Evaluation of the risk of intercostal artery laceration during thoracentesis in elderly patients by using 3D-CT angiography.

Objective: Our study was undertaken to determine the location of the tortuous intercostal artery in elderly patients by using 3D-CT angiography in order to prevent laceration during thoracentesis.

Methods: We evaluated the data of 3D-CT angiography of the intercostal artery in consecutive patients who had undergone contrast chest CT scan in our hospital from December 2007 to April 2008. We considered the "percent safe space" (the shortest lower rib-to-intercostal artery distance/the upper rib-to-lower rib distance) to be an index of safety that can be used to prevent laceration of the intercostal artery during thoracentesis.

Left ventricular pressure-volume relationship in conscious mice.

With the availability of transgenic models, the mouse has become an increasingly important subject for genetic-hemodynamic studies. Recently, we developed a technique to measure left ventricular (LV) pressure in conscious mice with an implanted LV polyethylene tube. We extended our new method by evaluating the LV pressure-volume relationship and examined the feasibility of this method in this study.

Alpha1-adrenergic receptors prevent a maladaptive cardiac response to pressure overload.

An alpha1-adrenergic receptor (alpha1-AR) antagonist increased heart failure in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), but it is unknown whether this adverse result was due to alpha1-AR inhibition or a nonspecific drug effect. We studied cardiac pressure overload in mice with double KO of the 2 main alpha1-AR subtypes in the heart, alpha 1A (Adra1a) and alpha 1B (Adra1b). At 2 weeks after transverse aortic constriction (TAC), KO mouse survival was only 60% of WT, and surviving KO mice had lower ejection fractions and larger end-diastolic volumes than WT mice.

Central sympathetic inhibition augments sleep-related ultradian rhythm of parasympathetic tone in patients with chronic heart failure.

Background: Abnormal sleep dynamics in patients with heart failure is one of the mechanisms for the relative predominance of central sympathetic outflow over parasympathetic tone. This study was designed to examine whether central sympathoinhibition could improve the sympathovagal imbalance related to rapid-eye-movement (REM)/non-REM ultradian sleep rhythm in these patients.

Methods And Results: Beat-by-beat RR intervals of overnight electrocardiogram were serially subject to power spectral analysis in 14 patients with chronic heart failure and 13 age-matched subjects with normal cardiac function.

New technique for measurement of left ventricular pressure in conscious mice.

Concern about the effects of anesthesia on physiological measurements led us to develop methodology to assess left ventricular (LV) pressure in conscious mice. Polyethylene-50 tubing filled with heparinized saline was implanted in the LV cavity through its apex via an abdominal approach and exteriorized to the back of the animal. This surgery was done under anesthesia with either an intraperitoneal injection of ketamine (80 mg/kg) and xylazine (5 mg/kg) (K+X) in 11 mice or isoflurane (ISF; 1.

The alpha(1A/C)- and alpha(1B)-adrenergic receptors are required for physiological cardiac hypertrophy in the double-knockout mouse.

Catecholamines and alpha(1)-adrenergic receptors (alpha(1)-ARs) cause cardiac hypertrophy in cultured myocytes and transgenic mice, but heart size is normal in single KOs of the main alpha(1)-AR subtypes, alpha(1A/C) and alpha(1B). Here we tested whether alpha(1)-ARs are required for developmental cardiac hypertrophy by generating alpha(1A/C) and alpha(1B) double KO (ABKO) mice, which had no cardiac alpha(1)-AR binding. In male ABKO mice, heart growth after weaning was 40% less than in WT, and the smaller heart was due to smaller myocytes.

Disparate force-frequency effects of pimobendan and dobutamine in conscious dogs with tachycardia-induced cardiomyopathy.

Background: This study was designed to examine how a calcium sensitizer, pimobendan, affected a force-frequency response (FFR) as compared to the beta-adrenergic agonist dobutamine.

Methods And Results: Left ventricular (LV) contractility and relaxation were evaluated by the slope (Ees) of the LV end-systolic pressure-volume relation and the time constant (Tau) of LV pressure decay. Using 6 conscious dogs with tachycardia-induced heart failure, the FFR was examined before and after administration of dobutamine (6 microg/kg/min) or pimobendan (0.