Chronic heart failure therapy used to remove or relief signs of cardiac disorders. Different cardiac inotropic are used for CHF treatment. The usual drug is digoxin but another cardiac inotropic drugs can be used for CHF therapy. Dopamine is one of these drugs that has a copiexity pharmacology. Dobutamine has a direct inotropic effect and is a synthetic analog of dopamine and seems to be a beneficial sympathomimetic amin for CHF treatment.

In this research, we tried to determination of induced E.C.G changes with theses drugs. We selected two independent groups. Each group included ten dogs. We never used any chemical drug for restraining because the sedative drugs affects on cardiac normal function. We obtain an electrocardiogram to determinate any cardiac disorders and dogs with cardiac problems were eliminated. These drugs resolved in dextrose (5%) with three different dilutions. Injectable drugs calculated based on drop per minute. The injection interval of different dilutions were ten minutes. Comparative study on normal electrocardiogram after injection of dopamine and dobutamine, indicates that:

1.  Decrease of S-T segment and innovation of shape of P&T waves.

2.  Exacerbation of normal sinus arrhythmias.

3.  Induced of ectopic atrial and ventricular contractions.

4.  Induced of tachycardia and different cardiac blocks.

Analyzing of statistic data with RB method (random block CRD) shows that:

1.  Decrease of P wave amplitude.

2.  Increase of T wave amplitude.

3.  Decrease of Q-T wave interval because of changes in heart rates.

With attention to effects and analysis of statistic data indicate that dobutamine is a choice drug for emergency treatment for C.H.F and dobutamine suitable cardiogenic shock.