Pathological Conditions: The Heart and Blood Vessels



Pathological Conditions: The Heart and Blood Vessels

Medical Terminology

Arrhythmias: Abnormal heart rhythms

Types of arrhythmias:

1. Heart block or atrioventricular block:

* Failure of proper conduction of impulses through the AV node to the

Bundle of His.

• Damage to SA node can cause impulses to be too weak to activate AV node which means that impulses fail to reach ventricles

• If failure occurs only occasionally causing heart to miss beat at regular intervals – partial heart block

• No impulses reach AV node from SA node means ventricles contract slower than the atria and are not coordinated – complete heart block

• RX: cardiac pacemaker – establish normal rhythm.

2. Flutter

• Rapid but regular contractions of atria or ventricles

• Heart rhythm may reach up to 300 beats per minute (BPM)

3. Fibrillation

• Rapid, random, ineffectual, and irregular contractions of the heart; 350 bpm or more

• Atrial fibrillation: wave of excitation passes through atrial myocardium more quickly than in atrial flutter.

• Defibrillator is used to reverse abnormal rhythm; aka cardioversion

• Automatic Implantable Cardioverter/Defibrillator (AICD) – implanted into chest wall to sense arrhythmias and correct them

• Radiofrequency catheter ablation (RFA): nonsurgical treatment used to treat arrhythmias; catheter placed in blood vessels leading up against heart muscle , delivers a high-frequency current to burn a small portion of muscle, aka ablation

4. Cardiac Arrest

• Sudden and often unexpected stoppage of heart movement

5. Palpitations

• uncomfortable sensations in chest associated with different types of arrhythmias

• Not necessarily indicate serious

• Two causes: premature ventricular contractions (PVCs), premature atrial contractions (PACs)

Congential Heart Disease: Abnormalities in heart at birth

1. Coarctation of the aorta (CoA) – Narrowing (coarctation) of aorta

2. Patent Ductus Arteriosus (PDA) – Small duct between aorta nad pulomonary artery which normally closes soon after birth, remains open

• Oxygenated blood flows from aorta to pulmonary artery

3. Septal Defects – Small holes in speta between atria (atrial septal defects ASDs), or ventricles (ventricular septal defects VSDs)

• Many septal defects will close spontaneously and others will require surgery

4. Tetralogy of Fallot – Congenital malformation of heart involving four distinct defects as follows:

• Pulmonary artery stenosis – Blood is not adequately passed to lungs for oxygenation

• Ventricular Septal Defect – Gap in septum allows deoxygenated blood to pass info left ventricle and from there to aorta

• Shift of aorta to right – oxygen-poor blood passes more easily from right ventricle to aorta

• Hypertorphy of right ventricle – myocardium works harder to pump blood through narrowed pulmonary artery

Congestive Heart Failure: Heart is unable to pump its required amount of blood as more blood enters heart from veins than leaves through arteries

Coronary Artery Disease: Dz of arteries surrounding the heart

• Three large vessels that arise from aorta and supply oxygenated blood to heart

• Artherosclerosis: deposition of fatty compounds on inner lining of coronary arteries

• Narrowing causes inflexibility and plugging up of vessel; roughened lining of artery may rupture or cause thrombotic occlusion

• Blood flow decreased = ischemia leading to necrosis; Area of dead myocardial tissue is infarction

• Angina pectoris – temporary difference between supply and demand of oxygen to heart muscle

• Rx – CABG

• Percutaneous transluminal coronary angioplasty (PTCA) – catherterization with balloons and stents

• Transmyocardial laser revascularization (TMLR) – laser makes holes in heart muscle to induce growth of new blood vessels

Endocarditis – Inflammation of inner lining of heart caused by bacteria; Rx. with antibiotics

Hypertensive Heart Disease – High blood pressure affecting the heart

• Caused by contraction of arterioles leading to increased pressure in arteries

• Heart has to pump more vigorously to overcome increased resistance in arteries

• Vessels lose elasticity, become like solid pipes and place increased burden on heart to pump blood thru body

Mitral Valve Prolapse (MVP) – Improper closure of mitral valve when heart is pumping blood

*Antibiotics are given at time of dental procedures to prevent valve from becoming infected.

Murmur – extra heart sound heard between normal beats

Pericarditis – Inflammation of membrane surrounding heart

• Caused by virus, bacteria, or idiopathic

• May need pericardiocentesis to remove excess fluid

Rheumatic Heart Disease – Heart disease caused by rheumatic fever

• Rheumatic fever – occurs usually in childhood, can follow a few weeks after a streptococcal infection

• Damages heart valves (esp. mitral valve); become inflamed and scarred

BLOOD VESSELS

Aneurysm – Ballooning out of artery caused by weakness in arterial wall or breakdown of wall due to atherosclerosis

• Danger is rupture

• Rx. Depends on location of vessel

• Small vessels in brain – occlusion of vessel with small clips

• Larger arteries – resection of vessel with synthetic graft

Peripheral vascular disease – blockage of blood vessels in lower extremities due to atherosclerosis

• Arteries in groin or upper leg narrow or become blocked, blood flow to lower leg and foot is reduced

Raynaud Phenomenon – Short episodes of pallor and numbness in fingers and toes due to temporary constriction of arterioles in skin

• Idiopathic but may be secondary to cold temperatures, emotional stress, ro cigarette smoking

Varicose Veins – Abnormally swollen and twisted veins, usually occurring in legs

• Due to damaged valves that fail to prevent backflow of blood

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