Department of cardiac muscle pathology and transplantation of organs and tissues

Unstable angina

Unstable angina pectoris: etiology, signs and symptoms, diagnostics, and methods of treatment

Unstable angina is one of the exacerbations of the ischemic heart disease, when due to some reasons there is an increase of frequency, duration and intensity of a heart pain accompanied by the gradually decreasing exercise tolerance. The patients with unstable angina are much more predisposed to the myocardial infarction compared to those with stable angina.


The main cause of unstable angina is a breakdown of the unstable atherosclerotic plaque (a lump mainly consisting of cholesterol and calcium) on the internal wall of the coronary arteries that results in formation of thrombi. This leads to a partial blockage of the artery’s lumen and insufficient blood supply to the cardiac muscle causing the complex of symptoms of unstable angina.

The risk factors are hyperlipidemia (increased level of cholesterol), obesity, physical inactivity, nicotine and alcohol abuse, anemia, toxicoses, diabetes, high blood pressure, increased blood viscosity, and psycho-emotional stress


During the stable angina attacks the patients complaint of retrosternal pressing, constricting and burning pain that may irradiate to the whole left part of the chest, the left arm, shoulder, scapula, mandibular and the left part of the face. Sometimes the pain can be localized only between the scapulae or characterized as a girdling pain. The pain may be accompanied by the fear of death, shortness of breath, dizziness and increased sweating.

The main symptoms of unstable angina are the following:

  • The pain becomes more frequent

  • The intensity of attacks increases

  • The duration of attacks exceeds 10-15 minutes and more

  • The attacks may occur both during the lesser physical activity (comparing with the earlier times) and at rest

  • A sublingual nitroglycerin administration is ineffective or provides only a temporary relief


​Classification dividing the unstable angina into 3 classes (the higher the class, the higher the risk of complications):

  • Class I – primary (preinfarction) angina is characterized by a new onset or intensified attacks within 1 month since the first angina attack
  • Class II – angina attacks at rest within 1 preceding month
  • Class III – angina attacks at rest within 48 preceding hours

There are several forms of unstable angina:

  • The new-onset angina developing within 1 month since the first angina attack and is characterized by retrosternal discomfort or pain which may irradiate to the left arm, neck, mandibular or epigastric area;
  • Accelerated angina with increased intensity and/or duration of the attacks provoked by the minimal physical exercise or at rest and accompanied by dyspnea and shortening of breath;
  • Postinfarction angina that developed within 24 hours to 8 weeks following the myocardial infarction or after the surgery (within 1-2 months following the coronary artery bypass grafting).


  • Complete blood count and blood biochemistry, as well as urinalysis, particularly for assessment of cholesterol level and a level of some specific blood enzymes that indicate the myocardial infarction.
  • Electrocardiography (ECG) shows the changes of ST segment and T wave.
  • Echocardiography (EchoCG) shows the possible myocardial contractility disorders and defines a number of specific signs of myocardial ischemia.
  • A 24-72-hours Holter monitoring.
  • Stress EchoCG is the method showing the zones of the disturbed myocardial contractility caused by physical exercise.
  • Myocardial scintigraphy is the method of the cardiac walls and chambers imaging by means of radiopharmaceutical agents’ administration and visualization of the radiation they emit.
  • Coronary angiography is a radio-opaque method of examination of the coronary blood flow which helps to see the thrombi or narrowing of the coronary vessels. 

Methods of treatment


A limited physical exercise regimen and a bland diet, anti-ischemic agents decreasing the myocardial oxygen demand (preductal, prolonged-release nitrates such as pentaerithrityl tetranitrate, sustac, nitrosorbide, nitrong); β-adrenoblockers (anaprilin, trasicor, propanolol), molsidomine (corvaton), calcium-channel blockers (verapamil, nifedipine), ACE inhibitors (perindopril, captopril), and diuretics. If the medication fails to reduce the pain syndrome, neuroleptanalgesia (used in myocardial infarction) may be performed.


The diagnostic coronary angiography may be extended to treatment surgery with performance of the immediate balloon angioplasty or stenting the coronary arteries (a special small mesh tube inserted into the lumen of the affected coronary artery to facilitate free blood flow). Among the other surgical methods, a coronary artery bypass grafting may be performed (creating an additional vascular bypass to the area of ischemia to facilitate a free blood flow).


In the case of a timely hospitalization and treatment, the prognosis is relatively favorable. Nevertheless, despite the therapy about 20% of patients during the first 2-3 months and 11% of patients during the first year after the instable angina was diagnosed develop a large-focal myocardial infarction.
Due to the complications, the prognosis is worsening and is determined by the type of pathology. For example, if the infarction is accompanied by the pulmonary edema but the therapy is adequate, the patient will survive; in the case of a thromboembolia of the pulmonary artery or ventricular fibrillation, death may be immediate.



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