What should I do if my pulse rate and heart rate are unequal, indicating a potential arrhythmia or cardiac issue?

Pulse Rate and Heart Rate Unequal: Pulse Deficit

If your pulse rate and heart rate are unequal (pulse deficit), this indicates an arrhythmia where not all heartbeats generate sufficient force to produce a palpable peripheral pulse—you need immediate evaluation to determine if this represents a hemodynamically significant arrhythmia requiring urgent treatment. 1

Immediate Assessment Required

A pulse deficit occurs when the apical heart rate (counted by auscultation over the heart) exceeds the peripheral pulse rate (counted at the radial or other peripheral artery), signaling that some cardiac contractions are too weak to generate a palpable pulse wave 1. This finding mandates:

• Attach continuous cardiac monitoring immediately to identify the underlying rhythm 2
• Obtain a 12-lead ECG without delay to characterize the arrhythmia, though this should not postpone immediate treatment if you are hemodynamically unstable 2
• Assess for hemodynamic instability: acute altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or signs of shock 2
• Monitor oxygen saturation and provide supplementary oxygen if needed 2

Common Arrhythmias Causing Pulse Deficit

The most frequent culprits include:

• Atrial fibrillation with rapid ventricular response: Irregular rhythm with variable stroke volumes means weaker beats don't produce peripheral pulses 2
• Frequent premature ventricular contractions (PVCs): Premature beats have inadequate filling time and reduced stroke volume 3, 4
• Ventricular tachycardia: May produce weak or absent peripheral pulses despite cardiac electrical activity 2
• Atrial flutter with variable AV conduction: Creates irregular ventricular response with varying pulse strength 2

Determine Stability and Urgency

If you have ANY of these unstable features, you need immediate synchronized cardioversion (or unsynchronized defibrillation if pulseless) 2:

• Acute altered mental status
• Ongoing chest pain suggesting ischemia
• Acute heart failure/pulmonary edema
• Hypotension (systolic BP <90 mmHg)
• Signs of shock

Critical threshold: When heart rate exceeds 150 beats per minute, symptoms of instability are more likely caused primarily by the tachycardia itself rather than an underlying condition, especially with impaired ventricular function 2. Below 150 bpm, the tachycardia is more often secondary to another problem (fever, dehydration, anemia) 2.

If Hemodynamically Stable

For stable patients with pulse deficit:

• Identify the specific arrhythmia using the 12-lead ECG 2
• Determine if rhythm is regular or irregular: Irregular suggests atrial fibrillation, multifocal atrial tachycardia, or atrial flutter with variable block 2
• Assess QRS width: Narrow (<120 ms) indicates supraventricular origin; wide (≥120 ms) suggests ventricular tachycardia or SVT with aberrancy 2
• Search for and treat reversible causes: hypoxemia, electrolyte abnormalities (especially hypokalemia/hypomagnesemia), drug toxicity, acute coronary syndrome, pulmonary embolism 2, 5

Critical Pitfalls to Avoid

Do NOT normalize a compensatory tachycardia: When cardiac function is severely impaired, cardiac output depends on maintaining a rapid heart rate because stroke volume is fixed—"normalizing" the rate can be catastrophic 2. Look for underlying causes first.

Do NOT use AV nodal blocking agents (adenosine, calcium channel blockers, beta-blockers, digoxin) if you have atrial fibrillation with pre-excitation (Wolff-Parkinson-White pattern on ECG), as these can paradoxically accelerate the ventricular rate and precipitate ventricular fibrillation 2.

Do NOT assume sinus tachycardia needs drug treatment: Sinus tachycardia (rate >100 bpm, up to approximately 220 minus your age) is a physiologic response—treat the underlying cause (fever, pain, hypovolemia), not the rate itself 2.

When to Seek Emergency Care

Go to the emergency department immediately if you experience 2:

• Syncope or near-syncope with the pulse deficit
• Severe dyspnea or inability to breathe comfortably
• Chest pain or pressure
• Confusion or altered consciousness
• Persistent symptoms despite rest

Refer urgently to a cardiac electrophysiologist if you have 2:

• Recurrent symptomatic episodes
• Pre-excitation pattern (Wolff-Parkinson-White) on baseline ECG
• Wide-complex tachycardia of unknown origin
• Drug-resistant or drug-intolerant arrhythmias

Monitoring Strategy

If the pulse deficit is documented but you remain stable, continuous cardiac monitoring with pulse oximetry is essential until the arrhythmia is characterized and treated 2. Establish IV access for potential medication administration 2. Have immediate access to defibrillation equipment, as certain arrhythmias can rapidly deteriorate to life-threatening rhythms 2, 5.