Irrigated radiofrequency catheter ablation guided by electroanatomic mapping for recurrent ventricular tachycardia after myocardial infarction: the multicenter thermocool ventricular tachycardia ablation trial.

BACKGROUND: Recurrent ventricular tachycardia (VT) is an important cause of mortality and morbidity late after myocardial infarction. With frequent use of implantable cardioverter-defibrillators, these VTs are often poorly defined and not tolerated for mapping, factors previously viewed as relative contraindications to ablation. This observational multicenter study assessed the outcome of VT ablation with a saline-irrigated catheter combined with an electroanatomic mapping system. METHODS AND RESULTS: Two hundred thirty-one patients (median LV ejection fraction, 0.25; heart failure in 62%) with recurrent episodes of monomorphic VT (median, 11 in the preceding 6 months) caused by prior myocardial infarction were enrolled. All inducible monomorphic VTs with a rate approximating or slower than any spontaneous VTs were targeted for ablation guided by electroanatomic mapping during sinus rhythm and/or VT. Patients were not excluded for multiple VTs (median, 3 per patient) or unmappable VT (present in 69% of patients). Ablation abolished all inducible VTs in 49% of patients. The primary end point of freedom from recurrent incessant VT or intermittent VT after 6 months of follow-up was achieved for 123 patients (53%). In 142 patients with implantable cardioverter-defibrillators before and after ablation for intermittent VT who survived 6 months, VT episodes were reduced from a median of 11.5 to 0 (P<0.0001). The 1-year mortality rate was 18%, with 72.5% of deaths attributed to ventricular arrhythmias or heart failure. The procedure mortality rate was 3%, with no strokes. CONCLUSIONS: Catheter ablation is a reasonable option to reduce episodes of recurrent VT in patients with prior myocardial infarction, even when multiple and/or unmappable VTs are present. This population remains at high risk for death, warranting surveillance and further study.

Bioabsorbable screw fixation in coracoclavicular ligament reconstruction.

The purpose of this study is to evaluate the biomechanical properties of stainless steel and bioabsorbable screw fixation of the clavicle to the base of the coracoid. Seven matched pairs of fresh frozen shoulders were prepared by removing all soft tissue except the acromioclavicular and coracoclavicular ligament complexes. The shoulders were randomly selected and fixed with 4.5-mm stainless steel (SS) screws, while contralateral shoulders were fixed with 4.5-mm poly L-lactic acid polymer (PLLA) screws. Pullout strength, stiffness, and elongation to failure were measured using an Instron Mechanical Tester (Model 4202). The average pullout strength of 720.6 +/- 244.9 N of the metal screws was not statistically different (p = 0.089) from that of the biodegradable screws of 580.4 +/- 188.6 N. The pullout strengths exerted by both these screws exceeded the reported strength (500 N) of the intact coracoclavicular complex indicating adequate initial pullout strength for coracoclavicular fixation.