NONPAROXYSMAL JUNCTIONAL TACHYCARDIA （NPJT）（2）

Sevenfy-fwo cases of NPT with A-V dissociation were reported. Thier range of ventricular rate was 60—150 per minute. According to the EGG manifestations they were divided into four groups:
1)A-V dissociation without depression of A-V conduction: The A-V dissociation was maintaind with a ventrcular rate exceeding the atrial rate. Occasionally, ventricular capture occurred when P wave appeared at the time when AV junctional tissue was nonrefacrory （incomplete AV dissociation）. In some cases, the sinus rate was close to the junctional rate and gradual shifting of the ventricular control from one pacemaker to another displayed as intermittent A-V dissociation. These conditions occurred frequently in postintracardiac surgery （8 case）, rhieumatic fever （6cases）, myocardiopathy （4 cases） and acute myocardial infarction （3 cases） etc.
2) A-V dissociation with depression of A-V conductiom; In this condition, the more rapid atria were under the control of the SA node while the slower ventricles under the control of the junction. 30 cases belonged to this group. Ten cases of persistent atrial fibrillation induced this arrhythmia due to digitalis excess or intoxicatinn. The other causes included postintracardiac surgery （8 cases）, rheumatic fever （4 cases）, cadiomyopathy （3 cases） and Cor pulmonale （1 case）. In patients with atrial fibrillation, digitalis mostly frequently gave rise to NPJT with A-V block. Less commonly observed arrhythmias included exit block from junctional pacemaker and bidirectional tachycardia which might reflect block action in subnodal or intraventricular tissue, and thier appearance often signified a grave prognosis.
3) The SA node and junctional pacemaker controling the atria and ventricles alternately; During the transition of control from one pacemaker to another, atrial fusion beats Usually appeared and in such a short period did partial AV dissociation occur. In this group, chronic heart lesions predominated.
4) Double junctional tachyardia; All 3 cases were associated wifh chronic heart diseases.
The majority of cases of NPJT with A-V dissociation are in association with acute lesions （e. g. operation trauma, inflammation, infarct） or digitalis excess or intoxication, The less common causes were metabolic or electrolyte disturbances. So long as the etiologic significance was concerned, NPJT with A-V dissociation differed distinctly from the variety without AV diasociation, the latter being often seen in normal persons or in patients who suffered from well-compensated chronic heart diseases. They were transitory and thief appearance seemed to have no prognostic significanne.