Monday, January 9, 2012
Increase in vessel tone may arrest the paroxysm and this is most effectively achieved by carotid sinus massage. All clinicians should be adept at carotid sinus massage which should be carried out as follows. The sinus is situated close to the bifurcation of the common carotid artery opposite the angle of the jaw. With the head turned to one side, the thumb should be placed over the position of maximum pulsation and firm massage applied up and down over the vessel and against the spine for not longer than 10 seconds, first on one side together. Mere pressure is rarely sufficient. The radial pulse should be felt with the other hand and the heart auscultator with the chest-piece of the stethoscope held over the apex beat. If possible the procedure should be monitored by a continuous ECG record. Simpler methods which can be used at home are sometimes effective, such as holding the breath for as long as possible or by performing the Val salve (forcible expiration with glottis closed ) or Muller (deep inspiration with glottis closed) man oeuvre. Retching or vomiting may terminate the throat or taking an emetic such as and can be given in the form of dioxin, 1 mg. intravenously, or an initial dose of 1 mg should digitalis fail drugs to stimulate the parasympathetic should be tried, e.g. neostigmine 1-2 mg. or acetylmethylcholine 10-25 mg. subcutaneously. Occasionally unpleasant side-effects result from such drugs, e.g. vomiting abdominal colic or even collapse. Atropine is the antidote which should always be on hand, 1.0 mg. being injected immediately should symptoms be alarming. Guanidine by mouth every two hours up 8 doses if necessary or intravenously in severe cases or procainamide as below may arrest the attack when all other measures have failed.