Introduction: Although in patients without cardiovas-cular risk factors or positive medical history most ca-uses of syncope are benign and do not require further evaluation, sometimes the syncope reveals an altered cardiac substrate. In patients with non-ischemic dilated cardiomyopathy (NIDCM) and reduced left ventricu-lar ejection fraction (LVEF) the most frequent etiology of syncope is ventricular tachycardia, but in many cases the etiology remains unknown.

Methods: A 49-year-old man with no medical history presented for a single syncope with no prodrome, while driving.Clinical examination was normal, including the orthostatic hypotension test.ECG showed ST depressi-on and negative T waves in V4-V6.Echocardiography revealed chambers dilation, global hypokinesia and LVEF of 10-15%.We excluded the most frequent cau-ses of NIDCM.Angiography showed normal coronary arteries. Cardiac MRI did not identify any specific eti-ology.The final diagnosis was idiopathic NIDCM.ECG monitoring identified episodes of nonsustained ventri-cular tachycardia which, in association with syncope’s features (unique, no prodrome, while driving), sustai-ned the diagnosis of arrhythmic syncope.The patient received an ICD, alongside the optimal treatment of heart failure.

Results: We present the case of a patient with idio-pathic NIDCM and a single syncope. A first peculiarity is the lack of symptoms due to HF despite severely reduced LVEF.Second, the syncope was the first signaling symptom regarding an altered cardiac substrate.The characteristics of syncope (single episode, no prodro-me, while driving) and ECG modifications oriented toward a cardiac syncope and further evaluation was considered.Another feature of this case is the decision of ICD therapy.ICD implantation as primary preven-tion in NIDCM remains controversial.To date there is insufficient data regarding this therapy’s benefit in pa-tients with NIDCM and syncope.However, small stu-dies revealed that the presence of syncope in patients with NIDCM associates a higher mortality and rate of sudden cardiac death (SCD). AHA/ACC guidelines for prevention of SCD and the European guidelines of management of syncope recommend ICD implantati-on for these patients.Also, because the patient is a pro-fessional driver the presence of the syncope (although single) and the ICD implantation impose restrictions on driving cars for public transportation, profoundly altering the patient’s socio-economic status.

Conclusions: The presence of an unique syncope co-uld be a marker of an altered cardiac substrate even in asymptomatic patients, apparently without cardiovas-cular risk. A throughout initial assessment, consisting of anamnesis, physical examination and electrocardi-ogram, is essential for the detection of patients with a high probability for cardiac syncope, whose optimal management is complex. Syncope in NIDCM is asso-ciated with a higher risk of sudden cardiac death and most probably requires the implantation of a cardiac defibrillator.