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Pharmacologic Support of Cardiac Failure Portrait of Dr. Gachet- vanGogh (1890)
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Objectives Pathophysiology of cardiac failure Pharmacology Therapeutic approaches Novel concepts Focus on Critical Care setting
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Cardiac Failure Classification Cardiac Cycle –Systolic vs Diastolic Heart Side –Right vs Left
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Systolic vs. Diastolic Systolic- Diminished ventricular contractility Diastolic- Diminished ventricular distensibility/passive relaxation (Lusitropy) –Ventricular hypertrophy –Myocardial ischemia (“Shock heart”) –Cardiac tamponade –Positive Pressure Ventilation End Diastolic Volume (not pressure) is the distinguishing factor
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Right Ventricular Dysfunction Predominantly systolic in nature Characterized by increased CVP –CVP ≥ PCWP Enlargement of RV bulging of septum into LV…interventricular interdependence Serum BNP (Brain-type or Atrial Natriuretic Peptide) –Systemic vasodilators, increase renal Na excretion –Sensitive marker (>100 pg/mL) –Accurate measure of degree of HF
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LV Dysfunction in the ICU 1/3 of pts in ICU will develop LV Dysfunction Cardiac Myocyte Insults –Catecholamines –Inflammatory mediators –Endotoxins –Cardiac contusion –Hypoxia/hypoperfusion –The role of stress?
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RV Dysfunction More common than suspected Usually systolic failure Ventricular pressures remain normal bc ventricle can stretch until pericardium impedes it TEE to measure RVEF Specialized Swan-Ganz catheters
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Cardiac Dysfunction Absence of CAD Unmasking of subclinical cardiac disease
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LEFT-SIDED HEART FAILURE Paul L. Marino. The ICU Book. 3 rd Ed. 2007. p.255-276
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The Vicious Cycle Inc. Preload Inc. Transmural pressure squeezed coronaries Diminished CO Increased Preload Increased Afterload Transmural pressure Ischemia…
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Vasodilators Nitrates –Nitroprusside –Nitroglycerin Nesiritide (Natrecor)- recombinant BNP
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Nitroprusside (Nipride) Systemic vasodilator –Arterioles > Venules Half-life: 1-2 min (thyocyanate excretion in days) Caution: –Cyanide Toxicity –Coronary Steal Syndrome
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Nitroglycerin Systemic vasodilator (and an explosive) –Veins > Arteries –Low dose: Venous dilation can further reduce CO Tolerance- can appear w/in 24h with continuous infusion Avoid in uncorrected anemia, hypovolemia, head trauma, tamponade
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Nesiritide (Natrecor) Recombinant human BNP –Stimulates cGMP Vasodilation, Natriuresis/Diuresis Avoid in hypotension
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Adrenergic Agonists Dobutamine Dopamine Milrinone
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Dobutamine Beta-1-receptor agonist Inotropy +++ Chronotropy +++ Reduces afterload (vasodilation) end organ perfusion Half-life- 1-2 minutes Increases myocardial O2 consumption danger in ischemic heart
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Dopamine D1 and Beta-1-receptor agonist –<3 Splanchinc vasodilation (D1) Natriuresis induction in kidneys –3-7 mcg/kg/min Inotropy +++ (B-1) –>7mcg/kg/min vasoconstriction afterload increase –>10 Systemic pressure support (Alpha-1)
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Milrinone (Primacor) Phosphodiesterase inhibitor (PDEi) –Chronotropy –Inotropy –Lusitropy Venodilator/Arteriodilator –Used in pulmonary HTN Half-life 1-2 hrs Negative effect on mortality in hospitlized pts (long-term treatment of chronic disease) MS Cuffe et al. Short term IV Milrinone for the acute exacerbation of chronic CHF: A prospective randomized trial. JAMA 2002 Mar 27
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Blood Pressure High BP Cardiac Failure –Afterload Reduction Vasodilators –Diuretics if unresponsive Normal BP Cardiac Failure –Inodilators Dobutamine/Milrinone/Epi –Diuretics if unresponsive Low BP Cardiac Failure (Decompensated) –Pressure restoration Dopamine –Vasoconstrictive, inotropic
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Diuretics IV Furosemide can drop CO 15-20% Can worsen decompensated HF Indicated if PCWP remains > 20 mmHg despite other agents Mainstay of Tx in Trauma population #1 Augmentation of CO Diuresis occurs naturally as renal perfusion improves (eliminate the need to retain Na & H2O)
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Levosimendan (Simdax) IV “inodilator” (Dobutamine, Milrinone) –Calcium sensitizer –Opens ATP-sensitive K+ channels in vessels Augments CO via –Positive inotropy –Systemic vasodilation Cardioprotective from ischemia
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Other Agents Thyroid Hormone –“Sick Euthyroid” patient –Enhances cardiac recovery after ischemia Methylene Blue –Experimental benefits –Inhibits NO production, halts SIRS response? –May be useful in septic shock –Pulmonary vasoconstriction?
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Takotsubo Cardiomyopathy “Broken Heart Syndrome” Tako-tsubo. (Jap.) “Fishing pot for trapping octopus” “Stress-Cardiomyopathy” severe emotional or physiologic stress, typically in elderly, in the absence of coronary disease Catecholaminergic insult to cardiac myocytes Supportive care = complete resolution
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Tako-Tsubo Dilated apex with basilar cardiac contraction
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