Objectives To assess the association of low-dose Droperidol administration in the emergency department with changes in the QTc interval.

Hypothesis Our study is designed to test the null hypothesis that there will be no clinically significant change in QTc interval after administration of 2.5mg of IV Droperidol during an emergency department visit.

The investigators plan to conduct ECG evaluation for QT interval both before and after patients are given 2.5 mg of droperidol. Specifically, a convenience sample of consenting adult patients, ages 18 years and older, who present to the ED, and are in a cardiac-monitored bed in the ED who, at the discretion of their treating physician, have an ECG recorded and then receive a dose of 2.5 mg of droperidol IV will be enrolled in our study. The investigators will then have a second ECG printed at least 5 minutes and no more than 30 minutes after the droperidol is given. Change in QT interval between the two ECGs will be documented. It may be necessary to review the EMR in order to document the time of droperidol administration.

These post-droperidol ECGs will not be stored in the electronic medical record nor read by a physician in real time. Treatment decisions regarding the patient's medical care in the ED will not be affected by these second ECGs; decisions about whether other ECGs may be needed will be made by the treating physician. The primary study outcome will be the percentage of the study population who experience a clinically significant increase in QTc after low-dose droperidol administration, defined as an increase in QTc of 20 ms or greater. Secondary outcome measures will be the mean change in QTc across the study population, and the percentage of the study population for whom the administration of low-dose droperidol is associated with an increase in QTc that re-classifies them as having a prolonged QTc (>450 ms in men and >470 ms in women).

Inclusion Criteria:

• ED patients ages 18 years or older in a cardiovascular-monitored bed who have both an ECG and a 2.5 mg dose of IV droperidol ordered by their treating physician will be eligible for inclusion.

Exclusion Criteria:

• Refusal to provide consent.
• Administration of droperidol before the first ECG is performed.
• Inability to complete the consent form and questionnaire due to clinical instability, severe pain, or disorientation as determined by a study physician.

• The population being studied will be a convenience sample of adult emergency department patients.
• Eligibility in the study will be based on the treating physician's decision to have administered droperidol and to obtain an ECG - participation in the study will not affect the patient's care.
• The minimum number of study subjects will be 100.
• The maximum number of study subjects will be 500.
• There will be no use of special subject populations.
• Investigators will also track how many eligible patients refuse to participate. (See "Participation Status" on the survey instrument, Data Collection Form)
• Written consent will be required for each participant at the top of the survey. (See "Survey Instrument", Data Collection Form)
• Patients will be enrolled only once.
• Participants will not receive any form of compensation and will not be billed for the additional ECG.
• Vulnerable adult populations may be included who are able to give consent to participate.

There is no plan to share IPD.