Introduction: The troponin complex regulates the contraction of striated muscles and consists of three subunits (troponin C, troponin T, and troponin I). Troponin C is a 18 ku protein that binds to calcium ions. Troponin T is a 37 ku protein that binds to tropomyosin, thereby attaching the troponin complex to the thin filament. Troponin I is a 24 ku protein that binds to actin and decreases troponin C affinity for calcium, thus inhibiting actin–myosin interactions. Material and Methods: We included 4748 consecutive patients who presented to the General medicine Department and casualty with suspected acute coronary syndrome to the M.R. Medical College and Basaveshwar Hospital, kalaburagi between 1 June 1999 and December 2001. All patients who had cardiac troponin requested by the attending clinician for suspected acute coronary syndrome were included. Results: There were 4870 patients with suspected acute coronary syndrome (mean age 61 ± 16 years, 57% men). The median cardiac troponin concentration was 5 ng/L (interquartile range 2–22 ng/L). There were 1151 (24%) patients with cardiac troponin concentrations above the URL (Group 5); 723 (15.2%) patients were classified as having type 1 myocardial infarction, 158 (3.3%) type 2 myocardial infarction, and 270 (5.7%) with myocardial injury. Conclusion: High-sensitivity cardiac troponin I is an excellent predictor of heart failure hospitalizations and cardiac death in patients with suspected acute coronary syndrome. Troponin concentrations may, in particular, be used to identify patients without myocardial infarction who are at risk of heart failure.