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REPAIRED TOF PATIENTS HAVE NORMAL RV BUT ABNORMAL LV DEFORMATION

ZI Khan, GA Wharton, GJ WilliamsYorkshire Heart Centre, Leeds, UK

Introduction: Strain imaging provides information on local myocardial deformation. Global left (LV) & right (RV) ventricular function is impaired to varying degrees in surgically repaired tetralogy of Fallot (rTOF) patients. Using strain imaging we assessed the local deformation characteristics of different regions of the LV+RV.

Method: rTOF patients were compared to normal controls. All subjects were imaged in the apical 2+4-chamber views superimposed with tissue Doppler imaging data. Longitudinal strain was calculated off line by placing the sample volume in the mid-ventricular and basal segments of the lateral, septal, inferior & anterior walls of the LV & the free wall of the RV. The results were averaged from 3 cardiac cycles.

Results are expressed as mean (±SD). 24 rTOF patients were compared to 15 age matched normal controls (31.38±10.38yrs v 32.07±9.87yrs, p=NS). There was no significant difference in strain between the basal+mid regions of the LV or RV in the normal population. In the rTOF group, strain was greatest at the base of the heart compared to the mid region in the RV (24.10±10.41% vs 17.3±9.05%, p=0.03), septum (25.75±8.32% vs 17.06± 5.66%, p<0.001), lateral (19.92±6.73% vs 15.07±6.93%, p<0.04), inferior (20.73±7.44% vs 15.86±5.31%, p<0.05) & anterior (22.23±8.56% vs 16.69±5.38%, p<0.05) walls of the LV. Basal strain of the LV was similar in both groups. However mid-septal (16.59±5.26% vs 24.07±10.54%, p=0.02), mid-lateral (14.97±7.06% vs 21.12 ±6.36%, p<0.01), mid-inferior (15.97±5.46% vs 21.53±6.92, p<0.02) & mid-anterior (16.31±5.35% vs 20.75±5.50, p=0.04) strain were significantly less. RV strain was similar to that of the normal population at both the basal & mid regions (24.65±10.31% vs 29.93 ±13.43%, p=NS and 16.99±9.14% vs 22.27±11.74%, p=NS, respectively).

Conclusion: Myocardial deformation of the RV is normal in rTOF subjects. However LV deformation is reduced. The pattern of abnormal deformation of the LV is regional suggesting this may be the result of ischaemic injury at the time of repair.

TRANSCRANIAL DOPPLER OR TRANSOESOPHAGEAL ECHOCARDIOGRAPHY FOR THE DETECTION OF VENOUS-TO-ARTERIAL CIRCULATION SHUNTS

S Sastry, A MacNab, K Daly, SG Ray, CN McCollumSouth Manchester University Hospital, Manchester, UK

Background: Contrast transcranial Doppler ultrasound (TCD) is simple, non-invasive and detects both cardiac and pulmonary venous-to-arterial circulation shunts (v-aCS). We compared the TCD detection of v-aCS with transoesophageal echocardiography (TOE) for patent foramen ovale (PFO).

Methods: We studied 39 patients aged 15–39 following ischaemic stroke (33) or myocardial infarction (6). “Standardised” TCD was performed 2 weeks before “simultaneous” TCD and TOE. Agitated saline contrast was injected intravenously twice at rest and twice each with cough and Valsalva provocation. In standardised TCD, the patient sat up and the Valsalva manoeuvre was to a pressure of 40 mmHg for five seconds immediately after contrast injection. During “simultaneous” TCD and TOE the patient was in the left lateral position, coughing was difficult and Valsalva was by epigastric pressure.

Results: On TOE, 16 of the 39 patients had a PFO, all also having more than 15 microbubble emboli on TCD within 12 cardiac cycles of intravenous contrast injection. In 14 of the 16, paradoxical embolisation was spontaneous and did not need provocation on standardised TCD. The number of microbubble emboli, at a median (IQR) of 20 (3–135) on standardised TCD was uniformly higher than 7 (1–43) on simultaneous TCD and 13 (6–42) on TOE, perhaps due to sedation, the lying position or inadequate provocation. The size of the PFO on TOE correlated closely with the number of microbubble emboli on standardised TCD (rs = 0.83, [0.70, 0.91]).

Conclusions: TOE is relatively insensitive to v-aCS as it is difficult to achieve adequate cough or Valsalva provocation. Standardised TCD is sensitive to the detection of v-aCS and PFO with more than 15 microbubbles within 12 cardiac cycles universally detecting PFO.

BENEFITS OF ANGIOTENSIN CONVERTING ENZYME INHIBITION IN CARDIAC FAILURE

SL Cunningham1, KH Parker2, J Mayet1, SAMcG Thom1, AD Hughes11St Mary’s Hospital, London, 2Physiological Flow Studies Unit, Imperial College, London, UK.

Wave intensity analysis (WIA) is a novel non-invasive technique that measures the working state of the heart, pressure wave reflection and arterio-ventricular interaction. WIA allows forward and backward waves to be distinguished, where wave intensity (dI) is a measure of the energy carried by a wave. Angiotensin converting enzyme inhibition (ACEI) is beneficial in heart failure and has been shown to reduce peripheral resistance, wave speed (c), augmentation index (AI) and wave reflection. WIA was used to investigate the haemodynamic effects of ACEI. 15 patients with heart failure (NYHA class II-III) were studied on two occasions with and without ACEI. In addition to brachial blood pressure (BP) and ejection fraction (EF), carotid arterial pressure (P) and flow were measured by tonometry and pulsed wave Doppler respectively. Forward and backward wave intensities, forward and backward pressures, carotid c, and AI were calculated. Data are means±SD, p was calculated by a paired Student’s t-test and data were log transformed where appropriate*. ACEI significantly reduced BP from 131±19/74±16 to 119±17/67±12 mmHg (p<0.001 systolic and p=0.02 diastolic). ACEI also caused a reduction in AI (−ACEI=26.3±10.7; +ACEI=21.7±13.7 %; p=0.09*) and c (−ACEI=15.2±8.4; +ACEI=11.8±5.5 ms−1; p=0.07). Wave reflections from the body (−ACEI=3.2±3.5; +ACEI=3.8±4.8%; NS) and head (−ACEI=17.2±10.8; +ACEI=18.8±9.9%; NS) were not affected by ACEI. ACEI significantly increased flow (−ACEI=0.59±0.20; +ACEI=0.66±0.17 ms−1; p=0.03). Ejection fraction also increased with ACEI from 32±20% to 39±16% (p=0.001), without an increase in early forward wave intensity (dI+c1) (−ACEI=22.6±13.9 mWm−2; +ACEI=24.4±17.4 mWm−2;NS) indicating that relatively more cardiac power is invested in achieving ejection than increasing pressure. These data suggest that the major haemodynamic effect of ACEI is to decrease peripheral resistance and to enhance the heart’s function as a flow source.

THE IMPACT OF HAND CARRIED ULTRASOUND DEVICES (HCU) IN THE CARDIAC OUTPATIENT CLINIC UPON THE REFERRAL PATTERNS TO THE ECHO DEPARTMENT

D Platts, M Thomas, P MacCarthy, M MonaghanKing’s College Hospital, London, UK

Small, portable, low cost, easy to use HCU devices are now freely available. The aim of this study was to evaluate the potential role of these devices in the cardiac outpatient setting and to assess how their use influences referral patterns to the echo department. Over a 5-month period, 75 patients in the cardiac clinic underwent a targeted study using the Philips Optigo HCU device. For each assessment, a proforma was completed, detailing: reason for echo, chamber size, systolic function, colour Doppler findings, presence of pericardial effusion, duration of study and outcome of examination.

75 cases (33F, 42 M, av. age 46 years). Referred by GP (60), Physician (11), Surgeon (3), Anaesthetist (1). Reason for echo: LV function (17), valve disease (11), SOB (11), AF (10), ECG changes (7), hypertension (6), palpitations (5), chest pain (2), presyncope/syncope (2), other (4). Av. scan time 1.9 mins (range 2–5). Outcome of HCU echo: prevented formal echo request 55 (29 normal, 26 abnormal – 25 of these only mild valve disease or a LV function abnormality), confirmed need for formal echo 12 (1 normal, 11 abnormal), study performed when normally would not 7 (4 normal, 3 abnormal), non-diagnostic study (1).

In 55 out of 75 patients (73%), the results obtained from the Philips Optigo HCU device prevented a formal referral to the echo department. In 12 cases, the HCU findings confirmed the clinician’s judgement for requesting a formal echo. In only 7 cases (9%) was it utilised when an echo would not normally be done. Thus, a brief examination (av. 1.9 mins) with a HCU device in the outpatient clinic can have a significant impact on referral patterns and hence workload, to the echo department, both by preventing a significant number of formal studies and also, by detecting an abnormality needing further assessment, confirming the need for a formal study.

VENTRICULAR REMODELING FOLLOWING MITRAL VALVE REPAIR

A Macnab, NP Jenkins, BJ Bridgewater, TL Hooper, SG RayWythenshawe Hospital, Manchester, UK

Background: There is limited information on the timescale of changes in left ventricular (LV) dimensions, volumes and systolic function in patients following mitral valve repair surgery.

Methods: We examined serial transthoracic echo studies of 40 consecutive patients with chronic severe mitral regurgitation (MR) 1 day prior to valve repair, then at 1 week and 6 months post surgery. LV end-diastolic diameter (LVEDD), volume (EDV), ejection fraction (EF) and regurgitant fraction (RF) were measured. The majority (35 patients) had degenerative disease.

Results: Baseline patient characteristics were: mean (SD) age 63 (13) years, 60% were male, 73% in sinus rhythm, 45% with EF>60% and 43% in NYHA grade III/IV. During follow-up 1 patient died and 2 had recurrence of severe MR (RF>55%). After 6 months EF was still significantly lower compared with baseline {mean (SD) EF 59 (8)% at baseline vs 50 (13)% at follow-up}. There was an immediate reduction in LV EDV but a more gradual change in LV EDD as shown in the bar charts. This pattern of change was independent of age, pre-operative cavity size, EF, NYHA status or presence of coronary disease.

Conclusions: Following successful mitral repair there is an abrupt fall in end-diastolic volume but a gradual drop in mid-cavity diameter implying continued ventricular remodelling over several months.

MATERNAL CARDIAC FUNCTION IN TWIN PREGNANCIES: A MODEL FOR PREECLAMPSIA?

N Kametas1, F McAuliffe1, E Krampl1, J Chambers2, KN Nicolaides11Harris Birthright Research Centre for Fetal Medicine, King’s College Hospital, London; 2Cardiac Department, St. Thomas’ Hospital, London, UK

The prevalence of pregnancy induced hypertension (PIH) and pre-eclampsia (PET) is increased in multiple pregnancies. Previous studies have demonstrated that PIH and PET are characterised by a hyperdynamic maternal circulation. It is possible that these changes also occur in normal twin pregnancies, but this has not been investigated before.

Methods: Echocardiography was performed in 125 singleton and 110 twin pregnancies at 10–42 weeks of gestation. Maternal cardiac output (CO) was the product of stroke volume and heart rate. Ejection fraction (EF) and fractional shortening (FS) reflected LV systolic function in the circumferential axis. The measurement of the displacement of the mitral annulus (MAD) towards the LV apex during contraction reflected LV systolic function in the longitudinal axis. Fourteen twin and 3 singleton pregnancies developed PIH or PET and were excluded from the analysis.

Results: The prevalence of hypertensive disorders was higher in twin compared to singleton pregnancies (11 % vs 2.3%, p<0.01). CO was higher in twin than in singleton pregnancies (8.2 vs 7 L/min, p<0.0001) as a result of higher stroke volume (100 vs 87.6 mls, p<0.0001) and heart rate (81.8 vs 80 bpm, p<0.0001). Mean arterial pressure (MAP) decreased until mid-pregnancy and subsequently increased towards term (pgestation<0.0001 for both populations). However the increment in MAP in twin pregnancies took place earlier and more abruptly after mid-pregnancy, resulting in higher MAP values at term in twin versus singleton pregnancies (pinteraction=0.03). EF (0.69 vs 0.67, p=0.007) and FS (0.39 vs 0.37, p<0.0001) were higher in twin pregnancies throughout pregnancy. MAD mirrored the changes of MAP, increasing up to 25 weeks and then declining towards term. Similar to MAP, after mid-pregnancy there was a crossover in MAD between singleton and twin pregnancies (pinteraction<0.01), suggesting an earlier compromise of longitudinal LV systolic function in twin versus singleton pregnancies.

Conclusions: In twin pregnancies even if uncomplicated, the maternal circulation is hyperdynamic and there is relative impairment in long axis function.

TISSUE DOPPLER ECHOCARDIOGRAPHY: A SIMPLE NON-INVASIVE METHOD TO OBJECTIVELY MONITOR RIGHT VENTRICULAR (RV) FUNCTION AFTER CABG

BS Wasan, N Patel, R Lane, R Stanbridge, B Glenville, SA Thom, RA Foale, J MayetSt Mary’s Hospital, and Imperial College, London, UK

Background: Tissue Doppler echocardiography (TDE) is a relatively new modality that permits the assessment of regional right and left ventricular function. Its main advantages over conventional echocardiography are that it 1) provides objective measures of systolic and diastolic function; 2) provides regional myocardial information; 3) is not dependant on image quality. RV dysfunction immediately after CABG is a recognised but poorly understood phenomenon. It is assumed that function improves back to normal with time after surgery. CABG on the beating heart without cardio-pulmonary bypass (‘off pump’) has gained increasing popularity. Improved post-operative ventricular function has been cited as an advantage over on pump surgery.

Methods: 30 patients (including 20 off pump cases) with 3-vessel coronary artery disease undergoing elective CABG each had pulsed wave TDI images obtained from the apex, visualising the tricuspid free wall annulus. RV systolic and diastolic velocities were compared immediately before, 5 days and 7 weeks after surgery. Regional mitral annular velocities were also studied for comparison.

Results: Each subject had a mean of 3.5 grafts. All had a graft to the right coronary artery. All left ventricular regional velocities showed a non-significant trend of improvement after surgery with time. Both systolic (S) and diastolic (E) velocities in the RV decreased considerably 5 days after CABG and this dysfunction continued to be present 7 weeks later: S pre 14.2±1.2, 5d 9.0±0.8*, 7w 7.6±1.0*. E pre 11.5±0.7, 5d 7.3±0.3*, 7w 5.7±0.8* (*p<0.01). The off pump group had a similar trend with no evidence of preserved RV function compared to the on pump group.

Conclusions: Significant RV dysfunction is present 2 months after CABG and this may have important clinical implications. TDE can provide a simple, non-invasive quantitative method for assessing RV function and monitoring recovery after surgery.

TISSUE DOPPLER ECHOCARDIOGRAPHY AS AN ADJUNCT TO ASSESSING DIASTOLIC FUNCTION IN ESSENTIAL HYPERTENSION

AS Sharp, BS Wasan, A Zambanini, RA Foale, AD Hughes, SAMcG Thom, J MayetSt Mary’s Hospital, and Imperial College London, UK

Background: The traditional assessment of diastolic function is limited by the way transmitral flow patterns vary as diastolic dysfunction becomes increasingly severe. It can be a challenge to easily separate normal from pseudonormal patterns.

Methods: In order to assess the prevalence of pseudonormal transmitral patterns in patients with uncomplicated essential hypertension we performed standard 2D and tissue Doppler echocardiography (TDE) in 127 patients. Using age matched normal data, we defined an E/A transmitral ratio of >1 coupled with a normal e wave deceleration time and a lateral wall E wave velocity below the 95% confidence interval as a pseudonormal picture.

Conclusion: Of the 32 patients who on traditional transmitral Doppler appeared to have normal diastolic function, five were found on TDE to have a significantly reduced E wave velocity, suggesting a pseudonormal picture. These patients have severe diastolic dysfunction. TDE velocities are easy to measure and are a useful adjunct in assessing diastolic function.

GLOBAL LV FUNCTION CAN BE ASSESSED USING ONLY ONE VIEW

ZI Khan, Wharton GA, Farrell A, GJ WilliamsYorkshire Heart Centre, Leeds, UK

Peak mitral annular descent velocity using tissue Doppler imaging (TDI) provides an accurate assessment of left ventricular (LV) systolic and diastolic function. For assessment of global LV function, analyses of 4 walls (lateral, septum, anterior and posterior) is required. However this is time consuming. We feel this is a major reason why this modality is not used in routine clinical practice. We sought to see if 2-site sampling (lateral & septal) from the apical 4-chamber view, which is considerably less time consuming, would provide the same information.

Method: All subjects underwent TDI of the apical 2 & 4-chamber views with the sample volume placed over the lateral, septal, inferior and superior aspect of the mitral annulus. Peak systolic (S), early (E) and late (A) diastolic velocities were measured and averaged from 3 cardiac cycles. 2-site measurements were recorded as S2, E2 and A2 and 4-site as S4, E4 and A4. Images digitally stored & analysed offline. Measurements were averaged from 3 cardiac cycles.

Results are expressed as mean (±SD). 72 consecutive subjects, aged 45±18.32yrs, attending for routine echocardiography were scanned. There was no significant difference between measurements taken at 2 or 4-sites for peak S (6.28±2.11 cm/s vs 6.32±2.08 cm/s, p=NS), E (8.16±3.39 cm/s vs 8.08±3.19 cm/s, p=NS), A velocity (6.75±2.60 cm/s vs 7.06±2.66 cm/s, p=NS), or E/A ratio (1.35±0.70 vs 1.29±0.69, p=NS). Excellent correlation was demonstrated between 2 & 4-site sampling in all patients for peak S (r=0.98, p<0.001), E (r=0.97, p<0.001), A velocity (r=0.95, p<0.001) and E/A ratio (r=0.96, p<0.001).

Conclusion: Apical 2-site sampling correlates significantly with 4-site sampling in patients with varying degrees of LV impairment. This method is considerably less time consuming. Apical 2-site sampling can be used to assess global LV function.

Normal data for lateral wall e wave velocity used:

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