Congestive heart failure (CHF) is a progressive condition where the heart muscle does not pump blood effectively enough to meet the body’s demands. This inefficiency causes blood to back up, leading to fluid leaking out of the blood vessels and accumulating in various tissues and organs, most noticeably in the lungs, legs, and feet. The sounds associated with CHF are primarily a consequence of this fluid accumulation in the lungs, which interferes with normal breathing and coughing.
The Signature Sounds of Fluid Buildup
The most characteristic auditory sign of fluid in the lungs due to CHF is the presence of sounds known as “crackles” or “rales.” These sounds are not heard by the unaided ear but are detected by a doctor using a stethoscope, especially over the lower sections of the lungs. They are caused by air moving through small airways and air sacs (alveoli) that are partially filled with fluid.
Fine crackles are often described as high-pitched, brief sounds, sometimes likened to the sound of hair being rubbed between fingers or Velcro being slowly torn apart. The physical mechanism is similar to the sudden opening of tiny, collapsed, fluid-filled structures. These sounds typically occur during inhalation, particularly in the mid-to-late phase of breathing.
As pulmonary edema worsens, the crackles become coarser, louder, and heard over a wider area of the lungs, extending upward toward the chest. The presence of these sounds, especially when they begin at the lung bases, is a strong indicator of pulmonary congestion. The intensity and location of the crackles often correlate with the severity of the fluid overload. The sounds may lessen or disappear following successful treatment, such as with diuretic medication.
Distinctive Sounds of a CHF Cough
A cough frequently accompanies the fluid accumulation in the lungs, often referred to as a “cardiac cough.” This cough is the body’s natural, albeit often ineffective, attempt to clear the fluid that has leaked into the airways. Unlike a dry, hacking cough caused by some medications, the CHF cough is typically described as wet, persistent, or gurgling.
The sound is distinctly “productive,” meaning it brings up material from the lungs. This expelled material, called sputum or phlegm, is often white or clear at first. As the condition progresses, the sputum may become pink or tinged with blood, and appear frothy or bubbly in texture. This frothy, pink appearance is a direct result of air mixing with the fluid and tiny amounts of blood from the congested lung tissue.
The cough can become particularly bothersome when lying flat, a symptom known as orthopnea. In this position, gravity allows the fluid to distribute more evenly across the lungs, increasing the irritation and triggering a more intense coughing fit. This persistent, wet cough is a significant sign that the heart failure is causing pulmonary congestion that requires medical attention.
When Sounds Signal Acute Distress
Certain sounds indicate a severe and sudden worsening of heart failure, known as acute decompensation, which is a medical emergency. One such sound is audible wheezing, sometimes called “cardiac asthma.” This wheezing is a high-pitched, whistling sound heard during breathing, caused not by allergy but by the fluid-filled airways narrowing, similar to what happens in asthma.
A patient in acute distress may also exhibit extremely rapid, shallow breathing, which can be noisy and labored. This is often accompanied by gasping or a struggle to catch a breath, known as dyspnea. The inability to speak a full sentence without pausing to breathe is a sign of severe breathlessness. Changes in the quality of the voice, such as a more “creaky” sound, can also occur due to fluid buildup affecting the laryngeal tissues. Any rapid escalation in breathing sounds, wheezing, or the onset of gasping signals a life-threatening situation.