Atria are the superficial chambers of the heart • Right atrium receive blood from systemic circulation through inferior and superior vena cava • Left atria receive from pulmonary circulation (lungs) through pulmonary veins • Atrial kick: Contraction of atria to push the remaining blood into the ventricles. 70% of the blood flow passively into the ventricles.

Cardiomyopathy Definition This is a disease of the heart muscle: - Cardio (heart),Myo (muscle), and Pathy (pathology) the myocardial heart muscle is affected. Cardiomyopathies are categorized as (extrinsic)- caused by external factors such as hypertension, ischemia, inflammation,\ and valvular dysfunction or as (intrinsic ) corresponding to myocardial diseases without identifiable external causes . Cardiomyopathy may be primary or secondary

Heart Surgery- A surgery in which the chest wall is surgically opened and heart is exposed. Surgery can be performed on the heart muscles, valves and the great arteries. This can be done through open, or closed heart surgery

Case scenario Mr. Zee aged 69 years was being observed at the A/E dept with c/o coughing, dizziness/fainting, dyspnea, palpitation, indigestion, haziness. Recently, he had a syncope episode at the work place and was treated and discharged on medication. He says sometimes he gets both chest pains and abdominal pains with associated indigestion

The electrocardiogram is the graphical representation of the electrical activity of the heart • It records the electrical activity of atrial ventricular cells in form of specific waveforms and complexes. • The first ECG was introduced by Willem Einthoven, a Dutch physiologist, in the early 1900s • ECG is an important diagnostic method in cardiac conditions.

Indications For ECG Monitoring Indicated for:- • To monitor a patient’s heart rate and rhythm • Evaluate the effects of disease or injury on heart function • Evaluate pacemaker function • Evaluate the response to medications • Obtain a baseline recording before, during, and after a medical procedure

The (AVN) Atrial Ventricular Node is a group of specialized cells located in the lower part of the right atrium above the tricuspid valve base. Its function is to Delay, Relay and Filter impulses as they pass through the Ventricles. The nodal cells have pacemaker properties and can pace the heart at a rate of 40-60b/min. Rhythms coming from the AV junction are called .Junctional dysrhythmias. The electrical impulse must travel backward ( Retrograde) to activate the atria.

A normal heartbeat results from an electrical impulse that originates from the hearts primary pace maker-(SA node) • The Normal sinus rhythm records the hearts electrical impulse that starts in the SAN spreading through the normal conduction pathway. • The SAN dominates other areas that may pace the heart slower and abnormally. All other rhythms will be compared to the Normal Sinus Rhythm

The ventricles (purkinje fibres) may assume the function of pacing the heart, they pace at a slower rate 20-40b/min which cannot sustain the body's perfusion requirements. Rhythms originating from the ventricles are called ventricular arrhythmias because they originate in the ventricles. Ventricular arrhythmias occur when:- a) The SAN fails to initiate an impulse b) The AVN does not pick to pace c) There is an irritable foci in the ventricular muscle

Sickle cell disease (SCD) • A group of hereditary disorders in which the normal adult hemoglobin (hemoglobin A) is partly or completely replaced by abnormal sickle hemoglobin (HgbS). • The most common genetic hematologic condition in children • Transmitted by autosomal recessive pattern of inheritance. • Patient with this condition is homozygous for the sickle cell gene, i.e. both genes are abnormal. • The basic defect responsible for the sickling of erythrocytes is contained in the globin fraction of hemoglobin • The mode of transmission is hereditary • The gene that determines the production of HgbS is situated on an autosome.