The Impact of Sonothrombolysis on Left Ventricular Diastolic Function and Left Atrial Mechanics Preventing Left Atrial Remodeling in Patients With ST Elevation Acute Myocardial Infarction

BACKGROUND

The diagnostic ultrasound-guided high mechanical index impulses during an intravenous microbubble infusion (sonothrombolysis) improve myocardial perfusion in acute ST segment elevation myocardial infarction, but its effect on left ventricular diastolic dysfunction (DD), left atrial (LA) mechanics and remodeling is unknown. We assessed the effect of sonothrombolysis on DD grade and LA mechanics.

METHODS

One hundred patients (59 ± 10 years; 34% women) were randomized to receive either high mechanical index impulses plus percutaneous coronary intervention (PCI) (therapy group) or PCI only (control group) (n = 50 in each group). Diastolic dysfunction grade and LA mechanics were assessed immediately before and after PCI and at 48 to 72 hours, 1 month, and 6 months of follow-up. Diastolic dysfunction grades were classified as grades I, II, and III. The LA mechanics was obtained by two-dimensional speckle-tracking echocardiography-derived global longitudinal strain (GLS).

RESULTS

As follow-up time progressed, increased DD grade was observed more frequently in the control group than in the therapy group at 1 month and 6 months of follow-up (all P < .05). The LA-GLS values were incrementally higher in the therapy group when compared with the control group at 48 to 72 hours, 24.0% ± 7.3% in the therapy group versus 19.6% ± 7.2% in the control group, P = .005; at 1 month, 25.3% ± 6.3% in the therapy group versus 21.5% ± 8.3% in the control group, P = .020; and at 6 months, 26.2% ± 8.7% in the therapy group versus 21.6% ± 8.5% in the control group, P = .015. The therapy group was less likely to experience LA remodeling (odds ratio, 2.91 [1.10-7.73]; P = .03). LA-GLS was the sole predictor of LA remodeling (odds ratio, 0.79 [0.67-0.94]; P = .006).

CONCLUSION

Sonothrombolysis is associated with better DD grade and LA mechanics, reducing LA remodeling.

The impact of ligation of proximal side branches on blood flow and functional status of the internal thoracic artery in coronary anastomosis

BACKGROUND

The effect of proximal side branches on the patency of the internal thoracic artery (ITA) is controversial. We used echocardiography and Doppler to verify the effect of ligation of branches on the flow and coronary flow reserve (CFR) of the grafted ITA in patients after coronary artery bypass grafting (CABG).

METHODS

We prospectively investigated 53 patients with preserved left ventricular ejection fraction (LVEF >50%) who underwent CABG of the ITA. In Group I (25 patients), major branches were ligated during ITA anastomosis to the left anterior descending (LAD) coronary artery, whereas no ligation was performed in Group II (28 patients). Systolic flow (SF), diastolic flow (DF), and total flow (TF = SF + DF) were measured by Doppler echocardiography at the proximal level of the ITA preoperatively, at early postoperative stage, and 6 months after surgery. Dobutamine stress echocardiography (DSE) was performed at 6 months to determine CFR.

RESULTS

The ITA flow was predominantly systolic before surgery and diastolic in the postoperative period. We found no differences between the groups in DF. On DSE, SF (19.5±9 mL/min vs 32.7±19 mL/min; P=.003) and TF (79±21 mL/min vs 101±47 mL/min; P=.037) were higher in Group II. There were no differences in CFR (1.9±0.46 vs 2.11±0.56; P=.143).

CONCLUSION

In patients with preserved LVEF, ligation of major side branches during anastomosis to the LAD does not alter ITA flow or CFR.

Safety and cardiac chronotropic responsiveness to the early injection of atropine during dobutamine stress echocardiography in the elderly

OBJECTIVE

To determine the safety and cardiac chronotropic responsiveness to early atropine dobutamine stress echocardiography (DSE) in the elderly.

DESIGN

Retrospective study of 258 patients >or= 70 years who underwent early atropine DSE and 290 patients >or= 70 years who underwent conventional DSE. In the early atropine protocol, atropine was started at 20 microg/kg/min of dobutamine if heart rate was < 100 beats/min, up to 2 mg. The cardiac chronotropic responsiveness in the elderly was compared with a control group of patients < 70 years matched for sex, myocardial infarction, diabetes, and treatment with beta blockers and calcium channel blockers.

RESULTS

The dose of dobutamine given to elderly patients was lower during early atropine than during conventional DSE (mean (SD) 29 (7) v 38 (4) microg/kg/min, p = 0.001). Early atropine DSE resulted in diminished incidence of ventricular extrasystoles, non-sustained ventricular tachycardia, bradycardia, and hypotension compared with conventional DSE. In comparison with patients < 70 years, elderly patients required lower doses of dobutamine and atropine and achieved a higher percentage of predicted maximum heart rate (92 (9)% v 88 (10)%, p = 0.0001). Except for more common hypotension (16% v 10%, p = 0.004), no other difference in adverse effects was observed between patients >or= 70 and < 70 years.

CONCLUSIONS

Early atropine DSE is a safe strategy in the elderly resulting in lower incidence of minor adverse effects than with the conventional protocol. Elderly patients presented adequate cardiac chronotropic responsiveness to early injections of atropine, requiring lower doses of drugs to reach test end points.