Clinical Examination of the Cardiovascular System

Becks Triad: The vital triad in cardiac emergencies

Dr. Rahul Kushwaha30th December 2019

An apprehension on Becks triad

Becks triad is a set of three medical signs correlated with acute cardiac tamponade. Acute cardiac tamponade is an emergency medical condition characterized by the accumulation of fluids around the heart that impairs its ability to pump blood. The signs related to beck’s triad are Low arterial blood pressure, increased neck vein distention, and Muffled heart sounds.

Becks triad is the standard diagnostic feature of cardiac tamponade. Sometimes narrow pulse pressure might also be observed. The concept of this diagnostic feature was developed by a resident and late professor of cardiovascular surgery, Claude Beck. 

Components of Becks triad

Dr. beck 1993, he told that if someone has these three features, you need to rule out cardiac tamponade.

The three-element of becks triad are:

• Low blood pressure with a narrowed pulse pressure 
• increased necks vein distention 
• Muffled heart sounds

Remember, this classical presentation is more common in patients with acute cardiac tamponade. Because in acute cardiac tamponade, hemodynamic stability is lost very rapidly. And these beck’s triad showing in patients shows that the cardiovascular system is not stable in such patients.

JVP in becks triad

1. Jugular venous pressure is very high
2. The pattern of the jugular vein is in the waveform

• There is lost ‘Y’ descent
• There is half ‘X’ descend.

JVP is the most sensitive sign of cardiac tamponade.

BP in Becks triad

• There is falling systematic arterial pressure with paradoxical pulse or pulses paradoxes.
• Tachycardia

Muffled heart sound in Beck’s triad

Usually with shifting apex beat. Or absent apex beat.

Physiology of Becks triad

JVP

When there is an atrial contraction, “A’ wave is formed. Atria start relaxing; pressure started falling suddenly. The ventricle contraction started. The tricuspid valve is closed, and there is little jerk in the Wave, which is called ‘C’ wave. After that, the atrium and ventricle are not connected. You don’t need to worry about the incident occurring in the ventricle

Now the atrium is progressively is relaxing. When atria are relaxing, the blood will come down, and pressure will also come down. This pressure coming down due to atrial relaxation is called ‘X’ descends.

.Eventually time will come the valve is still closed. And atria are filled. Now, there will be more venous return the cumulation of the blood will take the pressure slightly up. This pressure upward is due to venous accumulation. This is called the ‘V’ wave.

Eventually, the tricuspid valve will open, the accumulated will fall into the right ventricle. The intraventricular pressure is shallow due to the relaxation of the valve. When intraventricular pressure is lower than the interatrial pressure, the ventricular filling will occur. Atrial emptying immediately after the valve opening takes all the venous column down. And there will descend Wave, which is called ‘Y’ descend.

‘Y descend’ occur in the early diastole of the ventricle.

 The increased neck vein distension occurs in a non-supine position. The expanded neck vein distention is caused by reduced diastolic of the right ventricle, due to pressure being exerted on it by the expanding pericardial sac. This results in a backup of fluid into the veins draining into the heart, most notably, the jugular veins. Neck vein may not be distended in severe hypovolemia. 

BP

The physiological decrease in arterial blood pressure, which is the result of pericardial fluid accumulation within the heart that acts to impair the ventricular stretch, thus reducing stroke volume and cardiac output. These two factors are significant determinants of systolic blood pressure.

Higher diastolic pressure will cause an increase in intra-pericardial pressure. Increase intra-pericardial causes a decrease in the ventricular filling, which will lead to a decrease in end-diastolic volume.

Then, the EDV leads to a decrease in the myocardial stretch. This causes decrease myocardial contractility. The reduction in myocardial contractility leads to decreased stroke volume, and the Reduced stroke volume will decrease cardiac output.

This will ultimately lower systolic pressure, and finally, these are caused by reduced blood pressure in cardiac tamponade.

Muffled heart sound

The muffled heart sound is due to the muffling effects of the sound passing through the fluid surrounding the heart. 

• There is lots of fluid in pericardial space.
• When you put the stethoscope to the chest wall, the heart is very far away from the diaphragm. You can’t hear the sound very well.
• When the heart is compressed, it is not beating very well, and it does not produce enough sound.

Note: There will be a loss of apex beat or weakened apex beat.

Mnemonics for becks triad

Here are some easiest and enjoyable mnemonics for beck triad:

3Ds

• D= Distant heart sound
• D= Distended jugular veins
• D= Decrease arterial blood pressure

Clinical use 

Although the full triad is present only in a minority of cases of acute cardiac tamponade. The presence of the triad is considered pathognomonic for acute cardiac tamponade.

Cardiac tamponade needs to be differentiated from a tension pneumothorax in the shocked patient with distended neck veins. It is, most commonly the result of the penetrating trauma. Accumulation of a relatively small amount of blood into the non-distensible pericardial sac can produce compression of the heart and obstruction of the venous return, leading to decreased filling of the cardiac chambers during diastole.

All the patients with penetrating injury anywhere near the heart plus shock must be considered to have a cardiac injury until proven otherwise. Classically, the presentation consists of central venous pressure elevation, the decline in arterial pressure with tachycardia, and muffled heart sounds. This presentation is known as Becks triad, which is clinically used to diagnose cardiac tamponade. 

However, in cases in which major bleeding from other sites has taken place, the neck veins may be flat. A central line should be inserted, checking for rising central venous pressure. A high index of suspicion and further diagnostic investigations will be needed to make the clinical diagnosis is those cases that are not clinically obvious. 

These include an eFAST showing fluid in the pericardial sac. This is the most expeditious and reliable diagnostic tool, or chest radiography looking for an enlarged heart shadow. 

Becks triad vs Cushing’s triad

Beck’s triad and Cushing’s triad are both medical signs that indicate a critically ill patient. Beck’s triad is named after Dr. William B. Beck and is commonly associated with cardiac tamponade, a condition in which fluid accumulates in the pericardial sac surrounding the heart. Whereas Cushing’s triad, on the other hand, is named after Dr. Harvey Cushing and is associated with increased intracranial pressure (ICP), a condition in which pressure within the skull increases.

Beck’s triad consists of three key signs: low blood pressure, muffled heart sounds, and distended neck veins. whereas Cushing’s triad consists of three key signs: increased blood pressure, bradycardia (slowed heart rate), and irregular breathing patterns. 

It is important to note that while both triads may be present in critically ill patients, they are indicative of different underlying conditions. Healthcare providers should consider the presence of Beck’s triad in patients with suspected cardiac tamponade and consider the presence of Cushing’s triad in patients with suspected increased ICP.

Difference between becks triad and Kussmaul’s sign

Becks triad: Becks triad referred to distended neck veins, muffled heart sounds, and hypotension. Pulsus Paradoxux: decrease in systolic pressure with spontaneous inspiration. it is classically associated with cardiac tamponade. 

Kussmaul’s sign: Kussmaul sign is the paradoxical elevation of Central venous pressure during inspiration. Kussmaul sign is classically associated with constrictive pericarditis. Still, it occurs in only the minority of patients with constriction and is found in other conditions, such as myocardial infarction (MI), pulmonary embolism, and right ventricle infraction. 

Conclusion 

Becks triad refers to a group of cardiac signs usually observed to occur together. For memory purposes, beck triad is also called as “3Ds”, which you have seen in the pic above. The becks triad observation and findings of a cluster of cardiac signs were circulated in the journal of the American medical association, and soon after, the cardiac sign is known as beck triad. 

In general, beck’s triad is the result of heart compression. Usually, it is the diagnostic feature of acute cardiac tamponade. Cardiac tamponade is one of the medical emergencies. If you experience these features, please visit the nearest hospital. 

Frequently asked questions