Effect of heart rate on Doppler indexes of systolic function in humans.

Recent investigations have shown Doppler echocardiography to be useful in the noninvasive assessment of left ventricular systolic function. No data exist, however, regarding the influence of heart rate on Doppler measurements of aortic blood flow velocity and acceleration in humans. Thus, 12 normal volunteers underwent continuous wave Doppler ultrasound recording from the suprasternal notch at baseline and during progressive transesophageal atrial pacing at intervals of 10 beats/min between 90 and 140 beats/min while 100% atrial capture and 1:1 atrioventricular conduction were maintained. Subjects were studied both upright (n = 12) and supine (n = 10). With the subject upright at baseline (mean heart rate 77.8 +/- 10.6 beats/min), peak acceleration averaged to 16.8 +/- 3.4 m/s2, and peak modal velocity and flow velocity integral averaged 0.72 +/- 0.14 m/s and 8.4 +/- 2.1 cm, respectively. With pacing at 90 beats/min, peak acceleration decreased to 15.6 +/- 3.6 m/s2, a significant decline from baseline values (p less than 0.005). Similar declines were seen during pacing at 90 beats/min for peak modal velocity and flow velocity integral (0.64 +/- 0.16 m/s and 7.1 +/- 1.9 cm, respectively; both p less than 0.005 versus baseline values). At the peak pacing rate of 140 beats/min, average peak acceleration decreased to 12.8 +/- 3.1 m/s2, and peak modal velocity and flow velocity integral decreased to 0.52 +/- 0.11 m/s and 5.02 +/- 1.25 cm, respectively. A significant linear correlation (r greater than or equal to 0.97, p less than 0.0001) was obtained for the relation between heart rate and peak acceleration, peak modal velocity and flow velocity integral.(ABSTRACT TRUNCATED AT 250 WORDS)

Septic arthritis in the geriatric population.

Septic arthritis has emerged as an important infection in geriatric patients. Between 25% and 50% of all cases of nongonococcal bacterial arthritis in nonprosthetic joints occur in patients over the age of sixty years. Thirty-three percent of nongonococcal septic arthritis occurs in the geriatric population. In this retrospective study of geriatric septic arthritis, 22 patients were reviewed. The major predisposing factor was prior history of arthritis, with the knee being the most commonly affected joint. Staphylococcus aureus was the major pathogen, with gram-negative organisms accounting for a significant number of infections. We think that empiric antibiotic coverage for gram-negative organisms should be initiated at the time of treatment only in patients with multiple predisposing factors for septic arthritis. The disease also may be more indolent than previously reported, leading to delayed diagnosis, treatment, and increased morbidity and mortality.

Medical management of pneumococcal arthritis involving a knee prosthesis.

Septic arthritis involving prosthetic joints has been frequently reported, with Staphylococcus species being the pathogen most commonly noted. We report a case of septic arthritis of a prosthetic knee caused by Pneumococcus, a previously unreported pathogen in this condition, which uniquely responded to treatment with antibiotics.