The Whoosh, Swish, And Rasp: 7 Distinct Sounds That Reveal What A Heart Murmur Really Means

As of December 2025, a heart murmur is not a disease in itself, but rather an extra, unusual sound heard during a heartbeat, often described as a whooshing, swishing, blowing, or rasping noise. This sound is caused by turbulent—or rough—blood flow through the heart's four chambers and valves. While the classic "lubb-dupp" represents the normal closing of the heart's valves (S1 and S2), a murmur is the sound of blood encountering an obstacle or leaking backward, and understanding its unique characteristics is the key to determining if it is harmless or a sign of a serious underlying cardiac condition. The crucial difference lies in the sound's timing, intensity, and quality. Doctors, using a stethoscope for a process called auscultation, listen for subtle cues that pinpoint the issue. A loud, harsh sound is often more concerning than a soft, musical one, but the specific characteristics are what truly guide the diagnosis and subsequent treatment plan.

The Anatomy of a Murmur: When Does the Sound Happen?

The most critical factor in identifying a heart murmur is its timing relative to the two normal heart sounds, S1 (the "lubb") and S2 (the "dupp"). This timing categorizes the murmur as systolic, diastolic, or continuous, each pointing to different potential causes.

Systolic Murmurs: The Most Common "Whoosh"

A systolic murmur occurs during systole, the phase when the heart muscle contracts (pumps) and pushes blood out of the ventricles. They are the most common type and can be either innocent (harmless) or pathological (a sign of disease). * Ejection Murmur (Crescendo-Decrescendo): This sound gets louder and then softer. It is often caused by blood flowing through a narrowed valve, such as in Aortic Stenosis or Pulmonic Stenosis. * Pansystolic (Holosystolic) Murmur: This is a uniform, high-pitched sound that lasts throughout the entire systole. It often indicates blood leaking backward through a valve, a condition known as Mitral Regurgitation or Tricuspid Regurgitation.

Diastolic Murmurs: A Red Flag "Blowing" Sound

Diastolic murmurs occur during diastole, the phase when the heart muscle relaxes and the ventricles fill with blood. Diastolic murmurs are almost always pathological and require further investigation, such as an echocardiography. * Early Diastolic Murmur (Decrescendo): This is typically a high-pitched, blowing sound that starts immediately after S2 and fades away. The most common cause is Aortic Regurgitation or Pulmonic Regurgitation, where blood leaks back into the ventricles. * Mid-Diastolic Murmur (Rumbling): Often a low-pitched, rumbling sound, this can be caused by the turbulent flow of blood through a narrowed valve during the filling phase, such as in Mitral Stenosis or Tricuspid Stenosis.

Continuous Murmurs: The Constant "Machinery" Noise

A continuous murmur is heard throughout both systole and diastole without interruption. The classic example is the "machinery-like" murmur of a Patent Ductus Arteriosus (PDA), a congenital heart defect where a connection between two major blood vessels near the heart fails to close after birth.

The 7 Distinct Qualities of Heart Murmur Sounds

Beyond timing, the sound of a murmur is further characterized by its unique qualities, which help the cardiologist determine the specific source of the turbulent blood flow. These qualities are essential for a precise diagnosis.

1. Whooshing or Swishing: The most common description, often indicating a general turbulent blood flow, especially in innocent murmurs or mild regurgitation.
2. Blowing: A high-pitched sound, frequently associated with blood leaking backward through a valve (regurgitation), such as in Aortic Regurgitation.
3. Rasping or Harsh: A rough, grating sound that often suggests a significant structural problem, typically caused by blood being forced through a severely narrowed opening (stenosis), like severe Aortic Stenosis.
4. Musical or Humming: A specific, often low-pitched, vibratory sound. This quality is highly characteristic of the innocent Venous Hum, which is common in children and usually disappears when they stand up or turn their head.
5. Rumbling: A low-frequency sound, often heard when blood flows through a narrowed opening with low pressure, such as in Mitral Stenosis.
6. Crescendo: The sound starts soft and gets progressively louder. This pattern is typical of murmurs caused by blood accelerating through a stiff, partially open valve, like Aortic Stenosis.
7. Decrescendo: The sound starts loud and gets progressively softer. This pattern is characteristic of murmurs where the pressure difference driving the turbulent flow quickly diminishes, such as in Aortic Regurgitation.

Innocent vs. Pathological: Decoding the Murmur's Message

The single most important distinction a doctor makes is whether the murmur is innocent (functional) or pathological (abnormal).

Innocent Heart Murmurs

Innocent murmurs are caused by normal, but rapid, blood flow through a healthy heart. They are common in children, pregnant women, and people with temporary conditions that speed up blood flow, such as fever, anemia, or an overactive thyroid (hyperthyroidism). * Sound Characteristics: They are typically soft, musical, or humming (like the Still's Murmur or Venous Hum), systolic in timing, and may disappear or change when the person changes position. * Treatment: They require no treatment and often go away on their own, though some can persist for a lifetime without causing any health issues.

Pathological Heart Murmurs

Pathological murmurs are caused by structural heart problems, usually involving the heart valves or a septal defect (a hole in the wall between heart chambers). These conditions include valvular heart disease (like stenosis or regurgitation) or congenital heart defects. * Sound Characteristics: They are often harsh, loud, diastolic, or continuous. They are associated with other symptoms like shortness of breath, dizziness, or chest pain. * Diagnosis and Treatment: A newly detected pathological murmur, especially if diastolic or continuous, requires immediate follow-up with an Echocardiogram (an ultrasound of the heart) to visualize the heart's structure and function. Treatment focuses on the underlying cause and may involve medications (like blood pressure or heart rhythm controllers), surgical repair, or valve replacement. The key takeaway for anyone concerned about a heart murmur is to remember that the sound is a clue, not a sentence. The unique *whoosh* or *rasp* provides the cardiologist with a clear roadmap to the source of the turbulent flow, allowing for precise diagnosis and management.