What is the cause and management of indigestion and tachycardia?

Indigestion with Heart Racing: Evaluation and Management

When experiencing indigestion accompanied by heart racing, you must first urgently exclude life-threatening cardiac causes—particularly acute coronary syndrome—before attributing symptoms to gastrointestinal disease, as chest discomfort misinterpreted as "indigestion" represents myocardial ischemia in up to 40% of cases in patients over 40 years old. 1

Immediate Assessment Priority

Rule out cardiac emergencies first:

• Assess for hemodynamic instability including altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or shock 2
• Obtain a 12-lead ECG immediately to confirm rhythm and exclude ischemia 2
• In patients over 40 years without prior dyspepsia, chest "indigestion" should be considered myocardial ischemia until proven otherwise 1

Identify Reversible Causes of Tachycardia

Systematically evaluate for common treatable conditions:

• Check oxygen saturation and provide supplemental oxygen if hypoxemic 2
• Assess for infection/sepsis with fever and inflammatory markers 2, 3
• Review hemoglobin levels to exclude anemia 2, 3
• Evaluate for dehydration and hypovolemia 4, 2, 3
• Check thyroid function tests to exclude hyperthyroidism 4, 2, 3
• Consider pulmonary embolism as a life-threatening cause 2
• Assess pain levels and anxiety, as these commonly trigger tachycardia 2, 3
• Review all medications and substances: caffeine, beta-agonists (albuterol), aminophylline, catecholamines, illicit stimulants, and proton pump inhibitors 4, 3, 5

Critical Pitfall: Proton Pump Inhibitor Connection

Long-term PPI use for gastrointestinal symptoms can cause mineral deficiencies—particularly magnesium—leading to treatment-resistant tachycardia and arrhythmias:

• PPIs impair mineral extraction from food by reducing stomach acid 5
• Magnesium deficiency specifically causes cardiac arrhythmias that resist standard antiarrhythmic medications 5
• Check comprehensive mineral levels (magnesium, calcium, potassium) in patients on chronic PPIs presenting with tachycardia 5
• Consider PPI weaning with mineral supplementation if deficiencies identified 5

Distinguish Physiological from Inappropriate Sinus Tachycardia

Confirm true sinus tachycardia on ECG:

• Verify P waves are positive in leads I, II, and aVF, negative in aVR, with normal morphology preceding each QRS 2
• Normal sinus rate at rest is 50-90 bpm; sinus tachycardia exceeds 100 bpm 4

Physiological sinus tachycardia resolves with treatment of underlying cause:

• Expected with fever, dehydration, anemia, heart failure, hyperthyroidism, pain, anxiety, and exogenous substances 4, 2, 3
• Treatment focuses on correcting the primary condition, not rate control 2

Inappropriate Sinus Tachycardia (IST) is a diagnosis of exclusion:

• Defined as resting heart rate >100 bpm, average 24-hour rate >90 bpm, with debilitating symptoms (weakness, fatigue, lightheadedness, palpitations) unexplained by physiological demands 4, 2
• Must exclude all secondary causes, anxiety disorders, postural orthostatic tachycardia syndrome (POTS), atrial tachycardia, and structural heart disease before diagnosing IST 4, 2

Consider Postural Orthostatic Tachycardia Syndrome (POTS)

POTS commonly presents with both tachycardia and gastrointestinal symptoms:

• Characterized by exaggerated heart rate increase upon standing 6
• GI symptoms occur in the majority: nausea (86%), irregular bowel movements (71%), abdominal pain (70%), constipation (70%) 6
• Symptoms occur more than once weekly in 82% of patients 6
• The same autonomic dysfunction causing tachycardia impairs gut motility 6
• Distinguish from IST by predominant postural symptoms; avoid aggressive rate control as it may cause severe orthostatic hypotension 4

Management Algorithm

For physiological/secondary sinus tachycardia:

1. Aggressively treat the underlying reversible cause 2
2. Monitor for tachycardia-induced cardiomyopathy if rate remains persistently elevated 2
3. If additional rate control truly needed after addressing causes, consider IV diltiazem or verapamil 2
4. Avoid rate-controlling medications in patients with accessory pathways (WPW syndrome) as this accelerates conduction through the accessory pathway 2

For confirmed IST after excluding all reversible causes:

• Evaluation and treatment of reversible causes is Class I recommendation 4, 2
• Ivabradine is reasonable for ongoing management (Class IIa) 4, 2
• Beta blockers may be considered but are often ineffective or poorly tolerated due to hypotension (Class IIb) 4, 2
• Combination of beta blockers and ivabradine may be considered (Class IIb) 4, 2
• Exercise training may benefit but remains unproven 4, 2
• Recognize that lowering heart rate may not alleviate symptoms, and treatment is for symptom reduction only as prognosis is generally benign 4

For gastroesophageal reflux disease (if confirmed as cause of "indigestion"):

• Lifestyle modifications: weight loss and head of bed elevation improve esophageal pH and symptoms 7
• Medical therapy: antacids, H2-receptor antagonists, or proton pump inhibitors for acid suppression 7, 8
• Be cautious with long-term PPI use given potential for mineral deficiencies causing cardiac complications 5

Key Clinical Caveats

• Do not assume tachycardia is "inappropriate" without exhaustively excluding all physiologic causes 2
• A heart rate of 140 bpm may be entirely appropriate for certain physiologic stressors; the goal is treating the underlying cause, not necessarily normalizing the rate 2
• Syncope occurs in approximately 15% of patients with supraventricular tachycardia, usually just after initiation or with prolonged pause after termination 4
• Persistent supraventricular tachycardia for weeks to months with fast ventricular response can lead to tachycardia-mediated cardiomyopathy 4