Differential Diagnosis for 38 yo Female with Rapid Heart Rate and Palpitations

• Single Most Likely Diagnosis

  • Supraventricular Tachycardia (SVT): This condition is characterized by a rapid heart rate that originates above the ventricles. The symptoms of palpitations, especially when laying down, and the use of a compulsive cough (Valsalva maneuver) to slow the heart rate are classic for SVT. The Valsalva maneuver can sometimes terminate SVT episodes by stimulating the vagus nerve, which can help slow the heart rate.

• Other Likely Diagnoses

  • Anxiety or Panic Disorder: These conditions can cause palpitations and an increased heart rate, especially in situations that provoke anxiety, such as lying down. The compulsive cough could be a coping mechanism or a manifestation of anxiety.
  • Mitral Valve Prolapse: This condition can cause palpitations and is sometimes associated with anxiety. The physical stress of lying down might exacerbate symptoms.
  • Hyperthyroidism: An overactive thyroid gland can cause an increased heart rate and palpitations. Although less directly related to positional changes, it's a common cause of these symptoms.

• Do Not Miss Diagnoses

  • Cardiac Arrhythmias (e.g., Atrial Fibrillation, Ventricular Tachycardia): While less common, these conditions can be life-threatening and require immediate medical attention. The symptoms could be similar to SVT but might not respond to vagal maneuvers.
  • Pulmonary Embolism: Although the primary symptom is usually dyspnea, in some cases, a pulmonary embolism can cause tachycardia and might be associated with cough. It's crucial to consider this diagnosis due to its high mortality rate if untreated.
  • Cardiac Tamponade: This is a life-threatening condition where fluid accumulates in the sac around the heart, impeding its function. It can cause tachycardia among other symptoms and is critical to diagnose promptly.

• Rare Diagnoses

  • Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodes of palpitations, tachycardia, and hypertension. It's an uncommon cause of these symptoms but should be considered in the differential due to its potential severity.
  • Long QT Syndrome: A disorder of the heart's electrical activity that can cause sudden, uncontrollable, dangerous arrhythmias. It might present with palpitations and could be a consideration in patients with a family history or specific triggers.
  • Hypokalemia or other electrolyte imbalances: Certain electrolyte disturbances can lead to arrhythmias and palpitations. While not directly related to positional changes, they are important to rule out due to their potential to cause serious cardiac issues.