Immediate Assessment and Diagnostic Approach
This patient requires urgent evaluation for cardiac arrhythmia and potential splenic pathology, with immediate 12-lead ECG, orthostatic vital signs, and consideration of abdominal imaging given the pleuritic LUQ pain pattern. 1
Critical Initial Steps
Obtain a 12-lead ECG immediately to identify the rhythm, look for pre-excitation patterns (Wolff-Parkinson-White), QT prolongation, or conduction abnormalities that could explain palpitations and guide risk stratification. 1 The combination of palpitations with nausea and positional chest discomfort requires documentation of the underlying rhythm before any empiric treatment. 1
Measure orthostatic vital signs (lying and standing blood pressure and heart rate at 3 minutes) to assess for postural orthostatic tachycardia syndrome (POTS) or orthostatic hypotension, particularly given the blood pressure of 145/94 with pulse 68 at rest. 2 POTS commonly causes palpitations while sitting or upon standing, characterized by excessive heart rate increase (>30 bpm or >120 bpm) within 10 minutes of standing. 2
Characterize the Palpitation Pattern
Determine if the rhythm is regular or irregular, as this fundamentally changes the diagnostic approach. 1 Specifically assess:
- Onset and termination pattern: Sudden onset/offset suggests AVNRT or AVRT (reentrant tachycardias), while gradual onset suggests sinus tachycardia or anxiety. 1, 2
- Response to deep breathing or position changes: The fact that symptoms worsen with deep respiration and disappear in minutes suggests either a cardiac arrhythmia responsive to vagal tone or a pleuritic component. 1
- Associated symptoms: The presence of nausea is significant—approximately 15% of SVT patients experience gastrointestinal symptoms, and polyuria occurs in ~15% of SVT cases. 1
Address the Left Upper Quadrant Pain
The pleuritic LUQ discomfort that worsens with deep respiration requires consideration of splenic pathology, including spontaneous splenic hemorrhage or infarction, particularly if the pain is severe or associated with hemodynamic changes. 3 While rare, spontaneous retroperitoneal or splenic hemorrhage can present with LUQ pain, nausea, and can be life-threatening if not identified early. 3
Consider pericarditis in the differential, as it presents with chest discomfort that worsens with deep inspiration and can cause palpitations. 4 However, the localization to LUQ and brief duration (minutes) makes this less likely.
Immediate Management Decisions
If ECG Shows Normal Sinus Rhythm:
Stop all caffeine, alcohol, nicotine, and review all medications (including over-the-counter drugs and supplements) that may trigger arrhythmias. 1, 2
Teach vagal maneuvers (Valsalva maneuver, carotid massage) to perform during future episodes, as termination with vagal maneuvers confirms reentrant tachycardia involving AV nodal tissue. 1, 5
Consider empiric beta-blocker therapy only after excluding significant bradycardia (<50 bpm), which you have done (pulse 68). 1, 5 However, do not start Class I or III antiarrhythmic drugs without documented arrhythmia due to significant proarrhythmic risk. 1, 5
If ECG Shows Pre-excitation or Abnormalities:
Immediate referral to cardiac electrophysiology is mandatory for Wolff-Parkinson-White syndrome due to risk of sudden death. 1, 2 Pre-excitation with a history of paroxysmal regular palpitations suggests AVRT and requires urgent specialist evaluation. 1
Ambulatory Monitoring Strategy
Since symptoms are intermittent and resolve within minutes, order an event recorder or loop recorder rather than Holter monitoring. 1 Event recorders have superior diagnostic yield and are more cost-effective for symptoms occurring several times per week. 1 Reserve 24-48 hour Holter monitoring only for daily palpitations. 1
Monitoring must continue until symptoms occur while wearing the device—non-diagnostic monitoring should not be considered conclusive. 1 If symptoms occur less than twice monthly with severe features (syncope, presyncope), consider an implantable loop recorder. 1
Additional Workup Based on Clinical Context
Order echocardiography if sustained SVT is documented or if there is clinical suspicion of structural heart disease, as structural abnormalities cannot be reliably detected by physical examination alone. 1 The hypertension (145/94) warrants assessment for left ventricular hypertrophy or other structural changes. 1
Consider exercise stress testing if palpitations are clearly triggered by exertion, to detect exercise-induced arrhythmias and assess chronotropic response. 1
Check thyroid function tests to exclude hyperthyroidism, a common non-cardiac cause of palpitations. 1
Reassess renal function (creatinine, GFR) as baseline for medication decisions, particularly given the hypertension. 1
Red Flags Requiring Immediate Referral
Refer immediately to acute care or cardiac electrophysiology if any of the following develop: 1, 2
- Syncope or near-syncope with palpitations
- Chest pain or pressure during episodes
- Severe dyspnea or signs of heart failure
- Palpitations occurring during exertion
- Wide complex tachycardia documented on any rhythm strip
- Severe symptoms during palpitations (syncope, dyspnea)
Common Pitfalls to Avoid
Do not rely on automatic ECG analysis systems, as they are unreliable and commonly suggest incorrect diagnoses. 1
Do not dismiss the LUQ pain as unrelated—while palpitations are the primary concern, the pleuritic nature and association with nausea warrant consideration of splenic or diaphragmatic pathology, particularly if pain is severe or persistent. 3
Do not order comprehensive laboratory panels routinely—target testing based on clinical suspicion (thyroid function, electrolytes if indicated). 1
Optimize blood pressure control to reduce arrhythmia risk, and monitor for electrolyte abnormalities, particularly potassium, which affects arrhythmia risk. 1