Effect of TAK-954 on Gastrointestinal and Colonic Transit in Diabetic or Idiopathic Gastroparesis Participants

Inclusion Criteria

• Has diabetes mellitus with symptoms of gastroparesis and previously documented gastric emptying delay or previously documented idiopathic gastroparesis in the last 5 years.
• Has a body mass index (BMI) greater than or equal to (>=) 16 and less than or equal to ( ) 12 percent (%).
• Has other structural diseases/conditions that affect the gastrointestinal (GI) system.
• Are unable to withdraw drugs known to alter GI transit 48 hours prior to the study.
• Has clinically significant abnormal baseline safety laboratory values.
• Has preexisting hepatic disease that meets Child-Pugh Class B (moderate; total score 7 to 9 points) or C (severe; total score 10 to 15 points).
• Are without known preexisting hepatic disease who have 1 or more of the following:
• Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) >2 times the upper limit of normal (ULN).
• Bilirubin >1.5 times the ULN unless due to Gilbert's syndrome.
• International normalized ratio (INR) >1.5 unless on anticoagulation therapy.
• Has QT intervals with Fridericia correction method (QTcF) interval (>=) 460 millisecond (msec) or with other factors that increase the risk of QT prolongation or arrhythmic events at screening. Note: Participants with bundle branch block and a prolonged QTc interval, or with QTcF between 450 and 460 msec, should be reviewed by the Medical Monitor for potential inclusion.
• Has second or third degree atrioventricular (AV) block; AV disassociation; >5 beats of non-sustained VT at a rate >120 beats per minute (bpm); Electrocardiogram (ECG) changes consistent with acute myocardial ischemia or infarction.
• Has cardiac history that includes conditions requiring heart rate control (example, atrial fibrillation, atrial flutter, ventricular tachycardia, or other tachyarrhythmias).
• Has clinical evidence (including physical examination, ECG, clinical laboratory value and review of the medical history) of significant cardiovascular, respiratory, moderate or severe renal insufficiency (creatinine clearance <=60 mL/min), hematological, neurological, or psychiatric disease, or other disease that interferes with the objectives of the study.
• If female, are pregnant or lactating or intending to become pregnant before participating in this study, during the study, and 4 to 5 days (5 half-lives) PLUS 30 days after last dose of the study drug; or intending to donate ova during such time period.
• Are considered by the investigator to be alcoholics not in remission or known substance abusers. Have a history of alcohol consumption exceeding 2 standard drinks per day on average (1 glass is approximately equivalent to: beer [354 milliliter per [mL/] 12 ounces], wine [118 mL/4 ounces], or distilled spirits [29.5 mL/1 ounce] per day).