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Z Vered

Publications and source records attributed to Z Vered.

At least 37 records · Page 2Linked to original sources
PubMed2000

The effect of aortic valve replacement on left ventricular mass assessed by echocardiography.

AIMS: The aim of the study was to investigate whether aortic valve replacement (AVR) has different effects on the left ventricular mass (LVM) in patients with different types of aortic valve disease, i.e. aortic stenosis (AS), aortic regurgitation (AR), or combined disease. METHODS AND RESULTS: We studied 100 patients with AS; (n=57), AR; (n=22), and combined disease; (n=21). Each patient was evaluated before and up to 8.7 years (mean follow-up period 1.42 +/- 1.65 years) after operation by transthoracic echocardiography. LVM was calculated based on echocardiographic parameters. Following AVR, the LVM for the entire group decreased from 373 +/- 145 g to 280 +/- 102 g (P=0.0001). The AS subgroup lost 13.7 +/- 30.7% from the preoperative LVM, compared to 28.8 +/- 24.8% in the AR subgroup (P<0.05) and 23.1 +/- 33.1% in the combined subgroup. The preoperative LVM was higher among patients with AR vs. AS patients (501 +/- 173 g vs. 319 +/- 100 g respectively, P<0.05). The decrease in LVM was significantly higher in patients with preoperative AR compared to AS patients (165 +/- 150 g vs. 58 +/- 96 g, respectively, P<0.05). However, the postoperative LVM remained higher among the former. The only preoperative parameter (of the LVM formula) that was different between AR and AS patients was the left ventricular end diastolic diameter (68 +/- 11 mm vs. 51 +/- 7 mm, respectively, P<0.05). No significant differences were found in wall thickness among the groups studied. Univariate analysis showed that gender (male), type of aortic valve disease (AR vs. AS), and larger prosthetic valve diameter correlated significantly with greater decrease in postoperative LVM. In multivariate analysis comparing the above variables between AS and AR subgroups, only the patient's gender (i.e. male) was identified as an independent predictor of LVM regression. CONCLUSION: Patients with AR have a greater decline in LVM compared with patients with AS following AVR. The postoperative decline in LVM is higher among males and those with larger prosthetic valve diameter.

Aged↗
PubMed2000

Aspergillus niger endocarditis in an immunocompetent patient: an unusual course.

Aspergillus is an opportunistic nosocomial fungus generally associated with a high mortality rate. A niger has been rarely associated with infection, and most cases have occurred in patients who have recently undergone heart surgery or in immunocompromised patients. We present a case of an immunocompetent patient with A niger endocarditis which illustrates the difficulties in diagnosis and the possible insidious course of fungal endocarditis.

Aspergillosis↗
PubMed2000

Retrograde flow in the thoracic aorta in patients with systemic emboli: a transesophageal echocardiographic evaluation of mobile plaque motion.

STUDY OBJECTIVES: Blood flow in the aorta is complex and incompletely characterized. Mobile aortic plaques (MAPs), moving freely with the pulsatile aortic flow, in fact represent natural tracers that reflect the flow pattern itself. Our aim was to use MAP motion on transesophageal echocardiography (TEE) in order to characterize flow patterns in the atheromatous thoracic aorta of patients with systemic emboli. DESIGN AND PATIENTS: The study group was recruited from 250 patients referred for TEE to evaluate recent embolism. Among them, 22 patients (14 men and 8 women; mean +/- SD age, 66.3 +/- 7.2 years; 16 patients with cerebrovascular and 6 patients with peripheral emboli) with MAPs of > or = 3 mm in length formed the study group. The longest amplitudes of three spatial components of mobile lesion motions were measured: x (antegrade/retrograde [A/R]), y (up/down [U/D], and z (right/left [R/L]). RESULTS: A total of 33 mobile lesions were detected: 3 in the ascending aorta (1 patient), 13 in the arch (10 patients), and 17 in the descending aorta (11 patients). The length of mobile plaque components ranged from 3 to 13 mm; amplitudes of A/R, U/d, R/L, and retrograde flow motions ranged from 3 to 26 mm, from 1 to 16 mm, from 1 to 17 mm, and from 1 to 13 mm, respectively. Systolic rotational motion was clockwise in six patients (27%), counterclockwise in five patients (23%), incomplete (semicircle) in six patients (27%), and alternate clockwise/counterclockwise in five patients (23%). Diastolic rotational motion was clockwise in 5 patients (23%), counterclockwise in 6 patients (27%), and incomplete (semicircle) in 11 patients (50%). There were 18 multiple MAPs in seven patients: in all these cases, simultaneous rotations of MAP in different directions (as a marker for the presence of multiple vortices) were found. In nine patients with cerebral embolism, MAPs on the distal part of aortic arch solely were found; in five of them, all alternative potential sources of stroke were excluded. Therefore, retrograde cerebral embolism from distal aortic plaques in these patients is highly probable. CONCLUSIONS: Retrograde and rotational blood flow in the thoracic aorta probably exists in all patients with systemic emboli and mobile protruding aortic atheromas. Therefore, retrograde cerebral embolism from distal aortic plaques is theoretically possible.

Aged↗
PubMed2000

Spiral computerized tomography (dual helical mode) as a detector of aortic atheromas in patients with stroke and systemic emboli: additional benefit of the contrast-enhanced technique.

BACKGROUND: Protruding aortic atheromas are a potential source of stroke and systemic emboli. The single modality currently available for their detection has been transesophageal echocardiography. However, TEE does not allow full visualization of the upper part of the ascending aorta and proximal aortic arch. OBJECTIVES: To investigate whether double helical computerized tomography--both with and without contrast injection--may represent a useful technique for noninvasive detection of PAA in stroke patients. METHODS: Forty consecutive patients > or = 50 years of age who sustained a recent ischemic stroke and/or systemic emboli (within 15 days after the onset of the event) were enrolled in the study and underwent TEE and DHCT without contrast injection using thin slice acquisition (3.2 mm thickness and 1.5 mm reconstruction increment). In addition, the last eight consecutive patients, after obtaining an unenhanced scan, underwent a contrast-enhanced DHCT following peripheral intravenous injection of a small amount of contrast material (15 ml of diatrizoate). RESULTS: PAAs were demonstrated by TEE in 18 patients (45%); in 16 of them (89%) the atheromas were recognized by DHCT. Of the 22 patients without PAA on TEE, DHCT confirmed their absence in 18 (82%). DHCT yielded a sensitivity of 89%, a specificity of 82%, and an overall accuracy of 85%. The total number of protruding plaques detected by TEE was 43, of which 41 (95%) were correctly identified by DHCT. The mean thickness of the plaques was 5.6 +/- 2.4 mm on TEE, and 5.4 +/- 2.3 on DHCT (P = NS), with a good correlation between the modalities (r = 0.84). Contrast-enhanced DHCT scans demonstrated absolute equivalence to TEE in aortic areas defined as "clearly visualized by TEE." DHCT detected PAA between the distal ascending aorta and the proximal arch in seven patients; these atheromas were not included in the comparative analysis. In these "occult" areas, DHCT may be superior to TEE. CONCLUSIONS: DHCT without contrast injection using thin slice acquisition may become a useful modality for rapid noninvasive detection of PAA. Contrast-enhanced DHCT scans significantly improve imaging quality and may be superior to TEE in the upper ascending aorta and the proximal arch (areas not well visualized by TEE).

Aged↗
PubMed2000

Fluid dynamics and atherosclerosis development in the human thoracic aorta: a transesophageal echocardiographic evaluation of protruding aortic plaque distribution and motion.

The pathogeneses of atherosclerosis in the thoracic aorta is heterogeneous and still incompletely elucidated. Protruding aortic plaques (PAP), reliable markers of atherosclerosis development and extension, could be easily identified by transesophageal echocardiography (TEE). A close relation between atherosclerosis development in the thoracic aorta, stroke and peripheral emboli were established. The purpose of this study was to use PAP distribution and motion on TEE to characterize atherogenesis in the human thoracic aorta. Out of 569 consecutive patients (age range 18-83 years), 108 were referred for TEE to evaluate recent embolism (Group I). The remaining 461 patients were referred for TEE for reasons unrelated to embolism (Group II). The plaque thickness was measured perpendicularly to the aortic wall. In the subgroup of patients with multiple mobile lesions, multiple vortices were suggested to be present when simultaneous rotations in different directions were found. The presence of a fixed PAP was associated with a statistically significant, albeit moderate, increase in the risk for embolism (adjusted odds ratio 4.1). The presence of mobile lesions was linked to an abrupt augmentation in this risk (adjusted odds ratio 30.1). Among the 35 patients in Group I there were 69 PAP: 8 (12%) in the ascending, 28 (41%) in the arch and 33 (48%) in the descending aorta. A total of 34 mobile lesions was detected: 1 (one patient) in the ascending aorta, 15 (10 patients) in the arch and 18 (11 patients) in the descending aorta. There was no significant difference between the arch and the descending aorta regarding the frequency of the plaques in these regions, whereas the ascending aorta presented the lowest prevalence for atheromatosis. Diastolic retrograde and rotational flows were observed in all patients. There were 16 multiple mobile PAP in 6 patients: in all these cases simultaneous rotations of mobile aortic plaques (MAP) in different directions (highly suggestive for the presence of multiple vortices and significant flow instability) were found in the arch and the descending but not the ascending aorta. Protruding aortic plaques and signs of relative aortic flow instability (presence of vortices) are mainly observed in the human arch and in the descending aorta, whereas the ascending aorta presented the lowest prevalence for atheromatosis. This issue may have significant implications in the study of atherosclerosis development in the human thoracic aorta and the pathogeneses of embolic events.

Adolescent↗
PubMed1999

Conversion of recent onset paroxysmal atrial fibrillation to normal sinus rhythm: the effect of no treatment and high-dose amiodarone. A randomized, placebo-controlled study.

BACKGROUND: Spontaneous conversion of recent onset paroxysmal atrial fibrillation to normal sinus rhythm occurs commonly and is not affected by low-dose amiodarone treatment. METHODS: In a randomized, placebo-controlled trial of 100 patients with paroxysmal atrial fibrillation of recent onset (<48 h) we compared the effects of treatment with continuous intravenous amiodarone 125 mg per hour (total 3 g) and intravenous placebo. Patients in the placebo group who did not convert to normal sinus rhythm within 24 h were started on amiodarone therapy. RESULTS: Conversion to normal sinus rhythm occurred within 24 h in 32 of 50 patients (64%) in the placebo group, most of whom converted within 8 h. Lower conversion rates were observed in patients with hypertension, ischaemic heart disease or congestive heart failure and in patients with echocardiographic findings of left atrial diameter above 45 mm, ejection fraction below 45% or significant mitral regurgitation. However, in most patients these clinical or echocardiographic risk factors of decreases in conversion rate were not present. In such patients the spontaneous conversion rate was approximately 90%. The conversion rate during 24 h of treatment in the amiodarone group was 92% (P=0.0017, compared to the placebo group). In this group, the conversion rate was largely unaffected by baseline characteristics. Of the 18 patients who did not convert with placebo, 15 (85%) converted after being crossed over to amiodarone. All patients not responding to high-dose amiodarone were in chronic atrial fibrillation within 1 month. In patients still in atrial fibrillation after 8 h of treatment, the pulse rate decreased significantly more in the amiodarone as compared to the placebo group (83+/-15 vs 114+/-20 beats. min(-1), P=0.0014). CONCLUSION: The spontaneous conversion of recent onset paroxysmal atrial fibrillation is high and approaches 90% in specific clinical and echocardiographically defined subgroups. Intravenous high-dose amiodarone safely facilitates conversion of paroxysmal atrial fibrillation. However, such treatment should be reserved for patients with unfavourable risk factor profiles, not converting during 8 h of observation or requiring rate control.

Aged↗
PubMed1999

Allicin-induced decrease in formation of fatty streaks (atherosclerosis) in mice fed a cholesterol-rich diet.

BACKGROUND: Garlic (Allium sativum) has been considered to exhibit therapeutic features for many years. The effects of garlic on levels of serum lipids and on atherosclerosis have been investigated extensively. We have previously demonstrated that allicin, an active component of garlic, exerts a beneficial effect on lipid profile in hyperlipidemic rabbits. OBJECTIVE: To investigate the effects of allicin on formation of fatty streaks (atherosclerosis) and lipid profile in mice. METHODS: Allicin was extracted from garlic and kept in a buffer citrate solution at 4 degrees C. Sixty C57BL/6 mice were fed Paigen diet (17% fat, 1.25% cholesterol) for 15 weeks. Thirty randomly selected animals were administered allicin solution (9 mg/kg) and 30 were administered placebo. Blood lipid profile was evaluated five times during the study. At the end of the 15-week period, the animals were killed and the aortic sinus was evaluated for formation of fatty streaks (atherosclerosis). RESULTS: We observed no statistically significant differences between blood lipid profiles of groups. Microscopic evaluation of aortic sinus formation of fatty streaks (atherosclerosis), however, showed that values for mice in the allicin-treated group were significantly lower: areas of formation of fatty streaks (atherosclerosis) were 13,440 +/- 3310 and 23,410 +/- 3723 micron 2, respectively, for allicin-treated and control mice (means +/- SEM; P = 0.023). CONCLUSIONS: These results indicate that allicin reduces formation of fatty streaks (atherosclerosis) in hyperlipidemic mice. These changes do not seem to occur through an alteration in blood lipid profile.

Animals↗
PubMed1998

Usefulness of losartan, captopril, and furosemide in preventing nitrate tolerance and improving control of unstable angina pectoris.

Sixty consecutive normotensive patients with unstable angina pectoris, who were on continuous intravenous isosorbide dinitrate (ISDN) treatment and had not previously received angiotensin II receptor antagonists, angiotensin-converting enzyme (ACE) inhibitors, or diuretics were randomly assigned to treatment groups receiving intravenous ISDN for 72 hours. No additional treatment was given to group A (n = 15). Captopril, in a test dose of 6.25 mg, and followed by 12.5 mg 3 times daily for 24 hours and 25 mg 3 times daily for the next 24 hours, was given to group B (n = 15). The same dose of captopril plus 40 mg of furosemide in the morning were given to group C (n = 15). Losartan, in a single dose of 25 mg/day and increased to 50 mg after 24 hours was given to group D (n = 15). Nitrate tolerance was evaluated at 24-hour intervals at trough levels of each of the drugs by administering intravenous ISDN (1 mg bolus dose every 4 minutes) and recording the total ISDN test dose required to decrease the mean arterial blood pressure by > or =10%. Treatment with continuous ISDN only (group A) induced nitrate tolerance. The ISDN (mean +/- SD) test dose was 3.5 +/- 1.8 mg at baseline, increasing to 4.9 +/- 2.4 mg at 24 hours, and 8.0 +/- 3.0 mg at 48 hours. The addition of increasing doses of captopril to the continuous ISDN treatment (group B) completely prevented nitrate tolerance. Losartan, however, did not attenuate nitrate tolerance at 24 hours and attenuated it only partially at 48 hours. The addition of furosemide to captopril had no further effect on nitrate tolerance. Of 15 patients in group A (ISDN only), 4 (27%) experienced recurrent ischemic events requiring urgent coronary catheterization. No such events were recorded in group B (captopril), but did occur in 1 patient in each of group C (captopril plus furosemide) and D (losartan) (p = 0.083). Thus, the addition of captopril to the ISDN treatment regimen prevented tolerance to nitrates and improved angina control with apparent safety. Losartan also decreased nitrate tolerance, although to a lesser extent, and also improved angina control. The addition of furosemide to captopril conferred no further benefit.

Adult↗
PubMed1998

Automatic assessment of cardiac function from short-axis MRI: procedure and clinical evaluation.

Cardiac magnetic resonance imaging (MRI) provides a wealth of morphological and physiological information. Automatic extraction of this information is possible by implementing various image processing techniques. However, existing procedures mostly rely on extensive human interaction and are seldom evaluated on a clinical scale. In this study, a nearly automatic process that extracts physiological parameters from cardiac MR images has been both developed and clinically evaluated. Raw images were obtained in the short-axis view and acquired by a gradient-cho (GE) protocol. In images selected to be analyzed, the only manual step required is the indication of a point in the center of the left ventricle (LV). From a set of such images, the process extracts endocardial and epicardial contours and calculates left ventricular volumes, mass and ejection fraction (EF). The process implements novel approaches to image processing techniques such as thresholding and shape extraction and can be adapted to other acquisition protocols. The process has demonstrated a clear potential for accurate extraction of the endocardial contour but a lower one with respect to the epicardial contour as a result of the low contrast between myocardium and some surrounding tissues, generated by the gradient-echo protocol. The ability of the process to asses physiological parameters has been subjected to a systematic clinical evaluation, which compared parameters, derived manually and automatically, in 10 healthy subjects and 10 patients. The evaluation has indicated that although individual volumes and mass were not accurately assessed, the automatic process has shown high potential for assessing the ejection fraction with relatively high accuracy and reliability.

Adult↗
PubMed1998

Dual-helical CT for detecting aortic atheromas as a source of stroke: comparison with transesophageal echocardiography.

PURPOSE: To investigate whether unenhanced dual-helical computed tomography (CT) is useful in the rapid, noninvasive detection of protruding aortic atheromas. MATERIALS AND METHODS: Thirty-two consecutive patients at least 50 years of age who had recent ischemic stroke, systemic emboli, or both, underwent transesophageal echocardiography (TEE) and unenhanced dual-helical CT with thin sections (section thickness, 3.2 mm; reconstruction increment, 1.5 mm). RESULTS: TEE demonstrated protruding aortic atheromas 15 patients (47%); dual-helical CT depicted protruding aortic atheromas in 13 of those 15 patients (87%). Of the 17 patients without a protruding aortic atheroma at TEE, dual-helical CT helped confirm the absence in 14 (82%). Dual-helical CT yielded a sensitivity of 87%, a specificity of 82%, and an overall accuracy of 84%. Thirty-six protruding plaques were detected with TEE, of which 34 (94%) were correctly identified with dual-helical CT. Of those 34 plaques, 27 (79%) contained variable amounts of calcium and seven (21%) showed hypoattenuation suggestive of soft plaques and thrombi. In six patients, dual-helical CT depicted a protruding aortic atheroma between the distal ascending aorta and the proximal arch; these plaques were not included in the comparative statistics and were analyzed separately. CONCLUSION: Unenhanced dual-helical CT with thin sections appears to be useful for the rapid, noninvasive detection of a protruding aortic atheroma, especially in areas not clearly visualized with TEE.

Aorta↗
PubMed1998

Disrupted mobile aortic plaques are a major risk factor for systemic embolism in the elderly.

Protruding aortic plaques--especially those with mobile properties--on transesophageal echocardiography (TEE) are a potential source of stroke and systemic embolism in the elderly. Whether the various morphologies of atheromas with mobile components represent potential differences in the risk for embolic events has not been thoroughly elucidated. The goal of the present study was to determine the association between embolic events and the various types of mobile lesions in the thoracic aorta. Our population consisted of 569 consecutive patients (age 18-83 years) referred for TEE over 27 months; 108 (19%) of them were referred to evaluate recent embolism (cerebral in 97 and peripheral or both in 11; group I) and the remaining 461 were admitted for reasons unrelated to embolism (group II). In group I, 35 patients (32%) exhibited protruding plaques; those were fixed in 10 (9%) and with a mobile component in 25 (23%). In group II, plaques were found in only 13 patients (3%); fixed in 9 (2%) and mobile in 4 (1 %). Twenty-four patients with mobile lesions in group I were > 50 years old, and 21 of them (88%) were > 60 years old. While the presence of fixed plaques was associated with a moderate increase in the risk for systemic embolism (adjusted odds ratio 4.1; 95% confidence interval 1.3-56.4), mobile lesions were linked to a striking augmentation of this risk (odds ratio 30.1; 95% confidence interval 7.8-132.6). The majority of mobile lesions (76%) in group I represented disrupted atheromas with characteristic ulcerations or echolucency within the plaque suggestive of intraatheroma hemorrhage, whereas these TEE features were not observed in 89% of the mobile lesions in group II (p = 0.0003). We conclude that among the various types of mobile aortic lesions, the disrupted protruding plaques are a major risk factor for stroke and embolic events in the elderly.

Adolescent↗
PubMed1997

Echocardiographic imaging of a basket catheter for mapping and ablation of ventricular tachycardia in pigs.

Our objective was to assess the feasibility and efficacy of the recently described left ventricular simultaneous deployment of a new multi-electrode mapping catheter and a standard radio-frequency ablation catheter in pigs, with echocardiography monitoring and fluoroscopy guidance. Introduction and deployment of both catheters in five healthy anesthetized pigs were guided on-line by fluoroscopy and monitored with transthoracic echocardiography. Heart rate and femoral blood pressure were also continuously monitored. Both catheters were deployed for up to 5 hours. Three animals underwent three to five radio-frequency energy applications. Left ventricular dimensions obtained from long axis two-dimensional echocardiography imaging before and after basket-catheter deployment in the left ventricular cavity, were 3.9 +/- 0.3 versus 3.7 +/- 0.6 cm at end-diastole and 2.8 +/- 1.1 versus 2.6 +/- 0.8 cm at end-systole, respectively (mean +/- standard error of the mean, p > 0.05). Shortening fraction measured from long axis two-dimensional echocardiography images before and after catheter deployment was 28% +/- 10% versus 25% +/- 5%, respectively (mean +/- standard error of the mean, p > 0.05). Additional findings included the following: (1) good conformation of the multi-electrode mapping catheter to the left ventricular dimensions during diastole; (2) absence of catheter-induced aortic and/or mitral insufficiency, as well as left ventricular outflow tract obstruction; (3) absence of damage to mitral and aortic valves or to the left ventricular wall. Postmortem examination and hemodynamic measurements confirmed these findings and showed only minor subendocardial hemorrhages; (4) radio-frequency energy application produced intracavitary bubbles, which were demonstrable echocardiographically, enabling identification of the gross anatomic location of ablation sites. Echocardiography during simultaneous deployment of multi-electrode mapping catheter and radio-frequency ablation catheters enables estimation of mechanical interaction with the left ventricle and detects interaction with myocardial/valvular function. During radio-frequency energy application, bubble production may identify gross anatomic location of ablation.

Animals↗
PubMed1997

Stress echocardiography beyond coronary artery disease.

Doppler echocardiography has become the major diagnostic tool of evaluation of valvular heart disease and the cardiomyopathies because of its ability to provide valuable haemodynamic information accurately and non-invasively. It is therefore ideally suited for haemodynamic stress testing in these patients. In aortic stenosis, dobutamine echocardiography can distinguish severe from non-severe stenosis in patients with depressed left ventricular function, low transvalvular gradients, and a relatively small (flow-related) valve area at baseline. Patients with non-severe aortic stenosis increase cardiac output and valve area with dobutamine infusion while the transvalvular gradient does not change significantly. In severe aortic stenosis, the pressure gradient increases significantly with stroke volume, but valve area does not. In patients who fail to increase stroke volume (absent contractile reserve) and therefore do not show a change in haemodynamics, the severity of the lesion is 'indeterminate'; these patients are characterized by a very poor prognosis. In mitral stenosis, patients can be identified who increase valve area during exercise, which is the fundamental mechanism by which stroke volume can be increased in mitral stenosis. The increase in pulmonary artery pressure during exercise (assessed from tricuspid regurgitant signal) can be dramatically different in patients with comparable resting haemodynamics; therefore exercise echocardiography provides information which cannot be obtained from resting measurements alone and can help to guide medical and surgical therapy. Whether stress echocardiography may be similarly helpful in patients with regurgitant lesions is still a subject of investigation. Exercise Doppler echocardiographic studies following aortic valve replacement (small valves) can identify impairment of systolic and diastolic function indicative of 'valve prosthesis-patient mismatch'. In hypertrophic cardiomyopathy the dynamics of outflow obstruction can be assessed following exercise or pharmacological intervention. In dilative cardiomyopathy, contractile reserve can be assessed by dobutamine echocardiography which may help in evaluating prognosis, guiding heart failure therapy, and monitoring therapy with cardiotoxic chemotherapeutic agents.

Aortic Valve Insufficiency↗
PubMed1996

Percutaneous multielectrode endocardial mapping during ventricular tachycardia in the swine model.

BACKGROUND: Identification of critical areas within the ventricular tachycardia circuit is a prerequisite for catheter ablation. Currently, mapping during ventricular tachycardia, usually performed with standard catheters, is difficult and time-consuming and can be used only in patients with hemodynamically stable tachycardia. METHODS AND RESULTS: A total of 43 pigs underwent closed-chest induction of myocardial infarction. A basket-shaped catheter carrying 64 electrodes was deployed in the left ventricle during normal sinus rhythm. Unipolar pacing at 3 mA was successful in 78% of the basket catheter electrodes, demonstrating good electrode-tissue contact. Hemodynamic and echocardiographic measurements did not reveal any significant interference with myocardial or valvular function during or after catheter deployment. One hundred eighteen episodes of monomorphic ventricular tachycardia were induced in 28 pigs through right ventricular stimulation, 81 of which were mapped and analyzed. Ventricular tachycardia mapping was rapid, requiring only several beats and < 10 seconds to complete. Presystolic potentials, a possible target for ablation, were identified in 58% of the tachycardia episodes mapped. Pathological examination revealed only minor valvular and endocardial catheter-induced lesions immediately after mapping and none a month later. CONCLUSIONS: The multielectrode catheter enables rapid and safe percutaneous endocardial mapping of ventricular tachycardia in the swine model. Exploration of the clinical potential of the multielectrode catheter seems warranted.

Animals↗
PubMed1996

Shortened Doppler-derived mitral A wave deceleration time: an important predictor of elevated left ventricular filling pressure.

OBJECTIVES: The aim of this study was to investigate whether a new variable of mitral inflow, A wave deceleration time, identifies patients with elevated left ventricular filling pressures. BACKGROUND: In patients with an elevated left ventricular end-diastolic pressure, the increase in left ventricular pressure after atrial contraction rapidly exceeds left atrial pressure, resulting in abrupt cessation of the A wave. Therefore, we postulated that a shortening of A wave deceleration time might be a marker for elevated end-diastolic pressure. METHODS: Adequate pulsed Doppler mitral inflow velocities could be recorded in 40 of 44 consecutive patients undergoing cardiac catheterization with capillary wedge pressure in 20 patients, and within 1 h after left ventricular end-diastolic pressure recording in 20. Fifteen healthy volunteers were also studied. RESULTS: Left ventricular end-diastolic pressure was 8 to 35 mm Hg, and mean pulmonary wedge pressure was 6 to 37 mm Hg. Close correlations were found between A wave deceleration time and mean pulmonary wedge pressure (r = -0.87) and left ventricular end-diastolic pressure (r = -0.74). There were modest correlations between both pressures and peak E/A, E wave deceleration time and A wave duration, respectively; r = 0.59, -0.30 and -0.58 for capillary wedge and r = 0.25, -0.38 and -0.49 for end-diastolic pressures. A wave deceleration time </= 60 ms predicted left ventricular end-diastolic and mean pulmonary wedge pressures > 18 mm Hg, respectively, with a sensitivity of 67% and 89% and specificity of 100% for both. CONCLUSIONS: A shortened Doppler mitral inflow A wave deceleration time is a useful index of elevated left ventricular filling pressure.

Adolescent↗