In vitro validation of volumetric blood flow measurement using Doppler flow wire.

Determination of any volumetric blood flow requires assessment of mean blood flow velocity and vessel cross-sectional area. For evaluation of coronary blood flow and flow reserve, however, assessment of average peak velocity alone is widely used, but changes in velocity profile and vessel area are not taken into account. We studied the feasibility of a new method for calculation of volumetric blood flow by Doppler power using a Doppler flow wire. An in vitro model with serially connected silicone tubes of known lumen diameters (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 mm) and pulsatile blood flow ranging from 10 to 200 mL/min was used. A Doppler flow wire was connected to a commercially available Doppler system (FloMap(R), Cardiometrics) for online calculation of the zeroth (M(0)) and the first (M(1)) Doppler moment, as well as mean flow velocity (V(m)). Two different groups of sample volumes (at different gate depths) were used: 1. two proximal sample volumes lying completely within the vessel were required to evaluate the effect of scattering and attenuation on Doppler power, and 2. distal sample volumes intersecting completely the vessel lumen to assess the vessel cross-sectional area. Area (using M(0)) and V(m) (using M(1)/M(0)) obtained from the distal gates were corrected for scattering and attenuation by the data obtained from the proximal gates, allowing calculation of absolute volumetric flow. These results were compared to the respective time collected flow. Correlation between time collected and Doppler-derived flow measurements was 0.98 (p < 0.0001), with a regression line close to the line of equality indicating an excellent agreement of the two measurements in each individual tube. The mean paired flow difference between the two techniques was 1.5 +/- 9.0 mL/min (ns). Direct volumetric blood flow measurement from received Doppler power using a Doppler flow wire system is feasible. This technique may potentially be of great clinical value because it allows an accurate assessment of coronary flow and flow reserve with a commercially available flow wire system.

Impact of atropine injection on heart rate response during treadmill exercise echocardiography: a double-blind randomized pilot study.

We evaluated the effect of atropine on the heart rate (HR) response during treadmill exercise echocardiography. A potential limitation of treadmill exercise echocardiography is the requirement for postexercise imaging. Rapid recovery of HR and wall motion abnormalities may decrease test sensitivity. A double-blind randomized study was performed at a tertiary care center. Fifty-two patients (age, 63 +/- 9 years) with known or suspected coronary artery disease were injected with either 0.5 mg of atropine or saline before treadmill exercise echocardiography. HR response during and after exercise was recorded. Atropine resulted in a greater increase in HR before exercise (increase of 15 +/- 9 vs 5 +/- 7 beats per minute, P < 0.0001) and a higher HR rate during the first 5 minutes of exercise (P < 0.05). In recovery, there was an exponential decrease in HR in both atropine and control groups. However, at the end of image acquisition (66 +/- 15 seconds), the HR was higher in the atropine group (128 +/- 21 vs 115 +/- 19 beats per minute, P = 0.02) and remained higher throughout the 10-minute recovery period (P = 0.0015). Dry mouth was more common after atropine injection (P = 0.005); other side effects were similar. The extent and resolution of myocardial ischemia were comparable in both groups. Atropine injection before treadmill exercise echocardiography results in a higher HR during the acquisition of echocardiographic images; whether atropine could affect the diagnostic accuracy of tread mill exercise echocardiography requires further study.

Systolic and diastolic function with alternate and combined site pacing in the right ventricle.

UNLABELLED: We hypothesized that pacing at two ventricular sites simultaneously would activate the myocardium more rapidly and improve ventricular function. We studied the effect of pacing at the right ventricular outflow tract (RVOT) and the RV apex (RVA) on systolic and diastolic function. In 14 patients with a reduced systolic ejection fraction < 40% (mean EF 32% +/- 4%) we measured RV pressures, left ventricular pressures, EF, cardiac output, peak dP/dt, peak negative dP/dt, and the time constant of relaxation, Tau, during intrinsic rhythm, atrial pacing and DVI pacing at the RVA, the RVOT, and both RV sites combined in random order. Repeated measures analysis of variance showed no significant differences in any of these parameters. The highest absolute values of dP/dt were observed during sinus rhythm and the lowest with RVA pacing. This parameter tended to improve progressively with pacing in the RVOT and at both sites. Peak negative dP/dt showed a similar nonsignificant trend. CONCLUSION: These data suggest that in patients with poor LV function, there may be subtle improvements in diastolic and systolic function with pacing in the RVOT and at combined sites in the RV compared to traditional RVA pacing.

Paradoxical sinus deceleration during dobutamine stress echocardiography: description and angiographic correlation.

OBJECTIVES: This report characterizes the paradoxical sinus deceleration occasionally observed during dobutamine stress testing and determines its relation to myocardial ischemia. BACKGROUND: Dobutamine stress echocardiography is widely accepted as a noninvasive tool for evaluating coronary artery disease. With infusion of dobutamine, there is typically a dose-dependent increase in heart rate. However, in some patients, a paradoxical decrease in heart rate has been observed during high dose dobutamine infusion. METHODS: In 181 consecutive patients undergoing both dobutamine stress echocardiography and coronary angiography, electrocardiographic (ECG) data collected during dobutamine infusion were reviewed to identify patients with a decrease in heart rate. The clinical, stress echocardiographic, hemodynamic and angiographic correlates of patients with a decrease in heart rate were reviewed. RESULTS: A decrease in heart rate ranging from 7 to 64 beats/min occurred during high dose dobutamine infusion in 14 patients (8%, 95% confidence interval [CI] 6% to 10%), including 3 in whom a junctional rhythm developed. The decrease was sudden in five patients (36%, 95% CI 13% to 65%) and gradual in nine (64%, 95% CI 35% to 87%). A decrease in blood pressure (12 patients [86%], 95% CI 57% to 98%) with simultaneous chest pain (7 patients [50%], 95% CI 23% to 77%) and nausea (5 patients [36%], 95% CI 13% to 65%) was common. Significant coronary artery disease (> or = 50% diameter stenosis) was present in 8 (57%) of 14 patients (95% CI 29% to 82%). Two patients (14%, 95% CI 2% to 43%) had no clinical, ECG or echocardiographic evidence of ischemia and no significant coronary artery disease by angiography. There was no increased incidence of right coronary artery stenosis in patients with paradoxical sinus deceleration. CONCLUSIONS: Paradoxical sinus deceleration occurs in 8% of patients during dobutamine stress testing. Although most often observed in patients with coronary artery disease, it can occur in the absence of ischemia and coronary artery disease, and in some patients may be due to a vasodepressor reflex.

Is review of videotape necessary after review of digitized cine-loop images in stress echocardiography? A prospective study in 306 patients.

The interpretation of stress echocardiography has been made easier by the comparison of digitized prestress and poststress frame-grabbed images (cine-loops), each representing a portion of a single cardiac cycle. Often, review of these digitized images is substituted for review of the complete videotape record of the examination. An alternative is to review both the digitized images as well as the videotape record of the rest and stress images. To date, there has been insufficient documentation of whether these options (cine-loop images alone versus cine-loop images plus videotape) provide comparable or additive information. Therefore, we prospectively evaluated information obtained from review of cine-loop images versus combined review of cine-loop images and videotape records in 306 consecutive patients undergoing treadmill (213 patients, 70%) or dobutamine (93 patients, 30%) stress echocardiography. An experienced echocardiologist first reviewed the cine-loop images and scored the wall motion in 16 segments at rest and with stress. Next, the complete videotape record was reviewed with repeated wall motion scoring. A questionnaire comparing cine-loop and videotape images was completed at the end of each review. Digitization of images was technically inadequate in 14 patients (4%). In 116 (40%) of the other 292 patients, the regional wall motion assessment, after relying solely on cine-loop images, was modified with subsequent videotape review. In 40 patients (14%), these modifications resulted in a change in the final impression regarding whether the study result was normal or abnormal. In a multivariate analysis, age, gender, and type of stress echocardiography had no significant influence on discordance of the cine-loop image and combined cine-loop and video information. Stepwise logistic regression analysis identified poorer image quality (p < 0.0001) and regional wall motion abnormalities (p < 0.0001) as predictors of discordance between cine-loop and combined review. We conclude that relying solely on digitized cine-loop images representing a single cardiac cycle is not optimal, especially if the quality of the digitized images is suboptimal and if regional wall motion abnormalities are present. Thus we recommend a combined review of both cine-loop images and videotape images in the interpretation of stress echocardiography.

Isolated noncompaction of the myocardium in adults.

OBJECTIVE: To describe the entity of isolated ventricular noncompaction (IVNC) and present a series of cases of this rare disorder in an adult population. MATERIAL AND METHODS: We review a 10-year experience with the diagnosis of IVNC and discuss the clinical, echocardiographic, and pathologic features of this condition. Echocardiographic diagnostic criteria included the absence of coexisting cardiac abnormalities, the presence of prominent and excessive trabeculations of one or more ventricular wall segments, and intertrabecular spaces perfused from the ventricular cavity. Pathologic examination focused on regions with exaggerated trabeculations and deep intertrabecular spaces. RESULTS: IVNC is an unexplained arrest of myocardial morphogenesis previously encountered mainly in pediatric patients. Among 37,555 transthoracic echocardiographic studies performed at our hospital between January 1984 and October 1993, 17 cases of IVNC were identified in adult subjects (14 men and 3 women, 18 to 71 years of age). The mean time from onset of symptoms to correct diagnosis was 3.5 +/- 5.7 years, and the mean duration of follow-up was 30 +/- 28 months. Common clinical symptoms were heart failure, ventricular arrhythmias, and a history of embolic events. Two-dimensional echocardiography revealed 10 patients with left ventricular and 7 (41%) with biventricular IVNC. During a 6-year follow-up period, eight patients died and two underwent heart transplantation. CONCLUSION: Although the diagnosis of IVNC in an adult population is often delayed because of similarities with more frequently diagnosed conditions, two-dimensional echocardiography will facilitate the diagnosis of IVNC in this subset of patients. Because of the high incidence of heart failure, ventricular arrhythmias, and embolization in adults with IVNC, early diagnosis is important.

Comparison of ischemic response during exercise and dobutamine echocardiography in patients with left main coronary artery disease.

OBJECTIVES: This study sought to compare manifestations of myocardial ischemia evoked by exercise and dobutamine echocardiography in patients with left main coronary artery disease. BACKGROUND: During exercise testing, left ventricular cavity dilation, marked ST segment depression and blood pressure decrease indicate severe coronary artery disease. Whether these signs are comparably evoked by dobutamine echocardiography has not been described. METHODS: Fifty-four patients who underwent stress echocardiography (36 exercise, 18 dobutamine) and coronary angiography showing > or = 50% left main stenosis were analyzed. Electrocardiographic and blood pressure changes, symptoms, wall motion score indexes and sensitivity for coronary artery disease were compared. In 47 patients, the left ventricular endocardium was traced to quantify volumes and ejection fraction. RESULTS: Stress-induced regional wall motion abnormalities developed in 91% of patients; this was not different on exercise (89%) or dobutamine echocardiography (94%). Rate-pressure product and wall motion score index, similar at rest, tended to be higher after exercise than after dobutamine stress (p = 0.07 and p = 0.05, respectively). ST segment depression > or = 1 mm was more common with exercise (p = 0.005). Ejection fraction and end-systolic and end-diastolic volume indexes were comparable at rest in both groups. With exercise, ejection fraction decreased in 87% of patients, and end-systolic and end-diastolic volume indexes increased in 80%. In contrast, with dobutamine, decreased ejection fraction and increased volume indexes were infrequent. Ejection fraction was lower ([mean +/- SD] 45 +/- 19% vs. 54 +/- 12%, p = 0.007) and end-diastolic (69 +/- 26 vs. 50 +/- 17 ml/m2, p =0.02) and end-systolic (39 +/- 20 vs. 24 +/- 13 ml/m2, p = 0.02) volume indexes were higher after exercise than after dobutamine stress. CONCLUSIONS: On the basis of changes in regional wall motion both dobutamine and exercise echocardiography have a comparable high sensitivity in diagnosing myocardial ischemia in left main coronary artery disease. However, conventional signs of severe myocardial ischemia, including left ventricular cavity dilation and marked ST segment depression, occur more often with exercise than with dobutamine echocardiography.

Leaking giant aneurysm of the aortic root due to cystic medial necrosis with pericardial tamponade mimicking type-A aortic dissection.

The diagnosis of acute type-A aortic dissection is predominantly based on the demonstration of an intimal tear or a dissection membrane. We describe another pathogenetic mechanism in a patient with the typical features of acute aortic dissection with pericardial tamponade, and a giant aneurysm of the ascending aorta. However, no dissection membrane, rupture site, or intimal tear could be demonstrated by transesophageal echocardiography, intraoperatively, or histologically. The histological work-up showed an extreme form of cystic medial necrosis with intramural hemorrhages consistent with a leaking aneurysm. Hence, in a patient with a symptomatic aneurysm of the aortic root and pericardial tamponade, obvious intimal dissection or rupture does not always have to be present echocardiographically or intraoperatively. A different presentation can occur in the setting of an extreme medial necrosis, where blood leaks through the aortic wall causing intramural hemorrhages with intimal leaks invisible to the surgeon's or echocardiographer's eye. This process is clinically indistinguishable from type-A aortic dissection.

Pseudoaneurysm following aortic homograft: clinical implications?

OBJECTIVE: To determine the prevalence of pseudoaneurysm formation after aortic (left ventricular outflow tract) homograft implantation and to evaluate predisposing factors. METHODS: Echocardiographic data were analysed in 30 patients for evidence of pseudoaneurysm formation after homograft implantation. Pseudoaneurysm was characterised as a perfused echo-free space between the homograft and the native aortic wall communicating with the left ventricular outflow tract. Clinical data were analysed for potential predisposing factors for pseudoaneurysm formation. RESULTS: Pseudoaneurysms were found in 22 of 30 patients. Mean age, length of follow up after surgery, aortic systolic pressure gradient (15 (SD 12) v 10 (4) mm Hg), aortic root diameter, and size of the homografts were comparable in patients with and without pseudoaneurysm. preoperative infection, operating techniques, and whether first or reoperation did not affect pseudoaneurysm formation. However, pseudoaneurysms were often localised at the site of an abscess or a paravalvular leak after eradicated prosthetic valve endocarditis. CONCLUSIONS: (1) Doppler echocardiography demonstrates that pseudoaneurysm formation is common after aortic homograft implantation. (2) A prospective study is needed to clarify the prognostic importance of pseudoaneurysms. (3) The high incidence of pseudoaneurysm formation may lead to an improvement of surgical technique (application of fibrin glue).

[Stress echocardiography: development and significance]. / Stress-Echokardiographie: Entwicklung und Bedeutung.

Exercise electrocardiography is still the primary method used in the non-invasive assessment of coronary artery disease. Stress echocardiography is now being increasingly used as a more sensitive adjunct technique to assess ischemia. Ischemia provoked by stress can induce reversible wall motion abnormalities which are disclosed by cross-sectional 2-dimensional echocardiography and standard projections. The types of stress used are physical exercise (bicycle, treadmill), atrial pacing or pharmacologic stimulation. In the latter, the catecholamine dobutamine has emerged as preferable to the vasodilators dipyridamole and adenosine. The diagnostic accuracy of dobutamine stress echocardiography is comparable to that of bicycle or treadmill exercise echocardiography, but dobutamine stress echocardiography is technically simpler and can be performed in patients unable to exercise. Its sensitivity in diagnosing ischemic or viable myocardium is comparable to that of nuclear methods, MRI or PET. In contrast to nuclear methods, stress echocardiography is however free of radiation. In the assessment of patients with coronary artery disease, stress echocardiography has been shown to be valuable for diagnosis, preoperative risk stratification and determination of prognosis. Furthermore, low dose dobutamine echocardiography can be used to detect viable myocardium. Despite these very promising aspects of the method, there are recognized disadvantages and limitations: stress echocardiography is very time-consuming and operator-dependent; its sensitivity correlates strongly with the number of studies performed; analysis of wall motion is performed qualitatively on a purely subjective level, and hence lacks the objectivity of a quantitative approach. These factors emphasize the need for intensive research to render stress echocardiographic analysis more objective. Automatic boundary detection of left ventricular endocardium, color-Doppler-based tissue imaging and three-dimensional reconstruction offer interesting perspectives in rendering the subjective more objective.

Ventricular fibrillation in a patient with exercise-induced anaphylaxis, normal coronary arteries, and a positive ergonovine test.

Exercise-induced anaphylaxis (EIA) is a rare form of physical allergy. Although histamine release is a feature of EIA, and histamine provocation of coronary spasm has been described, serious cardiac arrhythmias in EIA have not been reported. Exercise-induced anaphylaxis was diagnosed in a survivor of out-of-hospital cardiac arrest due to ventricular fibrillation after ECG signs of coronary spasm. Coronary artery disease was excluded. Ergonovine provocation induced coronary spasm in this patient. This is, to the authors' knowledge, the first description of ventricular fibrillation in EIA, possibly due to coronary spasm.

[Heart contusions: pathological findings and clinical course]. / Contusio cordis: Pathologische Befunde und klinischer Verlauf.

After blunt chest trauma, myocardial contusion is frequently suspected, but diagnostic criteria are difficult to define and commonly accepted recommendations for duration and form of patient monitoring are lacking. We therefore conducted a retrospective review of the hospital records of 50 consecutively hospitalized patients with the diagnosis of myocardial contusion after blunt chest trauma, and analyzed the pathological laboratory, ECG and echocardiography findings as well as the associated injuries and cardiac-related complications. The average injury severity score was 25 +/- 8. Initially 98% of the patients were hemodynamically stable. In 90% there were abnormal enzyme levels consistent with myocardial injury. Typically, the maximum level of CPK-MB, LDH and CPK-MB/CPK (MB-fraction) was found initially and these values declined rapidly. The MB fraction normalized within 8 hours. In 32% of the patients there were the following ECG changes consistent with myocardial contusion transient: ventricular tachycardia (12%), ST/T changes (12%), complete right bundle branch block (10%), atrial fibrillation (4%), first degree AV block (2%). The episodes of ventricular tachycardia were registered within the first 24 hours; in 5 of these 6 patients the admission ECG was normal. An echocardiography was done in 64% of the patients and in 37% showed either a pericardial effusion, regional wall motion abnormalities, a pneumopericardium or an intramyocardial hematoma in the free wall of the right ventricle. One patient died of multiorgan failure during this hospitalization. There were no sudden cardiac deaths. The diagnosis of myocardial contusion is vital in unstable patients but also very important in hemodynamically stable patients, despite its low morbidity. The minimum program we recommend for diagnosis and monitoring should include enzyme levels (CPK, CPK-MB) and ECG controls. Echocardiography may be necessary as well. If during the initial compulsory 24 hour monitoring of ECG and hemodynamics no complications occur, further monitoring is not necessary.