A. Lin

Evaluation of a novel sphygmomanometer, which estimates central aortic blood pressure from analysis of brachial artery suprasystolic pressure waves.

Background: Central arterial pressure is a better predictor of adverse cardiovascular outcomes than brachial blood pressure, but noninvasive measurement by applanation tonometry is technically demanding. Method: Pulsecor R6.5 is a novel device adapted from a standard sphygmomanometer which estimates the central aortic pressure from analysis of low-frequency suprasystolic waveforms at the occluded brachial artery. A physics-based model, which simulates the arterial system using elastic, thin-walled tube elements and Navier–Stokes equations, is used to calculate arterial pressure and flow propagation. To determine the reliability of the device, we compared 94 central systolic pressures estimated by Pulsecor to the simultaneous directly measured central aortic pressures at the time of coronary angiography in 37 individuals. Results: There was good correlation in central SBP between catheter measurements and Pulsecor estimates by either invasive or noninvasive calibration methods (r = 0.99, P < 0.0001 and r = 0.95, P < 0.0001, respectively). The mean difference in central systolic pressure was 2.78 (SD 3.90) mmHg and coefficient of variation was 0.03 when the invasive calibration method was used. When the noninvasive calibration method was used, the mean difference in central systolic pressure was 0.25 (SD 6.31) mmHg and coefficient of variation was 0.05. Conclusion: We concluded that Pulsecor R6.5 provides a simple and easy method to noninvasively estimate central SBP, which has highly acceptable accuracy.

New ST-depression: an under-recognized high-risk category of ‘complete’ ST-resolution after reperfusion therapy

Aim: It is not known if there is an association between resolution of ST-elevation to ST-depression following fibrinolysis and 30-day mortality. Methods: In an ECG substudy of HERO-2, which compared bivalirudin to unfractionated heparin following streptokinase in 12,556 patients with ST-elevation myocardial infarction ECGs were recorded at baseline and at 60 minutes after commencing fibrinolysis. The main outcome measure was 30-day mortality. Results: Using summed ST-segment elevation and five categories of changes in the infarct leads, further ST-elevation, 0–30% ST-resolution, >30–70% (partial) ST-resolution, >70% (complete) ST-resolution, and new ST-depression occurred in 21.7, 24.9, 36.8, 14.8, and 1.8% of patients, with 30-day mortality of 12.3, 11.7, 8.0, 4.2, and 8.1%, respectively. For the comparison of new ST-depression with complete ST-resolution and no ST-depression, p<0.01 with 24-hour mortality 4.5 vs. 1.3%, respectively (p=0.0003). Patients with new ST-depression had similar peak cardiac enzyme elevations as patients with complete ST-resolution without ST-depression. On multivariate analysis including summed ST-elevation at baseline, age, sex, and infarct location, new ST-depression was a significant predictor of 30-day mortality (OR 1.82, 95% CI 1.42–4.29). Conclusions: In patients with complete ST-resolution following fibrinolysis, new ST-depression at 60 minutes developed in 10.8% of patients. These patients had higher mortality than patients with complete ST-resolution without ST-depression and represent a high-risk group which could benefit from rapid triage to early angiography and revascularization as appropriate.

Medical treatment of asymptomatic chronic aortic regurgitation

Chronic aortic regurgitation results in left ventricular (LV) dilation, increased LV work and, eventually, a decline in LV function and heart failure. An important question is whether pharmacological therapy could preserve LV function and delay the need for aortic valve replacement. Vasodilators have a number of theoretical advantages. By lowering blood pressure, they reduce the regurgitant volume and decrease LV afterload. This article summarizes the clinical studies that have evaluated vasodilators in asymptomatic patients with chronic aortic regurgitation. Some studies suggest favorable effects on LV function and clinical outcomes, but results are inconsistent, making it difficult to draw definite conclusions. In general, studies have been too small to reliably evaluate the overall benefits and risks of this treatment, and in several studies there was no significant difference in measured blood pressure by treatment allocation. For these reasons, decisions on whether vasodilators are indicated in individual patients must currently be based on clinical judgment alone.

Myocardial calcification after orthotopic heart transplantation

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Recurrent focal cardio-myocyte necrosis in severe aortic regurgitation

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Natriuretic Peptides in Severe Aortic Stenosis - Role in Predicting Outcomes and Assessment for Early Aortic Valve Replacement

The natriuretic peptides are a group of endogenous, structurally related hormones with natriuretic, diuretic and peripheral vasodilatory actions. (Hunt, 1997; Yandle, 1986; Yandle, 1993) They serve an important regulatory role in response to acute increases in ventricular wall stress. A large number of cardiac conditions may cause an elevation of plasma levels of natriuretic peptides. Clinically, natriuretic peptides are of value in ruling out heart failure in patients presenting acutely to the emergency department with dyspnoea. (Maisel et al., 2002). Natriuretic peptides could also be useful in evaluating the severity and prognosis of patients with aortic stenosis (AS). Severe AS causes an increase in afterload and end-systolic left ventricular (LV) wall stress that, over time, leads to concentric myocardial hypertrophy. (Wachtell, 2008) This anatomical change of the LV is characterized at the molecular level by the re-expression of fetal isogenes, including increased gene expression of natriuretic peptides in the ventricular cardiomyocytes. (Sadoshima, 1992; Cameron, 1996) This chapter reviews the existing data on natriuretic peptide measurement in AS, to summarize how these biomarkers can be utilized in clinical practice, and to explore their therapeutic implication concerning the optimal timing of aortic valve replacement in the setting of severe AS.