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LV Outflow Tract (lv + outflow_tract)
Selected AbstractsLong-Term Mechanical Consequences of Permanent Right Ventricular Pacing: Effect of Pacing SiteJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2010DARRYL P. LEONG M.B.B.S. Optimal Right Ventricular Pacing,Introduction: Long-term right ventricular apical (RVA) pacing has been associated with adverse effects on left ventricular systolic function; however, the comparative effects of right ventricular outflow tract (RVOT) pacing are unknown. Our aim was therefore to examine the long-term effects of septal RVOT versus RVA pacing on left ventricular and atrial structure and function. Methods: Fifty-eight patients who were prospectively randomized to long-term pacing either from the right ventricular apex or RVOT septum were studied echocardiographically. Left ventricular (LV) and atrial (LA) volumes were measured. LV 2D strain and tissue velocity images were analyzed to measure 18-segment time-to-peak longitudinal systolic strain and 12-segment time-to-peak systolic tissue velocity. Intra-LV synchrony was assessed by their respective standard deviations. Interventricular mechanical delay was measured as the difference in time-to-onset of systolic flow in the RVOT and LV outflow tract. Septal A' was measured using tissue velocity images. Results: Following 29 ± 10 months pacing, there was a significant difference in LV ejection fraction (P < 0.001), LV end-systolic volume (P = 0.007), and LA volume (P = 0.02) favoring the RVOT-paced group over the RVA-paced patients. RVA-pacing was associated with greater interventricular mechanical dyssynchrony and intra-LV dyssynchrony than RVOT-pacing. Septal A' was adversely affected by intra-LV dyssynchrony (P < 0.05). Conclusions: Long-term RVOT-pacing was associated with superior indices of LV structure and function compared with RVA-pacing, and was associated with less adverse LA remodeling. If pacing cannot be avoided, the RVOT septum may be the preferred site for right ventricular pacing. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1120-1126) [source] Noninvasive Assessment of Cardiac Resynchronization Therapy for Congestive Heart Failure Using Myocardial Strain and Left Ventricular Peak Power as Parameters of Myocardial Synchrony and FunctionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2002Ph.D., ZORAN B. POPOVI Resynchronization Therapy for Heart Failure.Introduction: Although invasive studies have shown that cardiac resynchronization therapy by biventricular pacing improves left ventricular (LV) function in selected heart failure patients, it is impractical to apply such techniques in the clinical setting. The aim of this study was to assess the acute effects of cardiac resynchronization therapy by noninvasive techniques. Methods and Results: Twenty-two patients enrolled in the InSync trial (age 64 ± 9 years, 18 men and 4 women; all with ejection fraction <35% and QRS >130 msec) were studied 1 to 12 months after pacemaker implantation during pacing, and while ventricular pacing was inhibited. Regional myocardial strains of the interventricular septum, LV free wall, and right ventricular free wall were derived from color Doppler tissue echocardiography. Peak power index was calculated as a product of simultaneously recorded noninvasive blood pressure and pulse-wave (PW) Doppler velocity of the LV outflow tract. The Z ratio (sum of LV ejection and filling times divided by RR interval) and tei index were calculated from PW Doppler data. During pacing, overall regional strain improved (P = 0.01), while the LV strain coefficient of variation decreased from 2.7 ± 2.4 to 1.3 ± 0.7 (P = 0.009). Additionally, peak power index improved from 84 ± 24 to 94 ± 27 cm· mmHg/sec (P = 0.004). The Z ratio increased from 0.71 ± 0.08 to 0.78 ± 0.07 (P = 0.0005), while the tei index decreased from 0.86 ± 0.33 to 0.59 ± 0.16 (P = 0.0002). Conclusion: Using novel noninvasive indices, we demonstrated that cardiac resynchronization therapy improves LV performance. [source] The Importance of Ventricular Septal Morphology in the Effectiveness of Dual Chamber Pacing in Hypertrophic Obstructive CardiomyopathyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2000PETKOW DIMITROW It has been reported that older patients with hypertrophic obstructive Cardiomyopathy (HOCM) benefited the most from dual chamber (DDD) pacing. Since in older patients the distribution of septal hypertrophy and left ventricular (LV) cavity shape differs from that in younger patients, we decided to study the efficacy of DDD pacing on the reduction of LV outflow tract (LVOT) gradient in different patterns of septal hypertrophy. We compared HOCM patients with nonreversed septal curvature, thus preserving the elliptical LV cavity contour (common in the elderly), (group I) versus patients with reversed septal curvature, deforming the LV cavity to a crescent shape (common in the young), (group II). Eighteen HOCM patients were studied (11 patients in group I and 7 patients in group II). After implantation of a DDD pacemaker, the LVOT gradient was measured using Doppler echocardiography at various programmed AV delay intervals to determine the maximal percentage decrease of LVOT gradient from baseline. The measurement was repeated after at least a 6-month follow-up (chronic DDD pacing). The baseline LVOT gradient was comparable between groups (79 ± 28 vs 81 ± 25 mmHg, P = 0.92). The LVOT gradient reduction at acute DDD pacing was significantly greater in group I than group II (61 ± 18% vs 23 ± 10%, P = 0.0001). This difference in favor of the patients from group I was maintained at midterm follow-up (69 ± 17% vs 40 ± 17% P = 0.0076). In conclusion, patients with normal septal curvature and preserved elliptical LV cavity shape had a greater reduction of LVOT gradient after DDD pacing than patients with reversed septal curvature deforming LV cavity. The proposed criterion assessing the septal curvature may be useful to predict the efficacy of DDD pacing in the reduction of LVOT gradient. [source] Treatment of severe valvular aortic stenosis and subvalvular discrete subaortic stenosis and septal hypertrophy with Percutaneous CoreValve Aortic Valve Implantation,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 5 2010Ariel Finkelstein MD Abstract Background: Percutaneous Aortic Valve Implantation (PAVI) is a procedure gaining popularity and becoming more widely used for the treatment of patients with severe aortic stenosis who are at high risk for surgery. Here we show, for the first time, that a successful and complete elimination of both valvular and subvalvular pressure gradients can be achieved with a slight modification of the valve implantation technique. Methods and Results: A 91-year-old woman presented with shortness of breath at rest, effort angina, and pulmonary congestion. Echocardiography revealed calcified aortic stenosis with a peak gradient of 75 mm Hg accros the valve, and discrete subaortic stenosis (DSS) and marked hypertrophy of the basal septum with systolic anterior motion of the mitral valve (SAM). The intra ventricular gradient had a dynamic pattern across the DSS and the septal hypertrophy and measured 75 mm Hg. The total gradient across the left ventricular outflow (valvular and subvalvular) was 125 mmHg. PAVI with a 23 mm CoreValve was performed with an intentional lower positioning of the valve towards the LV outflow tract; so that the valve struts cover the subaortic membrane and part of the thickened basal septum. At the end of the procedure, the SAM disappeared, and the left ventricular ouflow was widely open. At 1 month follow up the patient was asymptomatic, no pressure gradient was measured between the LV apex and the aorta. Conclusions: This is the first report of successful treatment of severe valvular aortic stenosis and combined subvalvular aortic stenosis due to DSS and septal hypertrophy with SAM with percutaneous aortic valve implantation. © 2010 Wiley-Liss, Inc. [source] | ||||||||||