Leadless Pacemaker: Report of the First Experience in Hawai'i.

We had the opportunity to implant the first leadless pacemakers in Hawai'i. This device represents a major change in pacemaker technology. This is a report of the first five cases and a review of the literature. All these devices were implanted via femoral venous access (versus conventional upper chest axillary/subclavian/cephalic routes), with an unique fixation mechanism allowing direct attachment to the ventricular myocardium (dispensing the usage of long transvenous electrode leads). The miniature generator can is over an order of magnitude smaller and lighter than the currently available ones. This article provides an understanding of the device design, implantation technique, the advantages and limitations, and the potential of this new pacemaker.

The effect of posture on Cheyne-Stokes respirations and hemodynamics in patients with heart failure.

STUDY OBJECTIVES: Cheyne-Stokes respirations occur in 40% of patients with heart failure. Orthopnea is a cardinal symptom of heart failure and may affect the patient's sleeping angle. The objective of this study was to assess the respiratory and hemodynamic response to sleeping angle in a group of subjects with stable heart failure. DESIGN: Twenty-five patients underwent overnight polysomnography with simultaneous and continuous impedance cardiographic monitoring. Sleeping polysomnographic and impedance cardiographic data were recorded. SETTING: The study was conducted in a sleep center. PATIENTS: All 25 patients had clinically stable heart failure and left ventricular ejection fractions < 40%. INTERVENTIONS: The patients slept at 0 degrees, 15 degrees, 30 degrees, and 45 degrees in random order. MEASUREMENTS AND RESULTS: Seventeen patients had Cheyne-Stokes apneas (index > 5/h) and 23 patients had hypopneas (index > 5/h). The hypopnea index showed no response to sleeping angle. The Cheyne-Stokes apnea index decreased with increasing sleeping angle (P < 0.001). This effect was seen only during supine sleep and non-rapid eye movement sleep and was absent in non-supine sleep, rapid eye movement sleep, and during periods of wakefulness. Thoracic fluid content index and left ventricular hemodynamics measured by impedance cardiography showed no response to sleeping angle. CONCLUSIONS: Changing the heart failure patient's sleeping angle from 0 degrees to 45 degrees results in a significant decrease in Cheyne-Stokes apneas. This decrease occurs on a constant base of hypopneas. The changes in Cheyne-Stokes apneas are not related to changes in lung congestion and left ventricular hemodynamics.