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Biomedical subjects

John Gorcsan

Publications and source records attributed to John Gorcsan.

At least 37 records · Page 2Linked to original sources
PubMed2005

Utility of echocardiographic tissue synchronization imaging to redirect left ventricular lead placement for improved cardiac resynchronization therapy.

An 80-year-old woman with severe symptomatic heart failure (ejection fraction of 13%), and left bundle branch block (QRS duration of 160 ms) underwent cardiac resynchronization therapy (CRT). She had significant baseline dyssynchrony with a septal to posterior wall delay of 160 ms by echocardiographic tissue synchronization imaging (TSI). Despite exhaustive efforts, a stable posterior-lateral coronary vein lead position could not be achieved with the standard percutaneous approach, resulting in anterior coronary vein lead placement. This resulted in no improvement in the patient's symptoms or ventricular function. Follow-up TSI revealed earlier activation of the anteroseptal site and worsened dyssynchrony with septal to posterior wall delay of now 290 ms. This information prompted surgical revision of the left ventricular (LV) lead position via limited thoracotomy and posterior-lateral epicardial lead implantation. Pacing at the new lead site resulted in a 30% increase in stroke volume and symptomatic improvement. TSI in this case redirected lead position in a clinical nonresponder, resulting in a favorable response to CRT.

Aged↗
PubMed2004

Meeting highlights of the 15th annual Scientific Sessions of the American Society of Echocardiography: June 26 to 30, 2004.

"Echocardiography is the heart of clinical cardiology" was an appropriate theme for the 15th Scientific Sessions of the American Society of Echocardiography. Care of the cardiovascular patient is constantly changing, and this meeting showcased how echocardiographic and Doppler methods continue to be critically important to detect and quantify disease, determine response to therapy, and guide clinical decision making in contemporary medicine. This highly successful five-day educational event attracted a record number of attendees and focused on disease-based clinical applications of the latest technological advances in cardiac ultrasound, including advances in diagnosis and treatment of heart failure, valvular disease, coronary disease, and congenital disease.

Coronary Disease↗
PubMed2004

A mechanism for immediate reduction in mitral regurgitation after cardiac resynchronization therapy: insights from mechanical activation strain mapping.

OBJECTIVES: We tested the hypothesis that an immediate reduction in mitral regurgitation (MR) after cardiac resynchronization therapy (CRT) results from improved coordinated timing of the papillary muscle insertion sites, using the novel approach of mechanical activation strain mapping. BACKGROUND: Heart failure patients with left bundle branch block often benefit acutely from CRT; however, the role and mechanism of reduction of MR are unclear. METHODS: Twenty-six consecutive patients undergoing CRT with at least mild MR were studied (ejection fraction 24 +/- 6%; QRS duration 168 +/- 30 ms). Echocardiographic Doppler and strain imaging was performed immediately before and the day after CRT, as well as in 10 normal control subjects. Mechanical activation sequence maps were constructed using longitudinal strain from 12 basal and mid-LV sites, with color coding of time-to-peak strain. RESULTS: Mitral regurgitation by the volumetric method consistently decreased after CRT: regurgitant volume from 40 +/- 20 ml to 24 +/- 17 ml and regurgitant fraction from 40 +/- 12% to 25 +/- 14% (both: p < 0.001 vs. baseline). Normal controls had uniform segmental time-to-peak strain, with a difference of only 12 +/- 8 ms between all segments. In contrast, CRT patients at baseline had a 106 +/- 74 ms time delay between papillary muscle insertion sites (p < 0.001 vs. normal). This interpapillary muscle time delay shortened after CRT to 39 +/- 43 ms (p < 0.001 vs. baseline) and was significantly correlated with reductions in mitral regurgitant fraction (r = 0.77, p < 0.001). CONCLUSIONS: Cardiac resynchronization therapy significantly and immediately reduced MR. Improved coordinated timing of mechanical activation of papillary muscle insertion sites appears to be a mechanistic contributor to immediate MR reduction by CRT.

Aged↗
PubMed2004

Quantification of radial mechanical dyssynchrony in patients with left bundle branch block and idiopathic dilated cardiomyopathy without conduction delay by tissue displacement imaging.

Cardiac resynchronization therapy has made assessment of cardiac dyssynchrony clinically important. To test the hypothesis that echocardiographic displacement imaging can quantify dyssynchrony, 22 patients with left bundle branch block (LBBB), 14 with idiopathic dilated cardiomyopathy (IDC) without electrical conduction delay, and 22 normal controls were studied using radial angle-corrected displacement imaging. Control subjects had coordinated wall movement, whereas patients with LBBB had dyssynchrony characterized by early inward anteroseptal movement and markedly delayed posterior, lateral, or inferior regions (157 +/- 99 ms; p <0.001 vs normal). An interesting subset of patients with IDC without conduction delay (36%) had dyssynchrony with anteroseptal to posterior wall delays of 169 +/- 56 ms (p <0.001 vs normal), similar to patients with LBBB.

Adult↗
PubMed2004

Usefulness of echocardiographic tissue synchronization imaging to predict acute response to cardiac resynchronization therapy.

Echocardiographic tissue synchronization imaging (TSI) consists of color-coding time-to-peak tissue Doppler velocities. This study of 29 patients who underwent cardiac resynchronization therapy (CRT) demonstrated that differences in baseline time-to-speak velocities of opposing ventricular walls by TSI were greater in 15 patients, with an acute hemodynamic improvement. A >/=65 ms delay from the anterior septum to the posterior wall using the apical long-axis view had 87% sensitivity and 100% specificity for predicting an acute response. Although a subgroup without acute improvement had later decreases in end-systolic volume, suggesting that acute response underestimates long-term effects, TSI has potential to assist in guiding CRT.

Aged↗
PubMed2004

Influence of hand-carried ultrasound on bedside patient treatment decisions for consultative cardiology.

To test the hypothesis that hand-carried ultrasound (HCU) may influence patient treatment on consultative cardiology rounds, 235 patients who were hospitalized (aged 65 +/- 10 years) were studied. First, routine treatment decisions regarding diagnostic workup and therapy were made from patient history, physical examination, 12-lead electrocardiogram, and chart data. Second, a goal-directed HCU study was performed in <10 minutes focusing on left ventricular global and regional function, wall thickness, and presence of pericardial effusion, followed by a reassessment of treatment decisions. HCU data influenced treatment decisions in 149 patients (63%); 50% had a change in medical therapy and 22% had a change in their diagnostic workup (most with changes in both). In all, 12 patients (5%) had an immediate change in the decision for cardiac catheterization or pericardiocentesis. Overall agreement for the above findings with subsequent full-size system echocardiography ranged from 92% to 100% (kappa 0.91-0.96). Goal-directed HCU has the potential to influence bedside patient treatment decisions and expedite health care.

Aged↗
PubMed2004

Impact of catheter ablation on pulmonary vein morphology and mechanical function.

INTRODUCTION: Previous reports have documented that radiofrequency catheter ablation of pulmonary veins induces a significant increase in the peak velocity of transvenous blood flow. Although the magnitude of the increase infers a state of pulmonary vein stenosis, there have been no reports of direct visualization of the ablation zone. METHODS AND RESULTS: In each of 23 subjects, the myocardium investing one or more pulmonary veins (total of 42 veins) was electrically isolated by applying a confluent circumferential ablation lesion to the atrial side of the venoatrial junction. Doppler measurements of transvenous flow velocity were made before and after ablation using phased-array intracardiac echocardiography. Direct visualization of the ablation zone was performed using rotating intracardiac echocardiography, permitting assessment of shape, cross-sectional area, phasic variation in cross-sectional area, and wall thickness. In a subset of 5 subjects, a more detailed assessment of the ablation and contiguous regions was performed using three-dimensional echocardiography (rotating transducer). Prior to ablation, venoatrial junctions demonstrated noncircular shape and marked phasic variation in cross-sectional area. There was a trivial transvenous pressure gradient. After ablation, there was a significant increase in both anterograde and retrograde flow velocities and pressure gradient, the magnitudes of which were inversely proportional to the preablation and postablation areas. Direct visualization of the ablation zone revealed circumferential wall swelling, reduced cross-sectional area, and diminishment in phasic variation in cross-sectional area. Similar observations were made at contiguous nonablated sites, diminishing in magnitude as a function of distance. CONCLUSION: Pulmonary vein ablation induces significant acute changes in morphology and mechanical function that extend beyond the ablation zone.

Adult↗
PubMed2004

Influence of alterations in loading on mitral annular velocity by tissue Doppler echocardiography and its associated ability to predict filling pressures.

STUDY OBJECTIVES: Early diastolic mitral annular velocity (E') by tissue Doppler echocardiography (TD) has been reported to be a load-independent index of left ventricular (LV) diastolic function, allowing the early diastolic mitral inflow velocity (E)/E' ratio to be used clinically to predict LV filling pressures. However, preload independence of E' has remained controversial, and E/E' may not consistently be predictive of LV filling pressures. Our objectives were to test the hypotheses that E' is affected by preload, and that alterations of preload, afterload, and contractility also affect E/E'. DESIGN, INTERVENTIONS, AND MEASUREMENTS: An open-chest dog model was used (n = 8). High-fidelity pressure and conductance catheters were used for pressure-volume relations, and E' was obtained by pulsed TD from the apical four-chamber view. Changes in preload and afterload were induced by vena caval and partial aortic occlusions, respectively. Data were collected during control phase and during infusions of dobutamine and esmolol to alter contractility. RESULTS: E' was consistently and significantly associated with acute decreases in LV end-diastolic pressure in each dog (n = 200 beats; r = 0.93 +/- 0.06 [mean +/- SD]). Similar results occurred with dobutamine and esmolol infusions. This preload sensitivity was reflected in E/E', which was inversely (rather than directly) correlated with LV diastolic pressure (r = - 0.67). E/E' was less affected by preload when diastolic dysfunction was induced by sustained partial aortic occlusion (time constant of relaxation increased from 46 +/- 19 to 53 +/- 21 ms, p < 0.001). CONCLUSIONS: E' was significantly influenced by preload with preserved LV function and low filling pressures (< 12 mm Hg); accordingly, E/E' was less predictive of LV filling pressures in this scenario. E/E' was more predictive of LV filling pressures in the presence of diastolic dysfunction.

Animals↗
PubMed2003

Regional correlation by color-coded tissue Doppler to quantify improvements in mechanical left ventricular synchrony after biventricular pacing therapy.

Cardiac resynchronization therapy (CRT) can improve cardiac function in patients with heart failure and left bundle branch block. To test a new synchrony index derived from mitral annular velocity by color tissue Doppler, 19 subjects were studied: 9 patients with heart failure and left bundle branch block at baseline and at 1, 3 and 6 months after CRT and 10 normal controls. The synchrony index in patients with heart failure was less than that in controls at baseline (r = 0.60 +/- 0.13 vs 0.94 +/- 0.02; p <0.01), but improved at 6 months after CRT (r = 0.77 +/- 0.09; p <0.05 vs baseline).

Aged↗
PubMed2003

Second-generation tissue Doppler with angle-corrected color-coded wall displacement for quantitative assessment of regional left ventricular function.

To test the hypothesis that a new tissue Doppler (TD) approach using angle-correction and transformation of velocity data to color-coded displacement data may objectively quantify regional left ventricular function, in vitro experiments were first performed with an oscillating echo target precisely controlled by a microstepping motor. Displacement varied from 1 to 15 mm (60 to 130 cycles/min) at angles of 0 degrees and 45 degrees to the echo transducer. Custom software transformed TD data to displacement data. Sixty-five subjects were then studied: 35 with wall motion abnormalities and 30 normal controls. Results were compared with independent visual assessment and caliper measurements of endocardial excursion from gray-scale images. In vitro displacement imaging strongly correlated with true displacement (r = 0.99, p <0.0001). In humans, peak transmural displacement discriminated normal results (6.3 +/- 3.2 mm) from hypokinesia (2.7 +/- 1.8 mm, p <0.05), akinesia (0.4 +/- 1.2 mm, p <0.05) from hypokinesia, and dyskinesia (-1.9 +/- 1.2 mm, p <0.05) from akinesia. Normal subendocardial displacement was 5.9 +/- 2.9 versus 4.0 +/- 3.9 mm in the epicardial layer (p <0.01). This displacement gradient was absent in abnormal segments. Displacement data correlated with endocardial excursion by calipers (parasternal views: r = 0.86, all views: r = 0.79, both p <0.0001). Overall accuracy of displacement imaging was 82% (kappa = 0.71) versus 66% (kappa = 0.43) for visual assessment with caliper data as the standard of reference. Angle-corrected displacement imaging was superior to routine visual assessment and is a promising new method to quantify regional left ventricular function.

Aged↗
PubMed2003

Non-invasive assessment of myocardial recovery on chronic left ventricular assist device: results associated with successful device removal.

BACKGROUND: Myocardial recovery may occur in patients with heart failure who are receiving left ventricular assist-device support, but identification of candidates for device removal remains challenging. We hypothesized that on-line quantitative echocardiography during trials of decreased device support alone or in combination with exercise cardiopulmonary testing can assess cardiac recovery to predict successful device removal. METHODS: We studied 18 patients with severe heart failure, aged 45 +/- 19 years, who received 234 +/- 169 days of assist-device support as a bridge to transplantation. We used echocardiographic automated border detection from mid-ventricular short-axis images and non-invasive arterial pressure to measure beat-to-beat responses in 2 to 5 minute trials of decreased device flow. We also assessed maximal oxygen consumption in 14 patients who could exercise. RESULTS: Six patients experienced myocardial recovery and underwent successful device removal; 12 remained device dependent. With transient, low assist-device flow, patients with device removal had increased echocardiographic stroke area of 27% +/- 36% vs -24% +/- 12% (p < 0.05) and fractional area change of 51% +/- 13% vs 23% +/- 11% (p < 0.05) in the patients who were device dependent. Estimates of pre-load-adjusted maximal power, a relatively load-independent index, were 6.7 +/- 2.1 mW/cm(4) in patients with successful device removal vs 1.2 +/- 1.2 mW/cm(4) in patients who were device dependent (p < 0.005). Maximal oxygen consumption was 17.2 +/- 1.4 ml/kg/min in patients with myocardial recovery vs 13.1 +/- 1.9 ml/kg/min in patients who were device dependent (p < 0.005) and correlated with pre-load-adjusted maximal power (r = 0.89, p < 0.001). Maximal oxygen consumption >16 ml/kg/min, increased stroke area, >40% increase in fractional area change, or pre-load-adjusted maximal power >4.0 mW/cm(4) with low device flow were associated with successful device removal (p < 0.05). CONCLUSIONS: On-line quantitative echocardiography alone or combined with exercise cardiopulmonary testing can assess myocardial recovery of patients receiving left ventricular assist-device support and has the potential to identify patients who are clinical candidates for device removal.

Adult↗
PubMed2003

Utility of hand-carried ultrasound for consultative cardiology.

Although the stethoscope has been an important part of the bedside cardiac diagnostic examination for generations of physicians, this clinical tool has been relatively unchanged in over 150 years. Echocardiography is established as an essential diagnostic imaging method for patients with known or suspected cardiovascular diseases. However, routine echocardiography systems are large and heavy, and although they are portable, they remain inconvenient for bedside patient rounds. Technologic advances have resulted in miniaturization of electronic components and small, lightweight ultrasound systems have been recently introduced. These hand-carried units offer clinically acceptable two-dimensional image quality for rapid "quick-look" bedside diagnostics, in particular focusing on global and regional left ventricular function and presence or absence of pericardial effusion. This article proposes a general approach to the rapid hand-carried ultrasound cardiac exam as an extension of the physical examination. It details case examples and reviews the initial clinical experience of hand-carried ultrasound on cardiac consultation rounds. Hand-carried ultrasound has promise to have an immediate impact on bedside patient management though expediting and facilitating the delivery of medical care.

Aged↗
PubMed2003

Normal values of left ventricular systolic and diastolic function derived from signal-averaged acoustic quantification waveforms: a multicenter study.

Automated border-detection techniques such as acoustic quantification have proven accurate and useful for quantifying left ventricular (LV) function. We acquired LV acoustic quantification waveforms from the parasternal short-axis window in 140 healthy patients in the age range of 16 to 78 years. Signal-averaged waveforms were analyzed for parameters of systolic and diastolic performance. The average fractional area change was 54 +/- 12%, and there were no significant changes in LV systolic function in the age range studied. There were significant changes in diastolic parameters with aging. The percentage of contribution to total LV filling occurring during atrial filling nearly tripled during the 6 decades studied, from 13% in the youngest cohort to 36% in the eighth decade of life. This study provides normal reference values for systolic and diastolic parameters of LV function determined from signal-averaged acoustic quantification waveforms acquired from the parasternal short-axis view in adult and adolescent patients over a wide age range.

Adolescent↗