Hypertrophic cardiomyopathy (HCM) is a genetic heart disease inherited in an autosomal dominant manner. It is caused by gene mutations that encode proteins involved in the contractile machinery of the heart. These mutations lead to the development of thickened walls in the left ventricle, which is the heart’s main pumping chamber.
This thickening of the ventricle walls, also known as hypertrophy, can cause several problems for the heart. One of the main issues is the obstruction of blood flow out of the heart. This can cause various symptoms, including shortness of breath, chest pain, fatigue, and dizziness. Another problem with HCM is diastolic dysfunction when the heart has difficulty relaxing and filling with blood during the resting phase of the heartbeat cycle.
This can lead to heart failure, which is when the heart cannot pump blood effectively throughout the body. In addition, people with HCM may be at an increased risk of developing myocardial ischemia when the heart muscle does not get enough oxygen and nutrients due to a reduced blood supply. This can cause chest pain and other symptoms.
Epidemiology
The prevalence of HCM in the general population worldwide is estimated to be around 0.2%, which translates to one in every 500 adults. This figure is based on echocardiographic studies conducted in various countries. HCM has been found to have a genetic component, and approximately 25% of first-degree relatives of patients with HCM show evidence of the condition on echocardiography.
Genetic testing has recently been developed and can be used to identify asymptomatic family members who carry the same sarcomere mutation as the affected individual. This can help to facilitate earlier diagnosis and intervention, which may prevent or delay the onset of complications. Although HCM is more common in males than females, inheritance of the condition does not follow sex predilection since it is autosomal dominant.
This means that an affected individual has a 50% chance of passing the condition on to each of their offspring, regardless of their gender. The most common presentation of HCM is in the third decade of life, although the condition can be present at any age, from newborns to elderly patients. It is important to note that some individuals with HCM may remain asymptomatic throughout their lives, while others may experience severe symptoms and complications.
Anatomy
Pathophysiology
Hypertrophic cardiomyopathy (HCM) is a genetic disorder that affects the structure of the heart muscle. In HCM, the heart muscle cells (myocytes) become abnormally thick, leading to problems with the heart’s ability to pump blood effectively. The underlying pathophysiology involves a complex interplay between genetic, cellular, and molecular factors.
The condition is caused by gene mutations that encode the proteins that constitute the heart muscle cells. These mutations can affect how the cells grow and divide, leading to the abnormal thickening of the heart muscle. The thickening of the heart muscle in HCM is not uniform and can occur in different parts of the heart, such as the ventricles, the septum, or both.
This results in different types of HCM, such as septal or apical HCM. The thickened heart muscle in HCM can also affect how blood flows through the heart. The thickened muscle can obstruct blood flow from the heart, causing left ventricular outflow tract obstruction (LVOTO). This obstruction can lead to chest pain, shortness of breath, and fainting. In addition to obstructing blood flow, the thickened heart muscle in HCM can also impair the heart’s ability to relax and fill with blood between heartbeats.
This can lead to diastolic dysfunction, which can cause symptoms such as fatigue, shortness of breath, and pulmonary edema. The thickened heart muscle in HCM can also lead to arrhythmias or abnormal heart rhythms. These arrhythmias can be caused by disruptions in the heart’s electrical activity due to the thickened muscle, as well as changes in the structure of the heart’s electrical pathways. Common arrhythmias in HCM include atrial fibrillation, ventricular tachycardia, and sudden cardiac arrest.
Etiology
Familial Hypertrophic cardiomyopathy is a Mendelian-inherited disorder that occurs in 50% of cases due to an autosomal dominant mutation in the gene responsible for the contractile elements of the heart. At least four chromosomes and six genes have been associated with HCM, with over 50 different mutations identified.
The symptoms and severity of hypertrophy expressed may vary depending on the mutation involved. Recent studies suggest that abnormal calcium kinetics in the myocardium may be responsible for inappropriate myocardial hypertrophy and specific features of HCM, particularly in patients with diastolic functional abnormalities.
Genetics
Prognostic Factors
Patients with hypertrophic cardiomyopathy used to have a mortality rate ranging from 1% to 4%, but this rate has improved in recent years. Even though HCM patients are asymptomatic, sudden death due to malignant arrhythmias can be their first clinical manifestation, particularly among young people with the highest mortality rate.
Early detection of HCM is crucial as it enables healthcare providers to recommend appropriate safe physical activity. In addition to sudden death, patients may experience atrial and ventricular arrhythmias and recurrent heart failure episodes if they have concomitant mitral regulation and diastolic dysfunction.
Clinical History
Clinical History
Dyspnea is the most frequently reported symptom in patients with hypertrophic cardiomyopathy; however, other symptoms such as syncope, angina, palpitations, orthopnea, dizziness, paroxysmal nocturnal dyspnea, congestive heart failure, and sudden cardiac death can also occur. Sudden cardiac death is considered the most severe and catastrophic presentation among these symptoms.
Physical Examination
Physical Examination
The physical exam reveals a double apical impulse caused by forceful contraction of the left atrium against a stiff left ventricle and a normal S1 and split S2, S3 due to heart failure. The jugular venous pressure shows a prominent wave, and the apical impulse is laterally displaced with a double carotid pulse.
A systolic ejection murmur is also present, which becomes less intense with increased preload or increased afterload (such as with vasodilator administration). Conversely, the murmur becomes more intense with a decrease in preload (such as during the Valsalva maneuver or standing) or afterload reduction.
Hypertrophic cardiomyopathy (HCM) is a genetic heart disease inherited in an autosomal dominant manner. It is caused by gene mutations that encode proteins involved in the contractile machinery of the heart. These mutations lead to the development of thickened walls in the left ventricle, which is the heart’s main pumping chamber.
This thickening of the ventricle walls, also known as hypertrophy, can cause several problems for the heart. One of the main issues is the obstruction of blood flow out of the heart. This can cause various symptoms, including shortness of breath, chest pain, fatigue, and dizziness. Another problem with HCM is diastolic dysfunction when the heart has difficulty relaxing and filling with blood during the resting phase of the heartbeat cycle.
This can lead to heart failure, which is when the heart cannot pump blood effectively throughout the body. In addition, people with HCM may be at an increased risk of developing myocardial ischemia when the heart muscle does not get enough oxygen and nutrients due to a reduced blood supply. This can cause chest pain and other symptoms.
The prevalence of HCM in the general population worldwide is estimated to be around 0.2%, which translates to one in every 500 adults. This figure is based on echocardiographic studies conducted in various countries. HCM has been found to have a genetic component, and approximately 25% of first-degree relatives of patients with HCM show evidence of the condition on echocardiography.
Genetic testing has recently been developed and can be used to identify asymptomatic family members who carry the same sarcomere mutation as the affected individual. This can help to facilitate earlier diagnosis and intervention, which may prevent or delay the onset of complications. Although HCM is more common in males than females, inheritance of the condition does not follow sex predilection since it is autosomal dominant.
This means that an affected individual has a 50% chance of passing the condition on to each of their offspring, regardless of their gender. The most common presentation of HCM is in the third decade of life, although the condition can be present at any age, from newborns to elderly patients. It is important to note that some individuals with HCM may remain asymptomatic throughout their lives, while others may experience severe symptoms and complications.
Hypertrophic cardiomyopathy (HCM) is a genetic disorder that affects the structure of the heart muscle. In HCM, the heart muscle cells (myocytes) become abnormally thick, leading to problems with the heart’s ability to pump blood effectively. The underlying pathophysiology involves a complex interplay between genetic, cellular, and molecular factors.
The condition is caused by gene mutations that encode the proteins that constitute the heart muscle cells. These mutations can affect how the cells grow and divide, leading to the abnormal thickening of the heart muscle. The thickening of the heart muscle in HCM is not uniform and can occur in different parts of the heart, such as the ventricles, the septum, or both.
This results in different types of HCM, such as septal or apical HCM. The thickened heart muscle in HCM can also affect how blood flows through the heart. The thickened muscle can obstruct blood flow from the heart, causing left ventricular outflow tract obstruction (LVOTO). This obstruction can lead to chest pain, shortness of breath, and fainting. In addition to obstructing blood flow, the thickened heart muscle in HCM can also impair the heart’s ability to relax and fill with blood between heartbeats.
This can lead to diastolic dysfunction, which can cause symptoms such as fatigue, shortness of breath, and pulmonary edema. The thickened heart muscle in HCM can also lead to arrhythmias or abnormal heart rhythms. These arrhythmias can be caused by disruptions in the heart’s electrical activity due to the thickened muscle, as well as changes in the structure of the heart’s electrical pathways. Common arrhythmias in HCM include atrial fibrillation, ventricular tachycardia, and sudden cardiac arrest.
Familial Hypertrophic cardiomyopathy is a Mendelian-inherited disorder that occurs in 50% of cases due to an autosomal dominant mutation in the gene responsible for the contractile elements of the heart. At least four chromosomes and six genes have been associated with HCM, with over 50 different mutations identified.
The symptoms and severity of hypertrophy expressed may vary depending on the mutation involved. Recent studies suggest that abnormal calcium kinetics in the myocardium may be responsible for inappropriate myocardial hypertrophy and specific features of HCM, particularly in patients with diastolic functional abnormalities.
Patients with hypertrophic cardiomyopathy used to have a mortality rate ranging from 1% to 4%, but this rate has improved in recent years. Even though HCM patients are asymptomatic, sudden death due to malignant arrhythmias can be their first clinical manifestation, particularly among young people with the highest mortality rate.
Early detection of HCM is crucial as it enables healthcare providers to recommend appropriate safe physical activity. In addition to sudden death, patients may experience atrial and ventricular arrhythmias and recurrent heart failure episodes if they have concomitant mitral regulation and diastolic dysfunction.
Clinical History
Dyspnea is the most frequently reported symptom in patients with hypertrophic cardiomyopathy; however, other symptoms such as syncope, angina, palpitations, orthopnea, dizziness, paroxysmal nocturnal dyspnea, congestive heart failure, and sudden cardiac death can also occur. Sudden cardiac death is considered the most severe and catastrophic presentation among these symptoms.
Physical Examination
The physical exam reveals a double apical impulse caused by forceful contraction of the left atrium against a stiff left ventricle and a normal S1 and split S2, S3 due to heart failure. The jugular venous pressure shows a prominent wave, and the apical impulse is laterally displaced with a double carotid pulse.
A systolic ejection murmur is also present, which becomes less intense with increased preload or increased afterload (such as with vasodilator administration). Conversely, the murmur becomes more intense with a decrease in preload (such as during the Valsalva maneuver or standing) or afterload reduction.
Hypertrophic cardiomyopathy (HCM) is a genetic heart disease inherited in an autosomal dominant manner. It is caused by gene mutations that encode proteins involved in the contractile machinery of the heart. These mutations lead to the development of thickened walls in the left ventricle, which is the heart’s main pumping chamber.
This thickening of the ventricle walls, also known as hypertrophy, can cause several problems for the heart. One of the main issues is the obstruction of blood flow out of the heart. This can cause various symptoms, including shortness of breath, chest pain, fatigue, and dizziness. Another problem with HCM is diastolic dysfunction when the heart has difficulty relaxing and filling with blood during the resting phase of the heartbeat cycle.
This can lead to heart failure, which is when the heart cannot pump blood effectively throughout the body. In addition, people with HCM may be at an increased risk of developing myocardial ischemia when the heart muscle does not get enough oxygen and nutrients due to a reduced blood supply. This can cause chest pain and other symptoms.
The prevalence of HCM in the general population worldwide is estimated to be around 0.2%, which translates to one in every 500 adults. This figure is based on echocardiographic studies conducted in various countries. HCM has been found to have a genetic component, and approximately 25% of first-degree relatives of patients with HCM show evidence of the condition on echocardiography.
Genetic testing has recently been developed and can be used to identify asymptomatic family members who carry the same sarcomere mutation as the affected individual. This can help to facilitate earlier diagnosis and intervention, which may prevent or delay the onset of complications. Although HCM is more common in males than females, inheritance of the condition does not follow sex predilection since it is autosomal dominant.
This means that an affected individual has a 50% chance of passing the condition on to each of their offspring, regardless of their gender. The most common presentation of HCM is in the third decade of life, although the condition can be present at any age, from newborns to elderly patients. It is important to note that some individuals with HCM may remain asymptomatic throughout their lives, while others may experience severe symptoms and complications.
Hypertrophic cardiomyopathy (HCM) is a genetic disorder that affects the structure of the heart muscle. In HCM, the heart muscle cells (myocytes) become abnormally thick, leading to problems with the heart’s ability to pump blood effectively. The underlying pathophysiology involves a complex interplay between genetic, cellular, and molecular factors.
The condition is caused by gene mutations that encode the proteins that constitute the heart muscle cells. These mutations can affect how the cells grow and divide, leading to the abnormal thickening of the heart muscle. The thickening of the heart muscle in HCM is not uniform and can occur in different parts of the heart, such as the ventricles, the septum, or both.
This results in different types of HCM, such as septal or apical HCM. The thickened heart muscle in HCM can also affect how blood flows through the heart. The thickened muscle can obstruct blood flow from the heart, causing left ventricular outflow tract obstruction (LVOTO). This obstruction can lead to chest pain, shortness of breath, and fainting. In addition to obstructing blood flow, the thickened heart muscle in HCM can also impair the heart’s ability to relax and fill with blood between heartbeats.
This can lead to diastolic dysfunction, which can cause symptoms such as fatigue, shortness of breath, and pulmonary edema. The thickened heart muscle in HCM can also lead to arrhythmias or abnormal heart rhythms. These arrhythmias can be caused by disruptions in the heart’s electrical activity due to the thickened muscle, as well as changes in the structure of the heart’s electrical pathways. Common arrhythmias in HCM include atrial fibrillation, ventricular tachycardia, and sudden cardiac arrest.
Familial Hypertrophic cardiomyopathy is a Mendelian-inherited disorder that occurs in 50% of cases due to an autosomal dominant mutation in the gene responsible for the contractile elements of the heart. At least four chromosomes and six genes have been associated with HCM, with over 50 different mutations identified.
The symptoms and severity of hypertrophy expressed may vary depending on the mutation involved. Recent studies suggest that abnormal calcium kinetics in the myocardium may be responsible for inappropriate myocardial hypertrophy and specific features of HCM, particularly in patients with diastolic functional abnormalities.
Patients with hypertrophic cardiomyopathy used to have a mortality rate ranging from 1% to 4%, but this rate has improved in recent years. Even though HCM patients are asymptomatic, sudden death due to malignant arrhythmias can be their first clinical manifestation, particularly among young people with the highest mortality rate.
Early detection of HCM is crucial as it enables healthcare providers to recommend appropriate safe physical activity. In addition to sudden death, patients may experience atrial and ventricular arrhythmias and recurrent heart failure episodes if they have concomitant mitral regulation and diastolic dysfunction.
Clinical History
Dyspnea is the most frequently reported symptom in patients with hypertrophic cardiomyopathy; however, other symptoms such as syncope, angina, palpitations, orthopnea, dizziness, paroxysmal nocturnal dyspnea, congestive heart failure, and sudden cardiac death can also occur. Sudden cardiac death is considered the most severe and catastrophic presentation among these symptoms.
Physical Examination
The physical exam reveals a double apical impulse caused by forceful contraction of the left atrium against a stiff left ventricle and a normal S1 and split S2, S3 due to heart failure. The jugular venous pressure shows a prominent wave, and the apical impulse is laterally displaced with a double carotid pulse.
A systolic ejection murmur is also present, which becomes less intense with increased preload or increased afterload (such as with vasodilator administration). Conversely, the murmur becomes more intense with a decrease in preload (such as during the Valsalva maneuver or standing) or afterload reduction.
Differential Diagnoses
Athlete’s heart
Glycogen storage disease
Hypertensive heart disease
Right ventricular hypertrophy
Restrictive cardiomyopathy
Sarcoidosis
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