Should a 31-year-old female with intermittent palpitations and a heart rate (HR) showing sinus rhythm with a range of 40-97 beats per minute (bpm) and a 2.4-second pause be referred?

From the Guidelines

This 31-year-old female with intermittent palpitations and a heart rate showing sinus rhythm with a range of 40-97 beats per minute (bpm) and a 2.4-second pause should be referred for further cardiac evaluation. The Holter monitor findings of sinus bradycardia (as low as 40 beats per minute), significant heart rate variability (40-97 bpm), and especially the 2.4-second pause are concerning and warrant specialist assessment, as they exceed the normal limits defined in the 2019 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1. This pause could indicate sinus node dysfunction or other conduction abnormalities, such as those described in Table 3 of the guideline, including sinus node arrest or sinoatrial exit block. The patient's symptoms of palpitations correlating with these findings further support the need for referral to a cardiologist or cardiac electrophysiologist. Some key points to consider in the referral process include:

• The patient's heart rate variability and pause duration, which may indicate underlying conduction tissue disease or sinus node dysfunction, as defined in the guideline 1
• The importance of avoiding exacerbating factors, such as excessive caffeine, alcohol, and stimulants, while awaiting specialist assessment
• The need for the patient to seek immediate medical attention if she experiences syncope (fainting), pre-syncope, severe dizziness, or chest pain The specialist will likely perform additional testing, such as:
• An echocardiogram to assess cardiac structure and function
• Extended monitoring to further evaluate heart rate variability and conduction
• Exercise stress testing to determine if intervention, such as medication adjustment or pacemaker placement, is necessary based on symptom severity and underlying cardiac function, as recommended in the guideline 1.

From the Research

Evaluation of Palpitations

The patient's symptoms of intermittent palpitations and a heart rate showing sinus rhythm with a range of 40-97 beats per minute (bpm) and a 2.4-second pause require further evaluation.

• The patient's history, physical examination, and basic electrocardiogram are essential in evaluating palpitations and may be crucial to finding a diagnosis 2.
• The presence of a 2.4-second pause may indicate sick sinus syndrome, which is a collection of disorders marked by the heart's inability to perform its pacemaking function 3.

Diagnostic Approach

The diagnostic approach to palpitations includes:

• Ambulatory electrocardiographic (ECG) monitoring, which is usually indicated if the etiology of palpitations cannot be determined from the patient's history, physical examination, and resting ECG 4.
• Event monitors, which are more effective and cost-effective than Holter monitors for most patients 5.
• Holter monitoring for 24 to 48 hours may be appropriate in patients with daily palpitations 4.

Referral Considerations

Considering the patient's age and symptoms, referral to a cardiologist or an electrophysiologist may be necessary to further evaluate and manage the patient's condition.

• The patient's symptoms and ECG findings suggest the possibility of sick sinus syndrome or other cardiac arrhythmias, which require specialized care 3, 6.
• The use of event monitors or Holter monitoring may be recommended to diagnose and manage the patient's condition 4, 5.