A Single Ascending Dose Study Assessing the Safety, Tolerability, PK and PD of MYK-491

Inclusion Criteria: * Weight between 60 and 90 kg inclusive * Resting heart rate of \< 80 beats per minute * Documented LVEF greater than or equal to 55% during Screening * Normal electrocardiogram (ECG) at Screening * Normal acoustic windows on transthoracic echocardiograms at Screening * All safety laboratory parameters within normal limits at Screening * History or evidence of another clinically significant disorder, in the opinion of the investigator. Exclusion Criteria: * Active infection * History of coronary artery disease * History of malignancy with the exception of in situ cervical cancer more than 5 years prior to Screening or surgically-excised non-melanomatous skin cancers more than 2 years prior to Screening * Positive serology tests at screening * Current use of tobacco or nicotine-containing products exceeding 10 per day.