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Biomedical subjects

Itzhak Kronzon

Publications and source records attributed to Itzhak Kronzon.

At least 19 recordsLinked to original sources
PubMed2008

The 'A-dip' of diastolic mitral regurgitation: an unusual Doppler flow pattern in a patient with severe aortic insufficiency and complete heart block.

This is an unusual case of diastolic mitral regurgitation (MR) with a high diastolic velocity jet and prolonged jet duration related to a combination of acute severe aortic insufficiency and high-degree atrioventricular block. This case illustrates an interesting hemodynamic phenomenon with multiple transient decreases in the pressure gradient between the left ventricle and left atrium during diastole related to a temporary increase in left atrial pressure associated with atrial contraction.

Adult↗
PubMed2006

Increase in circulating bone marrow progenitor cells after myocardial infarction.

BACKGROUND: Most circulating blood cells expressing the marker CD34 are bone marrow progenitor cells. These cells differentiate into cardiomyocytes, endothelial and smooth muscle cells after myocardial infarction in vivo. Mobilization of bone marrow progenitor cells into the peripheral blood after myocardial infarction may supply these cells to the heart. Rise in CD34+ cell concentrations following myocardial infarction would support the existence of myocardial-initiated mobilization. METHODS: Serial measurements of circulating CD34+ cells were made in 42 consecutive patients presenting with first ST-elevation myocardial infarction. Measurement of serum concentrations of monocyte chemoattractant protein-1, stromal derived factor-1, hepatocyte growth factor, interleukin-17 and thrombopoietin was also performed. Samples were drawn on day 1 after myocardial infarction, and on days 4, 8 and 12. Levels of CD34+ cells and cytokines were also measured in 15 controls. RESULTS: By day 8, the mean concentration of CD34+ cells rose by 74% above mean control level of 2527 cells/ml, and 41% above day 1 mean (P=0.02). This rise was sustained on day 12 (P=0.05). On day 1, there was a 9.3-fold rise in hepatocyte growth factor above the control level of 589 pg/ml (P=0.002). Hepatocyte growth factor levels declined from the day 1 mean of 6061 to 1485 pg/ml on day 12 (P=0.002). No significant change in stromal derived factor-1, interleukin-17, monocyte chemoattractant protein-1 and thrombopoietin was observed. Elevations in CD34+ cells and hepatocyte growth factor were not related to infarction size as estimated on echocardiography. CONCLUSIONS: Elevation in the concentration of circulating CD34+ cells after myocardial infarction suggests that myocardial initiated bone marrow progenitor cell mobilization exists in humans. The cytokines studied in our protocol are not likely to play a direct role in bone marrow progenitor cell mobilization.

Antigens, CD34↗
PubMed2005

Usefulness of myocardial perfusion echocardiography to identify obstructive coronary artery disease in patients with abnormal ventricular septal motion.

Twenty-three patients who had septal wall motion abnormalities and who underwent angiography within 2 weeks were evaluated by myocardial perfusion echocardiography. Mean perfusion score (plateau video intensity times the wash-in rate) was lower in segments that were supplied by obstructed coronary arteries in real time (7.5 vs 22.6 dB/s, p <0.005) and with end-systolic triggering (8.6 vs 20.9 dB/s, p <0.001). Lower mean septal perfusion scores (<12 dB/s) were seen in 14 of 16 patients who had obstructive septal coronary artery disease, and normal mean septal perfusion scores were seen in 6 of 7 patients who did not have obstructive septal coronary artery disease.

Aged↗
PubMed2005

Combined transesophageal echocardiography and transesophageal cardioversion probe: technical aspects.

A probe assembly for simultaneous transesophageal echocardiography and transesophageal cardioversion has been developed. This probe allows cardioversion with the delivery of much lower energy than the standard external approach. Details of the probe construction and its use are described, as is the prospect for future practice. The use of a combined probe may be the technique of choice for patients who require both cardioversion and transesophageal echocardiography.

Atrial Fibrillation↗
PubMed2005

Saphenous vein graft aneurysm masquerading as a right atrial mass.

We report a case of a large saphenous vein graft (SVG) aneurysm masquerading as a right atrial mass on transesophageal echocardiogram. Cardiac magnetic resonance angiography reliably made a diagnosis of SVG aneurysm extrinsically compressing right atrium. This case illustrates the importance of using combined imaging modalities for the diagnosis and management of cardiac masses.

Aged↗
PubMed2005

Pulmonary vein compression by tumor: an unusual Doppler flow pattern.

Pulmonary venous compression caused by a large lung mass was diagnosed in a 50-year-old female with metastatic renal cell carcinoma. The pulmonary venous flow pattern on Doppler revealed high flow velocity as well as the unusual finding of continued antegrade flow throughout the cardiac cycle (without reversal during atrial contraction). Extracardiac tumors can compress pulmonary veins, mimicking pulmonary vein stenosis. This may cause dyspnea due to elevated pulmonary venous pressures. This report describes an unusual pulmonary vein blood flow pattern in a patient with lung metastases.

Blood Flow Velocity↗
PubMed2005

Rare flow pattern in a patient with cor triatriatum.

Doppler echocardiography demonstrated a rare flow pattern due to cor triatriatum that is also present in subvalvular or supravalvular mitral stenosis: a forward gradient, in both systole and diastole.

Blood Flow Velocity↗
PubMed2004

Diastolic dysfunction: can it be diagnosed by Doppler echocardiography?

Heart failure with a normal ejection fraction (HFNEF) predominantly afflicts older, female individuals and is considered to be a consequence of diastolic dysfunction. Doppler echocardiography has become the standard method for identifying and characterizing diastolic function. However, the important distinction between Doppler measures of filling dynamics and true indexes of intrinsic ventricular diastolic chamber properties is not widely appreciated. Herein, we delineate physiologic measures of intrinsic ventricular diastolic function, as determined by pressure volume analysis, and compare and contrast these measures with those derived from Doppler echocardiography. Doppler-derived indexes of ventricular filling do not provide specific information on intrinsic passive diastolic properties, and thus, abnormal filling dynamics do not necessarily equate with intrinsic myocardial diastolic dysfunction. This raises a fundamental question as to whether delayed relaxation and/or stiffened passive properties are the unifying pathophysiologic mechanisms in all patients who present with HFNEF.

Aged↗
PubMed2004

Frequency of severe renal artery stenosis in patients with severe thoracic aortic plaque.

Atherosclerotic renal artery stenosis (RAS) is an underdiagnosed disorder and a treatable etiology of hypertension and renal insufficiency. All patients were referred for a transesophageal echocardiogram for various indications. Abdominal ultrasound was performed in 69 patients, 43 with severe thoracic aortic plaque (> or =4 mm) and 26 controls with no or mild plaque (< or =2 mm). Severe RAS (> or =60%) was defined as flow velocity > or =1.8 m/s and a renal:aortic ratio of > or =3.5. There were 8 cases of RAS (all severe) in the 43 patients with severe aortic plaque (19% vs 0% of controls; p = 0.02). Severe plaque (p = 0.02) and hypertension (p = 0.03) were correlated with RAS. On multivariate analysis, severe plaque (p = 0.017) and hypertension (p = 0.002) remained independently correlated with RAS. In a paired analysis, matched for age and gender (McNemar), severe plaque was significantly associated with RAS (p = 0.008). Severe thoracic aortic plaque is strongly associated with RAS, which is found in 19% of patients with severe plaque. Patients found to have severe aortic plaque on transesophageal echocardiography should be screened for RAS.

Aged↗
PubMed2004

Usefulness of transesophageal echocardiography using a combined probe when converting atrial fibrillation to sinus rhythm.

We studied the feasibility and efficacy of transesophageal echocardiography (TEE) combined with transesophageal cardioversion (TEC). Secondary aims were to study left atrial flow velocities before and 1 and 5 minutes after TEC, biochemical markers of myocardial damage, and patient tolerability. TEC after a short period of anticoagulation and exclusion of a clot with TEE was safe. TEC was well tolerated and efficacious. The use of a combined probe for TEE and TEC therefore can save time and be more effective. A custom-made probe for combined TEE plus TEC was used. TEC was performed with a step-up protocol (20 J to between 30 and 50 J) and with biphasic shocks. Presence of spontaneous echo contrast was scored. Cumulative energy needed to achieve sinus rhythm was calculated. Discomfort was scored on a scale of 0 to 10. Twenty-six patients underwent combined TEE/TEC. Sinus rhythm was achieved in 24 of 26 patients (92%) with a mean cumulative energy of 42.3 J. Sixteen of 26 patients were cardioverted with a 20-J shock, and 6 of these patients had early recurrence of atrial fibrillation. All biochemical markers were unaffected, and TEE/TEC was well tolerated. Left atrial appendage velocity decreased significantly after TEC. Thus, the use of a TEE/TEC probe offers effective cardioversion with low energy levels, is well tolerated, and hemodynamics during and immediately after cardioversion can be monitored. Early cardioversion after exclusion of a clot with this combined probe is time saving and cost effective.

Adult↗
PubMed2004

Semirigid partial annuloplasty band allows dynamic mitral annular motion and minimizes valvular gradients: an echocardiographic study.

BACKGROUND: Traditional mitral annuloplasty devices include both rigid rings, which restrict annular motion, and soft rings and bands, which can locally deform. Conflicting data exist regarding their impact on annular dynamics. We studied mitral annuloplasty with a semirigid partial band and with a nearly complete rigid ring. METHODS: Intraoperative three-dimensional transesophageal echocardiograms (n = 14) and predischarge transthoracic echocardiograms were retrospectively analyzed in patients undergoing mitral valve repair for degenerative disease with either a rigid ring (n = 77) or a semirigid partial band (n = 38). Each transesophageal echocardiogram was analyzed with TomTec three-dimensional software to produce cardiac cycle frame planimetry and to measure device geometry. Actual device sizes provided reference dimensions. Blinded analysis of Doppler data from transthoracic echocardiograms was performed. RESULTS: Validation of the quantitative transesophageal echocardiogram methodology revealed a 1.3% +/- 0.3% (mean +/- standard error of the mean) underestimation of actual linear dimension. With the semirigid partial band, systolic valve orifice area and intertrigonal distance decreased from 6.14 +/- 0.37 to 5.55 +/- 0.24 cm(2) (-9.6%; p = 0.01) and from 2.69 +/- 0.08 to 2.55 +/- 0.13 cm (-5.2%; p = 0.03), respectively. Systolic anterior-posterior distance decreased from 2.1 +/- 0.10 to 1.95 +/- 0.06 cm (-7.1%; p = 0.01) compared with diastole. In contrast, rigid ring orifice area was unchanged (4.12 +/- 0.15 to 4.10 +/- 0.16 cm(2); -0.5%; p = 0.48) during the cardiac cycle. Transthoracic echocardiography revealed significantly lower mitral inflow gradients with semirigid partial band (mean gradients compared with rigid ring, 4.0 +/- 0.3 versus 5.0 +/- 0.3 mm Hg; p = 0.02; peak gradients, 8.9 +/- 0.5 versus 11.1 +/- 0.5 mm Hg; p = 0.01). CONCLUSIONS: Three-dimensional transesophageal echocardiographic measurements of annular dynamics are valid and reliable when discrete annuloplasty devices are present. In contrast to the rigid ring, the semirigid partial band permits more physiologic geometric changes and is associated with lower postoperative mitral valve gradients.

Echocardiography, Doppler↗
PubMed2004

Diastolic right-to-left shunting in a patient with atrial septal defect and pericardial tamponade.

We present the case of a patient with an atrial septal defect who presented with hypotension, hypoxia, and cyanosis as a result of pericardial tamponade. The classic findings of pulsus paradoxus and low measured right heart output were not present. Echocardiography demonstrated the atrial septal defect, pericardial effusion, and diastolic chamber collapse. Furthermore, Doppler study showed not only a large left-to-right shunt but also a diastolic right-to-left shunt, which explained the patient's hypoxia.

Adult↗