What is Pulsus Alternans?
Pulsus alternans (PA) is a condition where the pulse alternates between strong and weak beats. It shouldn’t be confused with other conditions like pulsus paradoxus or electrical alternans. This condition is a result of changes in the strength of the pulse from one beat to the next, causing the pulse rate to be half of the electrical rate. This can be felt during a physical exam or seen on a heart ultrasound, also known as an echocardiogram.
This condition was first observed by Ludwig Traube in 1872. It’s most commonly found in people with severe heart damage and other heart-related conditions. There are different types of pulsus alternans, depending on which part of the heart is affected – they include left ventricular alternans, right ventricular alternans, and biventricular alternans.
The treatment and outcome for someone with pulsus alternans can vary greatly, primarily based on what’s causing it. However, it’s important to note that having this condition generally indicates a poor outlook. Pulsus alternans is usually found in patients with severe heart disease and can lead to a state where there is electrical activity in the heart but no pulse, known as pulseless electrical activity.
What Causes Pulsus Alternans?
Pulsus alternans is a condition that happens due to problems or stress on the heart. It can be linked to different parts of the heart – the left section, the right section, or both – depending on the root causes.
When it comes to the left part of the heart, pulsus alternans is usually an indication of severe issues, like heart muscle disease, a stiff aortic valve that doesn’t open properly, or coronary artery disease which involves blocked blood vessels that provide your heart muscle with oxygen and blood.
When we talk about the right side of the heart, pulsus alternans generally arises because of strain on this part of the heart. This is usually brought on by conditions like blockage of lung arteries or high blood pressure in the lungs. Other potential causes could be reactive airway disease or issues with the mitral valve, which controls blood flow between the left chambers of the heart, or heart failure on the left-hand side.
Pulsus alternans impacting both parts of the heart is very rare and has only been reported in a few cases. It is usually caused by severe issues in the left section of the heart or blockage in the coronary artery that supplies the front of the heart.
Also, build-up of excess fluid around the cardiac muscle (pericardial effusion) can be a reason for pulsus alternans. Different mechanisms could lead to this, like impaired blood flow and reduced muscle contraction of the heart.
Risk Factors and Frequency for Pulsus Alternans
Pulsus alternans, a pretty rare condition, is often linked to issues with the left part of the heart. This means that people with heart issues like heart failure, issues with heart muscle (cardiomyopathy), or narrowed and blocked heart arteries (coronary artery disease) have a higher risk of developing pulsus alternans. The risk is even higher for those who have had heart and vascular diseases before or smoke, have high blood pressure, high cholesterol, diabetes or had a stroke earlier. Currently, there aren’t any large-scale studies on this.
Signs and Symptoms of Pulsus Alternans
If a patient is diagnosed with pulsus alternans, a thorough cardiovascular exam should be carried out. This condition is often linked to heart failure, so patients might display clear symptoms of this, such as high jugular venous pressure, bibasilar rales (crackling sounds originating from the base of the lungs), and swollen limbs. Depending on the severity of the heart decompensation, the patient might also have fast heart rate, fast breathing rate, or low blood pressure. Other things to look out for include an aortic stenosis murmur, third heart sound (S3), or fourth heart sound (S4). Pulsus alternans is specifically characterized by alternating strong and soft pulses in the radial artery.
Pulsus alternans can be detected by feeling the pulse manually, using a blood pressure monitor (sphygmomanometer), or examining the waveforms of the artery and volume of red blood cells in the blood vessels. However, if the difference between large and small systolic beats exceeds 20 mmHg, it becomes harder to assess by just feeling the pulse. In this case, it’s more accurate to check the pulse in the femoral artery (in the thigh) rather than the brachial (in the arm), radial (in the wrist), or carotid (in the neck) arteries. When a blood pressure monitor is used, the cuff is inflated above the peak systolic pressure, then slowly deflated. The examiner first listens for the first loud systolic beat (first pressure) which only has the strong beats. Then, the cuff continues to deflate until all systolic beats can be heard (second pressure). The difference between these two pressures can be used to gauge the severity of pulsus alternans.
Testing for Pulsus Alternans
If your doctor suspects you might have a condition called pulsus alternans, which is a rhythm disorder where your heartbeat alternates between strong and weak pulses, they would recommend a full heart health check. So, what are these tests? Let’s break it down:
To start with, you would have some bloodwork done and a chest X-ray – these would show if there’s increased fluid pressure in your lungs, which often happens when your heart isn’t working efficiently. It would also reveal if there’s a protein called pro-BNP in your blood, which increases when your heart is under stress.
You’d also get an electrocardiogram (ECG or EKG), which is a test that records the electrical activity within your heart. But peculiarly, even if you have pulsus alternans, this EKG will often not show fluctuating electrical signals from beat to beat (a condition known as electrical alternans).
Lastly, an echocardiogram (a type of ultrasound of the heart) would be conducted. This test visualizes the physical contractions of the heart and measures the blood flow in your heart’s arteries. An echocardiogram can show the distinct alternating pattern of strong and weak heartbeats, which essentially confirms the diagnosis of pulsus alternans.
Echocardiography is very significant because occasionally, there could be a mismatch between the electrical signals in your heart and the heart’s mechanical contractions. This test offers the ability to spot such inconsistencies and provides a comprehensive understanding of how well your heart muscle is contracting, how the electrical signals are functioning, and the overall effectiveness of the heart in pumping blood through your body.
Treatment Options for Pulsus Alternans
Pulsus alternans is a sign that there might be an underlying heart problem. Handling this issue involves treating the actual heart issue. Treatments for ‘left ventricular alternans’ (where the left part of the heart is not working well) could involve methods for removing excess fluid from the body if ‘left-sided heart failure’ is present. This is a condition where the left part of the heart isn’t pumping blood as well as it should. Sometimes, it might require replacing the aortic valve (a major valve in the heart) if there’s severe ‘aortic stenosis’, which is when the aortic valve narrows, limiting blood flow to the rest of your body.
Both these situations have been linked to coronary artery disease, a disease that affects the arteries supplying blood to the heart. This is particularly seen when the ‘left anterior descending coronary artery’, one of the major arteries is affected. In such cases, checking for issues related to blood flow to the heart is recommended.
For ‘right ventricular alternans’ (where the right part of the heart is not working well), treatments may include ‘anticoagulation’ (in the case of a pulmonary embolism), medications to lower blood pressure in the lungs (for primary pulmonary hypertension), ‘Continuous Positive Airway Pressure’ (CPAP) or ‘Bilevel Positive Airway Pressure’ (BiPAP). These are therapies used for sleep apnea or obesity hypoventilation syndrome where your body struggles to breathe during sleep due to excess weight. Pulmonary embolism happens when a blood clot blocks a blood vessel in your lungs and pulmonary hypertension is when the pressure in the vessels that carry blood from your heart to lungs is too high.
What else can Pulsus Alternans be?
When a person has pulsus alternans, or a changing pulse, there could be several underlying causes doctors will consider based on the symptoms.
Issues with the left side of the heart might indicate:
- Reduced ejection fraction (a measurement indicating how much blood the left ventricle pumps out with each contraction)
- Cardiomyopathy (heart muscle disease
- Aortic stenosis (a narrowing of the heart’s exit valve)
- Coronary artery disease (blockages in the heart’s blood supply)
- Cardiac ischemia (reduced blood flow to the heart)
If the pulse alternates on the right side of the heart, this might point towards:
- Pulmonary embolus (a blood clot in the lungs)
- Pulmonary hypertension (high blood pressure in the lungs)
- Reactive airway disease (a term used for asthma-like symptoms)
- Mitral stenosis (a narrowing of the heart’s intake valve)
In rare cases, both sides of the heart can show a changing pulse, which could suggest possible problems with blood flow in the left anterior descending coronary artery, one of the major blood vessels of the heart.
It’s also noteworthy that pulsus alternans isn’t the same as electrical alternans. That’s an abnormal reading on an electrocardiogram, often indicating a fluid buildup around the heart.
What to expect with Pulsus Alternans
The outlook for a patient having pulsus alternans – a condition where the strength of the heartbeat varies with each pulse – can change depending on the root cause. Usually, the presence of pulsus alternans is seen as a sign of poor health, as it often indicates serious heart (ventricular) dysfunction.
To resolve pulsus alternans, it’s necessary to treat the causing heart condition, whether it’s in the left or right ventricle. For instance, a past study found that pulsus alternans went away after replacing a patient’s aortic valve, which was needed due to severe aortic stenosis – a condition where the heart’s aortic valve narrows, restricting blood flow.
Patients with irreversible cardiomyopathies – diseases of the heart muscle that make it harder for the heart to pump blood to the rest of the body – face a greater risk of worse outcomes because the root cause cannot be corrected.
Possible Complications When Diagnosed with Pulsus Alternans
There could be various complications tied to a medical condition known as pulsus alternans. The most concerning ones are life-threatening heart problems like heart attacks and abnormal heart rhythms, specifically in the ventricles. Although we don’t know the exact risk of experiencing these dangerous heart rhythms with pulsus alternans, there’s a theoretical increase in danger due to possible alterations in the way the heart conducts electrical signals.
Some studies also suggest a link between pulsus alternans and both irregular heart rhythms and reduced blood supply to the heart muscle. Other regular heart rhythm problems, such as atrial fibrillation and atrial flutter, might happen in situations where the heart is under stress or failing.
In severe cases of heart failure, pulsus alternans may lead to severe health complications. This can cause an unstable blood pressure and heart rate, difficulties in breathing, low oxygen levels in the body, liver congestion, and sudden kidney damage.
Potential Complications:
- Life-threatening heart conditions (e.g., heart attacks, abnormal heart rhythms)
- Alterations in heart’s electrical conduction
- Increased risk of irregular heart rhythms
- Atrial fibrillation and atrial flutter in stressful or failing heart conditions
- Severe health issues linked to heart failure, such as unstable blood pressure and heart rate
- Respiratory distress and low oxygen levels
- Congestion in the liver
- Sudden kidney damage
Preventing Pulsus Alternans
Pulsus alternans is a sign that points towards heart disease, especially issues with the left part of the heart, also known as the left ventricle. This indicates a poor outlook for the patient. When this sign is detected, it’s important to promptly manage and treat the underlying problem that is causing it.
