“…Apart from the mediastinal atrial electrode (Carlens et al, 1965;Lagergren et al, 1966a, b;Larsson et al, 1969;Larsson, 1970;Kleinert and Nahrstedt, 1974) there are two main approaches for introducing the electrode: implantation via thoracotomy Nathan et al, 1964;Center and Nathan, 1966;Silverman et al, 1968;Nusbaum and Levit, 1970;Cleveland et al, 1972;Mills and Ochsner, 1973;Perryman and Sealy, 1973) and transvenous techniques (Rodewald et al, 1964; Detector electrode for atrial triggered cardiac pacing Hunt and Sloman, 1968;Kastor et al, 1969;Moss et al, 1969;Kramer and Moss, 1970a, b;Kitamura et al, 1971;Vogel et al, 1971;Rosenkranz and Schaldach, 1971;Bleifeld et al, 1971;Smyth et al, 1971a, b;Porstmann et al, 1972;Zucker et al, 1973;Cappelen and Hall, 1974;Moss et al, 1974;Obel and Scott Millar, 1975;Rubenfire, 1975). Reviews of different methods have been given by Dodinot et al (1969), Sowton (1969), Benchimol and Goldstein (1969), Nathan et al (1971), DeSanctis (1971, and Furman (1973).…”