Eight-Principle Diagnostic Standards

Interpreting Blood Pressure Readings by Eight-Principle Diagnostic Standards

By Tina Chen and Wei-Yen (Jimmy) Chang, LAc, Dipl. Ac.

Whether approached by a seasoned long-term practitioner or someone just setting up practice, there are cases in which it is difficult to differentiate a patient’s condition according to classic Eight-Principle theory.

When a patient presents with complex symptoms, it is not always easy to come up with a confident, simple diagnosis and herbal prescription. The patient may be taking one or more pharmaceuticals that complicate the clinical presentation, which makes it difficult to know which symptoms are true and which are side-effects of the drug(s). The patient also may not tell his or her entire history or list of complaints for one reason or another.

Conversely, the difficulty in reaching a diagnosis may occur because the patient describes too many symptoms, whether they are related to the chief complaint or not. In other cases, contradictory elements are in play, such as when a patient exhibits all excess signs but states that he or she suffers from chronic fatigue syndrome. The patient may feel cold, but have a pulse that is forceful and rapid, and a tongue that is extremely red, with a definite yellow coating. One way or another, subjective complaints from patients may not always point to an immediate correct diagnosis.

One objective way to find out exactly whether the patient is truly suffering from deficiency, excess, heat or cold is to take the blood pressure and note the heart rate. Master Chang uses this method daily on all of his patients and has confirmed its practical usefulness through thousands of cases in 20 years of practice. Below is a brief summary of the patterns representing the most commonly seen complex types in the clinic.

Type 1: Systolic pressure (high) + Diastolic pressure (high) + Heart rate (fast) = Excess Heat

Patients with both high blood pressure and a fast heart rate are, without exception, suffering from an excess heat condition. Please note that these patients may complain that they are tired and depressed. However, if they have high blood pressure and a fast heart rate, tonic herbs should never be used, despite the fact that the patient complains of tiredness. The diagnosis is excess fire. This should be addressed with heat-clearing herbs.

Type 2: Systolic pressure (low) + Diastolic pressure (low) + Heart rate (slow) = Yang Deficiency

Patients who have low blood pressure and a slow heart rate are experiencing deficiency, mostly qi or yang deficiency. These deficiencies are best helped by tonic herbs; never give these patients sedating herbs.

Type 3: Systolic pressure (high) + Diastolic pressure (normal) + Heart rate (slow) = Deficiency Heat + Blood Stasis

Patients who belong to this category usually suffer from blood stasis, which may be the result of an old injury or surgery. The heart rate is slow because of blood stasis/obstruction of the blood flow. In turn, systolic pressure is increased, as the body attempts to maintain balance. The increased pressure and lack of flow result in heat from deficiency. Carefully selecting appropriate blood-moving and stasis-resolving herbs with herbs to clear deficiency heat will be the most helpful strategy for treating these patients.

Type 4: Systolic pressure (low) + Diastolic pressure (low) + Heart rate (fast) = Yin Deficiency Heat

The last group might appear to reflect heat because of the rapid rate, but the low blood pressure tells a different story: the insufficient quantities of blood and yin in circulation require a rapid heart rate to maintain positive circulation. This is similar to a car engine running with insufficient oil: eventually, heat begins to build up from the deficiency of lubricating yin. These patients are suffering from yin deficiency heat, and must be treated with herbs that tonify yin and sedate the deficiency heat.

Summary: Using Blood Pressure + Heart Rate for Eight-Principle Differentiation

This approach can provide a guideline to follow when confronted with a confusing presentation in the patient. Tongue and pulse diagnoses should be combined with this approach to reach an accurate diagnostic conclusion. Here is an example of a recent case that was addressed using this method.

Type Systolic Pressure Diastolic Pressure Heart Rate Diagnosis Herbs
Type 1 High High Fast Excess Heat Heat-clearing herbs
Type 2 Low Low Slow Yang Deficiency Tonic herbs
Type 3 High Normal Slow Deficient Heat + Blood Stasis Blood moving herbs + deficiency heat-clearing herbs
Type 4 Low Low Fast Yin Deficiency heat Tonify yin and sedate deficiency heat