drug strategies to improve cardiac function
How do drugs reduce workload of the heart
Cholinergic receptors
activated by ACH
Andrenergic Receptors
activated by NE
Beta-1 agonists:
response when stimulated
increased HR and contractility
Beta-1 agonists:
clinical use
treat conditions of cardiac decompensation
Beta-1 agonists:
impact
increases work load of the heart
Beta-1 antagonists:
response when stimulated
2. limit impact of sympathetic NS on heart
Beta-1 antagonists:
clinical use
treat compromised or diseased hearts
Beta-1 antagonists:
impact
2. reduces functional capacity
What are some conditions of cardiac decomposition (low CO)
- HF
Ionotropic agents used to:
When should IV + ionotropic agents be used
- volume overload with evidence of organ hypofusion
T/F: PT probably on hold with patients receiving IV ionotropic therapy
True
Ionotropic Agents:
Dopamine
naturally occurring catecholamine
precursor to NE
Ionotropic Agents:
Dopamine low dose
renal and splanchnic vasculature dilation = enhanced diuresis
Ionotropic Agents:
Dopamine mod dose
enhance cardiac contractility and HR
Ionotropic Agents:
Dopamine high dose
increased afterload through peripheral vasoconstriction
When is dopamine used for cardiac trx?
2. moderate HTN
Ionotropic Agents:
Dobutamine
Ionotropic Agents:
Milrinone
Digitalis is used to treat
T/F: Digitalis increases CO at rest and during exercise but does not prolong life
True
How does digitalis work
2. Increases AV node’s refractory period, decreasing ventricular response