Recurrent syncope in a young woman : A hidden case of Long QT syndrome

 

 

 

Recurrent syncope in young adults can be easily misdiagnosed as vasovagal and stress related. This clinical case study highlights a real world scenario where subtle ecg clues led to diagnosis of Congenital LONG QT syndrome – A potentially life threatening but treatable condition.

Introduction:

Syncope is a common clinical complaint, but recurrent unexplained syncope should raise suspicion for cardiac arrhythmias, especially in young patients. This MEDICOZ case study explores a 28-year-old woman with no comorbidities who presented with repeated fainting episodes and a strong family history of sudden cardiac death.

Patient Presentation :

A 28-year-old female software engineer presented with recurrent syncope for 3 months. Episodes occurred suddenly while standing and were not preceded by palpitations or neurological symptoms.

Key Symptoms:

1: Sudden fainting episodes

2: Mild injuries post-syncope

3: No chest pain or seizures

4: No medication use

5: Family history of sudden cardiac death

This patient profile is typical of cardiac syncope seen in LQTS.

Clinical Examination :

1: Blood Pressure: 110/70 mmHg

2: Heart Rate: 56/min (sinus bradycardia)

3: Cardiac Exam: Normal heart sounds

4: Neurological Exam: Within normal limits

Bradycardia combined with syncope can indicate channelopathy-related arrhythmias

Investigations & Diagnostic Workup :
1. ECG Findings (Most Crucial Clue )

• Sinus bradycardia
• QTc: 510 ms (prolonged)
• Notched T-waves in V2–V4

2. Laboratory Studies

• Electrolytes: Normal
• Thyroid function: Normal
• Magnesium: Normal

3. Holter & Imaging

• Holter: Intermittent ventricular bigeminy
• Echocardiography: Structurally normal heart

This ruled out structural cardiac causes and strengthened suspicion for Congenital LQTS.

Differential Diagnosis :

1. Congenital Long QT Syndrome (LQTS) – highly likely
2. Vasovagal syncope
3. Brugada Syndrome

Arrhythmogenic right ventricular cardiomyopathy (ARVC)

Hypothyroidism-related bradycardia (ruled out)

Final Diagnosis
🎯 Congenital Long QT Syndrome – Likely LQT2 Variant

Based on:

Prolonged QTc

1. T-wave morphology
2. Family history
3. Syncope episodes

Management Plan :

 Pharmacological Therapy

• Started on Nadolol (preferred in LQTS)

Lifestyle & Precautions :

1. Avoid QT-prolonging medications
2. Avoid sudden loud noises (LQT2 trigger)
3. Maintain hydration
4. Avoid competitive strenuous sports

Additional Measures :

1. Genetic testing advised
2. ICD discussed but deferred

Clinical Discussion :

Long QT Syndrome is an inherited cardiac disorder that increases the risk of torsades de pointes and sudden cardiac death. Many patients remain undiagnosed until a syncopal episode occurs. The QTc interval, T-wave morphology, and family history are the most important diagnostic markers.

Early diagnosis and beta-blocker therapy significantly reduce mortality.

Key Learning Points for Clinicians :

1. Always evaluate QTc in patients with unexplained syncope
2. Family history of sudden death is a major red flag
3. Beta-blockers are life-saving in LQTS
4. Avoid QT-prolonging medications
5. Early diagnosis improves survival

 

Attend a Short Quiz below:

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