Cardiac Arrhythmia Management

Diagnosis

Sinus tachycardia is confirmed on 12-lead ECG with a heart rate >100 bpm, normal P wave morphology, and P wave axis in frontal plane between 0° and 90°, as recommended by the American Heart Association 1
A 12-lead ECG is recommended to confirm sinus tachycardia and rule out other arrhythmias, along with basic laboratory tests such as complete blood count, thyroid function tests, and basic metabolic panel to assess for underlying causes, as suggested by the American Heart Association 2
A 24-hour Holter monitoring may be used to document heart rate patterns throughout daily activities and during sleep, although this is not routinely recommended, according to the European Society of Cardiology 2
Chest imaging may be considered if pulmonary pathology is suspected, according to the American College of Cardiology 2

Physiological factors that can cause sinus tachycardia include fever, pain, anxiety, dehydration, physical exertion, and emotional stress 3
Pathological factors that can cause sinus tachycardia include infection, hypovolemia, anemia, hyperthyroidism, heart failure, and pulmonary embolism 3
Medication/substance-related causes include stimulants (caffeine, alcohol, nicotine), prescribed medications (salbutamol, aminophylline, atropine, catecholamines), recreational drugs (amphetamines, cocaine, ecstasy, cannabis), and anticancer treatments (particularly anthracyclines) 4

First-line treatment for sinus tachycardia includes beta-blockers, which are particularly effective for tachycardia related to emotional stress and anxiety, and also beneficial for prognostic benefit after myocardial infarction and in heart failure, as recommended by the American College of Cardiology 4, 2, 5
Alternative treatments (if beta-blockers are contraindicated) include non-dihydropyridine calcium channel blockers (diltiazem or verapamil) and ivabradine (If-channel inhibitor), which may be considered in refractory cases or when beta-blockers are contraindicated 4, 2, 3
The American College of Cardiology recommends treating the underlying cause of sinus tachycardia, such as antibiotics for infection or fluid replacement for dehydration 2, 5
Radiofrequency ablation for sinus node modification should be considered only for highly symptomatic patients who cannot be adequately treated with medication, due to modest benefits and significant potential complications, according to the American College of Cardiology 3

In patients with signs of hemodynamic instability related to tachycardia, administration of oxygen, establishment of IV access, monitoring of vital signs, and performance of a 12-lead ECG are recommended, with consideration of synchronized cardioversion if tachycardia is the cause of instability, as recommended by the American College of Cardiology 6
The European Heart Journal recommends immediate DC cardioversion for hemodynamically unstable patients with wide QRS complex tachycardia 7
It is essential to avoid "normalizing" heart rate in compensatory tachycardias (e.g., heart failure) where cardiac output depends on elevated heart rate, as stated by the American Heart Association and the American College of Cardiology 6, 3

Regular physical exercise (reconditioning) and techniques of relaxation, such as cognitive behavioral therapy, may be beneficial for patients with sinus tachycardia, as suggested by the European Society of Cardiology 4, 2
Patients with persistent symptoms despite treatment may be referred to an electrophysiologist, according to the American Heart Association 2
The American College of Cardiology recommends reassessment of symptoms in 1-3 months, and consideration should be given to instructing patients to keep a symptom diary correlating anxiety episodes with heart rate 4, 8, 2