This study found that only 7.5% of acute heart failure patients had a normal ECG, higher than previous reports of 2%. Abnormal ECG findings like widened QRS duration and paced rhythm were associated with decreased survival, while a normal ECG and sinus rhythm were protective. Additionally, atrial fibrillation increased risk of rehospitalization but not mortality. When considered with other clinical data, ECG characteristics can help risk stratify heart failure patients and guide their management.