What is the significance of a consistently elevated pulse rate between 90 to 100 beats per minute (bpm) and how is it managed?

Management of Pulse Consistently Between 90-100 BPM

A pulse consistently between 90-100 bpm falls in the upper range of normal sinus rhythm and does not automatically require treatment, but mandates evaluation for underlying causes that could impact morbidity and mortality. 1

Understanding the Clinical Significance

The normal resting sinus rate is generally between 50-90 bpm, reflecting vagal tone. 1 Your pulse range of 90-100 bpm sits at the upper boundary of normal but below the technical definition of sinus tachycardia (>100 bpm). 1

However, this borderline elevation warrants attention because:

• Elevated resting heart rate (even in the 90-100 bpm range) has been associated with increased all-cause and cardiovascular mortality in multiple populations. 2, 3
• A heart rate ≥90 bpm over 24 hours can indicate inappropriate sinus tachycardia when accompanied by symptoms. 1
• High heart rate may reflect increased sympathetic tone, which is associated with insulin resistance, dyslipidemia, and increased cardiovascular strain. 3

Initial Evaluation Algorithm

First, systematically exclude reversible physiological and pathological causes: 1

Common Reversible Causes to Investigate:

• Fever or infection - Check temperature and inflammatory markers 1
• Dehydration - Assess volume status, orthostatic vital signs 1
• Anemia - Obtain complete blood count 1
• Hyperthyroidism - Check TSH and free T4 1
• Pain or anxiety - Clinical assessment for anxiety disorders 1
• Medications and substances:
  • Caffeine intake 1
  • Beta-agonists (albuterol, salmeterol) 1
  • Stimulant drugs (amphetamines, cocaine) 1
• Heart failure or structural heart disease - Consider echocardiography if clinically indicated 1
• Pulmonary embolism - Assess risk factors and consider if clinically appropriate 4

Obtain a 12-lead ECG to:

• Confirm the rhythm is sinus tachycardia rather than another supraventricular tachycardia 4
• Look for P waves upright in leads I, II, and aVF, and biphasic in V1 1

Management Based on Symptoms

If Asymptomatic with No Underlying Cause:

Treatment is generally not necessary, as the prognosis is benign. 1 The focus should be on:

• Lifestyle modifications:
  • Exercise training may be beneficial 1
  • Reduction of caffeine and stimulant intake 1
  • Stress management and treatment of anxiety if present 1
• Regular monitoring to ensure heart rate doesn't progressively increase 1

If Symptomatic (weakness, fatigue, lightheadedness, palpitations):

This may represent inappropriate sinus tachycardia (IST), which requires:

1. Evaluation and treatment of reversible causes is the first-line recommendation (Class I). 1

2. If symptoms persist after addressing reversible causes:

   • Ivabradine is reasonable for ongoing management (Class IIa recommendation). 1 This medication selectively reduces heart rate without other hemodynamic effects 1
   • Beta blockers may be considered (Class IIb recommendation), though they are often ineffective or poorly tolerated due to hypotension 1
   • Combination of beta blockers and ivabradine may be considered (Class IIb recommendation) 1

Critical Pitfalls to Avoid

• Do not assume the elevated heart rate is compensatory without investigating underlying causes. Normalizing heart rate without addressing the underlying pathology can be detrimental if the tachycardia is compensatory (e.g., in heart failure or hypovolemia). 4

• Recognize that lowering the heart rate may not alleviate symptoms in IST, and treatment should focus on symptom reduction rather than achieving a specific heart rate target. 1

• Do not use rate-controlling medications if accessory pathways (WPW syndrome) are present, as this can accelerate conduction through the accessory pathway. 4

• Distinguish IST from postural orthostatic tachycardia syndrome (POTS), as treatment to suppress sinus rate in POTS may lead to severe orthostatic hypotension. 1

When to Refer

Consider referral to an electrophysiologist if: 4

• Episodes are recurrent despite addressing reversible causes
• Inappropriate sinus tachycardia is suspected
• Symptoms are debilitating and refractory to initial management

Long-term Considerations

Even in the absence of symptoms, a consistently elevated resting heart rate in the 90-100 bpm range may warrant periodic reassessment, as it has been associated with increased long-term cardiovascular and all-cause mortality. 2, 3 Whether pharmacologically lowering the heart rate in asymptomatic individuals improves outcomes remains under investigation. 2