Does atrioventricular nodal re‑entrant tachycardia (AVNRT) cause symptoms every time it occurs?

Does AVNRT Always Cause Symptoms?

No, AVNRT does not always cause symptoms when it occurs. While AVNRT is typically paroxysmal and symptomatic, some episodes may be asymptomatic or minimally symptomatic, and the severity of symptoms varies considerably among patients.

Symptom Variability in AVNRT

The presence and severity of symptoms in AVNRT depends on multiple factors including episode duration, heart rate during tachycardia, patient age, and individual hemodynamic tolerance. 1

Common Symptomatic Presentations

When AVNRT does cause symptoms, patients typically experience:

• Palpitations are the hallmark symptom, reported in 22% to 86% of patients depending on the study population 2
• "Neck pounding" or "shirt flapping" sensations are highly specific for AVNRT, occurring due to cannon a-waves when the right atrium contracts against a closed tricuspid valve 1, 2
• Lightheadedness is common, though true syncope is infrequent (4-15% of cases) and more likely in elderly patients 1, 2
• Polyuria is particularly common with AVNRT due to elevated atrial natriuretic protein from increased right atrial pressures 1, 2
• Chest discomfort occurs in 5% to 47% of patients from increased myocardial oxygen demand 2

Asymptomatic or Minimally Symptomatic Episodes

The evidence clearly demonstrates that not all AVNRT episodes produce symptoms:

• In a pediatric study of patients with WPW pattern (which includes some with AVNRT), only 64% had symptoms at initial presentation, and an additional 20% developed symptoms during follow-up—meaning some never developed symptoms despite documented arrhythmia 1
• Patients are "most often asymptomatic at the time of evaluation" for paroxysmal arrhythmias, indicating episodes can occur without patient awareness 1
• The impact on quality of life "varies according to the frequency of episodes, the duration of SVT, and whether symptoms occur not only with exercise but also at rest" 1—this variability implies some episodes may be brief or well-tolerated enough to go unnoticed

Factors Affecting Symptom Severity

Elderly patients with AVNRT are more prone to syncope or near-syncope than younger patients, though paradoxically the tachycardia rate is generally slower in the elderly 1. This suggests that hemodynamic tolerance, not just heart rate, determines symptom severity.

Slow AVNRT (cycle length >600 ms, rate <100 bpm) can occur, particularly in elderly patients, and may be misdiagnosed as junctional rhythm but still causes significant symptoms including shortness of breath, chest tightness, dizziness, near-syncope, and syncope 3.

Clinical Implications

Diagnostic Pitfalls

• A major pitfall is misattributing SVT symptoms to panic or anxiety disorders, which occurs in 54% of patients, with women more likely than men to be mislabeled 2
• Physicians attributed symptoms to panic, anxiety, or stress in 54% of patients, with criteria for panic disorder fulfilled in 67% of patients with initially unrecognized SVT 1

When to Suspect Asymptomatic AVNRT

Consider that AVNRT may be occurring without clear symptoms when:

• Patients describe vague or intermittent palpitations that don't clearly correlate with documented episodes 1
• There is documented tachycardia on monitoring without corresponding symptom reports
• Episodes are very brief or occur during sleep

The paroxysmal nature of AVNRT with abrupt onset and termination is characteristic 1, but this doesn't guarantee every episode will be symptomatic enough for the patient to notice or report.