Methods, apparatus, and systems are provided to control contraction of the heart. At least one sensing element receives signals indicating electrical activity of sinus rhythm of the heart. The electrical activity is monitored and analyzed to detect an event. In addition, the electrical activity is monitored to detect, for example, premature stimulation and contraction of a portion of the heart, such as the left ventricle. Contraction in the pre-excited portion of the heart is then suppressed using electrical pulses. The heart may then be allowed to contract naturally, or a stimulating pulse may be applied to assist the heart in contracting.
