Differential Diagnosis for a 21-year-old Male with Elongated QRS, NIVCD, Pre-syncope, and Palpitations

Single Most Likely Diagnosis

• Hypertrophic Cardiomyopathy (HCM): This condition is characterized by an abnormal thickening of the heart muscle, which can lead to an elongated QRS duration and symptoms such as pre-syncope and palpitations due to obstructive or non-obstructive causes. The presence of a Non-Ischemic Ventricular Cardiomyopathy (NIVCD) further supports this diagnosis.

Other Likely Diagnoses

• Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): This condition involves the replacement of the right ventricular muscle with fatty tissue, leading to arrhythmias and potentially an elongated QRS. Symptoms like palpitations and pre-syncope can occur due to ventricular arrhythmias.
• Dilated Cardiomyopathy (DCM): Although less likely to cause an elongated QRS, DCM can lead to NIVCD and symptoms of heart failure, including palpitations and pre-syncope due to arrhythmias or reduced cardiac output.
• Bundle Branch Block (BBB): A condition where there is a blockage in the electrical conduction system of the heart, leading to an elongated QRS. However, it might not fully explain the symptoms of pre-syncope and palpitations without underlying structural heart disease.

Do Not Miss Diagnoses

• Brugada Syndrome: A genetic disorder that affects the heart's electrical system and can cause sudden cardiac death. It is characterized by an abnormal ECG pattern (not just an elongated QRS) and can present with symptoms like palpitations and pre-syncope.
• Long QT Syndrome: A condition that affects the heart's electrical system, leading to a prolonged QT interval on the ECG. It can cause arrhythmias, leading to palpitations, pre-syncope, and even sudden death.
• Wolff-Parkinson-White (WPW) Syndrome: A condition where an abnormal electrical pathway in the heart causes arrhythmias. It can lead to palpitations and pre-syncope and is a significant cause of sudden cardiac death if not treated.

Rare Diagnoses

• Left Ventricular Non-Compaction (LVNC): A rare cardiomyopathy characterized by a spongy appearance of the left ventricle. It can lead to arrhythmias, heart failure, and embolic events, potentially explaining the symptoms.
• Myotonic Dystrophy: A genetic disorder that affects muscle tone and can involve the heart, leading to conduction abnormalities, arrhythmias, and potentially an elongated QRS.
• Kearns-Sayre Syndrome: A rare mitochondrial myopathy that can affect the heart, leading to conduction abnormalities and arrhythmias.