Cardio III- ECG

functional syncytium

what cardiac muscle cells form, mechanically, chemically, and electrically connected to one another

individual cells work together as a whole

electrocardiogram

a recording of the electrical activity in the heart

noninvasive- uses electrodes placed on skin

tests for clinical abnormalities of electrical signal conduction in the heart

what does an ECG produce

characteristic waves and intervals from which we can infer cardiac functions

what is the conductor in an ecg

the body (currents in the body can spread to surface)

ecg components

P wave, QRS complex, T wave

what does the p wave precede

atrial contraction (ecg)

what does the qrs complex precede

ventricular contraction (ecg)

what does the t wave precede

ventricular relaxation (ecg)

why do waves always precede an action

excitation-contraction coupling

blood pressure

the force that blood exerts on the blood vessel wall

vital sign

unit is millimeters of mercury (mmHg)

presented as systolic/diastolic

systole

ventricular contraction

diastole

ventricular relaxation

normal blood pressure

systolic less than 120

and

diastolic less than 80

elevated blood pressure

systolic 120-129

and

diastolic less than 80

high blood pressure stage 1

systolic 130-139

or

diastolic 80-89

high blood pressure stage 2

systolic 140+

or

diastolic 90+

hypertensive crisis

systolic higher than 180

and/or

diastolic higher than 120

why is hypertension bad

increases risk of heart attacks, heart failure, aneurysms, organ failure

factors increasing blood pressure

obesity

sedentary activity

smoking and vaping

alcohol

stress

excess sodium

factors that can affect (±) blood pressure

age

medications

time of day

body temperature

hormonal changes

factors that decrease blood pressure

healthy diet

exercise

relaxation

meditation

adequate potassium

when do korotkoff sounds appear

when taking a manual blood pressure, hear at systole then stop at diastole

pulse

alternating surges of atrial pressure caused by ventricular contraction and relaxation

throbbing/rhythmic sensation that can be felt in various locations of the body

pulse pressure

systolic BP - diastolic BP

characteristics of pulse that give clinical information

regularity, strength, difficulty of detection

apical pulse

pulse at the apex of the heart

peripheral pulses

pulse anywhere away from the heart

includes superficial temporal artery, facial artery, common carotid, brachial, radial, femoral, popliteal, posterior tibial, dorsalis pedis artery