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McMaster Textbook of Internal Medicine

Sinus Tachyarrhythmias

How to Cite This Chapter: Acosta Velez JG, Amit G, Hernández Ruiz EA, Trusz-Gluza M, Leśniak W. Sinus Tachyarrhythmias. McMaster Textbook of Internal Medicine. Kraków: Medycyna Praktyczna. https://empendium.com/mcmtextbook/chapter/B31.II.2.6.5. Accessed October 30, 2024.
Last Updated: February 20, 2022
Last Reviewed: February 20, 2022
Chapter Information

Definition, Etiology, PathogenesisTop

Sinus tachyarrhythmias comprise various arrhythmias associated with different mechanisms, natural history, and prognosis.

1. Physiologic sinus tachycardia: A fast sinus rhythm (>100 beats/min) in response to a physiologic stimulus (exercise, stress) or pathologic condition (fever, hypovolemia, anemia, heart failure, thyrotoxicosis, pheochromocytoma, drugs).

2. Inappropriate sinus tachycardia: A sustained fast sinus rhythm (>100 beats/min) unrelated or disproportionate to the stimulus. It results from increased automaticity of the sinus node and its abnormal autonomic regulation. Most commonly observed in young women.

Clinical FeaturesTop

Inappropriate sinus tachycardia has variable clinical features and may range from being entirely asymptomatic to completely disabling. The most common symptoms include palpitations, chest pain, dyspnea, dizziness, and presyncope.

DiagnosisTop

Inappropriate Sinus Tachycardia

1. Exclude underlying systemic conditions. Electrocardiography (ECG) reveals persistent daytime sinus tachycardia (>100 beats/min) and P waves of the same morphology as in sinus rhythm. Response to daily activities is exaggerated and heart rate normalizes at night.

2. Tilt table testing can help to identify inappropriate sinus tachycardia that can lead to fainting, also known as postural tachycardia syndrome (POTS).

TreatmentTop

1. Classification of antiarrhythmic drugs: see Table 1 in Cardiac Arrhythmias.

2. Antiarrhythmic agents: see Table 2 in Cardiac Arrhythmias.

3. Beta–blockers are the first-line drugs in inappropriate sinus tachycardia. In patients not responding to this treatment, consider ivabradine. Catheter ablation to modify the sinus node is rarely required.

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