Acute coronary syndrome – 11/20/17

Unstable angina = symptoms with negative biomarkers and EKG
NSTEMI or STEMI = symptoms with positive biomarkers and EKG

Types of stress

  • Exercise
  • Dobutamine (works by increasing contractility)
  • Vasodilators – lexiscan or adenosine (not a true “stress” but causes vasodilation of the vessels and if there is an occlusion in one, then more blood will be shunted to the other ones leading to the “steal” phenomenon)

Types of imaging

  • EKG
  • Echo
  • Nuclear medicine study

When deciding what kind of stress and what kind of imaging to use you must take a few things into consideration:

  • If possible, always try to stress a patient with exercise as that gives you information about their exercise tolerance and functional capacity
    • Exercise can be paired with an EKG, echo, or nuclear medicine study
  • If a patient cannot exercise, consider dobutamine or a vasodilator
  • Dobutamine is best to use when a patient has a contraindication to a vasodilator e.g. a patient cannot use adenosine because they have bronchospastic airway disease (COPD or asthma)
    • Dobutamine can be paired with an echo or a nuclear medicine study
  • Vasodilators are ideal if a patient has a LBBB because it is not affected by the fact that in a LBBB you have a delayed contraction of the septum which can cause a false positive for obstruction if done with exercise or dobutamine
    • Vasodilators can only be paired with a nuclear study

Contraindications to using an EKG as your form of imaging are:

  • LBBB
  • Ventricular paced rhythm
  • ST changes > 1 mm

Anti-anginal medications:

  • BB
  • Nitrate (give a medication free period at night to avoid tachyphylaxis)
  • CCB
  • Ranolazine (4th line medication if the others have failed)

Aortic stenosis – 12/4/17

Most common etiologies of AS

  • Calcification of a normal aortic valve overtime with age
  • Bicuspid aortic valve
  • Rheumatic heart disease (usually associated with mitral valve disease)


  • Dyspnea (most common)
  • Angina
  • Syncope


  • Physical exam
    • Systolic ejection murmur at RUSB with radiation to the carotids
    • Any maneuver that decreases blood flow across the valve will cause a decrease in the sound of murmur (e.g. valsalva, handrip, or standing) whereas anything that increases blood flow across the valve will increase the sound of the murmur (e.g. squatting)
  • Transthoracic echo
    • Severe AS is AVA < 1 cm2, mean gradient greater or equal to 40, or max velocity greater than 4 m/s

Low-flow, low-gradient AS

  • If patient has an AVA < 1 cm2 but has a mean gradient < 35 mmHg, consider low-flow, low-gradient AS
  • To determine whether there is an intrinsic problem with the valve versus a pseduo-aortic stenosis due to myocardial dysfunction, do a dobutamine stress echo
  • If AVA remains unchanged and the mean gradient increases with dobutamine, the etiology is severe AS and the patient would benefit from valve replacement
  • If the AVA increases and the mean gradient doesn’t increase, this is a pseudo-aortic stenosis and the patient can be managed medically

When to treat?

  • Any patient who is symptomatic
  • An asymptomatic patient with EF < 50 or who is getting another cardiac surgery


  • AVR > TAVR if the patient is a surgical candidate
  • TAVR is good for high risk patients and has similar survival to AVR in high-risk patients
  • AV balloon valvuloplasty is a short-term bridge to TAVR as it only lasts a few months
  • Medical management is usually not beneficial if a patient has severe AS