Definition of Coma

In this article, we will discuss the Definition of Coma. So, let’s get started.


Coma is defined as a persistent loss of consciousness in which the subject lies with eyes closed and shows no understandable response to an external stimulus or inner need. The coma may vary in degree; and in deep coma, i.e. corneal, pupillary, pharyngeal reflexes are lost. The tendon and plantar reflexes also become absent. With lesser degree of coma (precoma), pupillary reflexes, reflex ocular movements and other brainstem reflexes are preserved and there may or may not be rigidity of the limbs and extensor plantar response.

The term coma refers to a deep sleep-like state from which the patient cannot be aroused. The stupor refers to a sleep-like state from which the patient can be aroused with vigorous stimuli and the patient tries to avoid the stimuli. Drowsiness means light sleep-like state from which patients can easily arouse and there is a brief period of alertness.


Causes of Ventricular Tachycardia

In this article, we will discuss various Causes of Ventricular Tachycardia. So, let’s get started.

Ventricular Tachycardia is a wide QRS (>0.12 sec) tachycardia consisting of 3 or more consecutive ventricular premature beats at a rate of >100 bpm. The sudden onset of a wide QRS tachycardia usually rings an alarm bell if the patient is symptomatic. If left untreated, VT may degenerate into a fatal ventricular flutter. VT may be sustained (persists for >30 seconds) or nonsustained (does not persist beyond 30 seconds). The sustained VT requires termination because of hemodynamic consequences. Repeated episodes (>2 in 24 hours) of VT require external cardioversion/defibrillation or DC shock therapy.


  • Acute myocardial infarction or ischemia
  • Cardiomyopathy (ischemic or idiopathic)
  • Electrolyte disturbance (e.g. hypokalemia, hypomagnesemia)
  • Drugs (e.g. digitalis and other proarrhythmics)
  • Myocarditis, mitral valve prolapse
  • Reperfusion
  • Ventricular aneurysm
  • Pacemaker mediated (e.g. DDD pacemaker)
  • Mechanically induced by a pacing catheter or flow-directed pulmonary artery catheter.
  • Idiopathic
  • Miscellaneous such as right ventricular dysplasia, Bergada syndrome, sarcoidosis.