Makindo Medical Notes

Related Subjects: |Examining the Arterial Pulse

Introduction

The arterial pulse is a vital sign that provides essential information about the cardiovascular system. Examination of the pulse helps assess heart rate, rhythm, and the character of arterial blood flow. Understanding the nuances of the arterial pulse waveform and its variations can aid in diagnosing various cardiac and systemic conditions.

The pulse waveform consists of a percussion wave generated by the ejection of blood from the heart, traveling along the arterial tree at a velocity faster than the actual blood flow. The dicrotic notch on the waveform represents the closure of the aortic valve and the onset of diastole.

Objectives of Pulse Examination

• Assess the rate of the heartbeat.
• Determine the rhythm and identify any irregularities.
• Evaluate the character and volume of the pulse.
• Check for any radio-radial or radio-femoral delay.
• Detect any specific pulse abnormalities indicative of underlying pathology.

Technique of Pulse Examination

The radial artery at the wrist is the most common site for pulse examination due to its accessibility. The examiner should:

• Ensure the patient's arm is relaxed and supported at heart level.
• Use the pads of the index and middle fingers to palpate the radial artery just proximal to the wrist crease.
• Apply gentle pressure to feel the pulse without occluding the artery.

Pulse Characteristics

The character of the pulse provides insights into cardiac output, arterial compliance, and peripheral resistance. Key characteristics include:

• Volume: Reflects the pulse pressure and stroke volume.
• Contour: The shape of the pulse wave, indicating the speed of upstroke and downstroke.
• Regularity: Consistency of the pulse rhythm.
• Equality: Comparing pulses on both sides to detect any asymmetry.

Pulse Character Variations and Their Clinical Significance

Pulse Character	Clinical Conditions	Description
Normal Pulse	Healthy individuals	Regular rhythm with normal volume and contour.
Bounding Pulse	Fever, hyperthyroidism, anemia, aortic regurgitation, patent ductus arteriosus	Increased pulse volume with a rapid upstroke and downstroke.
Collapsing (Waterhammer) Pulse	Aortic regurgitation, patent ductus arteriosus, high-output states	Forceful and rapidly collapsing pulse due to increased stroke volume and decreased peripheral resistance.
Slow-Rising Pulse (Anacrotic)	Aortic stenosis	Slow upstroke with a low amplitude, indicating delayed systolic ejection.
Bisferiens Pulse	Mixed aortic valve disease, hypertrophic obstructive cardiomyopathy	Double systolic peak due to combined stenosis and regurgitation.
Pulsus Alternans	Severe left ventricular dysfunction	Alternating strong and weak beats with regular rhythm.
Pulsus Paradoxus	Cardiac tamponade, constrictive pericarditis, severe asthma, tension pneumothorax	Exaggerated decrease (>10 mmHg) in systolic blood pressure during inspiration.
Jerky Pulse	Hypertrophic obstructive cardiomyopathy	Rapid upstroke with a sudden decline, also known as a spike-and-dome pulse.
Thready Pulse	Shock, hypovolemia	Weak and rapid pulse with low volume.
Absent Pulse	Arterial occlusion, aortic dissection, Takayasu arteritis	No palpable pulse due to arterial blockage or inflammation.
Radio-Femoral Delay	Coarctation of the aorta	Delayed femoral pulse compared to radial pulse.

Heart Rate

The normal resting heart rate for adults ranges from 60 to 100 beats per minute (bpm). Abnormal rates can indicate various cardiac or systemic conditions.

Bradycardia (Heart Rate < 60 bpm)

• Sinus Bradycardia: Normal in athletes; can be due to hypothyroidism, hypothermia, medications (e.g., beta-blockers), or increased vagal tone.
• Atrioventricular (AV) Block:
  • First-Degree AV Block: Prolonged PR interval without dropped beats.
  • Second-Degree AV Block (Mobitz Type I and II): Intermittent failure of AV conduction.
  • Third-Degree (Complete) AV Block: No conduction between atria and ventricles; ventricular rate is slow.
• Sinus Node Dysfunction: Sick sinus syndrome causing inappropriate bradycardia.

Tachycardia (Heart Rate > 100 bpm)

• Sinus Tachycardia: Physiological response to exercise, stress, pain, fever, anemia, hyperthyroidism.
• Supraventricular Tachycardia (SVT):
  • Atrioventricular Nodal Reentrant Tachycardia (AVNRT): Reentry circuit within the AV node.
  • Atrioventricular Reentrant Tachycardia (AVRT): Accessory pathway (e.g., Wolff-Parkinson-White syndrome).
• Atrial Flutter: Rapid atrial rate (typically ~300 bpm) with variable ventricular response (commonly 2:1 block resulting in ventricular rate ~150 bpm).
• Atrial Fibrillation: Irregularly irregular rhythm with varying ventricular response.
• Ventricular Tachycardia: Rapid ventricular rate originating from abnormal ventricular focus; can be life-threatening.
• Ventricular Fibrillation: Chaotic ventricular activity leading to loss of effective circulation; medical emergency.

Pulse Rhythm

Assessing the rhythm involves evaluating the regularity of pulse beats.

Rhythm Type	Clinical Conditions	Description
Regular Rhythm	Normal sinus rhythm, sinus tachycardia, sinus bradycardia	Equal intervals between beats.
Regularly Irregular	Second-degree AV block (Mobitz Type I), bigeminy (normal beat followed by a premature beat)	Patterned irregularity with repeating cycles.
Irregularly Irregular	Atrial fibrillation, multifocal atrial tachycardia	No discernible pattern; completely irregular intervals.
Extrasystoles (Ectopic Beats)	Premature atrial or ventricular contractions	Early beats interrupting the regular rhythm.

Pulse Deficit

In conditions like atrial fibrillation, not all heartbeats result in effective ventricular contractions palpable at the periphery. Comparing the apical heart rate (by auscultation) with the radial pulse rate can reveal a pulse deficit.

Radio-Radial and Radio-Femoral Delay

• Radio-Radial Delay: Unequal timing of pulses in both radial arteries suggests subclavian artery stenosis, aortic dissection, or compression by a cervical rib.
• Radio-Femoral Delay: Delay between radial and femoral pulses indicates coarctation of the aorta or significant atherosclerotic disease.

Clinical Examples and Associations

• Bounding Pulse: Hyperdynamic circulatory states; check for signs of fever, anemia, or thyrotoxicosis.
• Collapsing Pulse: Best felt by elevating the patient's arm above the head while palpating the radial pulse; indicative of aortic regurgitation.
• Pulsus Paradoxus: Measured using a sphygmomanometer; significant in cardiac tamponade and severe asthma exacerbations.
• Pulsus Alternans: Suggests severe left ventricular systolic dysfunction; may require echocardiography for assessment.

Conclusion

The examination of the arterial pulse is a fundamental clinical skill that provides valuable information about a patient's cardiovascular status. A systematic approach to assessing the pulse—evaluating the rate, rhythm, and character—can aid in the early detection of cardiac pathologies and guide further diagnostic investigations.

References

• Bickley LS, Szilagyi PG. Bates' Guide to Physical Examination and History Taking. 12th ed. Wolters Kluwer; 2017.
• Kasper DL, Fauci AS, Hauser SL, et al., editors. Harrison's Principles of Internal Medicine. 20th ed. McGraw-Hill; 2018.
• Epstein O, Perkin GD, Cookson J, de Bono DP. Clinical Examination. 4th ed. Mosby; 2008.
• Seidel HM, Ball JW, Dains JE, Benedict GW. Mosby's Guide to Physical Examination. 7th ed. Elsevier; 2011.
• McGee S. Evidence-Based Physical Diagnosis. 4th ed. Elsevier; 2018.