What causes symptoms of tachycardia, diaphoresis, and nausea, and how are they treated?

Racing Heart, Sweating, and Nausea: Causes and Management

The combination of tachycardia, diaphoresis (sweating), and nausea most commonly indicates acute coronary syndrome (ACS) or myocardial infarction and requires immediate evaluation with ECG and cardiac biomarkers, though other life-threatening conditions like pulmonary embolism, aortic dissection, and serious arrhythmias must also be rapidly excluded. 1

Immediate Life-Threatening Causes to Exclude

Acute Coronary Syndrome/Myocardial Infarction

• Chest discomfort accompanied by autonomic nervous system stimulation—presenting as pallor, diaphoresis, and nausea/vomiting—strongly suggests cardiac ischemia and should place the patient on the fast track for immediate evaluation. 1
• Nausea and vomiting frequently accompany acute coronary syndrome and point specifically to a cardiac cause of symptoms. 1
• Women with acute myocardial infarction more frequently present with associated symptoms including nausea, vomiting, and dyspnea compared to men. 1
• Obtain a 12-lead ECG immediately, though recognize its sensitivity for identifying ischemia may be as low as 50%, and 2-4% of patients with evolving myocardial infarction have normal ECG findings. 1

Other Critical Diagnoses

• Aortic dissection, pulmonary embolism, and pneumothorax can all present with tachycardia, diaphoresis, and nausea and must be considered in the differential diagnosis. 1
• Severe pain from any cause evokes sympathetic activation with associated vegetative symptoms including sweating and nausea. 1

Assessment of Tachycardia Type and Severity

Determine Hemodynamic Stability

• Assess immediately for rate-related cardiovascular compromise including acute altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or shock—if present, proceed to immediate synchronized cardioversion. 2
• When heart rate exceeds 150 beats per minute, tachycardia is more likely the primary cause of symptoms, especially if ventricular dysfunction is present. 3
• When heart rate is less than 150 beats per minute without ventricular dysfunction, tachycardia is less likely the primary cause and treatment should focus on the underlying condition. 3, 2

Identify Reversible Causes

• Check oxygen saturation immediately and provide supplemental oxygen if inadequate, as hypoxemia is one of the most common reversible causes of sinus tachycardia. 2
• Evaluate for signs of increased work of breathing, as respiratory distress commonly causes tachycardia. 3
• Assess for infection/sepsis by checking for fever and inflammatory markers. 1, 2
• Check hemoglobin levels to exclude anemia as a cause. 1, 2
• Evaluate for hypovolemia/shock, which commonly presents with tachycardia, diaphoresis, and nausea. 2
• Consider pulmonary embolism as a life-threatening cause. 2
• Assess for inadequate pain control or acute anxiety, both of which can trigger these symptoms. 1, 2
• Check thyroid function tests to exclude thyrotoxicosis. 1, 2
• Review medications and substances including stimulants, beta-agonists, aminophylline, catecholamines, cocaine, and amphetamines. 1, 2

Specific Tachycardia Syndromes

Physiological Sinus Tachycardia

• Physiological sinus tachycardia results from pathological causes including infection with fever, dehydration, anemia, heart failure, and hyperthyroidism, as well as exogenous substances like caffeine and stimulant drugs. 1
• Tachycardia is expected to resolve with correction of the underlying cause and does not require specific antiarrhythmic treatment. 1, 2

Inappropriate Sinus Tachycardia (IST)

• IST is defined as sinus tachycardia unexplained by physiological demands, with resting heart rates >100 bpm and average rates >90 bpm over 24 hours, accompanied by debilitating symptoms including weakness, fatigue, lightheadedness, and uncomfortable sensations of heart racing. 1
• IST is a diagnosis of exclusion—do not assume tachycardia is "inappropriate" without first excluding all physiologic causes including hyperthyroidism, anemia, dehydration, pain, anxiety, and exogenous substances. 1, 2
• Anxiety is an important trigger, and patients with IST may have associated anxiety disorders. 1
• Distinguish IST from postural orthostatic tachycardia syndrome, as treatment to suppress sinus rate may lead to severe orthostatic hypotension in the latter. 1

Supraventricular Tachycardia (SVT)

• SVT commonly presents with palpitations (including pulsation in the neck), chest pain, lightheadedness or dizziness, and dyspnea. 4
• Diagnosis is often delayed due to misdiagnosis as anxiety or panic disorder. 4
• Patient history is critical in uncovering the diagnosis, and a Holter monitor or event recorder may be needed to capture the arrhythmia. 4

Treatment Approach

For Physiological Sinus Tachycardia

• Aggressively search for and treat reversible causes—this is the primary therapeutic intervention, not rate control medications. 3, 2
• No specific antiarrhythmic treatment is required for physiological sinus tachycardia. 3
• Monitor closely for development of tachycardia-induced cardiomyopathy if the rate remains persistently elevated. 2, 5

For Inappropriate Sinus Tachycardia

• Evaluation for and treatment of reversible causes is the Class I recommendation for patients with suspected IST. 1
• Ivabradine is reasonable for ongoing management in symptomatic IST (Class IIa recommendation). 1
• Beta blockers may be considered for ongoing management, though they are often ineffective or not well tolerated due to hypotension. 1
• The combination of beta blockers and ivabradine may be considered. 1
• Recognize that lowering heart rate may not alleviate symptoms, and treatment is for symptom reduction only as the prognosis is generally benign. 1

For Supraventricular Tachycardia

• Acute treatment consists of vagal maneuvers first, followed by short-term or as-needed pharmacotherapy using calcium channel blockers or beta blockers when vagal maneuvers fail. 4
• If additional rate control is needed beyond initial therapy, consider intravenous diltiazem or verapamil (Class I recommendation for acute rate control). 2
• Combination therapy with digoxin plus beta-blocker is reasonable for rate control, though digoxin takes 60 minutes or more for onset. 2
• Catheter ablation is an option in patients with persistent or recurrent SVT who cannot tolerate long-term pharmacologic management. 4

Critical Pitfalls to Avoid

• Do not use rate-controlling medications in patients with accessory pathways (Wolff-Parkinson-White syndrome), as this can accelerate conduction through the accessory pathway and cause life-threatening arrhythmias. 2, 4
• Do not administer additional beta-blocker boluses if the patient has recently received a dose, as this risks bradycardia, heart block, hypotension, or heart failure exacerbation. 2
• Remember that a heart rate of 140 bpm may be entirely appropriate for certain physiologic stressors—the goal is not necessarily to normalize the rate but to treat the underlying cause. 3, 2
• Do not dismiss these symptoms as anxiety or panic disorder without first excluding cardiac and other life-threatening causes, as this is a common cause of delayed diagnosis. 4

Long-Term Considerations

Tachycardia-Induced Cardiomyopathy

• Persistent tachyarrhythmias with uncontrolled heart rate can cause ventricular systolic dysfunction and congestive heart failure. 5, 6
• This condition is reversible with rate control or rhythm correction, with left ventricular ejection fraction typically improving or normalizing within 6 months. 5, 6, 7
• However, recurrent tachycardia after initial recovery causes rapid decline in left ventricular function within 6 months, even though the initial impairment took years to develop. 7
• Sudden death is possible even after apparent recovery, suggesting a persistent substrate for life-threatening arrhythmia. 6, 7
• Careful long-term follow-up is required even after recovery from cardiac dysfunction. 6