What is the usual source of sudden death in an obese smoker?

Sudden death in an obese smoker is often associated with deep venous thrombosis (DVT), particularly because obesity and smoking both increase the risk for venous thromboembolism. In patients with DVT, blood clots can form in the deep veins of the legs. These clots have the potential to break loose and travel to the lungs, which can result in a pulmonary embolism (PE). A PE can obstruct blood flow to the lungs, leading to sudden cardiovascular collapse and death.

Obesity alone predisposes individuals to slower blood flow and increased pressure in the venous system, while smoking can cause vascular inflammation and contributes to thrombosis. Therefore, the combination of obesity and smoking significantly raises the risk for DVT and its complications, with sudden death being a possible outcome if a PE occurs.

In contrast, conditions like valvular disease, left heart failure, and endocarditis are also serious cardiovascular issues but are less commonly associated with the immediate risk of sudden death as a direct consequence of the lifestyle factors present (obesity and smoking) in this specific scenario.