"Bow-tie" mitral valve repair: an adjuvant technique for ischemic mitral regurgitation.

BACKGROUND: Current techniques of mitral valve repair rely on decreasing valve area to increase leaflet apposition, but fail to address subvalvular dysfunction. A novel repair has been introduced with partial left ventriculectomy, which apposes the anterior leaflet to a corresponding point on the posterior leaflet creating a double-orifice valve, with reported adequate control of mitral regurgitation. METHODS: We started to use the "bow-tie" repair as an adjunct to posterior ring annuloplasty in cases in which mitral regurgitation was not adequately controlled by decreasing mitral valve area (n = 6), or when placement of an annuloplasty ring was impractical (n = 4). Mean follow-up was 336 days (range, 82 to 551 days) with no postoperative deaths. RESULTS: Mitral regurgitation decreased from 3.6+/-0.5 to 0.8+/-0.4 (p < 0.0001), with a concomitant increase in ejection fraction from 33%+/-13% to 45%+/-11% (p = 0.0156) before hospital discharge. Mitral valve area, measured by pressure half-time, decreased from a mean of 2.5+/-0.3 to 2.1+/-0.3 cm2, with a mean transvalvular gradient of 4.5+/-2.0 mm Hg. In patients whose mitral valve was repaired using the bow-tie alone, mitral regurgitation was reduced from 4+, to a trace to 1+. Postoperatively, mitral valve area increased from 1.9 to 2.5 cm2 during exercise, further supporting the concept that this technique preserves mitral valve annular function. CONCLUSIONS: These observations suggest that the bow-tie repair may offer advantages over conventional techniques of mitral valve repair and should be considered as an adjunct, especially in patients with impaired left ventricular function.

Usefulness of intermittent monitoring of mixed venous oxygen saturation after stage I palliation for hypoplastic left heart syndrome.

Most deaths after stage I palliation for hypoplastic left heart syndrome have occurred within the first 24 hours after surgery. Efforts to improve 1-day survival should therefore have significant impact on improving overall survival. Early death has most often been attributed to low cardiac output and abnormalities of pulmonary to systemic flow ratio (Qp/Qs). Thirteen infants underwent stage I palliation and had a catheter inserted in the high superior vena cava (SVC) for intermittent measurement of SVC oxygen saturation. Calculation of Qp/Qs was achieved using SVC saturation as a mixed venous oxygen saturation, and estimating pulmonary venous oxygen saturation. Eleven patients survived, and 2 patients died within the first 24 hours. Abnormalities in Qp/Qs were noted in 12 of 13 patients after operation. In 10 of these 12 patients, there was a high Qp/Qs, which has been associated with poor outcome. High Qp/Qs was noted even in patients with acceptable arterial oxygen saturations (< 85%). SVC saturation increased in all survivors during the first 24 hours, and was associated with a decrease in Qp/Qs. Measurement of SVC oxygen saturation appears to be a valuable adjuvant in the postoperative management of infants after stage I palliation of hypoplastic left heart syndrome. Major abnormalities in Qp/Qs can be detected even with acceptable arterial saturations. With this information, early ventilator/pharmaceutical adjustments can be made which may improve stage I survival.

Determinants of pace-terminable ventricular tachycardia: implications for implantable antitachycardia devices.

The next generation of implantable antitachycardia devices incorporate antitachycardia pacing for the treatment of ventricular tachycardia. To evaluate the potential determinants of pace terminability, we analyzed 62 episodes of induced monomorphic ventricular tachycardia. We found that the tachycardia cycle length and cycle length variability are the major determinants of pace terminability. These findings should be considered in the designing of ventricular tachycardia detection and termination algorithms.