Heart Anatomy & ECG

KAAP 310

The Electrocardiogram (ECG)

• As we discussed last week, the electrical activity of the heart is determined by pacemakers (SA, AV node)

• By placing sensitive electrodes on certain parts of the body, we can recognize and record the “echoes” of the heart depolarizing and repolarizing

• Heart rate, Axis deviation (heart position), cardiac arrthymias and mechanical activity of heart can all be seen on a standard ECG.

A normal ECG readingP Wave: Depolarization of the right and left atria (atrial depolarization)QRS Complex: R & L ventriular depolarization, Atrial repolarization

masked by QRS complexT Wave: Repolarization of right and left ventricles

Reading & Interpreting an ECGIsoelectric Line: Point of departure of the depolarizing and repolarizing actions of the heart.

Interval: Period of electrical activity within and between heartbeatsSegments: Periods of no recorded activity in the heart

ECG Leads

• Particular arrangement of the electrodes with respect to one another is called a lead.

• We will be using a 3-lead model– A positive, negative and ground electrode will be placed on the subject• + on left ankle• - on right wrist• Ground on right ankle

ECG Notes

• QRS complex generally dominant in any ECG recording– Affected by many factors: Body mass, fat mass,

height, cardiovascular health (large LV mass will change the look of the complex)

Large & Small Block Calculations

BioPac Lab

• Four conditions will be recorded: Supine, Seated, Breathing deeply, and After exercise.

Minimize EMG artifact and baseline drift: • Subject’s arms and legs must be relaxed. • Subject must remain still and should not talk

during any recordings. • Make sure electrodes do not peel up and that

the leads do not pull on the electrodes.

BioPac Lab• First condition: Supine, eyes closed, relaxed• Second condition: Stand up quickly, settle back

down into seated position• Third condition: Five (5) deep inhales/exhales with

recorder counting• Fourth condition: Exercise – 15 pushups or 15

jumping jacks. Mind the cables – may unclip if necessary…don’t forget to re-attach!

• Optional active learning portion not required• Call your TA when you have collected all data

Data Review

• After your data file has been transferred to your laptop, open it with your BioPac analysis software and begin analyzing your data

• Data & questions can be completed on your computer and emailed to your TA (due next week)

Heart Models

• While your group is waiting to work with the BioPac software please use this time to begin reviewing the heart models

• These same models will be used for your first long quiz

• Feel free to use online resources and this presentation

• Models will be available next week during our dissection lab as well

Cardiac Anatomy

Interatrial Septum

Interventricular Septum

Figure 18.4b

(b) Anterior view

Brachiocephalic trunk

Superior vena cavaRight pulmonaryarteryAscending aortaPulmonary trunkRight pulmonaryveins

Right atrium

Right coronary artery(in coronary sulcus)Anterior cardiac veinRight ventricle

Right marginal arterySmall cardiac veinInferior vena cava

Left common carotidarteryLeft subclavian artery

Ligamentum arteriosumLeft pulmonary arteryLeft pulmonary veins

Circumflex arteryLeft coronary artery(in coronary sulcus)Left ventricle

Great cardiac veinAnterior interventricularartery (in anteriorinterventricular sulcus)Apex

Aortic arch

Auricle ofleft atrium

Figure 18.4d

(d) Posterior surface view

Aorta

Left pulmonaryarteryLeft pulmonaryveinsAuricle of leftatriumLeft atrium

Great cardiacvein

Posterior veinof left ventricleLeft ventricle

Apex

Superior vena cava

Right pulmonary artery

Right pulmonary veins

Right atrium

Inferior vena cava

Right coronary artery(in coronary sulcus)

Coronary sinus

Posteriorinterventricularartery (in posteriorinterventricular sulcus)Middle cardiac veinRight ventricle

Figure 18.7a

Rightventricle

Rightcoronaryartery

Rightatrium

Rightmarginalartery

Posteriorinterventricularartery

Anteriorinterventricularartery

Circumflexartery

Leftcoronaryartery

Aorta

Anastomosis(junction ofvessels)

Leftventricle

Superiorvena cava

(a) The major coronary arteries

Left atrium

Pulmonarytrunk

Figure 18.7b

Superiorvena cava

Anteriorcardiacveins

Small cardiac vein

Middle cardiac vein

Greatcardiacvein

Coronarysinus

(b) The major cardiac veins

Figure 18.4e

Aorta

Left pulmonaryarteryLeft atriumLeft pulmonaryveinsMitral (bicuspid)valveAortic valve

Pulmonary valveLeft ventriclePapillary muscleInterventricularseptumEpicardiumMyocardiumEndocardium

(e) Frontal section

Superior vena cava

Right pulmonaryarteryPulmonary trunkRight atrium

Right pulmonaryveinsFossa ovalisPectinate muscles

Tricuspid valveRight ventricleChordae tendineae

Trabeculae carneae

Inferior vena cava

Figure 18.8a

Pulmonary valveAortic valveArea of cutaway

Mitral valveTricuspid valve

MyocardiumTricuspid(right atrioventricular)valveMitral(left atrioventricular)valveAorticvalve

Pulmonaryvalve

(b)

Pulmonary valveAortic valveArea of cutaway

Mitral valveTricuspid valve

MyocardiumTricuspid(right atrioventricular)valve

(a)

Mitral(left atrioventricular)valveAortic valvePulmonaryvalve

Fibrousskeleton

Anterior