Observation of major pathological alterations in a young person involves etiological and clinical justifications, in order to properly assess, treat and control these conditions. The aim of this paper is to present severe, acute pathological lesions, installed in a young person, secondary to hypodiastolic heart failure, due to persistent supraventricular tachyarrhythmia, triggered by a post-traumatic external stimulus, with complete remission post-electrical conversion. Pathological and clinical modification are revealed, in a young person, shortly after a minor thoracic trauma, in the absence of traumatic injury but with high-frequency palpitations onset and progressive installation of vascular, visceral and interstitial stasis modifications, as well as of vascular and tissular hypoperfusion with reactive vasoconstriction. These clinical and paraclinical aspects were: stasis hepatomegaly with hepatojugular reflux, pulmonary congestion with stasis rales, peripheral edema, transudative polyserositis - pericarditis, hydrothorax, ascites, dilatation of inferior vena cava and suprahepatic veins, decrease of arterial blood pressure, tissue and cutaneous vasoconstriction. Anatomical and clinical aspects, with major alterations (Vth degree hepatomegaly, polyserositis, peripheral edema, tachyarrhythmic heart contractions, hypotension, pallor accentuated by vasoconstriction) acutely installed in a previously healthy young person, require a rapid lesions diagnosis and emergency treatment due to vital risk, control of acute heart failure manifestations remission and proper monitoring. Differential diagnosis was focused on determining possible aspects like: acute heart failure (of various etiology), internal post-traumatic lesions or hemorrhages, tuberculosis polyserositis, collagenosis, nephrotic syndrome, protein deficiencies, neoplasia with hepatic determinations, hematological diseases (lymphomas, leukemias), considered in young patients. Severe visceral, vascular and tissular pathological alterations were reactively induced in a young person, by stasis and hypoperfusion due to hypodiastolic heart failure caused by persistent supraventricular tachyarrhythmia triggered post-traumatic, on a proarrhythmic structural heart.