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What Can Doctors Learn from a Systolic-Diastolic Ratio?

Franklin Jeffrey
Franklin Jeffrey

In most doctors' offices, a patient's vital signs will be taken before the physician enters the examination room. One of the readings that will be recorded is the patient's blood pressure, which is expressed as the systolic rate over the diastolic rate. The systolic-diastolic ratio tells the doctor how much pressure is being exerted on the arteries when the heart contracts and relaxes. High blood pressure is a potentially dangerous condition in itself, but the systolic-diastolic ratio can also warn the doctor that the patient may have a problem with his heart, kidneys or circulatory system. Abnormally low blood pressure may be a symptom of dehydration, internal bleeding, certain inflammatory diseases or heart disease.

A heartbeat consists of two separate actions. The heart contracts, forcing blood out of the heart so that it can circulate throughout the body. This is the systolic phase. Following the contraction, the heart relaxes to allow blood to enter its chambers. The relaxed stage is known as the diastolic phase.

A blood pressure reading provides systolic and diastolic rates.
A blood pressure reading provides systolic and diastolic rates.

When analyzing a patient's blood pressure, the doctor will look at each number as well as the systolic-diastolic ratio. In patients over the age of 50, doctors normally pay more attention to the systolic number. As people age, the systolic rate normally increases as a result of plaque building up in the arteries and a tendency for the arteries to stiffen over time. If the systolic-diastolic ratio is greater than 140/90, the doctor knows that the patient may have high blood pressure.

In patients over the age of 50, doctors normally pay more attention to the systolic number.
In patients over the age of 50, doctors normally pay more attention to the systolic number.

If a younger patient displays a high systolic-diastolic ratio, the doctor may suspect an underlying condition may be causing the higher blood pressure. The doctor may evaluate the patient for a heart valve defect or ask if the patient is experiencing any symptoms of kidney disease. As blood pressure can vary a great deal from day-to-day or by the time of day, more than one reading is often needed to make a diagnosis.

Systolic blood pressure is the top number when reading blood pressure levels, and generally doctors recommend it be below 140.
Systolic blood pressure is the top number when reading blood pressure levels, and generally doctors recommend it be below 140.

Patients with an abnormally low systolic-diastolic ratio may need to be evaluated for internal bleeding. Ulcers and injuries are common causes of internal bleeding, as are aneurysms, or weaknesses in the walls of blood vessels, which can cause internal bleeding if they burst. Certain diseases, such as pancreatitis and diverticulitis, may also cause internal bleeding. The patient's blood pressure reading may provide the doctor with information pointing to one of these conditions.

Systolic blood pressure reflects the average pressure exerted on the arterial walls during the contraction of the heart.
Systolic blood pressure reflects the average pressure exerted on the arterial walls during the contraction of the heart.

Although a doctor may learn a great deal from a patient's systolic-diastolic ratio, blood pressure alone is not enough to allow a diagnosis. The doctor will also listen to the patient's heart, check his pulse rate, listen to his breathing and ask questions about other possible symptoms. Other vital signs, such as the patient's temperature and weight, will also be included in the doctor's evaluation.

Discussion Comments

anon937421

"Patients with an abnormally low systolic-diastolic ratio may need to be evaluated for internal bleeding." etc. There is very little here about the actual ratio, which would be the figure from dividing the systolic by the diastolic, often about 1.6.

Does that sentence really refer to the ratio, or to the two figures? For example, 80/50 would be a low blood pressure, but the ratio would be quite normal at 1.6.

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    • A blood pressure reading provides systolic and diastolic rates.
      By: Helder Almeida
      A blood pressure reading provides systolic and diastolic rates.
    • In patients over the age of 50, doctors normally pay more attention to the systolic number.
      By: auremar
      In patients over the age of 50, doctors normally pay more attention to the systolic number.
    • Systolic blood pressure is the top number when reading blood pressure levels, and generally doctors recommend it be below 140.
      By: dambuster
      Systolic blood pressure is the top number when reading blood pressure levels, and generally doctors recommend it be below 140.
    • Systolic blood pressure reflects the average pressure exerted on the arterial walls during the contraction of the heart.
      By: Alexandr Mitiuc
      Systolic blood pressure reflects the average pressure exerted on the arterial walls during the contraction of the heart.
    • In addition to checking blood pressure, medical professionals typically assess the patient's temperature and pulse rate.
      By: s_l
      In addition to checking blood pressure, medical professionals typically assess the patient's temperature and pulse rate.
    • Patients with an abnormally low systolic-diastolic ratio may need to be evaluated for aneurysms and internal bleeding.
      By: joshya
      Patients with an abnormally low systolic-diastolic ratio may need to be evaluated for aneurysms and internal bleeding.
    • Patients who have an abnormally low systolic-diastolic ratio may need to be evaluated by a doctor for internal bleeding.
      By: AntonioDiaz
      Patients who have an abnormally low systolic-diastolic ratio may need to be evaluated by a doctor for internal bleeding.
    • A patient's weight will be part of a doctor's evaluation.
      By: jovannig
      A patient's weight will be part of a doctor's evaluation.
    • A doctor will listen to a patient's heart when evaluating someone who has an abnormally low systolic-diastolic ratio.
      By: WavebreakMediaMicro
      A doctor will listen to a patient's heart when evaluating someone who has an abnormally low systolic-diastolic ratio.