Radial pressure waveform dP/dt max is a poor indicator of left ventricular systolic function.

BACKGROUND: The first derivative of left ventricular (LV) pressure over time (dP/dt max) is a marker of LV systolic function that can be assessed during cardiac catheterization and echocardiography. Radial artery dP/dt max has been proposed as a possible marker of LV systolic function and we sought to test this hypothesis. MATERIALS AND METHODS: We compared simultaneously recorded radial dP/dt max (by high-fidelity tonometry) with LV dP/dt max (by high-fidelity catheter and echocardiography parameters analogous to LV dP/dt max). In study 1, beat-to-beat radial dP/dt max and LV dP/dt max were recorded at rest and during supine exercise in 12 males (aged 61 +/- 12 years) undergoing cardiac catheterization. In study 2, 2D-echocardiography and radial dP/dt max were recorded in 54 patients (separate to study 1; 39 men; aged 64 +/- 10 years) at baseline and peak dobutamine-induced stress. Three basal septum measures were taken as being analogous to LV dP/dt max: 1. Peak systolic strain rate; 2. Strain rate (SR-dP/dt max) during isovolumic contraction (IVCT) and; 3. Tissue velocity during IVCT. RESULTS: In study 1 there was a significant difference between resting LV dP/dt max (1461 +/- 383 mmHg s(-1)) and radial dP/dt max (1182 +/- 319 mmHg s(-1); P < 0.001), and a poor, but statistically significant, correlation between the variables (R(2) = 0.006; P < 0.05). Similar results were observed during exercise. In study 2 there were weak (R(2) = -0.12; P = 0.01) to non-significant associations between radial dP/dt max and all echocardiographic measures analogous to LV dP/dt max at rest or peak stress. CONCLUSION: Radial pressure waveform dP/dt max is not a reliable marker of LV systolic function.

Relationship between myocardial perfusion and dysfunction in diabetic cardiomyopathy: a study of quantitative contrast echocardiography and strain rate imaging.

OBJECTIVE: To use quantitative myocardial contrast echocardiography (MCE) and strain rate imaging (SRI) to assess the role of microvascular disease in subclinical diabetic cardiomyopathy. METHODS: Stress MCE and SRI were performed in 48 patients (22 with type II diabetes mellitus (DM) and 26 controls), all with normal left ventricular systolic function and no obstructive coronary disease by quantitative coronary angiography. Real-time MCE was acquired in three apical views at rest and after combined dipyridamole-exercise stress. Myocardial blood flow (MBF) was quantified in the 10 mid- and apical cardiac segments at rest and after stress. Resting peak systolic strain rate (SR) and peak systolic strain (epsilon) were calculated in the same 10 myocardial segments. RESULTS: The DM and control groups were matched for age, sex and other risk factors, including hypertension. The DM group had higher body mass index and left ventricular mass index. Quantitative SRI analysis was possible in all patients and quantitative MCE in 46 (96%). The mean epsilon, SR and MBF reserve were all significantly lower in the DM group than in controls, with diabetes the only independent predictor of each parameter. No correlation was seen between MBF and SR (r = -0.01, p = 0.54) or between MBF and epsilon (r = -0.20, p = 0.20). CONCLUSIONS: Quantitative MCE shows that patients with diabetes but no evidence of obstructive coronary artery disease have impaired MBF reserve, but abnormal transmural flow and subclinical longitudinal myocardial dysfunction are not related.