BACKGROUND Despite advances in management, infective endocarditis remains a condition with high in-hospital and post-discharge mortality, especially when it is complicated by perivalvular extension and heart failure (HF). CASE REPORT Herein we describe two illustrative cases of endocarditis. The first case was complicated by left ventricle to right atrial fistula. The second cased was complicated by valvular perforation with a "windsock" appearance. Both patients developed acute HF. CONCLUSIONS Fistulas and severe valvular regurgitation are among the major causes of acute HF in the setting of infective endocarditis. In such cases, surgery should be considered to decrease mortality.