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C Attenhofer

Publications and source records attributed to C Attenhofer.

9 recordsLinked to original sources
PubMed2000

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.

Blood Flow Velocity↗
PubMed1998

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.

Analysis of Variance↗
PubMed1997

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.

Adult↗
PubMed1995

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).

Adult↗
PubMed1994

[Stress echocardiography: development and significance].

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.

Adenosine↗
PubMed1994

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.

Anaphylaxis↗
PubMed1992

[Heart contusions: pathological findings and clinical course].

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.

Adolescent↗