What is the diagnosis and management for an adult patient with a 1-month history of fluttery sensations from the left upper abdomen to the epigastric and right chest under the breast, without pain or dyspnea?

Diagnosis and Management of Fluttery Sensations from Left Upper Abdomen to Epigastric and Right Chest

This patient most likely has either a supraventricular arrhythmia (particularly atrial flutter or paroxysmal SVT) or diaphragmatic flutter, and requires immediate ECG evaluation and cardiac rhythm monitoring to differentiate between these conditions and guide appropriate treatment. 1, 2

Differential Diagnosis

Cardiac Arrhythmias (Most Likely)

Supraventricular tachycardia characteristically presents with "fluttering" sensations and is the primary concern given the symptom description and duration. 1

• Atrial flutter typically presents with palpitations that may be perceived across the chest and upper abdomen, with rates of 250-350 bpm at the atrial level and ventricular response commonly at 150 bpm with 2:1 AV conduction 3
• Patients with atrial flutter can present with insidious symptoms rather than acute distress, including exercise-induced fatigue or vague discomfort, which aligns with this patient's month-long symptom duration without dyspnea or pain 3
• Sustained palpitations lasting >30 seconds suggest true arrhythmia rather than benign awareness of normal rhythm 1

Diaphragmatic Flutter (Less Common but Important)

Diaphragmatic flutter presents with epigastric pulsations and can radiate sensations across the upper abdomen and lower chest, matching this patient's symptom distribution. 4, 5

• Classic diaphragmatic flutter involves involuntary contractions at 0.5-8.0 Hz, though high-frequency variants at 9-15 Hz exist 4
• Patients describe epigastric pulsations and sensations that can be mistaken for cardiac symptoms 4, 5
• This condition is rare but should be considered when cardiac workup is negative 5

Gastric Distension (Benign Consideration)

• Gastric distension from carbonation or gas can cause palpable pulsations in the right upper quadrant that patients perceive as cardiac, particularly when the distended stomach pushes against the diaphragm 1

Immediate Diagnostic Evaluation

Essential First Steps

Obtain a 12-lead ECG immediately, even though the patient is currently asymptomatic, to assess for pre-excitation patterns, baseline QTc prolongation, or other arrhythmia substrate. 1

• Check pulse during symptoms - any documented tachycardia >100 bpm at rest warrants cardiology evaluation 1
• Atrial flutter with 2:1 conduction presents with ventricular rate of exactly 150 bpm and can be mistaken for anxiety-related symptoms 1

ECG Findings to Identify

If atrial flutter is present, look for:

• Atrial rate of 250-350 bpm with characteristic "sawtooth" flutter waves best seen in leads II, III, aVF, and V1 2
• No isoelectric baseline between flutter waves 2
• Variable AV block producing different ventricular rates 2

If paroxysmal SVT is present, look for:

• Rate typically 150-250 bpm with extreme regularity 2, 6
• P waves hidden within or at terminal portion of QRS 2
• Pseudo S-waves in inferior leads and pseudo R' in V1 for AVNRT 2

Extended Monitoring

If initial ECG is normal but symptoms are recurrent over 1 month, arrange 24-48 hour Holter monitor or 30-day event monitor. 1

• Symptoms persisting despite lifestyle modifications for 2 weeks warrant this extended evaluation 1

Management Strategy

If Cardiac Arrhythmia is Confirmed

For hemodynamically stable atrial flutter:

• Beta blockers, diltiazem, or verapamil are first-line for acute rate control 3
• Elective synchronized cardioversion is indicated when rhythm-control strategy is pursued 3
• Catheter ablation of the cavotricuspid isthmus is definitive treatment for symptomatic or refractory atrial flutter 3

Critical anticoagulation consideration:

• Acute antithrombotic therapy is recommended in patients with atrial flutter, aligned with atrial fibrillation guidelines, given the 1-month symptom duration 3

If Diaphragmatic Flutter is Diagnosed

Diagnosis requires:

• Electromyography of the diaphragm showing repetitive discharges at 9-15 Hz 4
• Spirographic tracings showing high-frequency oscillations superimposed on tidal respiratory movements 4
• Ultrasound or thoracic videofluoroscopy can confirm diagnosis 5

Treatment options:

• Carbamazepine 200-400 mg three times daily led to disappearance or great improvement in all reported cases 4
• Noninvasive ventilatory support to rest the diaphragm has shown success in refractory cases 7

Lifestyle Modifications (Regardless of Diagnosis)

Limit caffeine intake from all sources (coffee, tea, energy drinks, sodas) as caffeine can trigger supraventricular arrhythmias through catecholamine release 1

• Check electrolytes, particularly potassium and magnesium, as deficiencies from chronic diuretic effect of caffeine can predispose to arrhythmias 1

Critical Pitfalls to Avoid

Do not dismiss symptoms as anxiety or gastric issues without objective cardiac evaluation - atrial flutter can present with insidious symptoms over weeks to months without acute distress 3

Atrial flutter with 2:1 conduction at exactly 150 bpm is frequently mistaken for sinus tachycardia or anxiety - always obtain ECG during symptoms if possible 1

If symptoms persist despite elimination of dietary triggers for 2 weeks, cardiac monitoring is mandatory - prolonged symptoms increase likelihood of true arrhythmia 1

Check for associated lightheadedness, presyncope, or syncope - these indicate hemodynamically significant arrhythmia requiring immediate evaluation 1