This contribution reviews the regulation of left ventricular pressure (LVP) fall by load and relates this regulation to left ventricular contractility. Load regulation of LVP fall has to be distinguished from neurohumoral regulation, from effects induced by arterial reflected waves and from long-term load effects on contractility. The response of LVP fall to a moderate elevation of systolic LVP is highly variable. It depends on the ratio between the actual systolic pressure and peak isovolumetric pressure, defined as "relative load". Up to a relative load of 81% to 84%, LVP fall accelerates. Above this relative load, LVP fall decelerates. Depending on the level of relative load there is a wide variety of effects ranging from moderate acceleration of LVP fall to marked deceleration of LVP fall. Acceleration of LVP fall in response to a load elevation is associated with normal cardiac function, while slowing of LVP fall is associated with impaired cardiac function. Similar but opposite effects are observed with reductions of systolic LVP. Effects of changes in systolic LVP on time constant tau reveal a fair correlation with systolic elastance (Ees), peak dP/dtmax and regional fractional shortening (or ejection fraction). There is an excellent correlation with measured isovolumetric LVP, indicating that contraction-relaxation coupling is close when contractility is expressed in terms of peak isovolumetric pressure. Assessment of contractility with systolic LVP-relaxation relation is precise and load independent and can be performed with the sole use of a high-fidelity pressure gauge positioned in the left ventricular cavity.

The ability of academic divisions of cardiology to pursue educational and research missions in an era of market-driven managed care is being increasingly jeopardized. Indeed, several academic medical centers have been sold to for-profit entities, and many cardiology divisions have been forced to decrease staff and faculty reimbursements. Despite these threats, the academic division has unique strengths: (1) premium quality of care, (2) a single employer, (3) a somewhat uniform practice culture, (4) high-volume operators performing interventional procedures, (5) expertise in highly technical aspects of cardiology, and (6) the availability of physicians for outreach ventures. Therefore, we hypothesized that the cardiology division could be strengthened by collaborating with the medical center in the development of an aggressive and proactive managed care strategy. To this end, we developed a cardiovascular network having the academic center as its central focus but including a group of high-quality and geographically dispersed community-based physicians. These physicians were attracted by an economic package that provided protection from downside risk, participation in our managed care initiatives, and geographic exclusivity in an over-crowded market. In turn, the community-based physicians increasingly used the academic medical center for tertiary care, resulting in increased volumes and incremental profitability. Using this paradigm, we have now recruited approximately 40 community cardiologists. The resulting network provides access to a university cardiologist in most of the surrounding urban and rural counties and will allow us to compete effectively for capitated contracts.

This article summarizes a 2-day workshop on the coronary microcirculation held in Bethesda, Md, in September 1994 and sponsored by the National Heart, Lung, and Blood Institute of the National Institutes of Health. The workshop explored a variety of topics pertaining to coronary microvascular physiology and pathophysiology. The latest methodologies that are being used to investigate the coronary microvasculature, including endoscopic microscopy of the intramural coronary microvasculature and micro-x-ray computerized tomography, were discussed. The most recent advances in the regulation of the coronary microcirculation-for example, myogenic and flow-dependent responses, KATP channels, and regional heterogeneity-were reported. The workshop touched on the relation of the microcirculation to clinically important conditions and offered recommendations for future research in this important area. Comparisons are made to recent advances in the peripheral circulation and current gaps in our knowledge concerning the coronary microcirculation. In recent years, research on the coronary microcirculation has made substantial advances, in part as a result of investigations in the peripheral microcirculation but also because of the application of unique methodologies. This research is providing new ways to investigate abnormalities of myocardial perfusion, an area of inquiry that until recently has been limited to examination of coronary pressure-flow relationships.

A wide variety of structural abnormalities are associated with the vast majority of cardiac arrests. However, there is no evidence of structural heart disease in approximately 5% of victims of sudden death, indicating that cardiac arrest in the absence of organic heart disease is more common than previously recognized. The risk of recurrence and the acute and long-term response to therapy are important but unanswered questions. Data from the small series reported so far are of limited value because of the lack of uniform criteria to define and diagnose idiopathic ventricular fibrillation (IVF).