F.J. Ten Cate

Principles and recent developments in ultrasound contrast agents

The behaviour of gas bubbles and gas encapsulated spheres as echographic contrast agents is reviewed. Compared with rigid spheres, gas bubbles are superior scattering agents and they offer a number of useful properties which can be exploited in a variety of ways. The analysis of their velocity of sound, back-scatter intensity, second harmonic emission and resonant frequency opens up new perspectives in the development of contrast agents for echocardiographic research with potential clinical applications.

Decreased Coronary Flow Reserve in Hypertrophic Cardiomyopathy Is Related to Remodeling of the Coronary Microcirculation

BACKGROUND Ischemia occurs frequently in hypertrophic cardiomyopathy (HCM) without evidence of epicardial stenosis. This study evaluates the hypothesis that the occurrence of ischemia in HCM is related to remodeling of the coronary microcirculation. METHODS AND RESULTS End-diastolic septal wall thickness was significantly increased in patients with HCM (25.8+/-2.9 mm) in comparison with cardiac transplant recipients (control subjects: 11.4+/-3.0 mm; P<0.05). Although the diameter of the left anterior descending coronary artery was similar in both groups (3.0+/-0.8 versus 3.0+/-0.5 mm, P=NS), the coronary resistance reserve (CRR=CRRbasal/CRRhyperemic), corrected for extravascular compression (end-diastolic left ventricular pressure), was reduced to 1.5+/-0.6 in HCM (P<.05; control, 2.6+/-0.8). Arteriolar lumen (AL) divided by wall area was lower in HCM (21+/-5% versus 30+/-4%; P<.05), and capillary density tended to decrease (from 1824+/-424 to 1445+/-513 per mm2, P=.11) in HCM. CRR was linearly related to normalized AL according to the formula CRR=O.1 AL-0.45 (r=.57; P<.05). Further analysis revealed that CRR, AL, and capillary density were all linearly related to the degree of hypertrophy. CONCLUSIONS Decrements in CRR were related to changes of the coronary microcirculation. Both the decrease in CRR and these changes in the coronary microcirculation were related to the degree of hypertrophy. All these factors might contribute to the well-known occurrence of ischemia in this patient group.

Progression to left ventricular dilatation in patients with hypertrophic obstructive cardiomyopathy.

Congestive heart failure with dilated left ventricle developed in two patients with symptomatic hypertrophic obstructive cardiomyopathy. Both patients previously underwent cardiac surgery for relief of their outflow obstruction. Alterations in structure and function of the left ventricle during their episode of cardiac failure and thereafter were documented by echocardiography. The findings suggest that progression to left ventricular dilatation is a potential complication in patients with hypertrophic obstructive cardiomyopathy.

Influence of the pattern of hypertrophy on left ventricular twist in hypertrophic cardiomyopathy

Background/objective: Left ventricular (LV) twist has an important role in LV function. The influence of the pattern of LV hypertrophy on LV twist in hypertrophic cardiomyopathy (HCM) patients is unknown. This study sought to assess LV twist in a large group of HCM patients according to the pattern of LV hypertrophy. Methods: The final study population consisted of 43 patients with HCM (mean age 43 (15) years, 31 men) and a typical sigmoidal (n = 16) or reverse septal curvature (n = 27) and 43 age-matched and gender-matched healthy control subjects. LV peak systolic rotation (Rotmax), LV peak systolic twist (Twistmax) and untwisting at 5%, 10% and 15% of diastole were determined by speckle tracking echocardiography (STE). Results: Compared to control subjects, HCM patients had increased basal Rotmax (−5.5° (2.3°) vs −3.4° (1.7°), p<0.001) and comparable apical Rotmax (7.3° (3.1°) vs 7.0° (2.2°), p = NS), resulting in increased Twistmax (12.4° (4.0°) vs 9.9° (2.7°), p<0.01). Untwisting at 5%, 10% and 15% of diastole was decreased in HCM patients (all p<0.05). There was a striking difference in apical Rotmax (9.4° (2.8°) vs 6.0° (2.6°), p<0.01) and Twistmax (15.3° (3.2°) vs 10.6° (3.3°), p<0.01) between HCM patients with a sigmoidal and reverse septal curvature. Conclusions: STE may provide novel non-invasive indices to assess LV function in patients with HCM. Apical Rotmax and Twistmax in HCM patients are dependent on the pattern of LV hypertrophy.

Clinical utility and cost effectiveness of a personal ultrasound imager for cardiac evaluation during consultation rounds in patients with suspected cardiac disease

Objective: To assess the clinical utility and cost effectiveness of a personal ultrasound imager (PUI) during consultation rounds for cardiac evaluation of patients with suspected cardiac disease. Methods: 107 unselected patients from non-cardiac departments (55% men) were enrolled in the study. After the physical examination the consultant cardiologist performed an echocardiographic study with a PUI. The final report was given instantly to the referring physician. All patients subsequently underwent a study with a standard echocardiographic device (SED). For each patient the consultant cardiologist noted whether the findings of the PUI were adequate for final diagnosis. The total cost when full echocardiography was used was compared with the cost when the PUI was used. The time interval from request to diagnosis was also compared. Results: In 84 (78.5%) patients no further examination with an SED was regarded as necessary. Twenty three patients (21.5%) required a further detailed examination with the SED because of the need for haemodynamic information. There was an excellent agreement for the detection of abnormalities between the two devices (96%). The total cost was €132 per patient with the SED and €75 per patient with the PUI. According to this study, the use of the PUI can lead to a 33.4% reduction of total cost. The mean time from request to diagnosis at the authors’ institution was four days for the SED and instantly for the PUI, for additional potential cost savings. Conclusions: Immediate echocardiographic assessment during consultation rounds can lead to significant cost savings and can shorten the time to diagnosis.

Cardiac involvement in adults with Pompe disease

Background.  Glycogen storage disease type II or Pompe disease is a neuromuscular disorder caused by deficiency of lysosomal acid α‐ glucosidase. Classic infantile Pompe disease results in massive left ventricular (LV) hypertrophy and failure. Although Pompe disease is often included in the differential diagnosis of LV hypertrophy the true frequency of cardiac involvement in adults with Pompe disease is not known.

Quantification of transpulmonary echocontrast effects

Videodensity of left heart and right heart were studied after intravenous injection of increasing dosages of 0.01-0.02 and 0.04 mL/kg bodyweight of Albunex in 10 healthy volunteers. The increase in videodensity in the left ventricle was always lower than in the right ventricle. Possible explanations are diffusion of gases caused by ambient pressures changes and change in microspheres distribution due to the sieving effect of the lung capillary bed. These phenomena were studied in vitro and were consistent with clinical observations. These limitations restrict a quantitative assessment of left heart echocontrast after intravenous injection.

Intracoronary albunex. Its effects on left ventricular hemodynamics, function, and coronary sinus flow in humans.

BACKGROUND Albunex is a recently developed ultrasonic contrast agent made from sonicated human serum albumin. The effects on left ventricular hemodynamics, function, and coronary sinus flow of intracoronary Albunex in humans have not been reported. METHODS AND RESULTS Eighteen patients with known or suspected coronary artery disease were examined at the time of coronary arteriography with simultaneous two-dimensional echocardiography and left ventricular catheter-tip manometry. Intracoronary injections of Albunex into the left main coronary artery were performed, as were injections of 5% human serum albumin and iohexol, a widely used angiographic contrast agent. Mean coronary sinus flow was determined before and after injections of iohexol and 2 mL of Albunex. Injection of 1 mL of Albunex induced no changes in any of the measured hemodynamic parameters (heart rate, peak left ventricular [LV] systolic pressure, LV end-diastolic pressure, positive or negative LV dP/dt, or time constant of relaxation) or echocardiographic determinants of LV function (regional wall motion and global ejection fraction). Injection of 2 mL or more of Albunex caused small, transient (less than 30 seconds) changes in measures of isovolumic relaxation (negative LV dP/dt; 95% confidence interval: mean, -2.41 [-4.3, -0.52] and tau 1; confidence interval mean, 3.52; [1.48, 5.58]) but not in functional measures. Intracoronary injection of 5% human serum albumin had no effect. Iohexol induced small but significant changes in both systolic and diastolic parameters, which lasted beyond 30 seconds after injection. Mean coronary sinus blood flow increased. CONCLUSIONS The effects of Albunex on hemodynamics, left ventricular function, and coronary sinus blood flow compare favorably with iohexol. Albunex can be considered to be an essentially inert contrast agent if used in patients with stable coronary artery disease.

Familial screening and genetic counselling in hypertrophic cardiomyopathy: the Rotterdam experience.

Hypertrophic cardiomyopathy (HCM) is a disease characterised by unexplained left ventricular hypertrophy (LVH) (i.e. LVH in the absence of another cardiac or systemic disease that could produce a similar degree of hypertrophy), electrical instability and sudden death (SD).Germline mutations in genes encoding for sarcomere proteins are found in more than half of the cases of unexplained LVH. The autosomal dominant inherited forms of HCM are characterised by incomplete penetrance and variability in clinical and echocardiographic features, prognosis and therapeutic modalities. The identification of the genetic defect in one of the HCM genes allows accurate presymptomatic detection of mutation carriers in a family. Cardiac evaluation of at-risk relatives enables early diagnosis and identification of those patients at high risk for SD, which can be the first manifestation of the disease in asymptomatic persons. In this article we present our experience with genetic testing and cardiac screening in our HCM population and give an overview of the current literature available on this subject. (Neth Heart J 2007;15:184-9.)

Dobutamine stress MRI versus threedimensional contrast echocardiography: It’s all Black and White

Dobutamine stress magnetic resonance imaging is considered the superior stress modality to detect wall motion abnormalities. In this report we demonstrate the strengths of a newly developed stress modality: dobutamine stress contrastenhanced real-time three-dimensional echocardiography. This stress modality may become a competitor of stress magnetic resonance imaging allowing fast acquisition and an unlimited number of left ventricular cross sections. Unfortunately, at the moment adequate imaging with stress realtime three-dimensional echocardiography is only possible in a minority of cardiac patients. (Neth Heart J 2008;16:217-8.)