02-05-2021

Low Pulse



  1. Causes Of Low Pulse Rate
  2. Causes Of Slow Heartbeat

Your doctor can check your heart rate to make sure it is normal. A normal resting heart rate for a healthy adult is somewhere between 60 and 80 beats per minute, according to the American Heart Association. When heart rate habitually drops below 60 beats per minute, the condition is called bradycardia. Normal blood pressure but low pulse rate. A 61-year-old male asked: what is the indication of normal blood pressure but low pulse rate? Jimmy Bowen answered. 34 years experience Physical Medicine and Rehabilitation. Blood Pressure: Not sure what your are asking. Normal blood pressure with a low pulse rate may be normal or abnormal based on. Bradycardia is a heart rate of less than 60 beats per minute (BPM) in adults. For the latest information about heart & vascular disorders, treatments, tests and prevention from the No. 1-ranked heart program in the United States.

Date Issued: February 19, 2021

The Coronavirus Disease 2019 (COVID-19) pandemic has caused an increase in the use of pulse oximeters, and a recent report (Sjoding et al.) suggests that the devices may be less accurate in people with dark skin pigmentation. The U.S. Food and Drug Administration (FDA) is informing patients and health care providers that although pulse oximetry is useful for estimating blood oxygen levels, pulse oximeters have limitations and a risk of inaccuracy under certain circumstances that should be considered. Patients with conditions such as COVID-19 who monitor their condition at home should pay attention to all signs and symptoms of their condition and communicate any concerns to their health care provider.

Recommendations for Patients and Caregivers

How to take a reading:

  • Follow your health care provider’s recommendations about when and how often to check your oxygen levels.
  • Be aware that multiple factors can affect the accuracy of a pulse oximeter reading, such as poor circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use, and use of fingernail polish. To get the best reading from a pulse oximeter:
    • Follow the manufacturer’s instructions for use.
    • When placing the oximeter on your finger, make sure your hand is warm, relaxed, and held below the level of the heart. Remove any fingernail polish on that finger.
    • Sit still and do not move the part of your body where the pulse oximeter is located.
    • Wait a few seconds until the reading stops changing and displays one steady number.
  • Write down your oxygen levels with the date and time of the reading so you can easily track changes and report these to your health care provider.

How to interpret a reading:

  • When taking pulse oximeter measurements, pay attention to whether the oxygen level is lower than earlier measurements, or is decreasing over time. Changes or trends in measurements may be more meaningful than one single measurement. Over the counter products that you can buy at the store or online are not intended for medical purposes.
  • Do not rely only on a pulse oximeter to assess your health condition or oxygen level.
  • If monitoring oxygen levels at home, pay attention to other signs or symptoms of low oxygen levels, such as:
    • Bluish coloring in the face, lips, or nails;
    • Shortness of breath, difficulty breathing, or a cough that gets worse;
    • Restlessness and discomfort;
    • Chest pain or tightness; and
    • Fast or racing pulse rate.
    • Be aware that some patients with low oxygen levels may not show any or all of these symptoms. Only a health care provider can diagnose a medical condition such as hypoxia (low oxygen levels).

When to contact your health care provider:

  • If you are concerned about the pulse oximeter reading, or if your symptoms are serious or getting worse, contact a health care provider.
  • If you think you may have COVID-19, contact your health care provider or local health department about getting a diagnostic test for COVID-19. Pulse oximeters cannot be used to diagnose or rule out COVID-19.

For more consumer information on pulse oximeters, see Pulse Oximeters and Oxygen Concentrators: What to Know About At-Home Oxygen Therapy.

Recommendations for Health Care Providers

  • Be aware that multiple factors can affect the accuracy of a pulse oximeter reading, such as poor circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use, and use of fingernail polish. Review the information in the sections below to better understand how accuracy is calculated and interpreted.
  • Refer to the device labeling or the manufacturer’s website to understand the accuracy of a particular brand of pulse oximeter and sensor. Different brands of pulse oximeters and even different sensors (finger clip versus adhesive) may have a different accuracy level. Pulse oximeters are least accurate when oxygen saturations are less than 80%.
  • Consider accuracy limitations when using the pulse oximeter to assist in diagnosis and treatment decisions.
    • Use pulse oximeter readings as an estimate of blood oxygen saturation. For example, a pulse oximeter saturation of 90% may represent an arterial blood saturation of 86-94%.
    • When possible, make diagnosis and treatment decisions based on trends in pulse oximeter readings over time, rather than absolute thresholds.

Device Description

A pulse oximeter is a device that is usually placed on a fingertip. It uses light beams to estimate the oxygen saturation of the blood and the pulse rate. Oxygen saturation gives information about the amount of oxygen carried in the blood. The pulse oximeter can estimate the amount of oxygen in the blood without having to draw a blood sample.

Most pulse oximeters show two or three numbers. The most important number, oxygen saturation level, is usually abbreviated SpO2, and is presented as a percentage. The pulse rate (similar to heart rate) is abbreviated PR, and sometimes there is a third number for strength of the signal. Oxygen saturation values are between 95% and 100% for most healthy individuals, but sometimes can be lower in people with lung problems. Oxygen saturation levels are also generally slightly lower for those living at higher altitudes.

There are two categories of pulse oximeters: prescription use and over the counter (OTC).

  • Prescription oximeters are reviewed by the FDA, receive 510(k) clearance, and are available only with a prescription. The FDA requires that these pulse oximeters undergo clinical testing to confirm their accuracy. They are most often used in hospitals and doctors’ offices, although they may sometimes be prescribed for home use.
  • Over-the-counter (OTC) oximeters are sold directly to consumers in stores or online and include smart phone apps developed for the purpose of estimating oxygen saturation. Use of OTC oximeters has increased as a result of the COVID-19 pandemic. These products are sold as either general wellness or sporting/aviation products that are not intended for medical purposes, so they do not undergo FDA review. OTC oximeters are not cleared by the FDA and should not be used for medical purposes.
Low pulse meaning

For more information on pulse oximeter regulation, see Pulse Oximeters - Premarket Notification Submissions [510(k)s]: Guidance for Industry and Food and Drug Administration Staff.

Interpretation and Limitations of Pulse Oximetry

Pulse oximeters have limitations and a risk of inaccuracy under certain circumstances. In many cases, the level of inaccuracy may be small and not clinically meaningful; however, there is a risk that an inaccurate measurement may result in unrecognized low oxygen saturation levels. Therefore, it is important to understand the limitations of pulse oximetry and how accuracy is calculated and interpreted.

FDA-cleared prescription pulse oximeters are required to have a minimum average (mean) accuracy that is demonstrated by desaturation studies done on healthy patients. This testing compares the pulse oximeter saturation readings to arterial blood gas saturation readings for values between 70-100%. The typical accuracy (reported as Accuracy Root Mean Square or Arms) of recently FDA-cleared pulse oximeters is within 2 to 3% of arterial blood gas values. This generally means that during testing, about 66% of SpO2 values were within 2 or 3% of blood gas values and about 95% of SpO2 values were within 4 to 6% of blood gas values, respectively.

Causes Of Low Pulse Rate

However, real-world accuracy may differ from accuracy in the lab setting. While reported accuracy is an average of all patients in the test sample, there are individual variations among patients. The SpO2 reading should always be considered an estimate of oxygen saturation. For example, if an FDA-cleared pulse oximeter reads 90%, then the true oxygen saturation in the blood is generally between 86-94%. Pulse oximeter accuracy is highest at saturations of 90-100%, intermediate at 80-90%, and lowest below 80%. Due to accuracy limitations at the individual level, SpO2 provides more utility for trends over time instead of absolute thresholds. Additionally, the FDA only reviews the accuracy of prescription use oximeters, not OTC oximeters meant for general wellness or sporting/aviation purposes.

Many patient factors may also affect the accuracy of the measurement. The most current scientific evidence shows that there are some accuracy differences in pulse oximeters between dark and light skin pigmentation; this difference is typically small at saturations above 80% and greater when saturations are less than 80%. In the recently published correspondence by Sjoding, et. al., the authors reported that Black patients had nearly three times the frequency of occult hypoxemia (low oxygen levels in the blood) as detected by blood gas measurements but not detected by pulse oximetry, when compared to White patients. It is important to note that this retrospective study had some limitations. It relied on previously collected health record data from hospital inpatient stays and could not statistically correct for all potentially important confounding factors. However, the FDA agrees that these findings highlight a need to further evaluate and understand the association between skin pigmentation and oximeter accuracy.

All premarket submissions for prescription use oximeters are reviewed by the FDA to ensure that clinical study samples are demographically representative of the U.S. population, as recommended by FDA guidance, Pulse Oximeters - Premarket Notification Submissions [510(k)s]: Guidance for Industry and Food and Drug Administration Staff. As described in this guidance, FDA recommends that every clinical study have participants with a range of skin pigmentations, including at least 2 darkly pigmented participants or 15% of the participant pool, whichever is larger. Although these clinical studies are not statistically powered to detect differences in accuracy between demographic groups, the FDA has continued to review the effects of skin pigmentation on the accuracy of these devices, including data from controlled laboratory studies and data from real world settings.

FDA Actions

The FDA is committed to the continued evaluation of the safety, effectiveness, and availability of medical devices, especially devices in high demand during the COVID-19 pandemic. The FDA is evaluating published literature pertaining to factors that may affect pulse oximeter accuracy and performance, with a focus on literature that evaluates whether products may be less accurate in individuals with darker skin pigmentation. The FDA has been working on additional analysis of premarket data, as well as working with outside stakeholders, including manufacturers and testing laboratories, to analyze additional postmarket data to better understand how different factors including skin pigmentation may affect pulse oximeter accuracy. Based on these findings, the FDA may reassess the content of the pulse oximetry guidance document.

The FDA will keep the public informed if significant new information becomes available.

Reporting Problems with a Pulse Oximeter

If you think you have a problem with a pulse oximeter, the FDA encourages you to report the problem through the MedWatch Voluntary Reporting Form.

Health care personnel employed by facilities that are subject to the FDA's user facility reporting requirements should follow the reporting procedures established by their facilities.

Questions?

If you have questions, email the Division of Industry and Consumer Education (DICE) at DICE@FDA.HHS.GOV or call 800-638-2041 or 301-796-7100.

Your heart will typically beat between 60-100 times each minute when you are at rest. Bradycardia refers to a heart rate that is below 60 beats per minute. In most cases bradycardia does not cause complications or symptoms, but this can be a serious condition because a low pulse rate means the heart is not pumping an adequate supply of oxygen rich blood to the rest of the body. There are several treatments including the implantation of a pace maker that can help to correct this condition if necessary.

Symptoms and Complications of Low Pulse Rate

Common Symptoms

When the organs and brain are not getting the oxygen content they need from the blood it can cause weakness, near-fainting, fainting, fatigue, dizziness, chest pains, shortness of breath, tiring easily during physical activity, memory problems and confusion.

Complications

The severity of complications from bradycardia will vary based on how low the pulse rate of the body is and what is causing the conduction problem in the body. Potential complications include heart failure, frequent fainting spells, sudden cardiac arrest or sudden death.

Causes of Low Pulse Rate

Causes Of Slow Heartbeat

  • Heart’s Electrical Problems. The sinus node acts as a natural pacemaker that controls the rhythm of the heart with electrical impulses. These pulses cross the atria which will cause the atria to start pumping blood in the ventricles. Then the impulses reach the atrioventricular node where a signal is transmitted to a cell bundle known as the bundle of His, transmitting a signal down to branches to the left and right ventricles, causing them to contract and pump. The left ventricle will pump oxygen to the body and the right ventricle will pump blood into the lungs to receive more oxygen. If the signals that control these impulses are disrupted it may lead to a low pulse rate.
  • Sinus Node Problems. If the signals from the sinus node pause, fail to discharge at a regular rate, discharge slower than normal or are blocked before they can make contact with the atria it can cause the pulse rate to alternate between fast and slow rhythms.
  • Heart Block. If something is blocking signals throughout any portion of the electrical pathway throughout the heart it can damage your body’s ability to maintain a normal pulse rate. A first degree block refers to a block between the atria and ventricles, which rarely causes symptoms and often does not require treatment. Second degree blocks prevent all signals from reaching the ventricles, causing some beats to be dropped or causing an irregular heart rhythm. A third degree block causes all impulses from the atria to fail to meet the ventricles, causing the bundle of His or other tissues to act as a separate pacemaker within the heart. This may cause unreliable signals and slow heartbeat. Bundle branch blocks interrupt the electrical signals in the left or right bundle branches. The severity of this block will vary based on whether or not both branches are affected and if another block is present.

Risk Factors of Low Pulse Rate

  • Age. Low pulse rate and the associated complications are significantly more likely in older adults.
  • Risks of Heart Disease. Damage age from heart disease will increase your risk of developing low pulse rate. Smoking, high cholesterol, using illegal drugs, high blood pressure, heavy alcohol use and psychological stress or anxiety can all contribute to these conditions.

Treatments for Low Pulse Rate

  • Cure Underlying Diseases. Underlying disorders such as obstructive sleep apnea or hypothyroidism may cause low pulse rate and will need to be treated for these symptoms to disappear.
  • Change Drugs. Some medications, including those for heart conditions, can cause you to develop a low pulse rate. Your doctor should check your medications and recommend alternatives or lower doses that could prevent these symptoms. If it is not possible to alter your medications it may be necessary to implement a pacemaker.
  • Use Pacemaker. A pacemaker is a cellphone sized device that is operated with a battery. It is inserted underneath the collarbone and wires with electrodes thread through your veins and into the heart to generate impulses to control your heart rate. Most models can also record information about your heart for your doctor to use to determine what future treatment will be necessary to prevent bradycardia symptoms.

Preventions of Low Pulse Rate

Prevent Heart Disease

  • Do Exercise and Eat Proper Diet. Following a heart healthy lifestyle with plenty of low-fat foods, vegetables, fruit and whole grains followed by plenty of exercise will help prevent heart disease.
  • Keep a Healthy Weight. Those that are overweight are at a much higher risk for heart disease.
  • Control Blood Pressure and Cholesterol. Adjusting your lifestyle and using medication can help you relieve high cholesterol and hypertension that can increase your risk of heart disease.
  • Quit Smoking. Working to quit smoking on your own or using a treatment plan from your doctor will significantly decrease your risk of heart problems.
  • Limit Alcohol Intake. Drinking alcohol in moderation or eliminating alcohol from your diet can improve your heart health. If you are having trouble controlling your alcohol intake you can work with your doctor to join an alcohol management program.
  • Avoid Illegal Drugs. Your doctor can help you find a program that will help you quit using illegal drugs that could be impacting your overall health.
  • Manage Your Stress. Avoiding stressors and learning techniques to help you cope with stress in a healthy way can help you maintain your heart health.
  • Check Regularly. Visiting your doctor for regular exams and reporting any symptoms to your doctor as soon as possible to help keep your heart health in check.

Treat Current Heart Problems

  • Follow Prescription. Talk with your doctor to make sure you understand your treatment plan and follow all instructions you have been given to ensure that your treatment goes as planned.
  • Report Changes. If you notice a change in your symptoms, new symptoms or your symptoms becoming worse, contact your doctor as soon as possible.