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Cardiac Emergencies | General Overview

Epidemiology: Cardiovascular Disease is number 1 killer, approx. 2600 die each day, High BP, Coronary Heart Disease, AMI, Angina, Stroke, Rheumatic heart disease and CHF, 1 in 5 adults has some form.

Risk Factors:

  • Age: death rates rise with each year of life Family history: predisposition
  • Hypertension: major risk factor BP>170/95 = 5 times higher risk
  • Lipids: high bad cholesterol
  • Smoking
  • Gender: males have higher risks
  • Diabetes

Cardiovascular system 

Stroke volume: amount of blood pumped into the cardiovascular system in one heart contraction Amount is usually around 70mL.

Depends on:

  • Contractility: the extent and velocity of muscle fiber shortening
  • Preload: the passive stretching force on the ventricular muscle at the end of diastole. More blood returning increases the preload, less blood returning decreases it. If the container (vessels) is greater than the fluid, you’ll have inadequate preload and a decrease in cardiac output.
  • After load: the pressure the ventricular muscles must generate to overcome the higher pressure in the aorta, and eject the blood out.

heartapMyocardium: Heart muscle

Epicardium: outside of the heart

Pericardium: thick set of two membranes surrounding the heart, inner is visceral,outer is perietal

Blood Pressure: the force that blood exerts against the walls of the arteries as it passes.

Systole: pressure within the arteries during heart contraction, concomitant pumping

Diastole: Relaxation phase, also indicates myocardial perfusion

 

Cardiac Output: amount of blood pumped each minute. Heart rate x stroke volume.

Cardiovascular system is closed so increasing cardiac output or vascular resistance increases blood pressure. Decreasing cardiac output or vascular resistance decreases BP.

Pulmonary Circulation: transports deoxygenated blood through the lungs, oxygenate it, and return it to the left side of the heart

Systemic Circulation: left ventricle pumps blood out to the body through SEMI-LUNAR (AORTIC) valve to the aorta

Coronary Circulation: where the heart muscle receives its blood supply, right main, left main etc. etc.. Five coronary veins empty into the right atrium via the coronary sinus.

Blood Vessels: closed system, sometimes called “the container”

  • Elastic, always adjusting their diameter
  • Responding to local tissue needs, bypassing less important tissues for vitals Sympathetic nervous system activates dilation and contraction

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