The pacemaker may have one to three leads, depending on the type of pacemaker needed to treat your heart problem. There are different types of pacemakers: Single-chamber pacemakers use one lead in the upper chamber (atria) or lower chamber (ventricles) of the right side of the heart.
The MexicanâAmerican War, also known as the Mexican War, the U.S.âMexican War or the Invasion of Mexico, was an armed conflict between the United States of America and the United Mexican States from 1846 to 1848.
The Mexican-American War was largely a conventional conflict fought by traditional armies consisting of infantry, cavalry and artillery using established European-style tactics. As American forces penetrated into the Mexican heartland, some of the defending forces resorted to guerrilla tactics to harass the invaders, but these irregular forces did not greatly influence the outcome of the war.