Carnitine Deficiency Cardiomyopathy: A Rare Late Diagnosis in Adulthood

Description of Clinical Presentation: A 33-year-old female was admitted to our hospital with symptomatic cholelithiasis. She had a history of dilated cardiomyopathy diagnosed at the age of 5 and mild intellectual disability. During hospitalization, a preoperative evaluation by the cardiology department was requested due to the possibility of cholecystectomy. She reported daily episodes of heart palpitations over the past month associated with nausea. She denied dyspnea, syncope and edema.


Physical examination revealed an irregular heart rhythm, HR 58 bpm, BP 90/60 mmHg, and no other relevant findings. She had a history of hospitalization for heart problems during childhood. She denied smoking or alcohol consumption, led a sedentary lifestyle, and had no significant family history. A nutritional diary revealed a high-carbohydrate diet. Her daily oral medications included furosemide, spironolactone, amiodarone, rivaroxaban, dapagliflozin, and metoprolol.


Electrocardiogram (ECG) showed atrial fibrillation with a rate of 76 bpm and left ventricular hypertrophy. Transthoracic echocardiogram showed a dilated left ventricle with increased myocardial thickness and a left ventricular ejection fraction (LVEF) of 32%. The right ventricle was slightly enlarged and dysfunctional. Moderate mitral and mild tricuspid regurgitation and PASP of 32 mmHg. Transesophageal echocardiography showed no atrial thrombus.


She underwent synchronized electrical cardioversion and her ECG subsequently showed sinus rhythm at 53 bpm, left bundle branch block (LBBB) and pre-excitation. After medical optimization, she was discharged for further outpatient evaluation.

Diagnostic Techniques and Their Most Important Findings: Cardiac magnetic resonance (CMR) was performed one month after discharge (Avanto 1.5 T Siemens) with steady-state free precession (SSFP) cine imaging, T2-weighted (T2W), and late gadolinium enhancement (LGE) sequences. Cine imaging showed a thickened left ventricle with preserved global function but inferior hypokinesia and markedly enlarged left chambers. The right ventricle had normal volumes and function. T2W images showed no significant signal abnormalities. LGE images revealed extensive non-ischemic fibrosis in the apical segments, mid-lateral segments, and posterolateral papillary muscle.

Learning Points from this Case: The patient had a history of dilated cardiomyopathy without a defined etiology since childhood. The combination of hypertrophic cardiomyopathy and fibrosis on CMR, together with pre-excitation suggested a possible storage or metabolic disease as the underlying cause. Genetic testing identified a pathogenic variant, c.653-2A >C (splice site in the intron), in homozygosity in the SLC22A5 gene, confirming the diagnosis of primary systemic carnitine deficiency, a disorder of fatty acid metabolism usually manifesting in the first year of life.


CMR enabled a more precise cardiac phenotype characterization, guiding further investigation. The patient is currently receiving oral carnitine supplementation and is being followed up as an outpatient in our cardiology department.

ECG before and after elétrica cardioversion
Cardiac MRI - Cine Imaging and T2W image
Late Enhancement Images