What is the typical heart rate range for patients with Supraventricular Tachycardia (SVT)?

Heart Rate Ranges in Supraventricular Tachycardia (SVT)

Supraventricular tachycardia (SVT) typically presents with heart rates between 150-250 beats per minute (bpm) in adults, with specific ranges varying by SVT subtype. 1

General SVT Heart Rate Characteristics

• SVT is characterized by a rapid, regular rhythm with abrupt onset and termination 1
• The American Heart Association defines SVT as tachycardias involving tissue from the His bundle or above, with heart rates exceeding 100 bpm at rest 1
• Heart rates in SVT generally range between 150-250 bpm, significantly faster than normal sinus rhythm 1, 2
• The mean heart rate in patients with paroxysmal SVT is approximately 186 bpm according to population studies 1
• In patients with underlying cardiovascular disease, the mean SVT rate tends to be somewhat lower at around 155 bpm 1

Heart Rate Ranges by SVT Subtype

Atrioventricular Nodal Reentrant Tachycardia (AVNRT)

• AVNRT is the most common form of SVT 3
• Ventricular rates in AVNRT often range between 180-200 bpm but can range from 110 bpm to >250 bpm 3
• In rare cases, AVNRT can present with heart rates <100 bpm 3

Atrioventricular Reentrant Tachycardia (AVRT)

• AVRT typically presents with heart rates between 140-250 bpm 1
• The rate of AVRT tends to be faster when induced during exercise 3

Atrial Flutter

• Atrial flutter typically has an atrial rate of approximately 300 bpm 1
• Ventricular response depends on AV conduction ratio (1:1 to 4:1) 3
• Antiarrhythmic drugs or atrial scarring can slow the atrial rate 1

Pediatric SVT Considerations

• In children, SVT generally exceeds 180 bpm 4
• In adolescents, SVT rates typically exceed 220 bpm 4
• Neonatal SVT is usually 260-300 bpm after the first 10-20 beats 3

Clinical Implications of SVT Heart Rate

• Heart rates <150 bpm in the absence of ventricular dysfunction are more likely secondary to an underlying condition 1
• Rates exceeding 150 bpm are more likely to cause hemodynamic compromise requiring immediate intervention 1
• The upper rate of physiologic sinus tachycardia is age-related (approximately 220 bpm minus the patient's age in years) 1
• In a study of untreated PSVT patients, the mean heart rate during spontaneous tachycardia was 203.5 ± 34.9 bpm (range 142-288 bpm) 5
• Interestingly, patients with longer tachycardia-free periods had significantly faster heart rates during tachycardia episodes 5

Diagnostic Considerations

• Heart rate alone should not be the only criterion for diagnosis; ECG characteristics and clinical presentation are essential for proper identification 1
• SVT typically shows an extremely regular R-R interval after the first 10-20 beats 3
• In 60% of SVT cases, P waves are visible but usually have a different morphology from sinus P waves 3
• In over 90% of infants and children with SVT, the QRS complex is narrow 3
• Persistent aberration (wide QRS) in SVT is exceedingly rare in infants, implying that in most infants with a QRS complex different from sinus rhythm, the diagnosis is more likely ventricular tachycardia 3

Understanding these heart rate ranges is crucial for accurate diagnosis and appropriate management of patients with SVT to reduce morbidity and improve quality of life.