The study proposes to develop a phenylephrine protocol to be used during transesophageal echocardiography, whereby intravenous phenylephrine would be used to increase afterload with the intent to mimic the awake hemodynamic profile and variation that occurs with normal physical activity. The expectation is to see changes in severity of Mitral Regurgitation (MR) grade with increasing afterload, which in turn can provide more accurate quantification of MR severity to assist in clinical decision making.

Routine echocardiography which is used to assess the severity of mitral regurgitation, sometimes underestimates the severity of mitral regurgitation, due to hemodynamic variations that occurs with normal physical activity and under the effect of sedation which is used to perform transesophageal echocardiography. By using phenylephrine during transesophageal echocardiography, the study intends to offset the hemodynamic variation that occurs with sedation and better assess the severity of mitral regurgitation, which would further assist in clinical decision-making regarding treatment. The goal of this study is to compare the severity of mitral regurgitation grade before and after the administration of phenylephrine during transesophageal echocardiography and to demonstrate a 25% increase in severity of mitral regurgitation grade compared to the baseline conditions, following the administration of phenylephrine.

Inclusion Criteria:

• Patients 18 years or older with MR on baseline echocardiographic evaluation who are scheduled to undergo TEE for further evaluation of mitral regurgitation.

Exclusion Criteria:

• The following patients will be excluded from the study:

  1. Patients who are not clinically eligible for TEE.
  2. Patients with contraindications to esophageal intubation.
  3. Patients with hemodynamic instability.
  4. Patients with acute decompensated heart failure (HF).
  5. Patients with un-revascularized severe coronary artery disease (triple vessel or left main disease).
  6. Patients with ongoing unstable angina or ongoing myocardial infarction (MI)
  7. Patients with significant arrhythmias including atrial fibrillation.
  8. Patients with uncontrolled hypertension (BP ≥ 150/90 mmHg).
  9. Patients with preexisting bradycardia (HR < 50) and heart blocks.
  10. Patients with severe symptomatic peripheral vascular disease.
  11. Patients with severe pulmonary hypertension (estimated systolic pulmonary arterial pressure sPAP ≥ 60mm Hg).
  12. Patients who are at high risk for intracranial bleeding such as patients with previous strokes, transient ischemic attack (TIA) and vascular malformations.
  13. Additionally, patients with mean arterial blood pressure MAP > 100 mmHg during TEE and those with severe MR, effective regurgitant orifice area (ERO > 39cm2) on baseline TEE evaluation will not be given phenylephrine and excluded from the study.