Distinguishing and Understanding Heart Sounds and Murmurs

How Can the First and Second Heart Sounds Be Distinguished?

• While auscultating, palpate the carotid artery. S₂ is the sound that occurs after the carotid pulsations, and S₁ is the sound that occurs immediately before them. The apex beat and this relationship are similar.
• The systolic and diastolic intervals are shorter at a normal heart rate. Experience allows one to identify this distinction.
• The sounds S₁ and S₂ indicate the start and finish of the shorter interval (systole), respectively. Practice is necessary for this.
• S₁ is the sound that occurs shortly prior to carotid pulsations.
• S₃ is the sound that is produced after the carotid pulsations.
• First and second heart sounds can also be recognized by their character; this requires lot of experience.

Features of Heart Sounds

Take note of the two features of heart sounds that are as follows:

• Level of intensity
• The Splitting Power

Intensity

Heart sounds can be trained to sound normally with practice.

First heartbeat.

The apex is where it is most audible, thus when you discuss its intensity, simply speak about the pinnacle.

The second heartbeat.

• Usually, it is possible to determine the strength of both of its components.
• P₂ is loud if S₂ is solitary and its intensity is high in the pulmonary area but low at the aortic area.
• A₂ is loud if S₂ is loud at the pulmonary and aortic areas.
• A₂ is soft if S₂ is mild in the aortic area and of normal intensity at the pulmonary area.
• While auscultating at the tricuspid and apex, focus on S₁.
• While auscultating the aortic and pulmonary zones, pay close attention to S₂.
• It's challenging to comprehend soft P₂. Soft or inaudible P₂ can be inferred indirectly from a single S₂ normal intensity.
• Both components can be readily observed and their intensities discussed if S₂ is divided.

Reasons for unusually loud heartbeats

Gentle sounds from both hearts

• Cardiopulmonary effusion
• Asthma
• A thick wall across the chest

Booming S1

• Stenosis of the mitral valve
• Hypertension

S1 Soft

• Regurgitation of mitral valve prolapses
• Heart attack
• Cardiac rheumatism

S1 fluctuating intensity

• Heart arrhythmia
• Whole heart block

Loud P₂

Heart hypertension

P2 Soft

Heart valve stenosis in the lung

Booming A2

Hypertension in the system

Comfortable A2

• Aortic stenosis
• Regurgitation of the aorta
• Dividing

First heartbeat:

Its division is rare and unimportant. The splitting of the second heart sound is highly common and important. Since P₂ is only audible in the pulmonary region, look for the splitting of S₂ there. There are three different ways to split S₂: normal splitting, fixed splitting, and reverse splitting.

Typical division: 

This indicates that there is a greater separation between A₂ and P₂ during inspiration than during expiration (splitting is more noticeable and sound becomes single during inspiration). It is described in more detail below. During inspiration, the cardiac output on the right side increases, while during expiration, the cardiac output on the left side increases.

The aortic valve typically closes before the pulmonary valve. The right ventricular stroke volume increases during inspiration due to an increase in the right atrium's venous return, which is brought on by an increase in negative intrathoracic pressure. The pulmonary valve closes later, P₃ increases, and the right ventricle takes longer to empty itself.

The pulmonary vasculature's blood-containing capacity increases when the lung expands during inspiration, allowing the lungs to hold on to more blood. This also results in a drop in the left atrium's venous return and a decrease in the left ventricular stroke volume. The aortic valve closes earlier, causing the left ventricle to empty itself more quickly and to create A₂ sooner.

As a result, P₂ is delayed and A₂ is early during inspiration, causing S₂ to split.

Cardiac Hemodynamics During Respiration Cycles

During expiry, the opposite happens. P₂ is early, there is a decrease in the right ventricle's stroke volume and venous return to the right atrium. A₂ is delayed, the left ventricle's stroke volume is raised, and more blood flows to the left atrium. Consequently, S₂ is either narrowly split or single during expiration.

From the discussion above, it's crucial to keep in mind that during inspiration, the right side of the heart produces more blood while the left side produces less; during expiration, the opposite happens.

Reasons for the typical S1 splitting

• In young adults and children, normal. Another name for it is physiological splitting.
• The branch block of the right bundle
• Right ventricle dilated
• Narrow-split pulmonary hypertension

Fixed splitting:

Blood moves from the left atrium to the right atrium in an atrial septal defect. Wide splitting of S₂ results from a three-fold increase in the right sided stroke volume and a delay in P₂. The communication between both atria results in the loss of the differential effect of respiration on the stroke volume of the two sides of the heart, and during inspiration and expiration, the interval between A₂ and P₂ stays constant. We refer to this as fixed splitting. The most significant indication of an atrial septal defect is this.

Reverse splitting:

The effect of respiration on S₂ splitting is reversed if left ventricular emptying is postponed to the point when the aortic valve closes after the pulmonary valve closes. Gallop rhythm, also known as triple rhythm, is the aural impression of a horse galloping and is produced when the third or fourth heart sound (S₃, S₄) is present.

Summation gallop:

A patient may be able to hear both S₃ and S₄. Both are appreciated independently at a low heart rate. S₃ and S₄ become intertwined and very near to one another when heart rate rises. We refer to this as summation gallop.

Presystolic gallop:

Indicates the presence of S₄.

Pericardial Knock

Due to an abrupt stop to the ventricle's early diastolic filling, constrictive pericarditis patients can hear this loud yet distant diastolic sound. This sound is similar to a distant third heartbeat.

Additional Sounds

These consist of the sounds of prosthetic valves, ejection clicks, and opening snaps.

First Picture

The mitral valve opens in mitral stenosis, causing a high-pitched, piercing sound. It can be heard shortly after S₂, with the peak strength occurring medial to the apex. When an opening snap is present, the valve cusps are stenosed but still moveable.

Clicks in Systolic Ejection

These sounds, which come shortly after S_1, are sharp systolic sounds caused by the faulty aortic and pulmonary valves opening. The A₁ region and apex are the finest places to hear the aortic click. Breathing has no effect on it. The pulmonary click intensifies during expiration and is most audible near the pulmonary area. When a click is audible in addition to other stenosis symptoms, the stenosis is valvular as opposed to supra- or sub valvular.

Reasons for the systolic click ejection

The Aortic click

• Strict aortic valve closure
• Aortic bicuspid valve

Heart-related click

• Stenosis of the pulmonary valves
• Pulmonary artery dilatation (idiopathic or as a result of pulmonary hypertension)

Mid-Systolic Click

A click is produced in the mid-systole of mitral valve prolapse, a condition in which a mitral valve cusp prolapses into the left atrium during systole. A late systolic murmur may follow.

Artificial Valve Sounds

There are two main types of prosthetic valves:

Biological gates

These sound like the typical heartbeat and are made of animal tissue.

Mechanical valves

Rather than only making two noises during closure or opening, these valves make four noises. These noises have a high pitch, a metallic tone, and a loud intensity. The mitral valve makes a loud opening snap sound and a metallic first heart sound. The aortic valve emits a loud ejection systolic click sound and a metallic second heart sound.

Murmurs

Compared to cardiac sounds, these noises are aberrant and last longer. One of three processes is responsible for them, which are created by the turbulence in blood flow.

• Excessive blood flow via a normal valve, such as during pregnancy or severe anemia. These murmurs are sometimes referred to as flow or functional murmurs.
• Normal blood flow via a narrowed valve, such as an aortic or mitral stenosis.
• Abnormal blood flow direction:
• A valve typically only permits one-way flow. Leakage, such as aortic or mitral regurgitation, may happen if it is abnormal.
• Abnormal communication that occurs outside the heart, such as persistent ductus arteriosus, or inside the heart, such as atrial or ventricular septal defects.

The Qualities of A Murmur

If a murmur can be heard, take note of its characteristics:

• Time
• Intenseness
• The most intense location
• Ionization
• Character
• Pitch
• Respiratory effect
• Posture effect

Timing

It will be adequate for a beginning to be able to distinguish between a diastolic and a systolic murmur. Auscultate while palpating the carotid artery. When the carotid pulse occurs, a systolic murmur occurs, and a diastolic murmur alternates.

Murmurs in Systolic

The systolic murmur comes in two main varieties. Systolic murmur per pan: It begins at S₁ and continues up to or past S₂.

Pan systolic Murmur Causes

1. Regurgitation of mitral valve prolapse
2. Regurgitation of tricuspids
3. Septal deficiency of the ventricles

Systolic Ejection Murmur

It occurs just before the second heart sound and finishes a little after the first. The murmur on either side is separated from the heart sounds by a pause. It is gentle at first, reaches its peak intensity in the middle, and then becomes less intense (on phonocardiography, it has a diamond shape).