Cardiac acetyl-carnitine plays an important role in fat metabolism. Decreased carnitine concentration has been reported in heart failure, but it has previously been difficult to measure acetyl-carnitine in-vivo. We show for the first time that it is possible to detect a clear acetyl-carnitine resonance at δ=2.1ppm without lipid contamination within the heart using a long echo time semi-LASER sequence at 3T. This validates the finding in skeletal muscle that the T2 of acetyl-carnitine is much longer than its surrounding lipid signals. Further work is underway to investigate variability of the acetyl-carnitine signal postprandially.