Dobutamine stress echocardiography (DSE) is widely used to evaluate myocardial ischemia or to clarify the differential diagnosis of chest pain. DSE is often complicated by insufficient heart rate response, hypotension or other adverse events. We report the results of the assessment of a modified protocol for DSE, in which 0.5mg of intravenous atropine administration was followed by dobutamine (DOB) infusion at 10 μg/kg/min. Three hundred twenty-two consecutive patients, 172 patients studied with the modified protocol and 150 controls undergoing conventional DSE, were compared. The percentage of patients attaining target heart rate (THR) via the modified protocol was significantly increased (65% vs. 35%, P<0.0001). The percentage of patients developing hypotension (defined as a decrease in systolic blood pressure (SBP) >25mmHg) was significantly decreased (<1% vs. 19%, P<0.0001). Fewer patients required the maximum dose (40 μg/kg/min) of DOB infusion. Peak heart rate (peak HR), peak HR:THR ratio, peak SBP, and the peak rate-pressure product were higher with the modified protocol, as compared to the conventional protocol (P<0.0001). DOB requirements were significantly reduced in patients not receiving βblockers (P<0.0001), but not in patients on βblockers (P=NS). The prevalence of arrhythmias, SBP>250mmHg, de novo intra-ventricular gradient development (>100mmHg) and intolerable symptoms did not differ between the groups. Coronary angiography was performed in 80 patients including in 45 patients with the conventional protocol and 35 patients with the modified protocol. No significant difference in sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the two protocols was observed. These results indicate that the modified protocol improves attainment of THR and prevents hypotension during DSE. Serious adverse events were not increased.
Background. A number of cardiovascular diseases show diurnal variation. However, it is unknown whether coronary circulation exhibits diurnal variation. Methods. The flow velocities in the left anterior descending coronary artery of 15 healthy men were measured by transthoracic Doppler echocardiography both at rest and during intravenous infusion of adenosine triphosphate at 7 AM, noon, 5 PM and 9 PM. Coronary flow velocity reserve (CFVR) was calculated as the ratio of hyperemic to basal mean diastolic flow velocity. CFVR at 7 AM was significantly smaller than that at 9 PM (p=0.001; 7 AM, 3.23 ± 0.66; noon, 3.89 ± 0.86; 5 AM, 3.46 ± 0.65; 9 PM, 4.41 ± 1.11, respectively). CFVR at 5 PM was also significantly smaller than that at 9 PM (p=0.008). Conclusions. Diurnal variation in CFVR exists in healthy men. This finding may be related to the diurnal variation in cardiovascular events.
Background. Although atrial septal defect is a common congenital heart disease, its evaluation by two-dimensional echocardiography is limited because the en face view of the atrial septum is not seen. We performed three-dimensional echocardiography to observe the en face view of atrial septal defect to measure the defect size, and we compared the results to surgical findings. Methods. We studied 17 patients (5 men and 12 women) who underwent surgical closure of an atrial septal defect using real-time three-dimensional echocardiography. The en face view of the defect was viewed, and short- and long-axis diameters of the defect were measured. The shape of the defect was also compared to surgical findings. Results. A significant positive correlation existed between long-axis diameter on three-dimensional echocardiography and that measured during surgery (y=0.89x+6.24, r=0.95, p<0.001). Short-axis diameter obtained on three-dimensional echocardiography was slightly greater than that measured during surgery, but a significant positive correlation existed (y=1.04x+3.57, r=0.91, p<0.001). In all patients, three-dimensional echocardiography showed an elliptical shape of the defect, which was similar to surgical findings. Conclusions. The dimensions and morphology of atrial septal defects measured by three-dimensional echocardiography matched well with surgical findings, suggesting that three-dimensional echocardiography is useful for preoperative planning.
Hemochromatosis represents primary or secondary deposition of an excessive amount of iron in many tissues and organs in the body. Recent studies have evaluated regional myocardial function by tissue Doppler echocardiography. Myocardial strain imaging facilitates the evaluation of regional myocardial function without being influenced by cardiac rotation and translation. Several studies have reported the usefulness of myocardial strain and myocardial strain gradient imaging in patients with various myocardial diseases. In this paper, we performed myocardial strain imaging in a patient with secondary hemochromatosis.