Impact of second harmonic imaging on the determination of the global and regional left ventricular function by 2D echocardiography: a comparison with MIBI gated SPECT.

AIMS: To evaluate the impact of second harmonic (SH) compared to fundamental mode (FM) imaging on the echocardiographic determination of ejection fraction (EF) and wall motion score index (WMSI), using MIBI gated SPECT as an independent reference. METHODS: Sixty-two consecutive patients underwent an echocardiography study and a MIBI gated SPECT over 24 hours. EF was estimated visually (estimated-E) and was calculated with the Simpson biplane method (Tracing-T), for both FM and SH. WMSI was determined by two independent echo-readers blinded to the nuclear imaging results. The same segmentation and scoring system was used for WMSI determined by MIBI gated SPECT. RESULTS: The percentages of unscored segments because of suboptimal endocardial border detection were 19.5% (FM) and 9.0% (SH). The correlation coefficients (r) between SPECT-EF and echo-EF were: FM (E)=0.705, FM (T)=0.546, SH (E)=0.771, SH (T)=0.743. Agreement between SPECT-EF and echo-EF was acceptable for both imaging modalities (mean of the difference +/- 2 S.D.): -2.8 +/- 18.5 (FM) and -3.5 +/- 16.4 (SH). Correlation coefficients (r) between WMSI calculated by SPECT and by echo were 0.715 (FM) and 0.789 (SH). Agreement between SPECT-WMSI and echo-WMSI was good for all imaging modes but better with SH compared to FM: 0.12 +/- 0.91 (FM), 0.10 +/- 0.77 (SH). The interobserver correlation coefficients (r) for the WMSI were 0.939 (FM) and 0.996 (SH). The agreement between the two observers was better for SH compared to FM. The systematic differences (mean differences) were 0.21 (FM) and -0.01 (SH), and the random differences between both observers (2 S.D.) decreased from 1.55 (FM) to 0.29 (SH). CONCLUSIONS: The use of SH echocardiography decreases the number of unscored segments. This results in an important gain in correlation and agreement for EF determination between echo and SPECT, and in a considerable decline of the interobserver variability for the echo-determined WMSI. WMSI determined by MIBI gated SPECT correlated closely with the SH WMSI, and agreement between both methods was excellent.

Prediction of functional outcome after myocardial infarction using BMIPP and sestamibi scintigraphy.

UNLABELLED: We determined the predictive value of combined beta-methyl iodophenyl pentadecanoic acid (BMIPP) and sestamibi scintigraphy for the functional outcome after myocardial infarction and compared the value of this approach with dobutamine echocardiography. METHODS: Rest BMIPP, rest sestamibi and low-dose dobutamine echocardiographic studies were obtained in 18 patients 4 to 10 days after infarction (mean 6.7 +/- 2.0 days). Six months later, a rest echocardiographic study was performed to assess functional outcome. RESULTS: Wall motion improved in 27/33 segments (82%) which showed mismatching but not in 19/21 segments (90%) with matched defects (p < 0.001). The accuracy of combined BMIPP and sestamibi SPECT in predicting segmental functional outcome was higher (85%) than that of sestamibi uptake alone (77%). Wall motion improved in 16/20 segments (80%) showing contractile reserve and not in 21/34 segments (63%) with the negative dobutamine test, giving an accuracy of 69% for dobutamine echocardiography. Combination of the two techniques resulted in higher positive (94%) and negative predictive values (94%). CONCLUSION: Mismatching of BMIPP and sestamibi uptake is predictive for long-term functional recovery after acute myocardial infarction. In contrast, segments with matched defects contain only scar tissue. Combined BMIPP and sestamibi scintigraphy offers increased accuracy compared to dobutamine echocardiography.

Abnormal free fatty acid uptake in subacute myocardial infarction after coronary thrombolysis: correlation with wall motion and inotropic reserve.

UNLABELLED: Iodine-123-free fatty acid analogs, such as beta-methyliodophenylpentadecanoic acid (BMIPP), allow for myocardial metabolic studies with SPECT. The goal of this investigation was to determine whether BMIPP uptake can be used to differentiate viable myocardium from scar tissue soon after coronary thrombolysis for acute myocardial infarction. METHODS: BMIPP and 99mTc-sestamibi (MIBI) myocardial distribution after injection at rest were analyzed in 22 patients 4 to 10 days after coronary thrombolysis. The relative uptake of the two tracers was compared on a segmental basis to the regional wall motion and to the inotropic reserve assessed by two-dimensional echocardiography and low-dose dobutamine stimulation. RESULTS: Three segmental patterns were identified in the infarct-related coronary artery territory. Segments with normal BMIPP and MIBI uptake showed normal wall motion. Segments with more reduced BMIPP uptake than MIBI uptake (mismatching) showed either normal wall motion or demonstrated inotropic reserve during dobutamine stimulation. Segments with matched defects always showed abnormal wall motion and did not demonstrate inotropic reserve, regardless of the MIBI uptake. CONCLUSION: In patients with subacute myocardial infarction, combined imaging of BMIPP and MIBI at rest might be more sensitive than MIBI or wall motion at rest alone to demonstrate myocardial areas that have been acutely ischemic. Mismatching is due to more severely depressed fatty acid metabolism than expected on the basis of the flow and is indicative of jeopardized, but viable myocardium. In dysfunctional segments, mismatching may correspond either to stunned or to hibernating myocardium. Matched defects are associated with scar tissue.

Role of side holes in guide catheters: observations on coronary pressure and flow.

When performing coronary angioplasty, guide catheter intubation of the ostium often leads to a damping of the pressure tracing. In contrast, when a guide catheter with side holes is used, the pressure tracing is most often superimposable to the pressure wave recorded through the side arm of a femoral artery sheath introducer. This pressure wave gives the reassuring impression of normal hemodynamics in the coronary artery. To illustrate the role of guide catheter side holes and that guide catheter pressure does not necessarily equal the actual coronary artery perfusion pressure, we report observations on trans-ostial pressure gradients at rest and during increased coronary flow rates. An abbreviated in vivo study of side holes on the maximal achievable blood flow, employing timed blood flow collections in 7F and 8F side hole guide catheters, was made in 10 patients. At high mean aortic pressure levels, the blood flow through the side holes did not exceed 80 and 60 mL/min for 8 and 7F guide catheters, respectively. These observations suggest that, under some conditions, the guide catheter may produce a resting or hyperemic trans-ostial gradient and that the flow provided only by the side holes of guide catheter is limited. Guide catheter interference with normal flow should be considered in interventional procedures even when arterial pressure appears normal.

Detection of late potentials on the averaged QRS signal recorded at rest and during a standardized stress test after acute myocardial infarction.

The high-amplification signal-averaged ECG (SAECG) allows the detection and analysis of late potentials (LP), which are related to a higher risk of severe ventricular arrhythmias in patients with myocardial disease and coronary artery disease. Because of excessive noise, this technique is usually performed at rest and occasionally immediately after interruption of exercise. Until now, however, it has not been used during exercise. The authors relate in this paper the method and results of the SAECG recorded at rest and during a standard stress test on 30 patients with a recent first myocardial infarction (day 10-14), in good condition, without ECG evidence of significant residual ischemia or bundle branch block. The SAECG was recorded during the steady state of a standardized stress test when a heart rate (HR) corresponding to 80% of the maximal HR was reached during a first test. Three patients had three criteria for LP, three others had two criteria, and two had only one. It has been impossible to analyze the SAECG during exercise because of excessive noise. One patient out of 30 in our study, 21 subjects had normal SAECG at rest and during exercise. None of the 6 patients with more than 1 abnormal criterion at rest became normal during the stress test despite a decrease of the duration criteria in all and an increase of the amplitude (root mean square) the terminal 40 ms (RMS40), as opposed to the 2 patients with just one positive criterion at rest (RMS 40 less than 25 muV) who became normal during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Group B streptococcal endocarditis mimicking mitral valve myxoma.

A patient with group B streptococcal endocarditis and large vegetations resembling mitral valve myxoma is described. Group B streptococcal endocarditis and the differential diagnosis of vegetations and cardiac tumors are briefly reviewed.

Recurrent pulmonary embolism: importance, diagnosis, management and prevention.

Pulmonary emboli, even small, cause irreparable lung damage. Recurrent pulmonary emboli further increase the amount of non functional lung tissue and may result in incapacitating respiratory disease or death. It is therefore mandatory that the disease be correctly diagnosed and adequately treated. As prevention is better than cure, every patient presenting with clinical signs of deep venous thrombosis (DVT) should be correctly explored. The site and size of thrombosis must be visualized preferably with contrast venography with imaging of the veins of the limbs, iliac veins and vena cava. Risk factors such as obesity, immobilization etc. must be taken into account. Underlying disease such as heart disease and venous insufficiency must be treated. Malignancy must be looked for as in a recent series of patients with primary DVT which were studied, 15% presented with an up till then unknown malignant disease. In patients presenting with recurrent DVT this percentage rose to 20%. When a patient presents with DVT of the femoro-iliac vena cava axis, aggressive treatment must be adopted. Fibrinolysis or if this is contra-indicated, thrombectomy will be used. A vena cava filter may be necessary and longterm anticoagulation is mandatory. The same rationale is applicable in cases of pulmonary embolus whether it is a primary event or a recurrence.