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Cardiac Arrhythmias

With few exceptions, the etiologies of cardiac arrhythmias like those of bradycardia can best be recalled using the mnemonic VINDICATE. The exceptions are from one pathophysiologic cause: obstruction and consequent dilatation of one or more of the chambers of the heart. Thus, mitral stenosis with obstruction and dilatation of the left atrium is a prominent cause of atrial arrhythmias, especially of auricular fibrillation. Hypertension and aortic stenosis may cause a number of atrial and ventricular arrhythmias. Pulmonary hypertension resulting from pulmonary emphysema, fibrosis, or pneumonia with consequent right ventricular and atrial obstruction and dilatation cause arrhythmias, especially atrial arrhythmias. Getting back to VINDICATE completes the recall of the causes of arrhythmias.



  • V—Vascular diseases include myocardial infarction, coronary insufficiency, and coronary artery emboli.


  • I—Inflammatory diseases include viral myocarditis, diphtheria, syphilis, tuberculosis, and Chagas disease.


  • N—Neoplasms include atrial myxomas, but the N also stands for neuropsychiatric causes. Paroxysmal atrial tachycardia is especially likely to result from emotional causes.


  • D—Degenerative diseases include Friedreich ataxia, myotonic dystrophy, myocardial fibroelastosis, and other myocardiopathies.


  • I—Intoxication suggests the largest number of causes of arrhythmia: Alcohol, caffeine, tobacco, digitalis, quinidine, propranolol, and procainamide are just a few. Diuretics cause electrolyte disturbances that may cause or contribute to cardiac arrhythmias.


  • C—Congenital disorders recall congenital heart diseases, many of which cause recurrent arrhythmias. The Wolff–Parkinson–White syndrome predisposes to atrial tachycardia. Muscular dystrophy may cause myocardiopathy and arrhythmias. Von Gierke disease and gargoylism also need to be remembered.


  • A—Autoimmune disorders suggest the arrhythmias of amyloidosis, sarcoidosis, scleroderma, periarteritis nodosa, and rheumatic fever.


  • T—Trauma suggests the arrhythmias in shock, burns, stab wounds to the heart, and head injuries. Electric shock is a cause of ventricular fibrillation.


  • E—Endocrinopathies should remind one of hyperthyroidism, a prominent cause of atrial fibrillation, Addison disease, and aldosteronism, which disturb the electrolytes sufficiently to cause arrhythmias. Pheochromocytomas may cause atrial tachycardia from the tremendous output of epinephrine.


Approach to the Diagnosis

The diagnosis depends a lot on the type of arrhythmia. Atrial premature contractions are usually benign, and an extensive workup is unnecessary unless other physical signs indicate the need for it. Infrequent ventricular premature contractions (VPCs) in otherwise healthy individuals probably can be handled the same way. When VPCs are frequent or multifocal, an exercise tolerance test, echocardiogram, and perhaps coronary angiography are indicated. Runs of ventricular tachycardia require an extensive workup, including coronary angiography, but usually there will be other signs to indicate the need for this.

Atrial tachycardia and fibrillation require a workup of hyperthyroidism and pulmonary disease, systemic hypertension, and congestive heart failure (CHF). Atrial obstruction and dilatation should be excluded by echocardiography. Carotid sinus massage will distinguish rapid atrial arrhythmias from sinus tachycardia.

Any arrhythmia warrants an electrocardiogram (ECG) and possibly repeated ECGs. The Holter monitor should be used if there is doubt about the type of arrhythmia.


Other Useful Tests



  • Complete blood count (CBC) (anemia)


  • Thyroid profile (hyperthyroidism, hypothyroidism)


  • Urinalysis (renal disease)


  • Chemistry panel (uremia, electrolyte imbalance)


  • Sedimentation rate (infection)


  • Serial cardiac enzymes (myocardial infarction)


  • Serum and urine osmolality (CHF)


  • Exercise tolerance test (coronary insufficiency)


  • Serial ECGs (myocardial infarction)


  • Signal-averaging ECG and electrophysiologic testing (localize site of irritable focus)


  • Pulmonary function tests (CHF, emphysema)


  • Echocardiogram (CHF, valvular heart disease)


  • Coronary angiogram (coronary insufficiency)


  • Drug screen (chronic drug abuse)


  • Hold all drugs (drug intoxication)


  • B-type natriuretic peptide (BNP) (CHF)


Cardiomegaly

If an x-ray film demonstrates cardiomegaly, the physician must find out what is causing this condition (Table 13). You have already listened to the patient and he or she does not have a murmur. This seems to exclude the common groups of causes—congenital and rheumatic heart disease. (It really does not.) The patient does not have hypertension and denies symptoms of heart failure. The ECG is normal. Now what do you do?







Cardiac arrhythmias, local causes.

This situation is all too common, and I hope this chapter will remedy that situation. The basic sciences of histology and physiology are, of course, the key to an immediate differential diagnosis. Remember that the heart is divided into three basic layers: endocardium, myocardium, and pericardium; each of these can be cross-indexed with the etiologic classification using the mnemonic VINDICATE. The pathophysiologic mechanism, obstruction, provides the remaining disorders in the differential diagnosis. This is applied to the pulmonary and systemic circulations and cross-indexed with the various etiologic groups. Let us begin with the endocardium.



  • V—Vascular lesions include the ball–valve thrombosis.


  • I—Inflammatory lesions bring to mind acute and subacute bacterial endocarditis and syphilitic valvular disease.


  • N—Neoplasms suggest an atrial myxoma.


  • D—Degenerative disease signals atherosclerotic valvular disease.


  • I—Intoxication does not suggest any particular condition, because most toxins involve the myocardium.


  • C—Congenital suggests a host of valvular and septal defects and transposition of the blood vessels of the heart.


  • A—Autoimmune suggests the important rheumatic carditis and also Libman–Sacks endocarditis of lupus erythematosus.


  • T—Trauma suggests all the valvular or septal defects that can occur from surgery.


  • E—Endocrine suggests the pulmonic and tricuspid valvular defects that result from carcinoid syndrome.









Table 13 Cardiomegaly




































































  V
Vascular
I
Inflammatory
N
Neoplasm
D
Degenerative and Deficiency
I
Intoxication Idiopathic
C
Congenital
A
Autoimmune Allergic
T
Trauma
E
Endocrine
Endocardium Ball valve thrombus Bacterial endocarditis
Subacute bacterial endocarditis
Syphilis
Myxoma Atherosclerotic valvular disease   Congenital valvular and septal defects Lupus endocarditis
Rheumatic fever
Valvular perforation or lacerating surgery Carcinoid syndrome
Myocardium Coronary insufficiency
Myocardial infarction
Congestive heart failure
Diphtheria
Trypanosomiasis
Syphilis
Viral myocarditis
Rhabdomyosarcoma Beriberi
Muscular dystrophy
Hemochromatosis
Alcoholism
Amyloidosis
Gout
Hurler disease
von Gierke disease
Myocardial fibroelastosis
Subaortic stenosis
Rheumatic fever
Rheumatic arthritis scleroderma
Traumatic aneurysm
Postpericardiotomy syndrome
Hyperthyroidism
Diabetic arteriolar sclerosis
Hypothyroidism
Pericardium Hemopericardium Tuberculosis
Viral pericarditis
Metastatic carcinoma   Idiopathic pericarditis   Rheumatic fever Hemopericardium  
Systemic
Circulation
Renal artery stenosis   Polycythemia vera
Hypernephroma
Anemia
Paget disease
Essential hypertension
Dissecting aneurysm
Coarctation of aorta
Patent ductus
Periarteritis nodosa
Glomerulonephritis
Arteriovenous fistula Adrenal tumor
Pulmonary
Circulation
Pulmonary embolism and infarction Chronic bronchitis and emphysema
Tuberculosis
Fungi
Carcinomatosis   Pulmonary fibrosis
Primary pulmonary hypertension
       







Cardiac arrhythmias, systemic causes.

In the myocardium, one encounters a large number of diseases; therefore, only the most common ones will be mentioned here.



  • V—Vascular should immediately suggest coronary insufficiency and myocardial infarction.


  • I—Inflammation could indicate viral myocarditis, but it would hardly be expected to remind one of diphtheria and syphilitic myocarditis because these rarely are seen.


  • N—Neoplasms of the myocardium are rare, thus rhabdomyosarcoma needs to be mentioned here for completeness only.


  • D—Degenerative and deficiency diseases should signal beriberi and muscular dystrophy, but these are also infrequently encountered.


  • I—Intoxicating and idiopathic disorders of the myocardium, especially alcoholism, are much more common. Others include hemochromatosis, amyloidosis, and gout.







    Cardiomegaly.


  • C—Congenital disorders include Von Gierke disease and myocardial fibroelastosis.


  • A—Autoimmune again suggests rheumatic fever and the collagen diseases.


  • T—Trauma suggests posttraumatic aneurysms.


  • E—Endocrine disorders include two treatable disorders: hyperthyroidism and hypothyroidism.

The pericardium is not frequently the cause of “cardiomegaly,” but tuberculosis and idiopathic pericarditis should be considered, as should hemopericardium, especially in the course of a myocardial infarction. Obstruction in the pulmonary circulation can result from the following:



  • V—Vascular from pulmonary infarction.


  • I—Inflammatory from chronic bronchitis and emphysema or from chronic infections such as tuberculosis and various fungi.


  • N—Neoplastic from primary or metastatic carcinoma.


  • D—Degenerative







    Cardiomegaly, local causes.


  • I—Idiopathic or Intoxication in pulmonary fibrosis and primary pulmonary hypertension.


  • C—Congenital disorders include pulmonic stenosis and hemangiomas.


  • A—Autoimmune diseases include collagen diseases.


  • T—Trauma may cause an arteriovenous aneurysm or pneumothorax obstructing the pulmonary circulation.


  • E—Endocrine disorders do not obstruct the pulmonary vasculature.

Under systemic circulation comes essential or secondary hypertension caused by coarctation of the aorta, periarteritis nodosa, or the many renal and adrenal diseases. Dissecting aneurysms of the aorta may rupture into the pericardium causing cardiomegaly.


Approach to the Diagnosis

The diagnosis of cardiomegaly can be further developed by a good history and the association of other symptoms and signs. Is there a history of hypertension, alcoholism, rheumatic fever, or other systemic disease? Has the patient experienced shortness of breath, angina, fever, joint pains, and so forth? Are there findings of pedal edema, hepatomegaly, or jugular venous distention (CHF)? Are there hypertension and proteinuria (renal disease or essential hypertension)?
Is there a significant heart murmur (congenital heart disease, rheumatic heart disease)?

The diagnostic workup will include a CBC, urinalysis, chemistry panel, sedimentation rate, chest x-ray, and ECG. At this point, it is wise to consult a cardiologist. Echocardiography will be helpful in diagnosing valvular heart disease, myocardiopathy, and pericardial effusion. If CHF is suspected, a venous pressure and circulation time as well as spirometry will support the diagnosis. Echocardiography can diagnose CHF by determining the left ventricular ejection fraction (LVEF). CT angiography will also be helpful. If there is unexplained fever, an antistreptolysin O (ASO) titer or streptozyme test should be ordered to rule out rheumatic fever, and perhaps serial blood cultures should be done to exclude subacute bacterial endocarditis. If there is hypertension, the patient may need a hypertensive workup (see page 237).


Other Useful Tests



  • Exercise tolerance test (coronary insufficiency)


  • Thallium scan (coronary insufficiency)


  • Phonocardiogram (valvular heart disease)


  • Antinuclear antibody (ANA) analysis (collagen disease)


  • Cardiac catheterization studies (congenital heart disease, rheumatic heart disease)


  • Angiocardiogram (valvular heart disease)


  • Coronary arteriogram (coronary insufficiency)


  • Thyroid profile (myxedema)


  • 24-hour urine catecholamine (pheochromocytoma)


  • Urine thiamine afterload (beriberi)


  • Muscle biopsy (collagen disease, trichinosis)


  • Computed tomography (CT) scan (mediastinal mass)


  • Magnetic resonance imaging (MRI) (dissecting aneurysm)






Chest pain.



Cervical Bruit

Anatomy is the key to the differential diagnosis of a cervical bruit. Visualizing the neck, we have the carotid, innominate, and subclavian arteries; the jugular, innominate, and subclavian veins; the thyroid, scalenus anticus muscle, and cervical ribs, all of which may be involved in this sign.

Arteries: This should prompt the recall of a carotid or subclavian artery stenosis (subclavian steal syndrome) or an aneurysm. It should also remind us of aortic murmurs that may be transmitted to the neck from a stenosed aortic valve, calcific aortitis, or an aortic aneurysm.

Veins: A venous hum may be heard in the neck as a result of a circuitous route that blood must take in the veins. This is of course usually benign.

Thyroid: This prompts the recall of the bruit heard over the thyroid in Graves disease.

Muscles: Occasionally a bruit is heard in the neck in patients with scalenus anticus syndrome or other forms of thoracic outlet syndrome.

Cervical rib: The subclavian artery may also be compressed by a cervical rib producing a cervical bruit.


Approach to the Diagnosis

A history of diaphoresis, weight loss, or heat intolerance would arouse suspicion of hyperthyroidism. A history of transient hemiplegia, amaurosis fugax, or other intermittent neurologic symptomatology should point to a carotid stenosis or subclavian steal syndrome. Physical findings of pallor or spoon nails would point to anemia. An enlarged thyroid prompts the suspicion of hyperthyroidism. If there is a diminished pulse on the side of the bruit, look for thoracic outlet syndrome or subclavian steal syndrome. The diagnostic workup may need to include a CBC, thyroid panel, and carotid duplex scan.

Consult a neurologist if there are objective neurologic signs. Four-vessel angiography needs to be considered if a carotid stenosis or subclavian steal syndrome is suspected. If the bruit seems to be transmitted from the chest, echocardiography may be needed.


Chest Pain

Hardly a day goes by in a busy practitioner’s office that he or she is not confronted with a patient complaining of chest pain. The main concern, of course, is to exclude an acute myocardial infarction, which is not an easy task in many cases. The practitioner frequently admits the patient for observation, which is the safe thing to do when there is any doubt. With a list of virtually all the diagnostic possibilities in mind, however, fewer patients will require admission for observation. Anatomy forms the basis for formulating such a list.

Visualizing the organs of the chest and cross-indexing them with the various etiologies (Table 14), one finds that at least 30 or 40 conditions must be considered. Proceeding from the superficial to the deep structures, one encounters the skin, considers herpes zoster, and looks for a rash. Next, there is muscle; trichinosis, dermatomyositis, and contusion of the muscle must be considered. Cough-induced contusions should not be forgotten. In the same layer, the ribs and cartilage remind one of rib fractures, Tietze syndrome, metastatic carcinoma, and multiple myeloma. Other rarer conditions of the rib are shown in Table 14.

Many causes of chest pain arise from the pleura. Pneumonia with pleurisy, empyema, pulmonary infarction, and neoplasms of the pleura must be considered. Tuberculous pleurisy and other infectious agents are not uncommon. In contrast, conditions of the lung are less likely to cause chest pain unless they involve the pleura: This is certainly true of pneumonia and neoplasms. A pneumothorax, however, is a very common cause of chest pain, especially in young adults.

Visualize the heart, and the pericardium comes to mind. This is a source of chest pain in acute idiopathic pericarditis, rheumatic carditis, and tuberculous and neoplastic pericarditis. The myocardium is the source of the most serious form of chest pain, myocardial infarction, but here again the pain is more severe if the pericardium is involved. Angina pectoris and chronic coronary insufficiency are common causes of chest pain arising from the myocardium. Myocarditis (e.g., viral) causes less severe pain, but inflammation of the myocardium from postinfarction syndrome or postpericardiotomy syndrome can be extremely painful. The endocardium is the source of mild chest pain in mitral valve prolapse.

Now visualize the other central structures: The esophagus reminds one of reflux esophagitis and hiatal hernia; the mediastinum suggests mediastinitis and substernal thyroiditis or Hodgkin lymphoma (usually not too painful); the aorta suggests dissecting aneurysms, and the thoracic spine suggests spinal cord tumors, osteoarthritis, Pott disease, fractures, herniated discs, as well as the other conditions listed in Table 14.

This chapter would not be complete unless referred pain to the chest was considered. Thus, abdominal conditions such as cholecystitis, pancreatitis, and splenic flexure syndrome may present with chest pain. Conditions of the neck that press the cervical nerves may also cause chest pain, particularly scalenus anticus syndrome, cervical ribs, and herniated discs of the cervical spine: Neurocirculatory asthenia is associated with atypical chest pain; a psychiatric evaluation will assist in this diagnosis.


Approach to the Diagnosis

A possible myocardial infarction must be the first consideration in all adults with acute chest pain, especially if there are significant alterations of the vital signs. Consequently, serial ECGs, serial cardiac enzymes including troponins, and hospitalization will often be necessary. Patients with non-STEMI chest pain may be evaluated by coronary CT angiography first. After this condition has been excluded, we can turn our attention to the other possibilities. A tablespoon of Xylocaine Viscous may be administered to rule out reflux esophagitis. Arterial blood gases, chest x-ray, and a lung scan or helical CT scan of the chest may be ordered to exclude a pulmonary embolism. The D-dimer test is sensitive for pulmonary embolism and dissecting aneurysm. Pulmonary angiography may be necessary in some cases. A chest x-ray may be ordered to rule out pneumonia. Acute chest pain related to esophagitis is often relieved by swallowing Lidocaine Viscous, an extremely useful tool in the differential diagnosis. Relief of

the pain with nitroglycerin under the tongue or by spray will support the diagnosis of coronary insufficiency. Tenderness of the costochondral junctions with relief on lidocaine injection into the point of maximum tenderness suggests Tietze syndrome (costochondritis). In cases of chronic chest pain, an exercise tolerance test with thallium scan should be done to rule out coronary insufficiency or myocardial infarction. CT angiography will easily diagnose a dissecting aneurysm. It may be wise to do immediate coronary angiography if the condition deteriorates so that balloon angiography, bypass surgery, or reperfusion therapy may be initiated. Dissecting aneurysm is revealed by CT scan or MRI of the chest. Do not forget that young patients may have an MI due to collagen disease or anomalous coronary circulation.








Table 14 Chest Pain

















































































































































  V
Vascular
I
Inflammatory
N
Neoplasm
D
Degenerative and Deficiency
I
Intoxication Idiopathic
C
Congenital
A
Autoimmune Allergic
T
Trauma
E
Endocrine
Skin   Herpes zoster              
Muscles   Epidemic pleurodynia
Trichinosis
Diaphragmatic abscess
    Intercostal neuralgia   Dermatomyositis Contusion
Cough-induced hemorrhage into muscle
 
Ribs and
Cartilages
  Osteomyelitis
Tietze syndrome
Metastatic carcinoma
Multiple myeloma sarcoma
Osteitis deformans       Fracture contusion Osteitis fibrosa cystica
Pleura Pulmonary infarction Pleurisy
Tuberculosis
Fungus
Empyema
Metastatic carcinoma
Mesothelioma
           
Lung   Pneumonia Carcinoma (primary and metastatic)   Pneumothorax   Pneumothorax    
Pericardium   Viral pericarditis
Rheumatic fever
Tuberculosis
Metastatic carcinoma   Uremia        
Myocardium Myocardial infarct
Coronary insufficiency
Myocarditis         Postinfarction syndrome Postcommissurotomy syndrome
Contusion
 
Aorta Aneurysm Aortitis   Medionecrosis       Ruptured aorta  
Esophagus   Ulcer
Esophagitis
Esophageal carcinoma   E.g., lye erosion Diverticulum
Hiatal hernia
  Ruptured esophagus  
Mediastinum   Mediastinitis Dermoid cyst
Hodgkin lymphoma
          Substernal thyroiditis
Thoracic
Vertebrae
  Osteomyelitis
Pott disease
Metastatic carcinoma Osteoporosis
Osteoarthritis
    Rheumatoid spondylitis Fracture
Herniated disc
Osteoporosis
Osteomalacia
Spinal Cord   Syphilis
Tuberculosis
Neuralgia
Tumor       Transverse myelitis Hematomyelia  


Other Useful Tests



  • CBC


  • Sedimentation rate (pneumonia, infarction)


  • Sputum smear and culture (pneumonia)


  • Bernstein test (reflux esophagitis)


  • Serum cardiac troponin levels (myocardial infarction)


  • D-dimer testing (pulmonary embolism)


  • Esophagoscopy (reflux esophagitis)


  • X-ray of the spine (radiculopathy)


  • Echocardiogram (pericarditis)


  • 24-hour Holter monitoring (coronary insufficiency)


  • Gallbladder sonogram


  • Ambulatory pH monitoring (esophagitis)


  • Helical CT scan (pulmonary embolism)


  • Single photon emission computed tomography (SPECT) scan (coronary insufficiency)


  • Therapeutic trial of antacids or proton pump inhibitors (reflux esophagitis, peptic ulcer)


  • CT coronary calcium scan.



Chest Wall Mass

The differential diagnosis of this symptom and sign is similar to that of chest pain: Anatomy is the key to both. After visualizing all the organs of the chest and cross-indexing them with the mnemonic MINT, a convenient and extensive differential list can be constructed as in Table 15. The discussion that follows will also concentrate on the most significant of these.








Table 15 Mass in the Chest Wall


















































  M
Malformation
I
Inflammation
N
Neoplasm
T
Trauma
Skin and Subcutaneous Tissue Neurofibroma
Venous engorgement
Sebaceous cyst
Cellulitis
Abscess
Lipoma Contusion
Muscle   Myositis (Rare) Contusion
Ribs Pigeon breast
Xiphoid prominence
Osteomyelitis
Tuberculosis
Tietze syndrome
Osteoma
Multiple myeloma
Metastatic carcinoma
Fracture
Contusion
Lungs and Pleura   Tuberculosis
Emphysema
Lung abscess
Carcinoma or mesothelioma with direct extension Hemorrhage
Pneumothorax
Subcutaneous emphysema
Heart and Pericardium Cardiomegaly
Aneurysm
Tuberculous or idiopathic pericarditis Metastatic carcinoma to pericardium Traumatic aneurysm
Aorta Aneurysm     Traumatic aneurysm
Mediastinum Superior vena cava obstruction Mediastinitis Hodgkin lymphoma
Dermoid cyst
 

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