Angina and Myocardial Infarction Quiz

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Questions and Answers

Which type of angina is characterized by an imbalance in coronary perfusion relative to myocardial demand?

Prinzmetal's variant angina

Stable angina (correct)

Crescendo angina

Unstable angina

What is the primary cause of unstable angina?

Chronic hypertension

Fissuring of atherosclerotic plaque (correct)

Myocardial hypertrophy

Coronary artery spasm

What distinguishes Prinzmetal's variant angina from other types of angina?

It causes immediate myocardial infarction.

It is related to coronary artery spasm. (correct)

It occurs only during physical exertion.

It is always relieved by rest.

Which symptom is NOT typical of stable angina?

Occurs predominantly at rest Signup and view all the answers

What is the typical duration of pain associated with unstable angina?

More than 20 minutes Signup and view all the answers

What percentage of myocardial infarctions occur in individuals younger than age 40?

10% Signup and view all the answers

Which statement is true regarding myocardial infarction?

It is caused by prolonged severe ischemia. Signup and view all the answers

Which type of angina can occur without any relationship to physical activity?

Variant angina Signup and view all the answers

What best describes the primary characteristic of diastolic heart failure?

Myocardial wall thickening without relaxation Signup and view all the answers

Which mechanism is NOT a response to maintain arterial pressure in heart failure?

Decreased peripheral vascular resistance Signup and view all the answers

What is the most common underlying etiology of diastolic heart failure?

Systemic hypertension Signup and view all the answers

Which disorder is most closely associated with systolic heart failure?

Dilated cardiomyopathy Signup and view all the answers

Which symptom is primarily associated with left-sided heart failure?

Rapid onset pulmonary edema Signup and view all the answers

In which patient demographic is diastolic failure more commonly observed?

Patients aged 65 years and older Signup and view all the answers

Which of the following is NOT a typical result of decreased left ventricular output?

Improved oxygenation of tissues Signup and view all the answers

Which adaptive response to heart failure involves a mechanism to enhance contractility?

Increased preload through volume expansion Signup and view all the answers

What is the primary cause of ischemic heart disease (IHD) in over 90% of cases?

Coronary atherosclerosis resulting in fixed obstruction Signup and view all the answers

Which of the following is not considered a non-atherosclerotic cause of ischemic heart disease?

Coronary atherosclerosis Signup and view all the answers

What characterizes angina pectoris in patients experiencing ischemic heart disease?

Recurrent attacks of substernal chest discomfort Signup and view all the answers

Which condition is included in the definition of acute coronary syndromes?

Unstable angina Signup and view all the answers

Which of the following describes the typical duration of pain associated with angina pectoris?

15 seconds to 15 minutes Signup and view all the answers

What typically triggers the onset of angina pectoris?

Transient myocardial ischemia during high myocardial demand Signup and view all the answers

What is the most likely outcome of untreated severe stenosis in a coronary artery during physical exertion?

Sudden cardiac death due to occlusion Signup and view all the answers

In ischemic heart disease, which of the following changes can result from acute plaque change?

Rupture and exposure of thrombogenic substances Signup and view all the answers

Which condition is primarily responsible for left ventricular hypertrophy due to increased pressure?

Aortic stenosis Signup and view all the answers

What is a common result of volume overload in the heart chambers?

Cardiac dilatation Signup and view all the answers

Which of the following statements is incorrect regarding the causes of right ventricular hypertrophy?

Systemic hypertension directly causes right ventricular hypertrophy. Signup and view all the answers

What characterizes concentric hypertrophy of the left ventricle?

Normal or reduced cavity diameter with increased wall thickness Signup and view all the answers

Which condition is least likely to cause cardiac dilatation?

Systemic hypertension Signup and view all the answers

Congenital heart disease may present in which of the following forms?

Both shunts and obstructive defects Signup and view all the answers

Which of the following is a potential cause of left ventricular dilatation?

Mitral insufficiency Signup and view all the answers

In which group is the incidence of congenital heart disease typically higher?

Newborn children Signup and view all the answers

What is the most common cause of a myocardial infarction?

Coronary artery atheromatous plaque rupture Signup and view all the answers

In which infarct does the plaque primarily affect the anterior part of the left ventricle?

Left anterior descending coronary artery infarct Signup and view all the answers

Which type of myocardial infarct is most frequently encountered?

Full-thickness or transmural infarct Signup and view all the answers

What characteristic defines subendocardial or laminar infarcts?

They can occur without critical coronary stenosis. Signup and view all the answers

Which coronary artery stenosis is associated with infarction of the posterior part of the left ventricle?

Right coronary artery Signup and view all the answers

What physiological process initiates thrombosis during myocardial infarction?

Platelet aggregation upon collagen exposure Signup and view all the answers

What is the primary cause of circumferential subendocardial infarction?

General hypoperfusion due to modest hypotension Signup and view all the answers

Which coronary artery stenosis is least commonly responsible for myocardial infarction?

Left circumflex coronary artery Signup and view all the answers

What is a common long-term complication following a myocardial infarction?

Chronic intractable left-heart failure Signup and view all the answers

Which condition is highlighted as a risk factor for recurrent myocardial infarction?

Coronary artery insufficiency Signup and view all the answers

In chronic ischaemic heart disease, what is primarily responsible for myocardial damage?

Coronary atherosclerosis Signup and view all the answers

What form of pericarditis is associated with Dressler's syndrome?

Immune-mediated pericarditis Signup and view all the answers

What is a significant pathological feature in chronic ischaemic heart disease?

Focal or diffuse myocardial fibrosis Signup and view all the answers

Sudden cardiac death occurs primarily within what time frame after cardiac symptoms begin?

24 hours Signup and view all the answers

Which mechanism is most commonly responsible for sudden cardiac death due to myocardial ischemia?

Fatal arrhythmias Signup and view all the answers

What kind of myocardial change may be present in chronic ischaemic heart disease?

Variation in fiber size and myocytolysis Signup and view all the answers

Study Notes

Heart Anatomy and Physiology

Adult male heart average weight: 300-350 grams
Adult female heart average weight: 250-300 grams
Right ventricle wall thickness: 0.3-0.5 cm
Left ventricle wall thickness: 1.3-1.5 cm
Heart wall primarily composed of myocardium
Myocardium covered externally by epicardium (visceral pericardium)
Myocardium lined internally by endocardium
Cardiac valves regulate blood transport
Two atrioventricular valves: tricuspid (right) and mitral (bicuspid) (left)
Two semilunar valves: pulmonary and aortic

Myocardial Blood Supply

Anterior descending branch (LAD) of left coronary artery supplies most of the apex, anterior surface of the left ventricle, adjacent third of anterior wall of the right ventricle, and anterior two-thirds of the interventricular septum.
Circumflex branch (LCX) of the left coronary artery supplies the left atrium and a small portion of the lateral aspect of the left ventricle.
Right coronary artery (RCA) supplies the right atrium, remainder of the anterior surface of the right ventricle, adjacent half of the posterior wall of the left ventricle, and posterior third of the interventricular septum.

The Conduction System

Sinoatrial (SA) node pacemaker located at the junction of the right atrial appendage and superior vena cava.
Atrioventricular (AV) node located in the right atrium along the atrial septum.
Bundle of His connects the right atrium to the ventricular septum.
Subsequent divisions into right and left bundle branches.
Further arborization into the Purkinje network.

Changes in the Aging Heart

Increased left atrial cavity size
Decreased left ventricular cavity size
Sigmoid-shaped ventricular septum
Aortic valve calcific deposits
Mitral valve annular calcific deposits
Fibrous thickening of leaflets
Buckling of mitral leaflets toward the left atrium
Lambl excrescences
Epicardial coronary arteries showing tortuosity
Decreased compliance in epicardial coronary arteries
Calcific deposits in epicardial coronary arteries
Atherosclerosis of epicardial coronary arteries
Decreased Myocardial mass
Increased subepicardial fat
Brown atrophy
Lipofuscin deposition
Basophilic degeneration of myocardium
Amyloid deposits
Dilated Ascending aorta with rightward shift
Elongated thoracic aorta
Sinotubular junction calcific deposits
Elastic fragmentation and collagen accumulation
Atherosclerosis in the aorta

Heart Failure

Impaired cardiac function unable to maintain adequate tissue metabolic needs.
Can be acute or chronic
Congestive heart failure (CHF) is the chronic form involving peripheral and lung congestion and edema.

Heart Failure: Adaptive Responses

Frank-Starling mechanism: Increased preload enhances contractility
Myocardial hypertrophy with or without chamber dilatation
Activation of neurohormonal systems (norepinephrine, renin-angiotensin-aldosterone axis, and atrial natriuretic factor).

Heart Failure: Systolic Failure

Insufficient ejection fraction (pump failure)
Caused by various disorders damaging or deranging left ventricle contractile function.
Commonly occurs in IHD, pressure or volume overload, dilated cardiomyopathy.

Heart Failure: Diastolic Failure

Left ventricle abnormally stiff and cannot relax during diastole.
Although cardiac function is preserved at rest, heart is unable to increase output in response to metabolic demand
More common in patients over 65 and women.
Hypertension is the most common cause; also diabetes, obesity, bilateral renal artery stenosis, massive LV hypertrophy, myocardial fibrosis.

Left-sided Heart Failure

Systemic hypertension
Mitral or aortic valve disease (stenosis)
Ischemic heart disease
Myocardial diseases (cardiomyopathies, myocarditis)
Restrictive pericarditis
Pulmonary congestion and edema causing dyspnea and orthopnea.
Decreased left ventricular output causing hypoperfusion and diminished oxygenation of tissues, leading to ischemic acute tubular necrosis, hypoxic encephalopathy,muscular weakness and fatigue in multiple organ systems.

Left-sided Heart Failure: Morphology

Hypertrophied often dilated left ventricle with secondary enlargement of left atrium that can lead to fibrillation.
Enlarged BOXCAR nuclei
Pulmonary congestion and edema (perivascular and interstitial transudate).
Accumulation of edema fluid in alveolar spaces with hemosiderin-laden macrophages (heart failure cells).
Dyspnea, orthopnea, and paroxysmal nocturnal dyspnea.
Low cardiac output reduces renal perfusion, activating the renin-angiotensin-aldosterone system and increasing salt and water retention.
Atrial dilation and release of natriuretic peptide.
Hypoxic encephalopathy in the brain.

Right-sided Heart Failure

Consequence of left ventricular failure; also intrinsic lung diseases, pulmonary or tricuspid valvular disease, pulmonary hypertension secondary to pulmonary thromboembolism, myocardial disease affecting the right heart and congenital heart disease with left-to-right shunt.
Systemic congestion in various tissues (subcutaneous oedema, passive congestion of liver, spleen, kidneys, ascites, hydrothorax, congestion of leg and neck veins)
Reduced cardiac output causing circulatory stagnation leading to anoxia, cyanosis, and extremities coldness.

Right-sided Heart Failure: Morphology

Congestive hepatomegaly (liver increased in size and weight): chronic passive congestion of cut surfaces
Centrilobular necrosis is a common condition in coexisting left sided failure and hypoxia
Cardiac sclerosis or cirrhosis in severe cases
Congestive splenomegaly
Ascitis
Kidney congestion, peripheral edema, azotemia
Venous congestion and hypoxia (CNS)
Pleural and pericardial effusions

Cardiac Hypertrophy

Increased size and weight of the myocardium.
Results from increased pressure load (e.g., valvular incompetence) or increased volume load.
Left ventricular hypertrophy: systemic hypertension, aortic stenosis/insufficiency, mitral insufficiency, coarctation of the aorta, occlusive coronary artery disease, congenital anomalies (septal defects, patent ductus arteriosus), conditions with increased cardiac output (thyrotoxicosis, anemia, arteriovenous fistula).
Right ventricular hypertrophy: pulmonary stenosis/insufficiency, tricuspid insufficiency, chronic lung diseases (emphysema, bronchiectasis, pneumoconiosis, pulmonary vascular disease), left ventricular hypertrophy and failure of the left ventricle

Cardiac Hypertrophy: Types

Pressure (concentric): Increased wall thickness, normal or reduced cavity diameter (e.g., hypertension or aortic stenosis).
Volume-overloaded: Dilatation and increased cavity diameter (e.g., mitral or aortic regurgitation).

Congenital Heart Disease

Abnormalities present from birth; commonly seen in premature infants.
Includes shunts (left-to-right or right-to-left), or defects causing obstructions to flow; complex combinations are also present
Examples include dextrocardia.
Table of frequencies of congenital cardiac malformations

Left-to-Right Shunts

Blood shunted from left to right side producing volume overload on right heart with increased pulmonary hypertension and RV hypertrophy
Common examples: ASD, VSD, PDA
Early disease: no cyanosis
Late disease: cyanosis
Pulmonary hypertension can lead to reverse blood flow (Eisenmenger Syndrome)
Mutation of TF TBX5 (ASD, VSD), mutation of TF NKX2.5(isolated ASD)

Atrial Septal Defect(ASD)

Isolated ASDs are about 10% of congenital heart diseases.
Three types of ASD depending on defect location: i) Fossa ovalis type, ii) Ostium primum type, iii) Sinus venosus type
Effects include volume hypertrophy of right atrium and ventricle and enlargement/changes in valves

Ventricular Septal Defect(VSD)

Most common congenital anomaly (about 30% of all congenital heart diseases).
Depending on location, VSDs may involve membranous septum (90%).
Reversal of the shunt (cyanosis) may be more common and earlier in VSD compared to ASDs
Volume hypertrophy of the right ventricle
Enlargement with changes in tricuspid and pulmonary valves.
Endocardial hypertrophy of the right ventricle, pressure hypertrophy of the right atrium, volume hypertrophy of the left atrium and left ventricle, and enlargement and haemodynamic changes in the mitral and aortic valves.

Patent Ductus Arteriosus(PDA)

Ductus arteriosus normally closes within first two days of life; its persistence after 3 months is abnormal.
Usually isolated, but can be associated with other anomalies (VSD, coarctation of aorta, pulmonary or aortic stenosis).
Volume hypertrophy of left atrium and ventricle
Enlargement of hemodynamic changes in mitral and pulmonary valves
Enlargement of the ascending aorta
High-pressure left-to-right shunt (machinery murmur).

Right-to-Left Shunts

Poorly oxygenated blood enters the systemic circulation leading to early cyanosis
Common examples: Tetralogy of Fallot, Transposition of great vessels

Tetralogy of Fallot

Common cyanotic congenital heart disease found in about 10% of children.
Four features: i) Ventricular septal defect (VSD), ii) Displacement of aorta to the right, overriding the VSD, iii) Pulmonary stenosis (obstruction), iv) Right ventricular hypertrophy, v) Right ventricular outflow obstruction.
Clinical severity depends on the degree of pulmonary outflow obstruction.
Boot-shaped heart, squatting posture increases PVR to decrease right-to-left shunt across VSD.

Transposition of Great Arteries

Complex malformations concerning the position of aorta, pulmonary trunk, atrioventricular orifices and atria to ventricles.
Incompatible with postnatal life in pure complete form
35% with VSD
Patent foramen ovale or PDA is 65%.

Obstructive Congenital Heart Disease

Congenital obstruction to blood flow.
Due to narrowing (coarctation of aorta), obstruction to outflow from the left ventricle (aortic stenosis and atresia), and obstruction to outflow from the right ventricle (pulmonary stenosis and atresia).

Coarctation of Aorta

Contracted or compressed portion (narrowing) of aorta
Localized narrowing in part of aorta but more commonly just distal to ductus arteriosus: post ductal, (adult form)
In 50% accompanied by bicuspid aortic valve
May have infants or babies.
Coarctation can also affect the infantile type or pre-ductal form of transverse aorta
Females tend to be affected more often than males.
Causes: Turner Syndrome
Symptoms: upper extremity HT (poor renal perfusion), Low pressure in lower extremities, collateral enlargement of intercostal and mammary arteries, (notching of the ribs), weak femoral pulses.

Ischemic Heart Disease (IHD)

Acute or chronic cardiac disability due to imbalance between myocardial supply and demand for oxygenated blood.
Primarily due to coronary artery disease, mostly atherosclerosis (over 90% cases).
Leading cause of death in males and females in industrialized nations.
Non-atherosclerotic causes (vasospasm, stenosis of coronary ostia, arteritis, etc.)
Clinical presentations: asymptomatic state, angina pectoris, acute myocardial infarction (MI), chronic ischemic heart disease (CIHD), myocardial fibrosis, Sudden cardiac death.

Stable or Typical Angina

Most common form; caused by chronic stenosing coronary atherosclerosis
Characterized by pain following physical exertion or emotional stress; relieved by rest.

Unstable or Crescendo Angina

Most severe form; often an indicator of impending MI.
Characterized by more frequent episodes, prolonged duration, and pain occurring at rest.

Prinzmetal's Variant Angina

Uncommon; caused by coronary artery spasm
Characterized by pain at rest unrelated to physical activity; often precipitated by coronary atherosclerosis/humoral vasoconstricors.

Myocardial Infarction (MI)

Death of cardiac muscle due to prolonged severe ischemia (often leading to "heart attack").
Can occur at any age, but 10% in those younger than 40 and 45% in those younger than 65.
MI pathogenesis is due to coronary artery occlusion, plaque disruption triggers Thrombus formation and Vasospasm
Leads to various sequelae, and complications.
Time intervals for various microvascular changes.
Clinical features for diagnosis: Pain, indigestion, apprehension, shock, oliguria, low-grade fever, acute pulmonary edema
ECG changes: ST-segment elevation in STEMI (most characteristic), other changes like T wave inversion, wide deep Q waves
Cardiac markers: Proteins and enzymes (CK, CK-MB, Troponin I, myoglobin) released into blood from necrotic heart muscle, measurements helpful in diagnosis and management.
Location of infarcts: left anterior descending, right coronary, left circumflex arteries (stenosis).

Complications of Myocardial Infarction (Short-Term)

Cardiac dysrhythmias (ventricular fibrillation, bradyarrhythmias, particularly with posterior infarcts).
Left ventricular failure.
Rupture of ventricular wall, septum.
Papillary muscle dysfunction.
Mural thrombus formation (can embolize).

Complications of Myocardial Infarction (Long-Term)

Chronic intractable left-heart failure.
Ventricular aneurysm formation
Recurrent myocardial infarction.
Dressler's syndrome (immune-mediated pericarditis).

Chronic Ischemic Heart Disease

Ischemic cardiomyopathy, myocardial fibrosis are the terms used for focal or diffuse fibrosis in myocardium characteristically found in elderly patients with progressive IHD.
Gradual development of CHF through decompensation over several years.
Coronary atherosclerosis, emboli, coronary arteritis, and myocarditis are contributing causes

Chronic Ischemic Heart Disease: Morphology

The heart may be normal in size or hypertrophied
Left ventricular wall shows foci of grey-white fibrosis in brown myocardium.
Scattered areas of diffuse myocardial fibrosis, especially around small blood vessels.
Intervening single fibres and groups of myocardial fibres showing variation in fibre size and foci of myocytolysis

Sudden Cardiac Death

Defined as death within 24 hours of cardiac symptoms onset.
Coronary atherosclerosis is the most common cause.
Mechanisms: fatal arrhythmias (ventricular asystole, fibrillation), critical coronary narrowing, superimposed thrombosis or plaque hemorrhage.

Cor Pulmonale

Pulmonary parenchymal or vascular disease, pulmonary hypertension, disease of right-sided cardiac chambers
Acute: Mostly PE (pulmonary embolism), RV (right ventricle) dilatation
Chronic: Mostly COPD (chronic obstructive pulmonary disease), RV hypertrophy then dilatation.

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Test your knowledge on various types of angina and myocardial infarctions in this informative quiz. Understand the differences between stable, unstable, and Prinzmetal's angina, as well as the typical symptoms and causes associated with them. Perfect for medical students and health professionals!