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23Impact of Coronary Sinus Flow on Lesion Morphologyduring RF Ablations

Sujitha Thavapalachandran ∗, M.A. Tony Barry, Toon-WeiLim, Karen Byth, David Ross, Pramesh Kovoor, AravindaThiagalingam

Westmead Hospital, Sydney, NSW, Australia

Introduction: It is recognised that ablation of the mitralisthmus line is difficult and we hypothesised that this maybe a result of flow within the coronary sinus (CS). We testedthis hypothesis using a novel ablation modelling systemwith high spatial (<100 �m) and temporal resolution (<1 s)utilising thermochromic liquid crystals.Methods: The phantom was constructed from a sheet ofthermochromic liquid crystal (TLC) sandwiched verticallybetween blocks of agar. A catheter was placed on the edgeof the TLC, and 37 ◦C saline pumped across the blocks tomimic blood flow. Gel and saline were adjusted to mimicmyocardial and blood impedance. TLC operating colourrange was 50–78 ◦C. The CS was modelled as a 5 mm diam-eter vessel located 4 mm below the endothelial surface.Ablations were performed with and without flow (i.e. flowof 100 ml/s or 0 mls/s through the CS) with 10 ablations ineach group. All ablations were performed using a Thermo-cool catheter (50 W, 50 ◦C, 120 s, 15 mL/min irrigant flow).Results: All ablation lesions performed without flow

MYOCARDIAL

24The Clinical Spectrum of Clozapine-induced Myocarditis

Kathlyn Ronaldson 1,∗, John McNeil 1, Andrew Taylor 2,Paul Fitzgerald 2, Duncan Topliss 2

1 Monash University, Melbourne, VIC, Australia; 2 Alfred Hos-pital, Melbourne, VIC, Australia

Background: Serious adverse effects, including myocardi-tis, limit the use of clozapine, an exceptionally effectivetreatment for schizophrenia. To date, no systematic studieshave been conducted of the clinical history of clozapine-related myocarditis.Context: In Australia, clozapine is typically initiated whilethe patient is hospitalised and compliance with weeklyblood monitoring is ensured by a clozapine coordinator.Cardiac monitoring guidelines are also followed.Purpose: To identify trends in a case series with signifi-cance for monitoring and diagnosis of clozapine-relatedmyocarditis.Method: Daily data on medication, symptoms and vitalsigns, together with all pathology results were docu-mented from the commencement of clozapine for eachpotential case of myocarditis. Cases were reviewed by thestudy Steering Group for compliance with the case defini-tion.

within the CS were transmural. In contrast, no ablationsperformed during flow within the CS were transmural(mean distance from CS = 0.74 ± 0.02 mm; p < 0.01).

Conclusion: Flow within the CS appeared to have a sig-nificant contribution to the lesion morphology. Theseresults suggest that abolishing flow within the CS duringmitral isthmus line ablation may allow transmural abla-tion lesions to be created without the need for ablationwithin the CS.

doi:10.1016/j.hlc.2008.05.024

Results: Of 48 potential cases reviewed, 31 met the casedefinition. Onset for 29 cases was in the third week of cloza-pine. Two patients died. The clinical course of myocarditisgenerally involved sequential rises in C-reactive protein(CRP), then troponin I/T and finally eosinophils. However,only 61% of cases had rises in eosinophils above the nor-mal range. The peak in eosinophils was delayed 0–7 (mean3.5) days after the troponin I/T maximum.Conclusion: Patients initiated on clozapine should bemonitored intensively in the third week for signs of thedevelopment of myocarditis. Eosinophilia should not berelied on as a diagnostic feature, but if CRP is raised,troponin I/T and ECG should be monitored over the fol-lowing days.

doi:10.1016/j.hlc.2008.05.025

25LV Dysplasia in the Absence of Complex Congenital HeartDisease: A New Entity?

Tanya Wood ∗, James Challen, Wendy Strugnell, MarkHansen, Richard Slaughter

Queensland Institute of Technology, Brisbane, Australia

Introduction: Abnormalities of ventricular developmentare common in complex congenital heart disease (CHD)but may also occur in its absence. Cardiac magneticresonance imaging (CMRI) is an ideal modality for demon-strating the spectrum of abnormalities that may occur.Method: We report findings in nine patients withabnormal ventricular morphology which could not becategorised according to previously described diagnostic

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criteria. All patients were referred for CMRI assessment offunction and viability. Steady-state free precession (SSFP)imaging was used for functional assessment. Standardparameters of function were calculated and indexed tobody surface area (BSA). Delayed enhancement imagingwas performed in short axis, four chamber and verti-cal long axis planes, 8–15 min after IV administration of0.2 mmol/kg of gadolinium-DTPA.Results: LV function was normal in five patients. Threepatients had indexed end-diastolic volumes (EDVi),masses (EDMi) and ejection fractions (EF) higher than thenormal range. One patient had higher than normal EDViand EDMi with normal EF. One patient had reduced EF.No patients had delayed enhancement.Morphological abnormalities included focal wall thinning,scalloping, clefts and pseudoaneurysm formation in theabsence of scarring. Abnormal trabecular development,muscle bands and papillary muscle abnormalities werealso.These features did not fulfil recognised diagnostic criteriafor previously described entities including isolated ven-tricular non-compaction. In four cases these abnormalitieswere associated with aortic coarctation, three of which alsohad bicuspid aortic valves.Conclusion: We describe a spectrum of morphologicalabnormalities within the ventricular wall that have notbeen previously described and are probably congenital inop

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Results: TM patients had a higher heart rate and a lowerbody surface area (BSA) than controls (p < 0.05 for both).SE, S′, EDE and E′ were all lower in TM (by 13%, 10%, 19%and 10%, respectively, p ≤ 0.005 for all). After adjustmentfor heart rate and BSA, TM remained an independentpredictor of a lower EDE (p = 0.001), SE (p < 0.05) and E′(p < 0.03), but not a lower S′. In TM subjects, the 5-yearaverage ferritin was an inverse correlate of SE (r = −0.42,p = 0.001) and S′ (r = −0.39, p = 0.002) but was not related toEDE or E′.Conclusion: In TM EDE is reduced proportionally morethan E′, SAE and S′, but neither EDE nor E′ appear to beaffected by iron overload. In contrast, both S′ and SAEhave modest inverse relationships with the extent of ironoverload.

doi:10.1016/j.hlc.2008.05.027

27Insights into Mitral Annular Early Diastolic Motion bySimultaneous Assessment of the Extent, Peak Velocity (E′)and Duration of Excursion

Bon Chou ∗, Lesley Donelan, Philip M. Mottram, StuartMoir, John S. Gelman, Roger E. Peverill

Monash Cardiovascular Research Centre, Monash Heart &Southern Health, Monash University Department of Medicine(MMC), Clayton, Victoria, Australia

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rigin. The clinical implications of these abnormalities arerobably mild and long-term outcomes are unknown.

oi:10.1016/j.hlc.2008.05.026

6ong Axis Left Ventricular Systolic and Diastolic Excur-ion in Thalassaemia Major—Divergent Relations withron Overload

on Chou 1,∗, Lesley Donelan 1, Don K. Bowden 2, Roger. Peverill 1

Monash Cardiovascular Research Centre, Monash Heart &outhern Health, Monash University Department of MedicineMMC), Clayton, Victoria, Australia; 2 Medical Therapy Unit,outhern Health, Clayton, Victoria, Australia

ackground: Thalassaemia major (TM) patients are sus-eptible to cardiac dysfunction due to iron overload andven TM patients with a normal ejection fraction haveeduced left ventricular (LV) long axis systolic (S′) andarly diastolic (E′) peak velocities. We investigated theossibility that measurement of the extent of mitral annu-

ar excursion during systole (SE) and early diastole (EDE)ould provide further insights into the subclinical LV dys-

unction found in TM.ethods: 58 TM patients (age 30 ± 7 years, 24 men) with

reserved LV ejection fraction were compared to 58 sexnd aged matched controls. TDI was performed at the lat-ral mitral annulus for measurement of SE, S′, EDE, and′. The average 5-year ferritin level was calculated in TMatients.

ackground: The peak velocity of early diastolic mitralnnular motion (E′) using tissue Doppler imaging (TDI) isn routine use as a surrogate of left ventricular (LV) relax-tion. We hypothesized that simultaneous assessment ofxcursion and timing would provide further insight intoV long axis function and its determinants. We investi-ated the relationship of early diastolic mitral annularxcursion (EDE), duration (EDdur) and E′ and also theelationship of these three TDI variables with age, LV

ass index (LVMI), heart rate (HR) and blood pressureBP).

ethods: Echocardiography was performed in 76 healthyubjects (age 30 ± 7 years, 38 men). LVMI was calculatedrom M-mode measurements. TDI signals were recordedt the septal border of the mitral annulus. EDE was mea-ured from the integral of the early diastolic TDI signal.nivariate and multivariate linear regression analysesere performed and only statistically significant (p < 0.05)

orrelations are shown.esults: E′ was positively correlated with EDE (r = 0.68)nd inversely correlated with EDdur (r = −0.28), whereasDE was positively correlated with EDdur (r = 0.23). EDEnd E′ were both inversely correlated with age (r = −0.35nd −0.50, respectively). The only correlate of HR wasDE (r = −0.25), the only correlate of diastolic BP was′ (r = −0.36) and the only correlate of LVMI was EDdur

r = 0.39). On multivariate analysis, E′ was independentlyorrelated with age (β = − 0.22), diastolic BP (β = − 0.19)nd EDE (β = 0.57).onclusion: E′ only provides a partial perspective on earlyiastolic mitral annular motion and its determinants in