Effects of adenosine infusion on systolic and diastolic left ventricular function after coronary artery bypass surgery: evaluation by computer-assisted quantitative 2-D and Doppler echocardiography

An acute increase in Left Atrial volume and left ventricular filling pressure during Adenosine administered myocardial hyperaemia: CMR First-Pass Perfusion Study

OBJECTIVE

To investigate whether left atrial (LA) volume and left ventricular filling pressure (LVFP) assessed by cardiovascular magnetic resonance (CMR) change during adenosine delivered myocardial hyperaemia as part of a first-pass stress perfusion study.

METHODS AND RESULTS

We enrolled 33 patients who had stress CMR. These patients had a baseline four-chamber cine and stress four-chamber cine, which was done at peak myocardial hyperaemic state after administering adenosine. The left and right atria were segmented in the end ventricular diastolic and systolic phases. Short-axis cine stack was segmented for ventricular functional assessment. At peak hyperaemic state, left atrial end ventricular systolic volume just before mitral valve opening increased significantly from baseline in all (91 ± 35ml vs. 81 ± 33ml, P = 0.0002), in males only (99 ± 35ml vs. 88 ± 33ml, P = 0.002) and females only (70 ± 26ml vs. 62 ± 22ml, P = 0.02). The right atrial end ventricular systolic volume increased less significantly from baseline (68 ± 21ml vs. 63 ± 20ml, P = 0.0448). CMR-derived LVFP (equivalent to pulmonary capillary wedge pressure) increased significantly at the peak hyperaemic state in all (15.1 ± 2.9mmHg vs. 14.4 ± 2.8mmHg, P = 0.0002), females only (12.9 ± 2.1mmHg vs. 12.3 ± 1.9mmHg, P = 0.029) and males only (15.9 ± 2.8mmHg vs. 15.2 ± 2.7mmHg, P = 0.002) cohorts.

CONCLUSION

Left atrial volume assessment by CMR can measure acute and dynamic changes in preloading conditions on the left ventricle. During adenosine administered first-pass perfusion CMR, left atrial volume and LVFP rise significantly.

Hemodynamic response to adenosine infusion before and after coronary artery bypass surgery

This study describes the hemodynamic dose-response characteristics of a titrated, continuous adenosine infusion before and 1 h (anesthetized), 1 week, and 1 year after coronary artery bypass graft (CABG) surgery. Average tolerated adenosine infusion rates were less 1 h and 1 week after surgery (128 +/- 23 and 118 +/- 27 microg/kg/min, respectively) than before (156 +/- 29 microg/kg/min) and 1 year after surgery (156 +/- 24 microg/kg/min). Heart rate (HR) increased with a 120-microg/kg/min adenosine infusion rate both preoperatively (21 +/- 11%) and 1 year postoperatively (16 +/- 8%). Systolic blood pressure (BP) decreased 26 +/- 11%, 14 +/- 7%, and 9 +/- 6% with 120 microg/kg/min adenosine for the three postoperative examinations. The integral of the outflow tract velocity with 120 microg/kg/min adenosine increased 49 +/- 22% and 29 +/- 12% after 1 h and 1 week, respectively, whereas its product with HR increased equally for all examinations (40 +/- 22%, 62 +/- 27%, 46 +/- 13%, and 39 +/- 11%). The average preoperative left ventricular area shortening was 45 +/- 10% and neither it nor end-diastolic left ventricular area (preload) changed with surgery, time after surgery, or with adenosine. A titrated adenosine infusion is well suited to patients requiring a pharmacologic provocation to expose reversible myocardial ischemia during the first hours or days after CABG surgery. The anesthetized and anemic patient are particularly unsuited for the commonly used fixed-infusion-rate protocol.