Somatisation Disorder as the Most Likely Diagnosis

Somatisation disorder is the most probable diagnosis for the given scenario, although it lacks sufficient criteria for a complete diagnosis. This disorder is characterised by recurring pains, gastrointestinal, sexual, and pseudo-neurologic symptoms that persist for years. To meet the diagnostic criteria, the patient’s physical complaints must not be intentionally induced and must result in medical attention or significant impairment in social, occupational, or other important areas of functioning. Typically, the first symptoms appear during adolescence, and the full criteria are met by the age of 30.

Among the other disorders, factitious disorder is the least likely explanation. The other three disorders are possible explanations, but they are not as likely as somatisation disorder.

Coronary Arteries and their Supply to Cardiac Conduction System

The heart’s conduction system is responsible for regulating the heartbeat. The following are the coronary arteries that supply blood to the different parts of the cardiac conduction system:

Sinoatrial Node
The sinoatrial node, which is the primary pacemaker of the heart, is supplied by the right coronary artery in 60% of cases through a sinoatrial nodal branch.

Atrioventricular Node
The atrioventricular node, which is responsible for delaying the electrical impulse before it reaches the ventricles, is supplied by the right coronary artery in 80% of individuals through the atrioventricular nodal branch.

Atrioventricular Bundle
The atrioventricular bundle, which conducts the electrical impulse from the atria to the ventricles, is supplied by numerous septal arteries that mostly arise from the anterior interventricular artery, a branch of the left coronary artery.

Left Bundle Branch
The left bundle branch, which conducts the electrical impulse to the left ventricle, is supplied by numerous subendocardial bundle arteries that originate from the left coronary artery.

Right Bundle Branch
The right bundle branch, which conducts the electrical impulse to the right ventricle, is supplied by numerous subendocardial bundle arteries that originate from the right coronary artery.

Management of Chest Pain in a Patient with Risk Factors for Cardiac Disease

Chest pain is a common presenting complaint in primary care and emergency departments. However, it is important to consider the possibility of an acute coronary syndrome in patients with risk factors for cardiac disease. Here are some management strategies for a patient with chest pain and risk factors for cardiac disease:

Arrange a 12-h troponin T assay before deciding whether or not to discharge the patient. A normal troponin assay would make a diagnosis of acute coronary syndrome unlikely, but further investigation may be required to determine if the patient has underlying coronary artery disease.

Do not discharge the patient with a diagnosis of costochondritis based solely on chest wall tenderness. This should only be used in low-risk patients with tenderness that accurately reproduces the pain they have been feeling on minimal palpation.

Do not discharge the patient if serial resting ECGs are normal. A normal ECG does not rule out an acute cardiac event.

Admit the patient to the Coronary Care Unit for monitoring and further assessment only if the 12-h troponin comes back elevated.

Do not discharge the patient and arrange an outpatient exercise tolerance test until further investigation has been done to rule out an acute cardiac event.

In summary, it is important to consider the possibility of an acute coronary syndrome in patients with chest pain and risk factors for cardiac disease. Further investigation, such as a 12-h troponin assay, may be required before deciding on appropriate management strategies.

Understanding ECG Analysis: The Normal Cardiac Axis

ECG analysis is a fundamental concept that is essential to understand early on. One of the key components of ECG analysis is the normal cardiac axis, which ranges from −30 to 90 degrees. If the axis is greater than 90 degrees, it implies right axis deviation, while an axis less than −30 degrees indicates left axis deviation.

To determine the axis, leads I, II, and III of the ECG are typically examined. A normal axis is characterized by upgoing waves in all three leads. In contrast, right axis deviation is indicated by a downgoing wave in lead I and an upgoing wave in leads II and III. Left axis deviation is indicated by an upgoing wave in lead I and a downgoing wave in leads II and III.

While −30 to −90 degrees is considered left axis deviation and not a normal axis, −30 to 60 degrees is a normal axis, but it does not cover the full spectrum of a normal axis. Therefore, the correct answer is -30 to 90 degrees. Understanding the normal cardiac axis is crucial for accurate ECG interpretation and diagnosis.

Coronary Arteries and their Associated ECG Changes

The heart is supplied with blood by the coronary arteries, and blockages in these arteries can lead to myocardial infarction (heart attack). Different coronary arteries supply blood to different parts of the heart, and the location of the blockage can be identified by changes in the electrocardiogram (ECG) readings.

Left (obtuse) Marginal Artery: This artery supplies the lateral wall of the left ventricle. Blockages in this artery can cause changes in ECG leads I, aVL, V2, V5, and V6, with reciprocal changes in the inferior leads.

Anterior Interventricular (Left Anterior Descending) Artery: This artery supplies the anterior walls of both ventricles and the anterior part of the interventricular septum. Blockages in this artery can cause changes in ECG leads V2-V4, sometimes extending to V1 and V5.

Posterior Interventricular Artery: This artery is a branch of the right coronary artery and supplies the posterior walls of both ventricles. ECG changes associated with blockages in this artery are not specific.

Right (Acute) Marginal Artery: This artery supplies the right ventricle. Blockages in this artery can cause changes in ECG leads II, III, aVF, and sometimes V1.

Right Mainstem Coronary Artery: Inferior myocardial infarction is most commonly associated with blockages in this artery (80% of cases) or the left circumflex artery (20% of cases). ECG changes in this type of infarct are seen in leads II, III, and aVF.

Understanding Coronary Arteries and ECG Changes in Myocardial Infarction

ECG Changes Associated with Hypo- and Hyperkalaemia

Hypokalaemia, or low levels of potassium in the blood, can cause various changes in an electrocardiogram (ECG). One of the most prominent changes is the appearance of U waves, which follow T waves and usually have the same direction. Hypokalaemia can also cause increased amplitude and width of P waves, prolonged PR interval, T wave flattening and inversion, ST depression, and Q-T prolongation in severe cases.

On the other hand, hyperkalaemia, or high levels of potassium in the blood, can cause peaked T waves, which represent ventricular repolarisation. Hyperkalaemia is also associated with widening of the QRS complex, which can lead to life-threatening ventricular arrhythmias. Flattening of P waves and prolonged PR interval are other ECG changes seen in hyperkalaemia.

It is important to note that some of these ECG changes can overlap between hypo- and hyperkalaemia, such as prolonged PR interval. Therefore, other clinical and laboratory findings should be considered to determine the underlying cause of the ECG changes.

Anatomical Landmarks for Cardiac Examination

When examining the heart, it is important to know the anatomical landmarks for locating specific valves and ventricles. Here are some key locations to keep in mind:

1. Fourth intercostal space, left parasternal area: This is the correct location for examining the tricuspid valve and the right ventricle, particularly when detecting a right ventricular heave.

2. Second intercostal space, left parasternal area: The pulmonary valve can be found at this location.

3. Second intercostal space, right parasternal area: The aortic valve is located here.

4. Fourth intercostal space, right parasternal area: In cases of true dextrocardia, the tricuspid valve and a right ventricular heave can be found at this location.

5. Fifth intercostal space, mid-clavicular line: This is the location of the apex beat, which can be examined for a left ventricular heave and the mitral valve.

Knowing these landmarks can help healthcare professionals accurately assess and diagnose cardiac conditions.

Auscultation of Heart Valves: Locations and Sounds

The human heart has four valves that regulate blood flow. These valves can be heard through auscultation, a medical technique that involves listening to the sounds produced by the heart using a stethoscope. Here are the locations and sounds of each valve:

Tricuspid Valve: This valve is located on the right side of the heart and can be heard at the left sternal border in the fourth intercostal space. The sound produced by this valve is a low-pitched, rumbling noise.

Aortic Valve: The aortic valve is located on the left side of the heart and can be heard over the right sternal border at the second intercostal space. The sound produced by this valve is a high-pitched, clicking noise.

Pulmonary Valve: This valve is located on the right side of the heart and can be heard over the left sternal border at the second intercostal space. The sound produced by this valve is a high-pitched, clicking noise.

Thebesian Valve: The Thebesian valve is located in the coronary sinus and its closure cannot be auscultated.

Mitral Valve: This valve is located on the left side of the heart and can be heard by listening at the apex, in the left mid-clavicular line in the fifth intercostal space. The sound produced by this valve is a low-pitched, rumbling noise.

In summary, auscultation of heart valves is an important diagnostic tool that can help healthcare professionals identify potential heart problems. By knowing the locations and sounds of each valve, healthcare professionals can accurately diagnose and treat heart conditions.

Common Congenital Heart Defects and their Characteristics

An endocardial cushion defect, also known as an AVSD, is the most prevalent cardiac malformation in individuals with Down Syndrome. This defect can lead to irreversible pulmonary hypertension, which is known as Eisenmenger’s syndrome. It is unclear why children with Down Syndrome tend to have more severe cardiac disease than unaffected children with the same abnormality.

ASDs, or atrial septal defects, may close on their own, and the likelihood of spontaneous closure is related to the size of the defect. If the defect is between 5-8 mm, there is an 80% chance of closure, but if it is larger than 8 mm, the chance of closure is minimal.

Tetralogy of Fallot, a cyanotic congenital heart disease, typically presents after three months of age. The murmur of VSD, or ventricular septal defect, becomes more pronounced after one month of life. Overall, the characteristics of these common congenital heart defects is crucial for proper diagnosis and treatment.

Common Heart Conditions and Their Characteristics

Aortic stenosis is a condition where the aortic valve does not open completely, resulting in dyspnea, chest pain, and syncope. It produces a narrow pulse pressure, a low volume pulse, and an ejection systolic murmur that radiates to the carotids. An enlarged right ascending aorta is a common finding in aortic stenosis. Calcification of the valve is diagnostic and can be observed using CT or fluoroscopy. Aortic stenosis is commonly caused by calcification of the aortic valve due to a congenitally bicuspid valve, connective tissue disease, or rheumatic heart disease. Echocardiography confirms the diagnosis, and valve replacement or intervention is indicated with critical stenosis <0.5 cm or when symptomatic. Aortic regurgitation is characterized by a widened pulse pressure, collapsing pulse, and an early diastolic murmur heard loudest in the left lower sternal edge with the patient upright. Patients can be asymptomatic until heart failure manifests. Causes include calcification and previous rheumatic fever. Ventricular septal defect (VSD) is a congenital or acquired condition characterized by a pansystolic murmur heard loudest at the left sternal edge. Acquired VSD is mainly a result of previous myocardial infarction. VSD can be asymptomatic or cause heart failure secondary to pulmonary hypertension. Mitral regurgitation is characterized by a pansystolic murmur heard best at the apex that radiates towards the axilla. A third heart sound may also be heard. Patients can remain asymptomatic until dilated cardiac failure occurs, upon which dyspnea and peripheral edema are among the most common symptoms. Mitral stenosis causes a mid-diastolic rumble heard best at the apex with the patient in the left lateral decubitus position. Auscultation of the precordium may also reveal an opening snap. Patients are at increased risk of atrial fibrillation due to left atrial enlargement. The most common cause of mitral stenosis is a previous history of rheumatic fever.