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Biomedical subjects

Mario Garcia

Publications and source records attributed to Mario Garcia.

8 recordsLinked to original sources

Quantitative real-time 3-dimensional stress echocardiography: a preliminary investigation of feasibility and effectiveness.

BACKGROUND: Use of rapidly emerging real-time 3-dimensional (3D) echocardiography promises to improve the diagnostic accuracy of stress echocardiography (SE). However, widespread acceptance of 3D-SE, based on real-time 3D echocardiography, is hampered in part by lack of efficient, accurate, and objective analysis tools. METHODS: We propose novel algorithms for interactive visualization, registration (alignment), and quantitative analysis of prestress and poststress real-time 3D echocardiography to facilitate an objective diagnosis. In a preliminary evaluation, two experts independently performed wall-motion analysis in 15 patients with known/suspected coronary artery disease, using the novel quantitative 3D-SE methods. RESULTS: Compared with previously reported values for conventional 2-dimensional SE, improved interexpert agreement (kappa = 0.85) was observed for segment-wise classification of normal/abnormal wall motion using the novel 3D-SE methods. Overall, 6 of 6 patients with abnormal myocardial segments were correctly identified by both experts with 3D-SE, compared with 4 of 6 with conventional 2-dimensional SE. CONCLUSION: Initial results are promising and indicate the feasibility and potential of our proposed quantitative 3D-SE methodologies for improving diagnosis of wall-motion abnormalities.

Adult↗

Granulocyte colony stimulating factor in patients with large acute myocardial infarction: results of a pilot dose-escalation randomized trial.

BACKGROUND: Preclinical studies suggest that administration of cytokines to mobilize stem cells and alter the postinfarction inflammatory cardiac milieu may enhance left ventricular function and survival. METHODS: Eighteen patients were randomized in a 2:1 double-blind fashion to granulocyte colony stimulating factor (G-CSF) (at 5 escalating to 10 microg/kg per day subcutaneously for 5 days [6 patients in each group]) or matching placebo. Principal safety and efficacy end points were rupture-free survival and recovery of left ventricular function, respectively. Mobilization into the systemic circulation of precursor CD34+ and CD117+ stem cells at 30 days were also assessed. RESULTS: Baseline characteristics of the 3 groups were well matched. Mean +/- SD creatine kinase-MB maximum was 349 (169) IU. Follow-up averaged 30 +/- 6, 21 +/- 11, and 11 +/- 6 months in the 3 groups, respectively. Precursor cell mobilization increased by a factor of 5 to 7 in the G-CSF-treated patients. There were no deaths or myocardial ruptures leading to tamponade through 30 days. Baseline and 30-day left ventricular ejection fraction in the placebo, 5-microg, and 10-microg dose groups were 33.7% (1.6) and 41.7% (8.2), 36.8% (7.5) and 41.3% (10.3), and 33.5% (4.8) and 38.7% (7.3), respectively (P = NS for all between-group comparisons). No differences between the G-CSF and placebo groups were noted in any other measure of left ventricular systolic or diastolic function 30 days after infarction. CONCLUSIONS: Despite demonstrated mobilization of precursor stem cells in a timely fashion, in this small, pilot-scale randomized trial involving patients with large myocardial infarction, we were unable to demonstrate improvement in left ventricular function at 30 days.

Aged↗

Extensive ablation during pulmonary vein antrum isolation has no adverse impact on left atrial function: an echocardiography and cine computed tomography analysis.

BACKGROUND: Although pulmonary vein antrum isolation (PVAI) may cure atrial fibrillation (AF) and improve left atrial (LA) function, the effect of extensive LA ablation on LA function is not well known. OBJECTIVE: To assess the impact of PVAI on LA function remotely postablation. METHODS: Consecutive patients undergoing PVAI had either transthoracic (TTE) and transesophageal (TEE) echocardiography (n = 41) or cine EBCT (n = 26) performed preablation and 6 months postablation. Only patients with paroxysmal and persistent, but not permanent, AF were included. Imaging was done in sinus rhythm for all patients. LA diameter (LAD), LA systolic and diastolic areas, and left atrial fractional area change (LFAC) were assessed by TTE. Transmitral (TMF), left atrial appendage (LAA), and pulmonary venous (PVF) Doppler flows were measured by TEE. Peak A on TMF, LAA peak emptying velocity (LAAF), and peak A reversal (AR) on PVF were used as surrogates of LA contractile function. Peak S on PV flow was used as a surrogate of reservoir function. LA areas, volumes, and LA ejection fraction (LAEF) were measured from cine EBCT. RESULTS: Mean radiofrequency ablation time was 45 +/- 21 minutes. All four PVs were isolated for all patients; there were no cases of PV stenosis. Echocardiography revealed a significant reduction in LAD and LA areas post-PVAI. Both peak A and peak AR were also higher post, while other variables showed strong trends toward improvement. In the subset of patients with persistent AF, post-PVAI improvements were seen in LA size, peak A, and even peak S (P = 0.04). Cine EBCT showed a significant decrease in both LA areas and volumes post-PVAI. There was also a significant improvement in LAEF post-PVAI from 17 +/- 6% to 22 +/- 5% (P = 0.01). CONCLUSION: Extensive ablation during PVAI does not cause deterioration in LA function, and may cause long-term improvement, especially in patients with higher AF burden.

Atrial Fibrillation↗

Bench repair of donor aortic valve with minimal access orthotopic heart transplantation.

While the number of people waiting heart transplantation increases, the number of organ donors decreases. This shrinking donor pool has prompted reassessment of donor selection for heart transplantation. Bench repair of a donor aortic valve was performed before minimal access orthotopic heart transplantation. Aortic insufficiency in the structurally normal tricuspid aortic valve was due to annular dilatation and was corrected with subcommissural annular plication. The postoperative period was uneventful. Follow-up at 4.5 years showed good results and no evidence of aortic regurgitation.

Aortic Valve↗

Minimally invasive left ventricular epicardial lead placement: surgical techniques for heart failure resynchronization therapy.

BACKGROUND: Epicardial lead placement for biventricular pacing is often a rescue procedure after failed coronary sinus cannulation. This study aims to determine perioperative and early postoperative outcome of minimally invasive left ventricular lead placement as a management strategy for heart failure, comparing minithoracotomy and endoscopic approaches. METHODS: From October 2002 through October 2003, 41 patients underwent minimally invasive left ventricular lead placement, 23 (56%) by minithoracotomy and 18 (44%) endoscopically. Thirty-one (76%) were males, 19 (46%) had previous cardiac surgery, 21 (51%) had ischemic cardiomyopathy, 17 (41%) were in New York Heart Association class III or IV, and 28 (65%) had implantable cardioverter-defibrillators. RESULTS: There were no in-hospital deaths, intraoperative complications, or failures to implant the left ventricular lead. Median operative time was longer for the endoscopic approach (188 minutes) than for minithoracotomy (151 minutes; p = 0.006). Preoperatively, the endoscopic group had more mitral regurgitation (median, 2.5 versus 1.0, respectively; p = 0.009). QRS duration was shorter postoperatively (mean change from preoperative, -32 +/- 24 ms; p < 0.0001); this change was unrelated to surgical approach. Impedance also was less postoperatively (mean change, -490 +/- 300 ohms; p < 0.0001), and the change was unrelated to surgical approach. Changes were greater the larger their preoperative values (p < 0.0001). Threshold increased with follow-up time (adjusted p < 0.0001), but impedance decreased (adjusted p = 0.0009); these trends were similar for both approaches. No changes were evident in left ventricular dimensions. CONCLUSIONS: Minimally invasive left ventricular epicardial lead placement is safe and effective, offering selection of the best pacing site with minimal morbidity; it can be considered a primary option for resynchronization therapy.

Aged↗

Tricuspid valve repair for biopsy-induced regurgitation in a heart transplant recipient.

Tricuspid regurgitation (TR) is a frequent complication after heart transplantation. The etiology of TR is multifactorial, but biopsy-induced flail leaflet is one of the most important mechanisms. A 61-year-old woman underwent heart transplant, but experienced several rejection episodes which required multiple surveillance endomyocardial biopsies. At three months after transplant, she required tricuspid valve repair due to symptomatic severe TR. The anterior leaflet was flail, with rupture of primary and secondary chordae. Valve repair was performed with a triple leaflet edge-to-edge technique. The procedure consisted of suture fixation of the prolapsed anterior leaflet joining to the septal and posterior leaflets, and placement of a 30-mm annuloplasty ring. The patient was uneventfully discharged home on day 7 with trivial TR. At a four-years post-transplant evaluation, she was in NYHA functional class I, with preserved ventricular function and trivial TR. She has been followed closely because of post-transplant coronary artery disease.

Biopsy↗

Increases in hypertension and blood pressure during pregnancy with increased bone lead levels.

Prior studies have revealed associations of current lead exposure (blood lead) and past lead exposure (bone lead) with risks of hypertension and elevated blood pressure. The authors examined the effects of blood and bone lead on hypertension and elevated blood pressure in the third trimester and postpartum among 1,006 women enrolled in Los Angeles prenatal care clinics between 1995 and 2001. The authors measured bone lead concentration by K-shell x-ray fluorescence in the tibia (mean = 8.0 micro g/g (standard deviation (SD) 11.4)) and calcaneus (heel) (mean = 10.7 micro g/g (SD 11.9)). Geometric mean prenatal and postnatal blood lead levels were 1.9 micro g/dl (geometric SD +3.6/-1.0) and 2.3 micro g/dl (geometric SD +4.3/-1.2), respectively. For each 10- micro g/g increase in calcaneus bone lead level, the odds ratio for third-trimester hypertension (systolic blood pressure > or =140 mmHg or diastolic blood pressure > or =90 mmHg) was 1.86 (95% confidence interval (CI): 1.04, 3.32). In normotensive subjects, each 10- micro g/g increase in calcaneus bone lead level was associated with a 0.70-mmHg (95% CI: 0.04, 1.36) increase in third-trimester systolic blood pressure and a 0.54-mmHg (95% CI: 0.01, 1.08) increase in diastolic blood pressure. Tibia bone lead concentration was not related to hypertension or elevated blood pressure either in the third trimester or postpartum, nor was calcaneus bone lead related to postpartum hypertension or elevated blood pressure. Past lead exposure influences hypertension and elevated blood pressure during pregnancy. Controlling blood pressure may require reduction of lead exposure long before pregnancy.

Adult↗