Beta Blockade and the Heart

1
Beta Blockade and the Heart

• John Hakim, M.D
• Cardiology Fellow
• West Virginia University
• Division of Cardiology

2
Beta Blocker Heart Attack Trial

• Randomized 4000 Patients to Placebo Vs.
  Propranolol
• 20 Reduction in Mortality in Propranolol group
• Despite a 17 rise in Triglycerides and a 6 rise
  in LDL

3
Beta Blockers in ACUTE MI

• Beta Blockers Reduce pain, and reduce need for
  analgesics presumably by reducing ischemia
• Most useful in patients with sinus tachycardia
  and HTN post MI

4
Beta Blockers in ACUTE MIProtocol (Braunwald)

• Exclude patients with Heart Failure (10 cm rales
  above diaphragm), hypotension lt90mmHG,
  Bradycardia lt60 bpm, and Heart Block.
• Metoprolol in three 5mg boluses q 5 min
• Stop if HR lt60 or SBP lt100mmHg
• If stable, give oral metoprolol 50mg q6h x 2 days
• Then switch to 100mg BID or Toprol XL (IV
  esmolol useful in patient with relative
  contraindication.)

5
What not to give Post Acute MI

• Unlike Beta Blockers, calcium antagonists are of
  little value in AMI and may, in fact, be
  hazardous.

6
Effects of Beta Blockers Post MI

• Immediate reduces cardiac index, heart rate and
  blood pressure. Net effect is to reduce
  myocardial oxygen consumption/minute/beat.
  (Reduces Chest Pain)
• Reduces infarct Size in Acute MI
• Diminishes circulating levels of free fatty acids
  by antagonizing lipolytic effects of
  catecholamines. (FFA augment O2 consumption and
  increases incidence of arryhthmias.

7
Effects of Beta Blockers Post MI(Pre-Thrombolytic
Era)

• ISIS-1
• 16,000 patients randomized
• reduction of mortality among patients randomized
  to IV atenolol Vs. placebo.
• Meta analysis of 27 trials (27,000 patients) IV
  followed by oral beta blockers
• 15 relative reduction in mortality, non fatal
  reinfarction, and nonfatal cardiac arrest

8
Effects of Beta Blockers Post MI

• TIMI-II trial (Thrombolytics in MI)
• Recurrent ischemia and reinfarction were reduced
  by immediate vs. delayed use of metoprolol.
• mortality and LV function were not improved by
  immediate metoprolol.
• Therefore beta-blockers are beneficial, but may
  not enhance the salvage of myocardium due to
  early reperfusion.

9
Effects of Beta Blockers Post MICurrent
Recommendations

• Patients with hyperdynamic state ( sinus
  tachycardia, HTN, no CHF or bronchospasm, no
  heart block)
• Patients seen in the first 4 hours of their MI
• Regardless of whether thrombolytics are used
• Beta-Blockers indicated for people with
  persistent or recurrent ischemic pain

10
Beta Blockers and Idiopathic Dilated
Cardiomyopathy

• Chronic Beta-Blockers increase the number of Beta
  adrenergic receptors on the Heart
• Reduced ischemia and more efficient oxygen
  utilization (Study done w/ metoprolol)
• Detectable improvement in Cardiac Output (and EF)
  after three months.
• Long term structural changes of decline in LV
  volume and Mass after 12-18 months.

11
Other Beta Blocker Indications

• Arrhythmias associated withthyrotoxicosis,
  pheochromocytoma
• excess catecholamine state.
• Arrhythmias initiated by excercise or emotion
  often respond to propranolol
• Metoprolol may be helpful in controlling rate of
  multifocal atrial tachycardia

12
Question

• Peri-operative myocardial ischemia is the single
  most important reversible risk factor for
  mortality and cardiovascular complications
  annually.
• Is there any way to prevent perioperative
  myocardial ischemia during non cardiac therapy?

13
Perioperative Cardiovascular Morbidity and
Mortality

• In patients who are at risk for coronary artery
  disease who must undergo non-cardiac surgery,
  treatment with atenolol during hospitalization
  can reduce mortality and the incidence of
  cardiovascular complications for as long as 2
  years after surgery. (N Eng J Med
  19963351713-20)

14
Perioperative Cardiovascular Morbidity and
Mortality

• In patients with CAD standard practice is to
  control heart rate pre-op and intra-op.
• Post-op tachycardia may precipitate ischemia
• Beta-blockade can modulate the post-op
  sympathetic response.
• Preventing ischemia prevents morbidity and
  mortality.