Ischemic Heart disease

Ischemic Heart diseaseCauses and symptoms

1-Angina Stable Angina Unstable Angina Variant Angina decubitus angina nocturnal angina

2-Myocardial infarction STEMI NSTEMI

  

ischemic heart disease (IHD): is a disease characterized by  reduction blood supply of the heart muscle, usually due to coronary artery disease 

ischemic heart disease

Epidemiology • most common cause of cardiovascular morbidity and mortality

• atherosclerosis and thrombosis are the most important pathogenetic mechanisms.

• peak incidence of symptomatic IHD is age 50-60 (men)

and 60-70 (women) M>F

Etiology 1- Decreased coronary blood flow due to mechanical

obstruction such as: Atheroma Spasm of coronary artery Thrombosis Embolism Coronary artreritis

2- Increased myocardial oxygen requirement : Increased cardiac output :thyrotoxicosis Myocardial hypertrophy: aortic stenosis , hypertension

3- Decreased flow of oxygenated blood : anemia

Angina pectoris Is a clinical syndrome characterized by paroxysmal chest

pain due to transient myocardial ischemia . It may occur whenever there is imbalance between myocardial oxygen supply and demand the most common cause is atherosclerosis .however angina may also develop in aortic stenosis and hypertrophic cardiomyopathy even there is no coronary atheroma

Chest pain or discomfort is usually felt as:pressure,heaviness,tightening,squeezing,

Chest pain or discomfort Pain in your arms, neck,

jaw, shoulder or back accompanying chest pain

Nausea Fatigue Shortness of breath Anxiety Sweating Dizziness

Angina symptoms include:

Stable Angina Atherosclerotic coronary artery disease occurs when the heart has to work harder than normal, during

exercise typical: retrosternal chest pain, tightness or discomfort radiating to left(± right) shoulder/arm/ neck/jaw, brief duration, lasting <10-15 min associated with diaphoresis, nausea, anxiety typically relieved by rest and nitrates

Emotional stress Exertion Exposure to very hot or cold temperatures Eating ( Heavy meals) And Smoking

Variant AnginaA spasm in a coronary artery Usually happens when you're resting, unrelated to exercise, relieved by nitrates typically occurs between midnight and 8 AM,

The coronary arteries can spasm as a result of:Exposure to coldEmotional stressMedicines that tighten or narrow blood vesselsSmokingCocaine use

SYNDROME X Coronary microvascular disease that affects the heart’s

smallest coronary arteries.

Typical symptoms of angina but normal angiogram

May show definite signs of ischemia with exercise testing

Unstable Angina

Due to spasm and partial obstruction of coronaries. Occurs even at rest Is unexpected (new onset) Is usually more severe and lasts longer than stable angina,

may be as long as 30 minutes May not disappear with rest or use of angina medication May lead to complete occlusion of vessel causing MI

Myocardial Infarction Myocardial infarction, commonly known as a heart attack, is the irreversible

necrosis of heart muscle secondary to prolonged ischemia (total obstruction)

Typical symptoms of myocardial infarction include sudden chest pain, shortness of breath, nausea, vomiting, palpitations, sweating weakness, light-headedness Collapse/syncope

Severe pain described as a sensation of tightness, pressure,crushing or

squeezing. radiating to left(± right) shoulder/arm/ neck/jaw Chest pain usually lasts for more than 15 minutes Not relieves by rest

Ischemic Heart diseasePhysical examination

Physical examination & signs in angina:

•For most patients with stable angina, physical examination findings are normal. Diagnosing secondary causes of angina, such as aortic stenosis, is important.

•Vital signs especially blood pressure

•A positive Levine sign (characterized by the patient's fist clenched over the sternum when describing the discomfort) is suggestive of angina pectoris.

•Look for physical signs of abnormal lipid metabolism (eg, xanthelasma, xanthoma) or of diffuse atherosclerosis (eg, absence or diminished peripheral pulses, increased light reflexes or arteriovenous nicking upon ophthalmic examination, carotid bruit).

•Examination of patients during the angina attack may be more helpful. Useful physical findings include third and/or fourth heart sounds due to LV systolic and/or diastolic dysfunction and mitral regurgitation secondary to papillary muscle dysfunction.

•Pain produced by chest wall pressure is usually of chest wall origin.

Physical examination & signs in unstable angina and myocardial infarction

Abnormal physical findings are often absent; when present, they are often non-specific.

An unremarkable physical examination is not uncommon. Perform a quick assessment of patients' vital signs, and perform a cardiac examination.

Specific diagnoses that must be explicitly considered are the following:

•Aortic dissection

•Leaking or ruptured thoracic aneurysm

•Pericarditis with tamponade

•Pulmonary embolism

•Pneumothorax

Unstable angina differs from stable angina in that the discomfort is usually more intense and easily provoked, and ST-segment depression or elevation on ECG may occur.

Otherwise, the manifestations of unstable angina are similar to those of other conditions of myocardial ischemia, such as chronic stable angina and myocardial infarction.

Increased autonomic activity may manifest as diaphoresis or tachycardia, and bradycardia may result from vagal stimulation from inferior wall myocardial ischemia.

A large area of myocardial jeopardy may manifest as signs of transient myocardial dysfunction and typically signifies a higher-risk situation. Signs include the following:

•Systolic blood pressure less than 100 mm Hg or overt hypotension

•Elevated jugular venous pressure

•Dyskinetic apex

•Reverse splitting of the second heart sound

•Presence of a third or fourth heart sound

•New or worsening apical systolic murmur due to papillary muscle dysfunction

•Rales or crackles

Vital signs and appearance are two of the most important aspects of the physical exam.

Vital Signs In the evaluation of a patient presenting with ACS hypotension (systolic blood pressure <100 mm Hg), tachycardia (pulse >100) and bradycardia (pulse <60 bpm) indicate that a patient is at higher risk.

As with the assessment of all patients, other abnormal vital signs such as hypoxia, tachypnea (RR >19), hypothermia (T <95 F) or fever (T >100.3 F) should raise concern, although they are not specifically suggestive of ACS.

If aortic dissection is considered in the differential diagnosis, blood pressure should be checked in both arms (>20 mm Hg differential is suggestive of aortic dissection).

Appearance of the Patient A patient who appears anxious, diaphoretic, with pale skin and who is in obvious respiratory distress should demand immediate attention.

Eyes The eye exam is typically not the focus of a physical exam for ACS, however, details such as pale conjunctiva (suggestive of anemia), exopthalmos (suggestive of hyperthyroidism), or cotton-wool spots (suggestive of hypertension), or retinopathy (suggestive of diabetes) on fundoscopic exam should be noted as they may allow for the identification of potential precipitants of or risk factors for myocardial ischemia.

Ear Nose and Throat The ears and nose are typically not the focus of a physical exam for ACS.

However, the examination of the buccal mucosa can help to determine a patient's volume status, as can the examination of the right internal jugular vein pulsations (JVP).

A JVP which is elevated greater than 4 cm above the sternal angle (9 cm above the right atrium) is considered elevated and reflects elevated right atrial pressure.

Heart The cardiac exam should evaluate for signs of cardiac failure, such as a 3rd heart sound ("gallop," from early diastolic filling from left ventricular systolic failure), a 4th heart sound ("gallop," from late diastolic filling from a stiff left ventricle, as from diastolic heart failure) or a new / increased systolic murmur of mitral regurgitation (as from papillary muscle rupture).

The presence of a pericardial rub would suggest pericarditis instead of ACS.

Lungs Bibasilar rales are suggestive of congestive heart failure and pulmonary edema. However, the absence of adventitious lung sounds does not preclude diastolic heart failure.

Abdomen The abdominal exam is typically not the focus of a physical exam for ACS. However, a finding of a expansile, pulsatile mass in the upper abdomen suggests an aortic aneurysm and requires further urgent evaluation.

Extremities Assess the lower extremities for edema, suggestive of heart failure. It is also important to palpate the radial, femoral and pedal pulses. Unequal radial pulses are suggestive of aortic dissection. Weak pedal pulses are suggestive of peripheral vascular disease. Femoral pulses are important to document in the event that cardiac catheterization is necessary.

Neurologic The neurological examination is typically not the focus of a physical exam for ACS. However, mental status at the time of the initial assessment should be documented for future reference, should the patient's mental status deteriorate during the period of observation.

Also, headache in the context of chest pain and severe hypertension (i.e., SBP > 210 mm/Hg or a DBP > 120 mm/Hg) would support a diagnosis of hypertensive emergency as a cause for ACS.

Ischemic Heart diseaseInvestigation

1-ECG Differential diagnosis of ST segment depression Myocardial Ischemia LVH Severe hypertension Cardiomyopathy Anemia Hypokalemia Digitalis effect

Differential diagnosis of ST segment elevation

Myocardial infarction Prinzmetal’s angina Ventricular aneurysm (post MI ) Acute pericarditis Myocarditis Hypothermia

2-Exercise Tolerance Test (ETT)

This is the most useful noninvasive procedure for evaluation the patient with angina. Ischemia that is not present at rest is detected by precipitation of typical chest pain or ST segment elevation during the exercise using treadmill

When history is suggestive of angina pectoris but ECG is normal , then the exercise test should be done.

The test involves recording the 12-lead ECG before , during and after exercise.

The test consists of a standardized incremental increase in the external workload while the patient’s ECG, symptoms and the blood pressure are continuously monitored. A variety of exercise protocols are utilized, the most common being the Bruce protocol which increases the treadmill speed and elevation every 3 mins until limited by symptoms.

This test discovers any limitation in exercise performance and establishes the relationship between chest pain and the typical ECG sings of myocardial ischemia.

Positive test is one which ST segment is depressed by 1mm(one small square )

More severe disease presents with ST depression more 2 mm at low workload or at heart rate less than 70% of age predicted value, or hypotension develops during exercise.

ETT Report:

Degree of ST depression Development of arrhythmia or conduction defect

during and post exercise. Duration of exercise. Achievement of age predicted target heart rate ( 220

minus age ) Development of chest pain during exercise. Hemodynamic response  

Indications:

To confirm the diagnosis of angina To determine the severity of limitation of activity

due to angina To asses prognosis in patient with known coronary

disease. To evaluate response to therapy.

Contraindications:

Acute myocardial infarction ( less 2 days ) High risk unstable angina Decompensated HF Cardiac arrythmias with symptoms Heart block Acute myocarditis and pericarditis Severe aortic stenosis Severe HOCM Uncontrolled HTN

Interpretation:

Overall sensitivity of ETT is about 60-75% and specificity 80%. The test may be falsely + or – in 15% of cases therefore negative test does not rule out IHD and positive test without symptoms does not always confirm IHD. If ERR is inconclusive then IHD should be confirmed by thallium scan. ECHO and angiography.

Echocardiograph

It reveals segmental wall motion abnormalities which indicate ischemia or prior infarction. It can be performed at rest while sensitivity increase if performed after exercise or stress given by dobutamine (called dobutamine stress echo)

Isotope scanning

Thallium scan and technetium scan shows areas of reduced uptake of radioactive isotope (thallium and technetium) by the myocardium. This test is performed at rest and during stress (produced by exercise or dipyridamol or dobutamine)

A perfusion defect present during stress but not all rest indicates reversible myocardial ischemia, whereas a persistent perfusion defect on scan during both phases (rest and stress) usually indicates previous myocardial infarction.

Thallium scanning is positive in 75-90% of patients with significant coronary disease. False positive test may occur in women due to breast tissue.

Indication:

When ETT is not diagnostic (equivocal or contrary to the clinical impression such as positive test in asymptomatic patient).

When patient is unable to perform exercise e.g. patient of unstable angina, aortic stenosis or handicapped patients. In these patients stress is produced by alternatives methods such as drugs e.g. dipyridamol dobutamine or adenosine

To distinguish ischemia from myocardial infarction. To localize regions of ischemia. To identify whether the myocardium is viable or not, because

revascularization via surgery or angioplasty may be beneficial only for viable myocardium.

Coronary angiograph

Coronary angiography visualizes the location and severity of coronary after stenosis. Narrowing greater than 50% of luminal diameter is considered clinically significant, although most lesion producing ischemia are associated with narrowing more than 70%.

 

Indication:

Coronary angiograph is indicated in patient whom coronary revascularization (angioplasty or by-pass) is being considered because of uncontrolled stable angina who have failed to improve on adequate medical regimen

To diagnose chest pain of uncertain cause when noninvasive tests have failed to detect the cause. Diagnostic angiography is now rarely performed because diagnosis is usually made on history and non-invasive tests.

Unstable angina Post myocardial infarction angina Severe left ventricle dysfunction after MI Non Q-wave MI Strongly positive ETT