Hello, and thank you for your question! Regarding your concern I recommend you to to visit your doctor GP and have a routine check up; as you are on a chronic therapy for heart failure; and as you declare not pleasant situation with your well being recently. Medical consultation will rule out any problems that may have been raised during your maintenace therapy; to control Complete blood count, blood glucose, an ECG, any side effects of therapy, any possible digoxin toxicity (if so blood digoxin level should be checked up; together with renal, kidney function tests and serum electrolytes; physical examination coupled with a chest X-ray film will rule out any pulmonary complication (or other triggering factors); if symptoms of heart failure decompensations will be present then a cardiologist visit coupled with a cardiac ultrasound would be the best choice for you. So don t forget to visit your doctor as soon as possible. Hope to have been helpful to you. Greetings by Dr. Iliri