A 72-year-old man with a 10-year history of hypertension presents with progressive dyspnea on exertion, orthopnea, and lower extremity edema. Physical examination reveals a laterally displaced point of maximal impulse, an S3 gallop, and crackles at both lung bases. Echocardiography shows a left ventricular ejection fraction of 32% with global hypokinesis. Which of the following pathophysiologic mechanisms most directly explains the development of his lower extremity edema?
- A)Increased sympathetic tone causing selective renal vasoconstriction
- B)Decreased cardiac output causing reduced renal perfusion and sodium retentionGABARITO
- C)Increased systemic vascular resistance leading to elevated afterload
- D)Pulmonary hypertension secondary to left-to-right shunting
- E)Impaired lymphatic drainage from venous obstruction
Explicação
In systolic heart failure, reduced cardiac output activates compensatory mechanisms including the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system. Decreased renal perfusion triggers renin release, leading to sodium and water retentio... Ver explicação completa e trilha adaptativa →