"Clinical evaluation of a single-pass implantable electrode for all modes of pacing. The ""Crown of Thorns"" lead."" Physiological pacing was instituted in 17 patients (11 men and 6 women), mean age 67 years (range 33-77 years), using a variety of multiprogramable generators attached to a permanent single-pass dual chamber electrode. Eleven patients were paced in VAT mode (Cordis 208A or Siemens-Elema 625 generator), two patients in DVI mode (Intermedics Cyberlith IV generator) and four patients in DDD mode (Siemens-Elema 664/P33 or Telectronics Autima unit). Mean intracardiac P wave amplitude was 2.0 mV +/- 0.78/SD, range 0.7-3.6 mV. and mean atrial and ventricular pacing thresholds were 1.0 V and 0.5 V, respectively. Fourteen patients had completely successful A-V pacing during a follow-up period of 4-13 months (mean 7 +/- 2.7 months). Two failures were associated with malposition of the atrial crown and occurred exclusively with the Cordis 208A generator. In both patients generator replacement using a more sensitive unit (Siemens-Elema 625) resulted in successful VAT pacing for most of the time. Complete failure of A-V pacing occurred in only one patient who died from coronary artery disease after four months of follow-up. Thus, all of the remaining 16 patients achieved long-term (6 months) satisfactory physiological pacing using this new lead. We conclude that the ""Crown of Thorns"" electrode is a successful single-pass unipolar lead and can be used with all types of dual chamber generator for all modes of pacing."