PCT - Cardiovascular

Inotropic Agents

  • Definition: Agents that affect the strength of heart contractions.

  • Nitrates: The primary drugs that decrease inotropy.

  • Recognition: The patient's unconscious state may indicate a cardiac anomaly.

Common Anti-Dysrhythmic Medications

  • These medications are not required to be memorized but should be recognized:

    • Digoxin: Commonly used for Congestive Heart Failure (CHF).

    • Sotalol: A beta-blocker.

    • Verapamil: A calcium channel blocker.

    • Key Focus: Only essentials to know are Nitro, ASA, and Digoxin.

Management of Congestive Heart Failure (CHF)

  • Digoxin: Often prescribed to patients with CHF.

  • Blood Pressure Formula: Blood Pressure = Heart Rate x Stroke Volume.

    • Reducing heart rate or stroke volume can lower blood pressure.

    • Medications may include beta-blockers or diuretics to manage high blood pressure.

Diuretics

  • Function: Increase urine production to reduce blood volume and stroke volume, thus lowering blood pressure.

  • Lifestyle Modification: Patients may be advised to decrease salt intake before diuretic prescription.

  • Mechanism: Diuretics promote sodium excretion, which can lead to potassium loss; hence different types of diuretics like potassium-sparing options exist.

  • Examples of Common Diuretics:

    • Hydrochlorothiazide: A frequently prescribed diuretic.

    • Furosemide (Lasix): Common for high blood pressure management.

Antihypertensives

  • Types of Antihypertensives:

    • Diuretics: Manage blood pressure.

    • Beta-Blockers: Help reduce heart rate.

    • Calcium Channel Blockers: Also antihypertensive agents.

    • ACE Inhibitors: Prevent the conversion of angiotensin I to angiotensin II, thereby lowering blood pressure and can cause angioedema as a side effect.

    • Angiotensin Receptor Blockers (ARBs): Similar effect but different mechanism.

Renin-Angiotensin-Aldosterone System (RAAS)

  • Angiotensinogen: A hormone released by the kidneys.

  • Process: If blood pressure drops, renin is released, converting angiotensinogen to angiotensin I; eventually becomes angiotensin II which raises blood pressure via vasoconstriction and fluid retention.

  • ACE Inhibitors Identification: Medications ending in "-pril" indicate ACE inhibitors.

Blood Thinners

  • Function: Prevent formation of blood clots; do not dissolve existing clots.

  • Prescribed For:

    • Patients with history of recurrent blood clots.

    • Atrial fibrillation and artificial heart valves.

  • Common Medications:

    • Warfarin (Coumadin): Traditionally used; anticoagulant derived from rodenticide.

    • Newer Agents: Pradax, Xarelto, Eliquis.

Conditions Necessitating Blood Thinners

  • Patients prone to blood clots or with previous history of clots receive anticoagulants.

  • Increased bleeding risk noted with minor traumas, especially during procedures like venipuncture.

Difference Between Antiplatelets and Anticoagulants

  • Antiplatelets: Prevent platelets from clumping together (aggregation).

  • Anticoagulants: Interfere with clotting proteins in the blood.

  • Aspirin (ASA): Common antiplatelet, prevents clot formation but does not dissolve clots.

Clot Busters

  • Thrombolytic Agents (e.g., tPA): Dissolve clots already formed to restore blood flow.

  • Diagnostic Procedures: Angioplasty uses catheter and balloon to open narrowed arteries, preventing future blockages.

  • Key Point: Aspirin does not dissolve existing clots; effective in stopping clot enlargement during acute events.