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Abstracts
ABSTRACTS
pacemaker implantation. This study describes the development of the echocardiography CRT programme at St Vincent’s Hospital, Sydney. Methods: At the outset of the programme, multiple echocardiography parameters were measured using Philips HP 5500 and GE Vivid-5 machines. All measurements were made according to ASE guidelines and were averaged over three cardiac cycles. As the programme developed, the protocol was streamlined, concentrating on septal/lateral wall tissue Doppler (TDI) measurements and mitral valve Doppler inflow. Pacemaker optimization used simultaneous echocardiography and pacemaker interrogation, with measurement of parameters at a variety of programmed AV delays and VV offsets. Results: Sixty-nine patients were referred for screening for dyssynchrony in the first 12 months of the programme; mean age 61 ± 9 years, mean LV ejection fraction 26 ± 15%, mean LVEDD 72 ± 10 mm; mean lateral-septal wall delay 55 ± 15 ms. Forty-three patients were referred for pacemaker optimization after CRT implantation; in 29 of these patients, AV delays were adjusted, and in 13, VV offsets were adjusted. In the 21 patients both screened and optimized, LVEF improved in 10 patients, MR decreased significantly in 9, and the mean lateral-septal wall delay decreased to 25 ± 10 ms. Conclusions: CRT is an important therapy in patients with heart failure. This report describes the successful implementation and evolution of the first 12 months of a CRT-echocardiography programme to support the CRT in a large heart failure service. doi:10.1016/j.hlc.2007.06.250 246 Left Ventricular Hypertrophy Affects the Timing of Untwisting: Changes in Timing may Provide a Novel Index of Diastolic Function A.T. Burns ∗ , A. La Gerche, A.I. MacIsaac, D.L. Prior Cardiac Investigation Unit, St Vincent’s Hospital, Melbourne, Australia Cardiac torsion and untwisting may provide important new insights into cardiac function in health and disease. There is limited data on the timing of untwisting velocity relative to the cardiac cycle and established indices of diastolic function and it is not known whether disease states alter this timing. Methods: We analysed echocardiograms of 14 patients (9 males, mean age 49 ± 3) with normal ECGs and normal resting regional wall motion. Using speckle tracking imaging, the timing of the following events was recorded: peak radial and circumferential early diastolic strain rate (RSRe and CRSe) and untwisting velocity derived by subtraction of basal rotation rate from apical rotation rate. Times (ms ± S.E.M.) are relative to mitral valve opening (MVO). Results: In patients with normal LV mass index (LVMI, n = 11), the onset of untwisting preceded aortic valve closure (−114 ± 8, p < 0.004) and peak untwisting velocity occurred before MVO (−26 ± 9, p < 0.003). As LVMI
Heart, Lung and Circulation 2007;16:S1–S201
increased, the time to onset of untwisting increased (r = 0.56, p < 0.04). CSRe and RSRe occurred after MVO (16 ± 9 and 26 ± 9, both p < 0.03) but preceded peak mitral annular motion (42 ± 5, NS) and peak mitral inflow (54 ± 4, NS). Conclusions: Normal LV untwisting occurs before the mitral valve opens and therefore may be a novel load-independent index of diastolic function. Further investigation is required to elucidate whether the observed delay of untwisting with LVH may contribute to diastolic dysfunction. doi:10.1016/j.hlc.2007.06.251 Affiliate Nursing 247 Percutaneous Transluminal Septal Myocardial Ablation—A Viable Treatment for Hypertrophic Obstructive Cardiomyopathy? The MonashHeart Experience J. Koutsoubos ∗ , S. Hope, W. Thai, P. Antonis, J. Gelman, I.T. Meredith Monash Cardiovascular Research Centre, MonashHeart Southern Health and Monash University, Melbourne, Victoria, Australia Background: Hypertrophic obstructive cardiomyopathy (HOCM) is the most common genetic cardiovascular disease, transmitted as an autosomal dominant trait, resulting in asymmetric septal hypertrophy, hyperdynamic ventricle, and a dynamic left ventricular outflow tract (LVOT) pressure gradient. Historically, treatment included medical management, pacing, surgical myomectomy, and recently, percutaneous transluminal septal myocardial ablation (PTSMA). Long-term efficacy and safety of PTSMA for symptomatic relief of HOCM remains to be established. Method: All patients received baseline and postprocedural echocardiograms in which data were analysed, followed by 6 week, 6 month, 12 month, and annual echocardiograms thereafter. Infarct size, NYHA classification and procedural complication rate were examined. Results: Forty-one procedures were undertaken in 38 patients (59 ± 16 years), with median follow-up of 31 months (3 weeks–76 months). LVOT gradient decreased immediately post-procedure (P < 0.001), with a further drop at 6 weeks (P < 0.05) and no change thereafter. Left ventricular end diastolic dimension remained unchanged. Interventricular septum thickening decreased at one year (P < 0.001). NYHA classification symptoms improved at one year (P < 0.001). Five patients had pacemakers prior to their procedure, three required pacemakers during PTSMA admission and one at three weeks post-procedure. No deaths were reported. Conclusions: On medium-term follow-up, PTSMA is safe, associated with symptomatic relief, and sustained reduc-