friend working in the NHS. Although for some time I’d been recording my own heartbeat through the use of a contact mic, the signal was low and the sounds are a reverberation through muscle, skin, tissues, bone. I was aware also of the use of the Doppler for recording foetal heartbeats. An echocardiogram uses a doppler to hear the whole heart cycle and to listen to each heart valve, the right rhythm indicative of a healthy heart. It is one of the most common tests for electrical activity. What I was trying to ascertain though was could a printed ecg heart wave rhythm be translated into different frequencies. When the sinus wave peaked did that correlate to a particular pitch? Could we hear the sound of our hearts in a different way?
I started to look into the shape of an ECG waveform:
positive deflection – when the electrical activity of the heart travels towards a lead. negative deflection – when activity travels away from a lead.
The electrical activity of the heart flows in many directions at once – the wave on a ECG represents the average direction.
Height of a wave – amount of electricity flowing in that direction. A regular sinus rhythm 60 -100 beats per min (82bpm). Ultrasound – above 20Khz (20,000Hz).
Reflecting on ECG waveforms and recording my heartbeat gave me the rhythm translated as a sound wave. On further conversation with both cardiologists I discovered that the Doppler is velocity based and the signal will be different from the ECG, ie the doppler is listening to the speed of blood circulating around the heart, the ECG is recording the electrical signal. It’s the electrical signal I want to map the sound of. They suggested I need a physics expert and that’s where I’ve reached a stopping point. It may be that this can be translated into a bigger project, to begin mapping the body and it’s sonic capacity in different ways. To work in collaboration with a team. It may also be a non starter.
This mini research however and the notion of measuring velocity and thinking of volumes of liquid set me thinking of the capacity of the heart, it’s holding capacity, it’s significance as a vessel, or set of chambers, not only in a physical sense but in a metaphorical one.
A holding of expectation, a carrier of emotions, a signifier of feeling.