Influence of propranolol infusion on cyclic variation of myocardial integrated backscatter in hypertrophic obstructive cardiomyopathy.

It has been demonstrated that cyclic variation, assessed by myocardial integrated backscatter, reflects regional myocardial contractile function. The aim of this study was to investigate the influence of administration of beta-blocker propranolol on cyclic variation in patients with hypertrophic cardiomyopathy and persistent left ventricular (LV) pressure gradient and to test the hypothesis that the reduction of LV pressure gradient would be related to the change in regional contractile function. Before and after 2 mg propranolol infusion, transthoracic echocardiography with integrated backscatter analysis was performed on 11 patients (8 men and 3 women, mean age 54 +/- 12 years old). Integrated backscatter curves were obtained from the ventricular septum and LV posterior walls. With propranolol infusion, there was a significant reduction of LV fractional shortening (0.39 +/- 0.08 to 0.34 +/- 0.09, P <.01) and LV pressure gradient (83 +/- 40 mm Hg to 42 +/- 32 mm Hg, P <.001). In the posterior wall, the magnitude of cyclic variation significantly decreased (7.1 +/- 2.2 dB to 5.6 +/- 1.8 dB, P <.01), whereas in the septum, no apparent change in this parameter was observed (5.8 +/- 2.1 dB to 4.7 +/- 1.9 dB). Our findings suggest that in this form of cardiomyopathy, (1) the posterior wall myocardium is more susceptible to negative inotropic effects than the septum; (2) the reduction of LV pressure gradient is not related to that of regional wall motion; and (3) poor response of the ventricular septum is possibly because of more severe myocardial disarray and hypertrophy.

Prediction of functional recovery of the left ventricle after coronary revascularization in patients with prior anterior myocardial infarction: a myocardial integrated backscatter study.

Cyclic variation (CV) of myocardial integrated backscatter (IBS), which reflects intrinsic contractile performance, can predict myocardial viability in patients with a reperfused acute myocardial infarction (MI), but the use of this method has not been validated for chronic left ventricular (LV) dysfunction. The aim of this study was to examine whether myocardial IBS was useful for predicting LV functional recovery after coronary revascularization in 17 patients with prior anterior MI and LV dysfunction (ejection fraction <50%). Within 24 h of the revascularization procedure (percutaneous transluminal coronary angioplasty or coronary stenting), IBS curves were obtained by placing the region of interest on the anterior wall on the short-axis IBS image. The patients had repeat left heart catheterization at 3 or 6 months after the revascularization procedure, and were grouped according to the patterns of the IBS curve within the anterior wall. In 8 patients (group A), the IBS curve had a synchronized pattern with the magnitude of CV > or = 3.5, and in the remaining 9 patients (group B), the curve had either an asynchronized pattern or the magnitude of CV was less than 3.5 dB even in the case of synchronized pattern, or both. At baseline, there were no significant differences in LV functional indices between the 2 groups. After the follow-up period, the LV end-systolic volume decreased (75 +/- 21 ml to 56 +/- 20ml, p = 0.05), LV ejection fraction increased (35 +/- 12% to 50 +/- 14%, p = 0.014), and LV end-diastolic pressure decreased (19 +/- 10 mmHg to 13 +/- 6 mmHg, p = 0.02) in group A, whereas only the LV ejection fraction increased (34 +/- 9% to 40 +/- 11%, p = 0.03) in group B; LV end-systolic volume (72 +/- 19 ml to 66 +/- 16 ml, p = 0.126) and LV end-diastolic pressure (18 +/- 12 mmHg to 14 +/- 8 mmHg, p = 0.184) showed no significant changes. In conclusion, IBS is valuable for predicting LV functional recovery after coronary revascularization in patients with LV dysfunction caused by a remote anterior MI. A large-scale study is be needed to establish these data.

Prognostic implications derived from ultrasonic tissue characterization with myocardial integrated backscatter in patients with dilated cardiomyopathy.

BACKGROUND: Various clinical parameters have been reported to predict survival in patients with dilated cardiomyopathy (DCM). Myocardial ultrasonic integrated backscatter (IB) imaging has a potential to perform in vivo tissue characterization. The present study was performed to examine whether myocardial IB analysis can predict the prognosis of DCM patients. METHODS AND RESULTS: We prospectively carried out echocardiographic examinations with IB analysis in 43 patients with DCM (31 males, 12 females) under the standard treatment. IB analysis was performed in the left ventricular wall and the calibrated (subtracting pericardial data) myocardial IB intensity (IBI) was obtained from the interventricular septum and the left ventricular posterior wall. After the follow-up (8-39 months), 31 followed a good clinical course, but eight had cardiac death, one had partial left ventriculectomy for uncontrolled heart failure and three were hospitalized for worsening heart failure. Beta-blocker responded in 27 (87%) of the 31 with good clinical course, but it did not respond in 11 among the 12 with poor course. In these 12 DCM, left ventricular fractional shortening (LVFS) was lower (good: 18+/-5%, poor: 14+/-4, P<0.03) and calibrated IBI was higher in both the septum (good: -16.4+/-5.6 dB, poor: -11.1+/-4.2 dB, P<0.006) and the posterior wall (good: -19.5+/-3.6 dB, poor: -13.8+/-5.6 dB, P<0.004). On the Cox proportional hazard model analysis, only calibrated IBI in the septum >-17 dB, the cut-off score of calibrated IBI discriminating non-responders to beta-blocker therapy in our previous report, was related to the poor outcome (chi(2)=4.43, P=0.035). The stepwise multivariate analysis revealed that both calibrated IBI in the septum>-17 dB (chi(2)=4.43, P=0.035) and LVFS<15% (chi(2)=3.89, P=0.049) were useful to predict the poor clinical outcome. The event free rate assessed by the Kaplan-Meier method was also significantly reduced in patients with calibrated IBI in the septum >-17 dB (chi(2)=6.594, P=0.01) and calibrated IBI in the posterior wall>-17 dB (chi(2)=4.215, P=0.04). However, LVFS<15% (chi(2)=3.576, not significant) did not contribute to discriminating the event free rate in the clinical course. CONCLUSIONS: The present study demonstrated that myocardial IB intensity was higher in DCM patients who followed a poor clinical course rather than in those with a good outcome. Therefore, it is clarified that myocardial ultrasonic tissue characterization in DCM patients is useful for assessing their clinical outcome after receiving not only the standard treatment but also beta-blocker therapy.

Long-term outcome of a residual scar from myocardial infarction after coronary artery bypass grafting: a 100-month study using myocardial perfusion scintigraphy.

The prognosis for patients with a residual scar from myocardial infarction (MI) after coronary artery bypass grafting surgery (CABG) has not been fully evaluated, so the present study retrospectively evaluated such patients with stress myocardial single photon emission computed tomography (SPECT) at 100 months after CABG. The study group consisted of 24 subjects (23 males, 1 female; mean age, 59+/-9 years) in whom CABG had been performed more than 100 months (mean follow-up period 135+/-25 months) previously. The 24 subjects were classified into 3 groups according to their summed stress score (SSS) and summed reversibility score (SRS) in the early period after CABG. Eight subjects with MI (SSS> or =2 and SRS<2) were classified into the group MI, 8 subjects with ischemic myocardium (SSS> or =2 and SRS> or =2) was classified into the group RE, and 8 subjects with normal perfusion (SSS<2 and SRS<2) was classified into group N. None of the subjects in group MI required revascularization. Cardiac events occurred in 4 of the group RE patients and all required revascularization. As to the SPECT scoring system, the long-term SSS of group MI (6.4+/-3.1) was not different from that in the early periods (4.3+/-4.0; NS). However, the long-term SSS values of group RE (8.8+/-6.2) were significantly greater than those soon after CABG (3.4+/-1.8; p=0.03). In group N, there was also no difference in the SSS values between the early period (0.3+/-0.5) and the long-term period (0.0+/-0.0; NS). Patients with a residual scar from MI in the early period after CABG did not worsen over a period of 100 months. Moreover, there was no significant difference in the SPECT score in the segment with the residual scar in the short or long term after CABG. However, the extent of reversibility was directly associated with the presence of clinical events. Therefore scintigraphic imaging remains an important and clinically relevant risk stratification tool. Stress myocardial SPECT, early after CABG, can be used to predict the possibility of future cardiac events or the need for revascularization.