HEART RATE & RHYTHM changes that pathologically affect CO

tachycardia

HR above 100beats/min

sns triggers fight or flight during activity, stress, or to compensate during shock or heart attack

epinephrine binds w/ beta receptors of heart and increases HR

neurohormonal influences of symp Nerv Syst on TACHYCARDIA

triggers hypopolarization (reduction in necessary stimulus to trigger muscle action)

certain electrolyte changes such as hyperkalemia may cause

bradycardia

HR below 60 bpm

•Vagus nerve secretes acetylcholine which decreases HR

neurohormonal influences of the parasympathetic nervous system on BRADYCARDIA

hypokalemia causes HYPERpolariztion, which INCREASES required stimulus to trigger muscle action

electrolyte changes affecting bradycardia

Right coronary artery feeds SA node and AV node

why does ichemia (narrowing or blockage) of RCA trigger bradycardia

-Iscemic or infarcted tissue interferes w/ normal impulse conduction

electrolyte imbalance especially potassiium

age related wear and tear

causes of dysthythmia

-Chaotic series of electrical impulses in the atria that causes them to quiver ineffectively instead of contracting smoothly

atrial fibrillation

long-term hypoxic strain on myocardium, or a chronic problem such as heart failure

most common causes of atrial fibrilation

Atrial kick and loss of cardiac output

SEQUELA OF ATRIAL FIBRILATION:

small but sometimes significant decrease in CO

atrial kick

The atria perform a small, coordinated contraction at the end of diastole to push extra blood into the ventricles

loss of cardiac output

•If the atria quiver instead of contracting properly, cardiac output (CO) decreases because the "atrial kick" is missing.

Blood Pooling ("Sludge"),

Left Atrial Thrombi & Stroke,

Right Atrial Thrombi & Pulmonary Embolism (PE)

pooling of blood in atria; etiology & sequelae:

blood pooling “sludge”

When atria quiver instead of pumping properly, blood stagnates and creates ideal conditions for blood clots (thrombi

left atrial thrombi & stroke

Clots in the left atrium can break loose and travel to the brain as emboli, causing a stroke (with symptoms like one-sided weakness, confusion, and brain ischemia).

right atrial thrombi & pulmonary embolism

•Clots in the right atrium can travel to the lungs, causing a PE (with symptoms like shortness of breath, chest pain, hemoptysis, and shock).

ventricular fibrillation

chaotic series of electrical impulses in the ventricles that causes them to quiver ineffectively instead of contracting smoothly

ventricular fibrillation

what is the DEADLIEST dysrhymia

it results in NO CO at all. Causes NO perfusion to brain

why is ventricular fibrillation the DEADLIEST dysrythmia