Ultrafast time-resolved soft x-ray photoelectron spectroscopy of dissociating Br2.

The dissociation of excited state Br2 is probed with the novel technique of ultrafast soft x-ray photoelectron spectroscopy. Excited Br2 molecules are prepared in the dissociative (1)Pi(u) state with 80 fs, 400 nm pulses, and a series of photoelectron spectra are obtained during dissociation with pulses of soft x-ray light (47 nm, 26.4 eV, 250 fs). The formation of Br atoms is readily detected and the data support an extremely fast dissociation time for Br2 on the order of 40 fs. Amplitudes of the pump-probe features reveal that the ionization cross section of atomic Br at 47 nm is approximately 40 times larger than that of Br2.

Factors influencing the outcome of balloon aortic valvuloplasty in the elderly.

This study describes the short- and long-term outcome of 44 consecutive percutaneous balloon aortic valvuloplasty procedures performed in 42 elderly patients (age 77.8 +/- 7 years) with calcific aortic stenosis. The initial success rate was 95%, with the peak aortic valve pressure gradient declining from a mean of 82 +/- 32 mm Hg to 44 +/- 23 mm Hg and aortic valve area increasing from a mean of 0.59 +/- 0.15 cm2 to 0.83 +/- 0.40 cm2. One procedure-related death occurred and an additional three patients died less than or equal to 30 days after balloon aortic valvuloplasty. These patients all had New York Heart Association (NYHA) class IV heart failure symptoms prior to the procedure and their mean left ventricular ejection fraction (LVEF) (28 +/- 7%) was lower than that of hospital survivors (52 +/- 13%) (as was their ratio of left ventricular [LV] wall thickness-to-cavity ratio [0.50 +/- 0.10 versus 0.70 +/- 0.15]). At the time of hospital discharge after valvuloplasty, 76% of patients were asymptomatic or markedly improved (NYHA class I or II). After a mean follow-up of 15.5 months (range 2 to 26 months), however, 10 patients had died and 15 had undergone aortic valve replacement for recurrence of NYHA class III or IV symptoms. The adjusted 1- and 2-year survivals were 0.68 and 0.62, respectively, and adjusted 2-year event-free survival was 0.25. Proportional hazard regression analysis indicated that LVEF less than 40% was the only variable affecting survival (p less than 0.01) and was a possible indicator of event-free survival (p = 0.07).(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanism of aortic balloon valvuloplasty: fracture of valvular calcific deposits.

Balloon valvuloplasty has been shown to acutely reduce the hemodynamic and symptomatic severity of calcific aortic stenosis. The mechanism by which this improvement is accomplished is not known. At necropsy, three patients who died after hemodynamically successful aortic balloon valvuloplasty were found to have aortic valve calcific deposits fractured at one or more sites. These findings suggest that fracture of leaflet calcium represents the basis for successful aortic balloon valvuloplasty.

Intracoronary thrombolytic therapy in acute myocardial infarction: a prospective, randomized, controlled trial.

A prospective, randomized trial was designed to assess the efficacy of intracoronary thrombolytic therapy with streptokinase (STK) in acute myocardial infarction. Sixty-four patients with acute myocardial infarction were randomized within 6 hours of onset of symptoms to 1 of 3 groups. Sixteen patients were treated by conventional means (control group). Nineteen patients underwent coronary arteriography and received corticosteroids and intracoronary and intravenous nitroglycerin (NTG group). Twenty-nine patients received management identical to that of the NTG group, with the addition of intracoronary STK therapy (STK group). Recanalization was demonstrated in 21 of 29 patients (72%) in the STK group. Global and regional ejection fraction (EF) was determined by radionuclide ventriculography before any intervention and 7 to 10 days later. No significant improvement in global EF was achieved in the control and NTG groups. In STK patients as a group, global EF did not increase significantly; however, in patients recanalized with STK, EF improved from 42 +/- 17% to 49 +/- 16% (p = 0.023). All groups showed wide variability of response. Improvement in global EF of more than 5% was noted in 44% of patients recanalized with STK. When subgrouped on the basis of initial global EF of 45% or less or more than 45%, only patients recanalized with STK with an initial EF of 45% or less had an improved global EF (from 30 +/- 10% to 42 +/- 10%, p = 0.015).(ABSTRACT TRUNCATED AT 250 WORDS)

Valve replacement for aortic regurgitation: long-term follow-up with factors influencing the results.

One hundred consecutive cases of valve replacement for aortic regurgitation performed between 1967--1971 were analyzed to identify and quantitate factors related to a favorable result. Of 83 perioperative survivors, 78% (n = 65) became asymptomatic and 58% (n = 48) were alive 5--9 years postoperatively. The cause of aortic regurgitation affected both the speed of progression of symptoms and the postoperative result. Death due to myocardial failure may be prevented by optimal timing of operation. Accordingly, we identified variables that discriminated between patients who had an excellent postoperative result and those who died of myocardial failure. The most important discriminators were the severity (p = 0.03) and duration (p = 0.04) of dyspnea, the extent of therapy for heart failure (p = 0.001), physical findings of left ventricular failure (p = 0.002), the cardiothoracic ratio (p = 0.007), the resting pulmonary capillary wedge pressure (p = 0.01), and a cardiac index less than 2.2 1/min/m2 (p = 0.03). The data suggest that evidence of left ventricular failure, even of mild degree, is an indication for operation in patients with severe aortic regurgitation.