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S16 Abstracts Heart, Lung and Circulation2009;18S:S1–S31

Methods: All patients admitted to Hutt Hospitalbetween September and December 2007, 73 patientsscreened, and criteria according to Modified Framing-ham Clinical Criteria for Diagnosis of Heart Failure—58patients included, 15 patients excluded as not match-ing the criteria and clinical notes not available. Weaudited ethnicity, gender of patients, admission diag-nosis, comparing admission and discharge medication,predisposing factors, co-morbidities, echo/ECG/BNP lev-els/CXR, length of stay and also % of patient being followup after 9 months.

Results: This audit of 58 patients admitted with con-firmed diagnosis of Heart Failure identified approximateequal ratio of male (55%) and female (45%), median ageof 72, median length of stay 5 days, majority admit-ted under cardiology (72%) rather than general medicine(28%), ECG 53% has arrhythmia and 47% in sinus rhythm,LV dysfunction on echo-mild 31%/moderate 29%/severe40%, CXR-cardiomegaly 76%, pulmonary congestion 62%,pleural effusion 36%, normal 5%, patient has BNP level-64%, Diagnosis accuracy 83%, 81% patients had follow up,Mortality on admission 8%, Mortality after 1 year of followup 19%, Heart Failure nurses follow up 55%.

Conclusion: Diagnostic accuracy of heart failure is highin Hutt Hospital, heart failure nurses contribute to mostpatients’ follow-up and mortality is high after 1 year-19%.

outcomes were good, but no differences between PPCI andlytics were observed in cost, mean length of stay (6.2 ± 2.9days vs. 6.1 ± 2.8 days), 1-year repeat MI (5% vs. 7%), orunplanned rehospitalisation (31% vs. 50%).

Conclusions: Eligible patients had a high rate of receiv-ing reperfusion, predominantly mechanical. Outcomesincluding 1-year survival are good and appear not to dif-fer by strategy. It may be reasonable to maintain a flexibleapproach to mode of reperfusion but utilising PPCI inmore patients with anterior STEMI, and high rates of res-cue PCI for lytic failure. No disadvantage was observedfor thrombolysis, but a question remains whether sim-ilar optimal outcomes would occur with lower rates ofPPCI/rescue.

doi:10.1016/j.hlc.2009.04.038

36ARE FAILED ICD SHOCKS DUE TO CHANGING VEN-TRICULAR FIBRILLATION CHARACTERISTICS?

P Larsen 1,∗, N Lever 2

1 Department of Surgery and Anaesthesia, University of Otago,Wellington, New Zealand2 Green Lane Cardiovascular Service, Auckland Hospital andDepartment of Medicine, University of Auckland, Auckland,New Zealand

doi:10.1016/j.hlc.2009.04.037

35COMPARISON OF PRIMARY PERCUTANEOUS CORO-NARY INTERVENTION WITH THROMBOLYTICTHERAPY FOR ST ELEVATION MYOCARDIALINFARCTION IN DUNEDIN HOSPITAL 2007

HJ Kwon 1,∗, VHT Chen 1,2, GT Wilkins 1,2, MJAWilliams 1,2

1 Department of Medical and Surgical Sciences, University ofOtago, Dunedin, New Zealand2 Cardiology Department, Dunedin Hospital, University ofOtago, Dunedin, New Zealand

Background: Primary percutaneous coronary interven-tion (PPCI) is considered optimal therapy for ST segmentelevation myocardial infarction (STEMI). We reviewedoutcomes of a protocol which still allows a flexibleapproach to reperfusion, to assess potential differentialsbetween PPCI and lytic therapy.

Methods: A retrospective observational study of allreperfusion eligible STEMI cases presenting to DunedinHospital in 2007.

Results: 59 cases were identified. 40/59 (68%) receivedPPCI, 14/59 (24%) received lytics, and 5/59 (8%) did notreceive acute reperfusion. TIMI (4.9 ± 0.8 vs. 3.7 ± 1.3,p = 0.12) and GRACE (155 ± 13 vs. 144 ± 19, p = 0.36) riskscores did not differ but there were significantly moreanterior STEMIs in PPCI vs. lytic groups (63% vs. 21%,p = 0.01). 5/14 (36%) of lytic patients received rescue PCIand only 1/14 patient with lytic failure did not receive res-cue. Overall 1 year survival was 95%, process/procedural

Background: Defibrillation is regarded as a probabilisticevent with any given shock only having a certain chance ofterminating ventricular fibrillation (VF). An alternative tothis proposition is that the apparent probabilistic natureof defibrillation may be due to differences in the underly-ing characteristics of successive episodes of VF. This studycharacterised VF episodes and compared those preced-ing successful and failed shocks delivered by implantedcardioverter defibrillators (ICDs).

Methods: We identified 14 patients who had a clinicalepisode of VF where the first ICD shock failed to terminatethe arrhythmia. We extracted electrogram data of the VFepisode from the ICD, along with the signal from a secondVF episode that preceded a successful shock. We deter-mined the dominant frequency (DF) of VF using spectralanalysis, and the regularity using autocorrelation, andthen compared frequency and regularity between pairedepisodes.

Results: The VF episodes preceding the failed shockshad significantly higher DFs (mean 4.9 vs. 4.5 Hz, p = 0.02)and were significantly more regular (peak autocorrelation0.62 vs. 0.52, p = 0.03) than the VF episodes that were suc-cessfully terminated.

Conclusion: VF episodes that preceded failed shockswere faster and more regular than VF episodes precedingsuccessful shocks. This raises the possibility that failure todefibrillate may not be due to probabilistic characteristicsof defibrillation, but rather may be due to episode-to-episode differences in the properties of the underlyingre-entrant mechanisms involved in VF.

doi:10.1016/j.hlc.2009.04.039