What Is Systolic Heart Murmur?

Introduction 

Our heart is a strong muscular organ that beats around 100,000 times a day, pumping blood to your tissues and organs. The blood delivers oxygen and nutrients to your tissues and organs while simultaneously carrying away waste products. The heart does an incredible job at keeping us alive so must recognise any changes so that we can receive the appropriate treatment and care as soon as possible. 

In this article, we will discuss what systolic heart murmurs are and the underlying causes, treatments and prevention options. 

Understanding heart murmurs 

The heart and your blood vessels work seamlessly together to provide blood to all areas of the body. These blood vessels include: 

• Arteries: carrying oxygen-rich blood from the heart to all areas of the body 
• Capillaries: A link between the arteries and veins that exchange nutrients, water, carbon dioxide and waste products between the blood and tissues 
• Veins: carry blood that lacks oxygen to your heart 

Your heart is divided into 4 chambers, with the right side receiving the blood lacking in oxygen (deoxygenated blood) and pumping it to the lungs to receive a fresh supply of oxygen. This is then pumped back into the left side of the heart (oxygenated blood), ready to be delivered to all areas of the body. 

A heart murmur happens when the blood does not flow properly to the heart. It’s usually not a sign of concern but it’s important to speak to your doctor about receiving the appropriate care as it can be dangerous if left untreated. Your doctor will listen to the blood flow through your heart through a stethoscope and if they hear an extra unusual sound in your heart, they may send you to take further tests. It is described as a blowing sound that can be heard during a heartbeat. 

Basics of heart sounds

The heart has four valves, two on the left and two on the right, acting as gates to move the blood through the heart correctly. The thumping sound of our heartbeat is the blood filling up in the chambers as the valves open and close.¹ Your doctor will check your blood pressure to measure how hard your heart works to deliver oxygenated blood around your body. Your blood pressure is measured by two components: 

• Systole: represented as the top number of your blood pressure reading which determines how much blood is forced out to the rest of the body. 
• Diastole: the lower number of your blood pressure readings when your heart relaxes and the chambers fill with blood.

What causes heart murmurs

A heart murmur can be harmless and the blood flow might simply flow faster than normal. Heart murmurs can commonly affect younger children as they go through growth spurts. Adults can also be affected. They can happen for several reasons which include: 

1. Turbulent blood flow

Blood flow can be described as laminar or turbulent. In a healthy person, the blood flow is usually smooth like a boat sailing through a calm river. A turbulent blood flow occurs when there is a disruption in the normal blood flow and can be described as chaotic. Several factors can cause turbulent blood flow such as such as blockages, high blood pressure and narrowing of blood vessels. If left untreated it can cause serious damage to your health so it’s important to maintain a healthy and smooth blood flow.²

2. Valvular problems

Blood leaking backwards (regurgitation) due to the valves not closing tightly can cause a systolic murmur. A mitral regurgitation occurs when the mitral valve on the left side of the heart does not close properly causing the blood to leak backwards. These problems can often arise from old age, affecting over 2% of the total population. The most common cause is papillary muscle rupture, which is a rare and potentially fatal heart attack where the mitral valve prolapses and the valve becomes loose.³

3. Structural heart issues

Abnormalities in the structure or function of your heart can lead to a systolic heart murmur. Structural heart issues can begin from birth until old age, and you might not need treatments, but it’s important to keep your heart in check by regularly meeting with your cardiologists. 

Typical symptoms include dizziness, fatigue and tightness or pain in your chest. If you experience these symptoms or have any concerns with your health, it's important to seek medical assistance.

Common causes of systolic heart murmurs 

Aortic stenosis

Aortic stenosis is a common valvular disorder that obstructs the left ventricle (the thickest wall of the heart chamber that pumps oxygenated blood to all areas of the body). Aortic stenosis can lead to systolic murmur as it takes longer for the blood to pass through the valve.⁴

Ventricular septal defect (VSD)

1. Explanation of VSD

A ventricular septal defect is a heart disorder commonly seen in children where a hole or opening in the septum separates the two lower chambers of the heart. The blood can leak through the hole and create an extra noise as your heart is pushing blood out to the body. As your doctor listens to your heart through a stethoscope, they can differentiate the murmurs between mitral regurgitation and VSD. The murmur of VSD becomes louder towards the sternum (flat bone located at the chest) and mitral regurgitation becomes louder away from the sternum.⁵ 

Systolic heart murmur explained 

The timing of a murmur during a cardiac cycle is important to determine the correct diagnosis of an individual. As we listen to our heart, we typically hear the “lub dub” sound. This can be clinically described as the S1 and S2 heart sounds. Systolic heart murmurs are heard between S1 and S2 sound. Systolic murmur can be grouped into either:

• Systolic ejection murmurs - Heard after S1 and ends just before S2
• Holosystolic (also known as pan systolic)  - begins after the S1 and continues up to the S2 making it difficult to hear.
• Late systolic - begins after S1 and may or may not continue to S2

Characteristics of systolic heart murmurs

1. Location

Finding the source of the heart murmur is important and they can be described using the four main listening posts:⁶

• Aortic valve post - a valve between the left ventricle and the aorta, ensuring oxygenated-rich blood does not flow back into the left ventricle (found near the top right side of your chest)
• Pulmonary valve post - lies between the right ventricle and the pulmonary artery (located at the top left side of the chest)
• Tricuspid valve post - located between the right lower heart chamber and the right upper chamber (at the bottom left side of your chest)
• Mitral valve post - a valve between the left chamber and the left ventricle (bottom centre of your chest)

2. Radiation

The murmurs are intense at a specific listening post but can radiate to other listening posts or other areas of the body. For example, a mitral regurgitation can radiate on the left side. This causes difficulties in diagnosing the condition as it is difficult to determine whether there are multiple murmurs or one murmur that is radiating to multiple sites. Your doctor will send you to do an echocardiography (ECG) to help determine the exact place of the murmur. 

3. Intensity

Your doctors will grade the intensity or how loud the murmur can be heard. This is graded on a scale of 1-6:⁶

• Grade 1: Faint or barely audible murmur
• Grade 2: Audible but gentle murmur
• Grade 3: Easily audible
• Grade 4: Loud murmur with a thrill
• Grade 5: Loud and can be heard through a stethoscope
• Grade 6: Very loud murmur that is audible without a stethoscope

4. Pitch 

The pitch can determine the pressure gradient across the lesion. High-pitched murmurs mean there is a large pressure gradient while low-pitched murmurs have a low pressure gradient across the lesion. The pitch can be described as blowing, harsh or musical.⁶

5. Profile

The profile describes changes in the intensity of a murmur. They can either be:⁶

• Crescendo: murmur that gets louder 
• Decrescendo: murmur that gets softer and quieter
• Crescendo-decrescendo: a murmur that gradually gets louder and then quieter 
• Uniform: a murmur where the intensity stays the same throughout the cardiac cycle

Diagnosis and evaluation 

Your doctor will listen to your heart and measure your blood pressure. For any abnormalities with your heart, you will be sent for further testing which includes:

1. Echocardiogram: A type of ultrasound scan to look at the heart and surrounding blood vessels and is preferably used for the detection of vascular diseases. Your doctor will use a probe which sends out sound waves creating echoes as the sound waves bounce off different areas of the body. The echoes are picked up and create a picture of your heart. There are several types of echocardiogram and most people will have a Transthoracic echocardiogram. Your doctor will determine the best diagnosis tool for your situation. It is a painless procedure, a same-day procedure.
2. Cardiac catheterization: a long thin tube is inserted into your arm, and x-ray images are taken as the contrast medium is injected through the long tube. The contrast medium helps visualise blood vessels and see if there are any blocked blood vessels. The wound site is likely to be swollen, so it’s important to rest and avoid worsening your health. 

Treatment and management 

You may have a harmless murmur, which usually does not require any treatment but if this happens often, you may require treatment to help manage your condition and reduce the frequency of a systolic heart murmur. A systolic heart murmur treatment plan can include a combination of medications like Angiotensin-converting enzyme (ACE), beta-blockers or blood thinners.⁷ You may need surgery if your heart condition is severe; options can include valve repair or replacement. Your doctor will discuss the best course of treatment if necessary. They will create a treatment plan, answer any questions you may have and discuss your family history. 

There’s no sure way of preventing a systolic heart murmur but you can strengthen your overall heart health by exercising for at least 2 hours or more a week; eating a rich diet full of fibre, fruits and vegetables; avoiding smoking, minimising alcohol consumption and reducing stress as much as possible. 

Summary

A systolic heart murmur is usually audible through a stethoscope and is not a sign of concern. Problems with your heart will manifest as tightness in your chest, shortness of breath and fatigue. If you experience these symptoms, it’s important to address your concerns with a healthcare specialist to diagnose your condition and, if necessary, determine the best course of treatment. The causes of a systolic heart murmur could be valvular issues where the blood does not flow correctly and leaks backwards. In this case, you may require surgery to fix this. Your doctor will carefully listen to your heart sounds and make notes on the intensity, location, radiation, pitch and profile of the lesion. You must take care of your general health by regularly exercising, eating a balanced diet and sleeping 8-9 hours to prevent serious problems with your heart.