Brief summary of evidence supporting the efficacy of biofeedback for non-cardiac related chest pain:
The amount of change in heat rate with change in breathing is an index of vagal tone. It is simple to evaluate relationships between heart rate variability and respiration using biofeedback equipment.
Gevirtz and his team (e.g., DeGuire et al 1996) as well as many others have shown that there is a solid relationship between anxiety and non-cardiac related chest pain. They have also shown that abnormal patterns of respiration well known to lead to feelings of anxiety due to changes in concentration of carbon dioxide, also result in non-cardiac chest pain. The literature indicates that between 51 and 90% of non-cardiac related chest pain is associated with hyperventilation. Retraining breathing patterns results in long term (at least three years) control of stress related cardiac pain symptoms and hyperventilation related symptoms such as anxiety. See Gevirtz's placebo controlled, long term follow-up studies (e.g. DeGuire et al 1996) for details of their findings. It is emphasized that correction of these breathing patterns relieves the chest pain or eliminates it all together without further intervention to correct an anxiety disorder. Thus, it is the sequeli of incorrect breathing which create both anxiety and chest pain for many patients - not an underlying anxiety disorder which results in incorrect breathing.
The newest approach involves using biofeedback to maximize heart rate variability in relation to respiration in order to treat cardiac pain. The idea is that variability increases and decreases as people breath in and out. Patients are trained to maximize variability by watching the display. The technique is currently called "Resonant Frequency Training" (RFT) and was previously called respiratory sinus arrhythmia biofeedback (RSA). The literature supporting the technique's efficacy is solid (e.g. Gevirtz 1999, Gevirtz 2002, Lehrer et al 2000).
* Much of the information provided here is from Carolyn Yucha and Christopher Gilbert's 2004 book "Evidence Based Practice in Biofeedback & Neurofeedback" AAPB, Wheat Ridge, CO.