Antianginal Agents. Antidysrythmic Agents

Coronary Ischemia: Supply and Demand Economics

Coronary Ischemia: Supply and Demand Economics

The Grip of Angina

Supply-Demand Mismatch

Myocardial Oxygen Demand Heart Rate Wall Stress Contractility Adapted from Runge et al, Netter’s Cardiology

Determinants of Myocardial Oxygen Supply

Determinants of Myocardial Oxygen Supply

Coronary Flow Reserve Adapted from Maseri A, Ischemic Heart Disease, Churchill Livingstone, 1995

Angina Pectoris (Chest Pain) When the supply of oxygen and nutrients in the blood is insufficient to meet the demands of the heart, the heart muscle aches. The heart demands a large supply of oxygen to meet the demands placed on it.

Antianginal Agents Nitrates Beta blockers Calcium channel blockers

Antianginal Agents: Therapeutic Objectives Minimize the frequency of attacks and decrease the duration and intensity of anginal pain Improve the patient’s functional capacity with as few side effects as possible Prevent or delay the worst possible outcome, MI

Nitric Oxide Opie LH: Heart Physiology Lippincot Williams & Wilkins, 2004

Antianginal Agents: Nitrates Available forms: Sublingual Ointments Buccal Transdermal patches Chewable tablets Inhalable sprays Capsules Intravenous solutions

Antianginal Agents: Nitrates Side Effects Headache Usually diminish in intensity and frequency with continued use Tachycardia, postural hypotension Tolerance may develop

Nitrate Tolerance Occurs with chronic administration of long acting nitrates. Efficacy of drug diminishes with chronic exposure (tachyphylaxis). Tolerance readily reverses with nitrate free interval.

Adrenergic Receptors Beta1 Beta2 Alpha SA node, AV node, His-Purkinje system Myocardium Juxtaglomerular apparatus Adipocytes Beta2 Peripheral and coronary vasculature Bronchi Peripheral Muscle Uterine Muscle Alpha Peripheral circulation Beta-1 Beta-2 Alpha Adapted from Runge et al, Netter’s Cardiology

Antianginal Agents: Beta Blockers Mechanism of Action Decrease the HR, resulting in decreased myocardial oxygen demand and increased oxygen delivery to the heart Decrease myocardial contractility, helping to conserve energy or decrease demand

Antianginal Agents: Beta Blockers Therapeutic Uses Antianginal Antihypertensive Cardioprotective effects, especially after MI

Antianginal Agents: Calcium Channel Blockers verapamil (Calan) diltiazem (Cardizem) nifedipine (Procardia)

Role of Calcium Channels in Myocardial Contraction Opie LH, Heart Physiology, Williams Lippincott and Williams 2004

Role of Calcium Channel in Vascular Smooth Muscle Function Opie LH, Heart Physiology, Williams Lippincott and Williams 2004

Antianginal Agents: Calcium Channel Blockers Mechanism of Action Cause peripheral arterial vasodilation Reduce myocardial contractility (negative inotropic action) Result: decreased myocardial oxygen demand

Antianginal Agents: Calcium Channel Blockers Therapeutic Uses First-line agents for treatment of angina, hypertension, and supraventricular tachycardia Short-term management of atrial fibrillation and flutter Several other uses

Antianginal Agents: Calcium Channel Blockers Side Effects Very acceptable side effect and safety profile May cause hypotension, palpitations, tachycardia or bradycardia, constipation, nausea, dyspnea

Treatment of Ischemic Heart Disease

Antianginal Agents: Nursing Implications Patients should not take any medications, including OTC medications, without checking with the physician. Patients should report blurred vision, persistent headache, dry mouth, dizziness, edema, fainting episodes, weight gain of 2 pounds in 1 day or 5 or more pounds in 1 week, pulse rates under 60, and any dyspnea.

Antianginal Agents: Nursing Implications Alcohol consumption and hot baths or spending time in jacuzzis, hot tubs, or saunas will result in vasodilation, hypotension, and the possibility of fainting. Teach patients to change positions slowly to avoid postural BP changes. Encourage patients to keep a record of their anginal attacks, including precipitating factors, number of pills taken, and therapeutic effects.

Antianginal Agents: Nitroglycerin Nursing Implications Instruct patients in proper technique and guidelines for taking sublingual NTG for anginal pain. Instruct patients never to chew or swallow the SL form. Instruct patients that a burning sensation felt with SL forms indicates that the drug is still potent.

Antianginal Agents: Nitroglycerin Nursing Implications Patients are taught to take up to three tablets every 5 minutes. If no relief from chest pain is obtained after three tablets, they should seek medical assistance. Absorption nitroglycerin ointments best over a nonfatty and nonhairy portion of skin. The upper torso is the preferred site of application. The nurse should wear gloves when applying to prevent transdermal absorption by the applier. The ointment is measured as one straight line on the nitroglycerin patch and is gently spread over paper and applied, but not rubbed, into the skin.

Antianginal Agents: Nitroglycerin Nursing Implications Instruct patients to keep a fresh supply of NTG on hand; potency is lost in about 3 months after the bottle has been opened. Medications should be stored in an airtight, dark glass bottle with a metal cap and no cotton filler to preserve potency.

Antianginal Agents: Nitroglycerin Nursing Implications Instruct patients in the proper application of nitrate topical ointments and transdermal forms, including site rotation and removal of old medication. To reduce tolerance, the patient may be instructed to remove topical forms at bedtime, and apply new doses in the morning, allowing for a nitrate-free period.

Antianginal Agents: Nitroglycerin Nursing Implications Instruct patients to take prn nitrates at the first hint of anginal pain. If experiencing chest pain, the patient taking SL NTG should be lying down to prevent or decrease dizziness and fainting that may occur due to hypotension. Monitor VS frequently during acute exacerbations of angina and during IV administration.

Antianginal Agents: Nitroglycerin Nursing Implications IV forms of NTG must be contained in glass IV bottles and must be given with infusion pumps. Discard parenteral solution that is blue, green, or dark red. Follow specific manufacturer’s instructions for IV administration. Use special IV tubing provided or non-PVC tubing.

Antianginal Agents: Calcium Channel Blockers Nursing Implications Blood levels should be monitored to ensure they are therapeutic. Oral CCBs should be taken before meals and as ordered. Patients should be encouraged to limit caffeine intake.

Antianginal Agents: Beta Blockers Nursing Implications Patients taking beta blockers should monitor pulse rate daily and report any rate lower than 60 beats per minute. Dizziness or fainting should also be reported. Constipation is a common problem. Instruct patients to take in adequate fluids and eat high-fiber foods.

Antianginal Agents: Beta Blockers Nursing Implications These medications should never be abruptly discontinued due to risk of rebound hypertensive crisis. Inform patients that these medications are for long-term prevention of angina, not for immediate relief.

Antidysrhythmics Dysrhythmia Antidysrhythmics Any deviation from the normal rhythm of the heart Antidysrhythmics Drugs used for the treatment and prevention of disturbances in cardiac rhythm

Heart and Conduction System

Resting Membrane Potential of a Cardiac Cell

Abnormal Heart Rhythms Arrhythmia BPM tachycardia 150-250 bradycardia <60 atrial flutter 200-350 atrial fibrilation >350 prem. atrial cont. variable prem. vent. cont. vent. fibrilation

Premature Ventricular Contraction

Action Potential A change in the distribution of ions causes cardiac cells to become excited. The movement of ions across the cardiac cell’s membrane results in the propagation of an electrical impulse. This electrical impulse leads to contraction of the myocardial muscle.

Action Potentials: Phases (SA Node)

Action Potentials: Purkinje Fiber

Action Potentials: Intervals

Abnormal Heart Rhythms Caused by: ischemia, infarction, alteration of body chemicals Symptoms: palpitations, syncope, lightheadedness, visual disturbances, pallor, cyanosis, weakness, sweating, chest pain, hypotension