Difference between apical and radial pulse

Introduction

        The Apical pulse refers to the cardiac activity felt by palpation over the precordium. Apex beat is the outermost and lowermost point of maximum cardiac activity felt by palpation over the precordium. Apical impulse is the inspectory correlate of apex beat.

     Radial pulse is a peripheral pulse which is the result of beating of the heart as felt through the walls of radial artery. What is felt at the periphery (radial artery) is not the blood flowing through the arteries but the shock wave that travels along the walls of the arteries as the heart contracts each time producing a rhythmic wave.

Difference in features

    Apical pulse is felt by palpation or feeling by the hand, over the precordium i.e. left chest region,  with the patient in a lying or sitting position whereas the radial pulse is felt at the outer corner of the wrist joint.

           Apical pulse can be evaluated with the help of a stethoscope placed over the 5th intercostal space, just inside the mid-clavicular line while the Radial pulse is palpated by the tip of three central fingers placed along the outer aspect of the wrist. The Radial pulse is counted for one minute as beats per minute (pulse rate) while the Apical pulse can be counted with the help of stethoscope for one minute (heart rate).

Difference in utility

       The apical pulse defines the character of heart contractions better as it is much closer to the heart. Well sustained, strong contractions are seen in concentric left ventricular enlargement (due to hypertension, Aortic stenosis) and give the pulse a  heaving character. Ill-sustained, strong contractions are seen in hyperdynamic states like anemia, thyrotoxicosis and fever and give it a different  character. In mitral stenosis, a doctor might report a tapping apex beat.         Volume of the radial pulse can be low in conditions like cardiac shock,  hypotension due to blood loss, plasma loss as in dengue, etc.

         Cardiac arrhythmias will result in irregular apical and radial pulse. Arrhythmia can be either regularly irregular (constant missed beats- bigeminy, trigeminy) or they can be irregularly irregular (ventricular flutter, ventricular fibrillation). When the apical and radial pulses are too fast then it is referred to as tachycardia and is seen in conditions like fever, trauma with blood loss, hyperthyroidism, anxiety, etc. The pulses can be slower than the normal range of 60-100 beats/minute and will be referred to as bradycardia which can be physiological in athletes, pathological in hypothyroidism, heart block, etc.

     Radial pulse can provide information regarding the state of the blood vessel which is identified by the feel of artery between the two pulsations, normally soft but tends to become hard when atherosclerosed.

    Palpation of both radial and apical pulse simultaneously is important to diagnose conditions like coarctation of aorta which produce a difference in the two pulses; it is more likely to have a slight delay in the radial pulse due to decreased supply of the blood to the lower limbs.

Summary:

The apical pulse is the rhythmic beating of the heart felt through the chest wall using a stethoscope or hand as a result of heart’s contractions. The radial pulse is the contractile wave that passes through the wall of the radial artery of the forearm due to heart’s contractions, felt along the wrist joint.

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