Intravascular Extraction of Chronic Pacemaker Leads: Efficacy and Follow-Up

Extraction of chronic pacemaker leads has been recommended for infections, prevention of venous thrombosis, migration, and possible perforation. Success with constant traction techniques has been variable, and the cost and morbidity of open chest surgical procedures are prohibitive. Efficacy of a new system for lead extraction using intravascular techniques was analyzed. The system (Cook Pacemaker) uses a locking stylet, which is secured at the distal electrode by counterclockwise rotation to reinforce the lead and facilitate traction, and dilator sheaths that are used to free the lead from adhesions in the venous system. In a series of 56 patients (ages 19–88)who presented for lead extraction because of erosion (5), infection (14), lead replacement (35), or other (2), 86 leads were extracted. Thirty-two were atrial leads and 54 ventricular; 23 had active fixation and 63 passive. Average duration of implant was 58 ±42 months (range 1–264). Eighty-four leads were totally removed and two partially removed. For these two leads, the distal tip was not removed; in both cases the locking stylet was not secured at the distal electrode due to obstruction within the lead. Two patients developed arm edema following the procedure, which resolved with elevation. One patient developed a subclavian thrombosis, which resolved with warfarin anticoagulation. Four patients have expired due to unrelated causes. In conclusion, this intravascular approach for extraction of chronic leads is effective, and the procedure is safe when performed by experienced personnel.     

LITONIT: EVALUATION OF CLINICAL EFFECTIVENESS

Clinical data are presented on a new anti-alcoholic drug, litonit.A substantial reduction in the pathological addiction to alcoholtakes place under the effect of litonit, and a stable aversivereaction to alcohol develops The new drug is distinguished byits low toxicity, good tolerance, and its failure to cause disordersof the liver and kidneys even after chronic administration.     

Single residue modifications of the delta opioid receptor selective peptide, [d-Pen2,d-Pen5]-enkephalin (DPDPE)

Six analogs of the highly delta opioid receptor selective, conformationally restricted, cyclic peptide [d -Pen²,d -Pen⁵]enkephalin, Tyr-d -Pen-Gly-Phe-d -PenOH (DPDPE), were synthesized and evaluated for opioid activity in rat brain receptor binding and mouse vas deferens (MVD) smooth muscle assays. All analogs were single amino acid modifications of DPDPE and employed amino acid substitutions of known effects in linear enkephalin analogs. The effect on binding affinity and MVD potency of each modification within the DPDPE structural framework was consistent with the previous reports on similarly substituted linear analogs. Conformational features of four of the modified DPDPE analogs were examined by ¹H NMR spectroscopy and compared with DPDPE. From these studies it was concluded that the observed pharmacological differences with DPDPE displayed by diallyltyrosine¹-DPDPE ([DAT¹]DPDPE) and phenylglycine⁴-DPDPE ([Pgl⁴]DPDPE) are due to structural and/or conformational differences localized near the substituted amino acid. The observed enhanced μ receptor binding affinity of the carboxamide terminal DPDPE-NH₂ appears to be founded solely upon electronic differences, the NMR data suggesting indistinguishable conformations. The observation that the α-aminoisobutyric acid substituted analog [Aib³]DPDPE displays similar in vitro opioid behavior as DPDPE while apparently assuming a significantly different solution conformation suggests that further detailed conformational analysis of this analog will aid the elucidation of the key structural and conformational features required for action at the δ opioid receptor.