A 70-year-old man is evaluated in emergency department for symptoms of dyspnea, orthopnea, and paroxysmal nocturnal dyspnea. His past medical history is significant for hypertension, type 2 diabetes, chronic kidney disease, and hypothyroidism. Medications are furosemide, enalapril, atorvastatin, metformin, and insulin.On physical examination he has generalized cardiomegaly and pulmonary and systemic venous hypertension. The ECG is shown in Figure below. What is the cardiac rhythm seen on the ECG?