Does the brain control heart electrical impulses? if not, what does? both my cardio and neurologist say me heart electrical system is unbalanced, that the contraction phase is longer than my relaxation phase, causing me "chest" pain. what medicines are

Electrical systems: Our bodies have cells that are ALL electrically active,there are numerous interconnects via multiple modalities(nerves,hormones etc) between the various systems that your attributed statement does not make sense;try talking again with the physicians such that through repetition you gain better insight into what they are trying to impart;failing this seek other opinion but become body educated

Pacemaker: The heart has its own pacemaker that generates the electrical impulses. This pacemaker can be influenced by brain impulses & hormones. Did your cardiologist say your problem was from birth, or that it developed later? Given your heart medications, I wonder if your cardiologist thinks you may need an artificial pacemaker? You'll need to discuss your condition and treatment with a cardiologist.

See below: The brain can increase or slow down heart rate via the autonomic nervous system which has connections to the heart. The hearts electrical system(conduction system) is under control of the hearts pacemaker. Neither one can make contraction longer than relaxation. If that were so their wouldn't be time for the heart to refill prior to the next contraction.