James A. Arrowood

Early Echocardiography Can Predict Cardiac Events in Emergency Department Patients With Chest Pain

STUDY OBJECTIVE Accurate diagnosis in emergency department patients with possible myocardial ischemia is problematic. Two-dimensional echocardiography has a high sensitivity for identifying patients with myocardial infarction (MI); however, few studies have investigated its diagnostic ability when used acutely in ED patients with possible myocardial ischemia. Therefore we investigated the ability of ED echocardiography for predicting cardiac events in patients with possible myocardial ischemia. METHODS Echocardiography was performed within 4 hours of ED presentation in 260 patients with possible myocardial ischemia, and was considered positive if there were segmental wall motion abnormalities or the ejection fraction was less than 40%. ECGs were considered abnormal if there was an ST-segment elevation or depression of greater than or equal to 1 mm, or ischemic T-wave inversion. Cardiac events included MI and revascularization. RESULTS Of the 260 patients studied, 45 had cardiac events (23 MI, 19 percutaneous transluminal angioplasty, 3 coronary bypass surgery). The sensitivity of echocardiography for predicting cardiac events was 91% (95% confidence interval 79% to 97%]), which was significantly higher than the ECG (40% [95% CI 27% to 55%]: P < .0001), although specificity was lower (75% [95% CI 69% to 81%] versus 94% [95% CI 90% to 97%]; P < .001). Addition of the echocardiography results to baseline clinical variables and the ECG added significant incremental diagnostic value (P < .001). With use of multivariate analysis, only male gender (P < .03, odds ratio [OR] 2.4 [1.1 to 5.3]), and a positive echocardiographic finding (P < .0001, OR 24 [9 to 65]) predicted cardiac events. Excluding patients with abnormal ECGs (N = 30) did not affect sensitivity (85%) or specificity (74%) of echocardiography. CONCLUSION Echocardiography performed in ED patients with possible myocardial ischemia identifies those who will have cardiac events, is more sensitive than the ECG, and has significant incremental value when added to baseline clinical variables and the ECG.

Comparison between 2-dimensional echocardiography and myocardial perfusion imaging in the emergency department in patients with possible myocardial ischemia☆☆☆★

BACKGROUND Accurate identification of patients at high risk for acute coronary syndromes among those seen in the emergency department (ED) with possible myocardial ischemia and nonischemic electrocardiograms is problematic. Both 2-dimensional echocardiography and myocardial perfusion imaging with technetium-99m sestamibi can identify patients at low and high risk; however, comparative studies are lacking. METHODS AND RESULTS Patients initially considered at low or moderate risk for myocardial ischemia on the basis of the presenting history, physical examination, and electrocardiogram underwent both echocardiography and myocardial perfusion imaging within 4 hours of ED presentation. Positive echocardiography was defined as the presence of segmental wall motion abnormalities or moderate to severe global systolic dysfunction; positive perfusion imaging was defined as a perfusion defect in association with abnormal wall motion, thickening, or both. End points included MI, percutaneous transluminal coronary angioplasty, and positive stress perfusion imaging. Both imaging procedures were performed in the ED on 185 patients. Six patients had MI, and an additional 4 patients underwent percutaneous transluminal coronary angioplasty. Echocardiography and perfusion imaging were positive in all 10. Overall agreement between the 2 techniques was high (concordance 89%, kappa coefficient 0.74) in the 27 patients who had MI or underwent coronary angiography. For all patients, concordance was 89%, with a kappa coefficient of 0.66. CONCLUSIONS Agreement between echocardiography and perfusion imaging with technetium-99m sestamibi is high when used in patients in the ED with possible myocardial ischemia. Both techniques identified patients at high risk who required admission and those who could be safely discharged directly from the ED.

Ventricular sensory endings mediate reflex bradycardia during coronary arteriography in humans.

It has been suggested that the response to the intracoronary injection of radiographic contrast is reflex in origin and results from stimulation of ventricular sensory endings. Cardiac transplantation results in denervation of the ventricles, and thus, may interrupt the afferent limb of this reflex. In contrast, the recipient sinus node and atrial remnant remain innervated, leaving the efferent cardiac limb of this reflex intact. We hypothesized that if contrast-induced reflex bradycardia and hypotension occurred from stimulation of ventricular chemosensitive endings, then this response would be abolished after cardiac transplantation. To test this hypothesis, we determined the changes in recipient (innervated) and donor (denervated) sinus-node rates (SNR) and mean arterial pressure during selective right (RCA) and left coronary artery (LCA) injection during arteriography in cardiac transplant patients and in patients with intact cardiac innervation. An increase in the recipient SNR was observed in cardiac transplant patients during left and right coronary injections (LCA, 6.6 +/- 1.7 beats/min; RCA, 2.4 +/- 1.4 beats/min) compared with a decrease in the control subjects (LCA, -15.3 +/- 2.3 beats/min; RCA, -6.9 +/- 1.9 beats/min; p less than 0.05 vs. control). This occurred despite significant and comparable decreases in mean arterial pressure in cardiac transplant patients (LCA, -12.7 +/- 2.3 mm Hg; RCA, -11.4 +/- 2.2 mm Hg) and control subjects (LCA, -18.7 +/- 1.7 mm Hg; RCA, -10.7 +/- 1.6 mm Hg). The donor SNR slowed for LCA injection (-5.4 +/- 2.1 beats/min, p less than 0.05) and RCA injection (-3.0 +/- 1.7 beats/min), which, for the LCA, was less than the slowing of control subjects (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of combined metformin and oral contraceptive therapy on metabolic factors and endothelial function in overweight and obese women with polycystic ovary syndrome

In this randomized, double-blind, placebo-controlled study, 19 overweight women with polycystic ovary syndrome were randomized to a 3-month course of either metformin plus combined hormonal oral contraceptive (OC) (n = 9) or OC plus matched placebo (n = 10). After 3 months, both treatments had similar effects on androgen levels, lipid profile, insulin sensitivity, and serum inflammatory markers, but flow-mediated dilatation increased by 69.0% in the metformin plus OC group while it remained unchanged in the OC group. CLINICAL TRIAL REGISTRATION NO: NCT00682890.

Primary Left Ventricular Mural Endocarditis Diagnosed by Transesophageal Echocardiography

Primary left ventricular mural abscess was detected by transesophageal echocardiography and was confirmed at necropsy in a 44-year-old woman with Staphylococcus aureus bacteremia and cerebrovascular embolism. In two occasions, transthoracic echocardiography failed to show the mural abscess in this patient. Because of the aggressive nature of primary mural endocarditis, early use of transesophageal echocardiography is recommended in patients with Staphylococcal bacteremia and suspected endocarditis even in the absence of valvular abnormalities detectable by the transthoracic approach.

Improved identification of posterior left ventricular pseudoaneurysms by transesophageal echocardiography

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Doppler echocardiographic assessment of an impedance-based dual-chamber rate-responsive pacemaker

Rate-responsive pacing allows patients with chronotropic incompetence to achieve more physiologic heart rate responses to exercise. One sensor currently being investigated uses impedance-derived measurements of changes in right ventricular stroke volume to alter the pacing rate. Correlation of pacemaker-derived measurements of stroke volume with an accepted method of stroke volume measurement has not been performed. The relative changes in impedance-derived stroke volume were compared in 10 patients with an impedance-based dual-chamber rate-responsive pacemaker (Precept DR, Cardiac Pacemakers, Inc.) with simultaneous Doppler echocardiographic measurements of right and left ventricular stroke volume. These comparisons were made during pacing at 2 heart rates (70 and 100 beats/min) and 3 AV intervals (150, 200 and 250 ms) while in a supine resting state, during lower body negative pressure to -30 mm Hg, and while performing 25% maximal handgrip. Pacemaker-derived stroke volume decreased by 7 to 11% and Doppler time-velocity integral measurements decreased by 14 to 19% in response to an increase in pacing rate (p = NS). There was also no significant difference by either technique in the mean stroke volume change when the atrioventricular interval was varied. Both techniques detected a decrease in stroke volume during lower body negative pressure, ranging from -7 to -20% by pacemaker, and -17 to -38% by Doppler. Overall, the pacemaker stroke volume measurements responded in an appropriate direction to each intervention, signaling the pacemakers ability to detect directional change in stroke volume. The Precept DR may aid in the programming of parameters such as atrioventricular interval and heart rate by allowing for optimization of stroke volume in individual patients.