Cardiac Arrhythmias: Or something else? Differential Diagnosis

Congenital malformations, deformities, and chromosomal abnormalities (Q00-Q99).

  • Accessory (supernumerary) conduction pathways (Wolff-Parkinson-White syndrome, WPW syndrome; AV nodal re-entrant tachycardia, AVNRT).
  • Cardiac vitias (congenital heart defects).
  • Ion channel disorders
    • Brugada syndrome – is classified as “primary congenital (congenital) cardiomyopathies” and there the so-called ion channel disorders; in 20% of cases of the disease is an autosomal dominant point mutation of the SCN5 gene; Characteristic are the occurrence of syncope (brief loss of consciousness) and cardiac arrest, which first occurs due to cardiac arrhythmias such as polymorphic ventricular tachycardia or ventricular fibrillation; patients with this disease are apparently completely heart healthy, but can already suffer sudden cardiac death (PHT) in adolescence and early adulthood.
    • Congenital long-QT syndrome (LQTS) – belongs to the group of ion channel diseases (channelopathies); heart disease with pathologically prolonged QT interval in the electrocardiogram (ECG); disease is either congenital (inherited) or acquired, then usually as a result of an adverse drug reaction (s. below “Cardiac arrhythmia due to drugs“); can lead to sudden cardiac death (PHT) in otherwise heart-healthy people.Note: QTc cut-off is 480 ms; screening for long-QT should be done from a QTc of 460 ms if clinically suspicious syncope/s have occurred.

Respiratory System (J00-J99)

Blood, blood-forming organs – immune system (D50-D90).

Endocrine, nutritional, and metabolic diseases (E00-E90).

Cardiovascular system (I00-I99).

  • Atrioventricular reentry tachycardia via an accessory pathway (AVRT).
  • Bradycardic arrhythmias (heart rate: <60 beats per minute):
    • Bradyarrhythmia absoluta
    • Higher-grade, sinuatrial and atrioventricular blockages.
    • Carotid sinus syndrome (carotid sinus syndrome; synonyms: hypersensitive carotid sinus syndrome (HCSS), hypersensitive carotid sinus syndrome) – hyperactive carotid sinus reflex, the cause of bradycardia to short-term asystole (complete cessation of electrical and mechanical cardiac action for more than 2 seconds; in carotid sinus syndrome: 6 seconds or a drop in blood pressure of at least 50 mmHg systolic)/acute circulatory arrest with syncopal symptoms; carotid sinus hypersensitivity can be detected in 20% of all patients over 60 years of age, but less than 1% have detectable carotid sinus syndrome
    • Sinus node syndrome in terms of bradycardia–tachycardia syndrome, if applicable.
  • Cor pulmonale – dilatation (widening) and/or hypertrophy (enlargement) of the right ventricle (main chamber) of the heart due to pulmonary hypertension (increase in pressure in the pulmonary circulation: pulmonary arterial mean pressure (mPAP) > 25 mmHg at rest – normal mPAP is 14 ± 3 and does not exceed 20 mmHG), which may be due to various diseases of the lung
  • Dilated cardiomyopathy (heart muscle disease) – systolic pump dysfunction with cardiomegaly (enlargement of the myocardium (heart muscle)) and impaired ejection fraction (EF; ejection fraction).
  • Endocarditis (inflammation of the inner lining of the heart).
  • Heart disease of different genesis
  • Heart failure (cardiac insufficiency)
  • Hypertension (high blood pressure)
  • Coronary artery disease (CAD; coronary artery disease).
  • Pulmonary embolism
  • Myocardial infarction (heart attack)
  • Myocarditis (inflammation of the heart muscle)
  • Pericarditis (inflammation of the pericardium)
  • Rheumatic fever (synonym: streptococcal rheumatism); reactive disease that usually occurs after infection with group A streptococci (Lancefield classification).
  • Sick sinus syndrome (sinus node disease).
    • Sinus bradycardia (< 60 heartbeats per minute), SA block (sinuatrial block), sinus arrest (sinus node arrest).
    • Bradycardia-tachycardia syndrome, bradycardic phases of the heartbeat (< 60 beats per minute) alternating with tachycardic phases (> 100 beats per minute); this is often associated with an inadequate rate rise during exercise (chronotropic incompetence)
  • Tachycardic arrhythmias (heart rate: > 100 beats per minute).
  • Atrial flutter
  • Atrial fibrillation (VHF)

Infectious and parasitic diseases (A00-B99).

  • Lyme disease *
  • Brucellosis (Malta fever) * – Infectious disease transmitted from animals to humans.
  • Dengue fever *
  • Yellow fever *
  • Influenza (flu) *
  • Tetanus (tetanus) *
  • Typhoid * – infectious disease with severe diarrhea.

* bradycardia

Mouth, esophagus (food pipe), stomach, and intestines (K00-K67; K90-K93).

Musculoskeletal system and connective tissue (M00-M99).

  • Eosinophilic granulomatosis with polyangiitis (EGPA), formerly Churg-Strauss syndrome (CSS), (synonyms: allergic granulomatous angiitis; Churg-Strauss granulomatosis; Churg-Strauss syndrome).
  • Rheumatic diseases of different genesis
  • Rheumatoid arthritis – chronic inflammatory multisystem disease, usually manifested in the form of synovitis (inflammation of the synovial membrane).
  • Sarcopenia (muscle weakness or muscle wasting).
  • Sjögren’s syndrome – autoimmune disease (excessive reaction of the immune system against the body’s own tissues) from the group of collagenoses, which leads to a chronic inflammatory disease or destruction of the exocrine glands, with the salivary and lacrimal glands most often affected.
  • Scleroderma – group of rare diseases associated with leathery connective tissue hardening of the skin.
  • Vasculitides – inflammatory rheumatic diseases characterized by a tendency to inflammation of the (mostly) arterial blood vessels.

Neoplasms – tumor diseases (C00-D48).

  • Pheochromocytoma – neuroendocrine (affecting the nervous system) catecholamine-producing tumor of the chromaffin cells of the adrenal medulla (85% of cases) or sympathetic ganglia (nerve cord that runs along the spine in the thoracic (chest) and abdominal (stomach) regions).
  • Plasmocytoma (multiple myeloma) → hypercalcemia (tumor-induced hypercalcemia (calcium excess) (TIH)) – serum calcium > 3.5 mmol/l = hypercalcemic crisis: polyuria (increased urination), exsiccosis (dehydration), hyperpyrexia (extreme fever: higher than 41 °C), cardiac arrhythmias, weakness and lethargy, and somnolence to coma.

Psyche – Nervous System (F00-F99; G00-G99).

Symptoms and abnormal clinical and laboratory findings not elsewhere classified (R00-R99)

  • Fever
  • Cachexia – emaciation of the organism (emaciation) due to profound disturbance of one or more organ functions.
  • Meteorism (flatulence)
  • Sinus bradycardia
  • Sinus tachycardia
  • Syncope (brief loss of consciousness) – arrhythmias usually occur shortly after fainting. In patients with
    • Low-risk (CSRS), half of the serious arrhythmias became apparent within the first 2 hours after admission to the emergency department.
    • Moderate- and high-risk within 6 hours.

    3.7% of patients with syncope are arrhythmic within 1 month of syncope.

Genitourinary system (kidneys, urinary tract – sex organs) (N00-N99).

  • Acute renal failure
  • Chronic renal failure (kidney weakness; process that leads to a slowly progressive reduction in kidney function)
  • Climacteric (menopause; menopause in women).

Injuries, poisonings, and other consequences of external causes (S00-T98).

  • Polytrauma
  • Shock, unspecified
  • Burns
  • Poisonings

Other differential diagnoses

  • Children, adolescents → respiratory sinus arrhythmia (RSA) – physiologic fluctuation of heart rate due to respiration (respiratory synchronous fluctuation of heart rate):
  • Older age → bradycardia
  • Malnutrition → Micronutrient deficiency (vital substances): potassium, magnesium, calcium.
  • Stimulants:
    • Caffeine consumption
    • Alcohol
    • Tobacco (smoking)
  • Drug use:
    • Cocaine
  • Physical activity
    • Competitive athletes → bradycardia
      • Professional American football players – 5.5-fold increased risk of developing atrial fibrillation (adjusted odds ratio, OR: 5.5; 95% confidence interval: 2.0-15.4)
  • Psycho-social situation
    • Anxiety
    • Excitement
    • Stress

Medication

Environmental stress – intoxications (poisonings).

  • Poisonings of different genesis

Further

  • Heart failure (heart failure) patients with wearable cardioverter defibrillator (WCD) who walk less than 3,600 steps daily have a ventricular tachycardia and arrhythmia risk (originating from the ventricle) that is increased approximately fourfold.