Acute ischaemic ventricular septal defect (VSD) is a severe complication of acute myocardial infa... more Acute ischaemic ventricular septal defect (VSD) is a severe complication of acute myocardial infarction. We present the unusual case of a 66-year-old man with a haemodynamically stable acute posterior basal ischemic VSD, who was managed successfully with hybrid primary coronary artery bypass grafting followed by delayed percutaneous VSD closure, with an excellent intermediate-term outcome. We feel this management strategy should be considered in selected patients with acute posterior VSDs and stable clinical status.
Small scale cycles deposited over 10–100 kyr are a common component of Phanerozoic shelfal deposi... more Small scale cycles deposited over 10–100 kyr are a common component of Phanerozoic shelfal deposits. A combination of detailed outcrop analysis and data-mining from published literature of cycles largely deposited in greenhouse regimes reveals a series of recurring sedimentological, paleoecological, and taphonomic motifs. In general, each cycle is composed of three to four components:(a) a basal skeleton-rich bed with evidence of condensation and, in some cases mineralization;(b) a medium-dark gray siliciclastic ...
Tsunamis are frequent events in modern marine environments but evidence of their passing in subti... more Tsunamis are frequent events in modern marine environments but evidence of their passing in subtidal ancient epicontinental sea deposits is elusive. It has been suggested that this is due to mis-identification or poor preservation potential. Herein a numerical modelling approach is used to show that tsunami propagation in one large ancient epicontinental sea was hindered by the damping effect of shallow bathymetries and reflection, refraction and diffraction from emergent landmasses. The Imperial College Ocean Model (ICOM) is used for this study and is first validated against data from the Sumatra-Andaman Tsunami of December 2004. A palaeobathymetric dataset is then presented for the Hettangian (Lower Jurassic) Laurasian Seaway with idealised tsunami sources situated on the continental shelf and within the adjacent oceanic basin. Results show that tsunamis forced from within ocean basins adjacent to the epicontinental sea are rapidly attenuated over the continental slope and fail to propagate great distances onto the shelf. Similarly, the sedimentological effect of tsunamis forced from within the epicontinental sea is also restricted. It is concluded that tsunami deposits in ancient epicontinental seas are most likely to occur in relative proximity to the source region and this must contribute to their scarcity in the geological record.
The rhythmically bedded limestone-marl-shale succession of the Blue Lias Formation (Lias Group, E... more The rhythmically bedded limestone-marl-shale succession of the Blue Lias Formation (Lias Group, Early Jurassic age) of Kilve in Somerset (SW England) preserves a suite of large conical concretions that formed around methane seeps. These are 1-2 m high, and elliptical in plan (axes 2-4 m), with an outer limestone shell forming the flanks of the cone. The cone flank is composed of micritic carbonate (20-30 cm thick), which locally includes sheets and pods of intraclasts and bioclasts. The cycle-forming limestone beds of the host strata are composed of dark grey micrite with carbon-isotope values (δ 13 C = 0.6 to 0.8‰) consistent with carbon sourced from a mixture of seawater and by sulphate reduction, and oxygen-isotope values (δ 18 O = −6‰) suggesting some degree of later diagenesis. The pale grey micrite that forms the sides of the mounds includes three-dimensional ammonites and intraclasts, and thus cemented close to the sedimentwater interface prior to compaction. The mound-forming carbonate is markedly isotopically light with respect to carbon, but not with respect to oxygen (δ 13 C = − 24.3 to −26.4; δ 18 O = −2 to −3.5‰). The isotope signature indicates that cements were probably derived from a mixture of sources that included biogenic methane. The intraclasts within the limestone suggest that syn-depositional physical brecciation and mixing of cements had occurred, and thus mixing of methane rich-fluids with the overlying surface waters is likely also to have occurred. The relatively heavy oxygen-isotope values may be indicative of anaerobic oxidation of methane. The mound-bearing interval of the Blue Lias Formation is benthos-poor and comprises predominantly laminated black shales, characteristic of poor bottom water oxygenation. The largest of the mounds is however, capped with fossiliferous breccias. Thus the mounds either formed benthic islands that elevated the biota into an oxic zone or, alternatively, they may have supported a chemotrophic community. Although cold seep deposits have been documented previously they are still comparatively rare. This example is one of the oldest in Europe, and is unusual amongst described ancient seeps in preserving relief that extended above the ancient seafloor.
More than two thirds of beds in the lowest Jurassic, Blue Lias Formation lack ammonites, which ar... more More than two thirds of beds in the lowest Jurassic, Blue Lias Formation lack ammonites, which are commonly preserved in irregular or planar-bedded, bioturbated limestones, very rarely in laminated limestones and almost never in laminated black shales. Ammonites are preserved in 3D in nodular and planar-bedded limestones and at any orientation to bedding. Co-occurrence with macrobenthos and absence from beds without benthos suggest that Blue Lias ammonites were nektobenthonic. Scour structures and imbrication of ammonites in the Best Bed imply presence of traction currents. Lack of epifauna on large cephalopod shells (and other fossils) implies rapid deposition in event beds. Blue Lias deposition was episodic, not slow and continuous as the fine grain size implies. Undistorted trace fossils, uncrushed ammonites and stable isotope values all suggest early cementation of limestone beds from pore waters of a similar composition to contemporary Jurassic sea water. A clear diagenetic trend exists, with limestones having least, and laminated black shales most, modified stable isotope values. Contrast between trace fossil fills and host sediment demonstrates that Blue Lias rhythms are primary, but limestone beds have been diagenetically cemented.
Traumatic aortic arch rupture is associated with a high mortality rate. Historically, the mainsta... more Traumatic aortic arch rupture is associated with a high mortality rate. Historically, the mainstay of treatment has been emergency open repair with cardiopulmonary bypass. This has had significant associated mortality and morbidity in a group of patients who often have multiple injuries.
Background: To evaluate our surgical results for Acute Ischaemic Ventricular Septal Defect and su... more Background: To evaluate our surgical results for Acute Ischaemic Ventricular Septal Defect and suggest practice guidelines.
Gorham's ... more Gorham's disease is a very rare disorder of uncertain aetiology, characterised by non-neoplastic proliferation of vascular or lymphatic channels within bone leading to resorption and replacement of osseous matrix with angiomatous tissue. Fewer than 200 cases have been reported in the literature. The complication of chylothorax is associated with a high morbidity and mortality. We present the case of a 17-year-old male with Gorham's disease of the sternum, clavicle and rib, complicated by bilateral chylothorax. Despite thoracic duct ligation and radiotherapy, the patient progressively deteriorated and died 36 weeks following initial presentation.
sented in cardiogenic shock; 6/14 suffered anterior STEMI. Overall, median time to reperfusion (d... more sented in cardiogenic shock; 6/14 suffered anterior STEMI. Overall, median time to reperfusion (door-toballoon or aspiration) was 122 minutes (range 84-166). For the six patients presenting within working hours (weekdays 8 am to 5 pm), the median reperfusion time was 125 minutes (range 84-154 minutes), compared with 112 minutes (range 92-166 minutes) in the eight patients presenting outside working hours. Only one patient achieved reperfusion within 90 minutes from presentation. Twelve of fourteen patients achieved TIMI 3 flow in the culprit vessel after PCI. Two patients required nonemergency surgical revascularisation during the same admission and one patient underwent a later staged PCI in another vessel. All patients survived to hospital discharge, as did 12/13 followed to 30 day follow-up. Conclusion: Helicopter transfer for PPCI from Whangarei to Auckland Hospital is a feasible treatment strategy for patients presenting with STEMI. Improvements are required if the full benefits of this strategy are to be realised.
Orthotopic heart transplantation was done by the biatrial technique initially and the bicaval tec... more Orthotopic heart transplantation was done by the biatrial technique initially and the bicaval technique has become popular recently. This study aims to determine if bicaval technique is advantageous. Consecutive transplants performed between 1996 and 2001 were divided into two groups-37 patients done by bicaval and 38 by biatrial technique. Data accumulation was by retrospective study of patient charts. Both groups had similar preoperative variables. There were no differences in low cardiac output (18.9% versus 26.3%, p = 0.62), intraaortic balloon pump insertion (16.2% versus 15.7%, p = 1.0), re-exploration (13.5% versus 18.4%, p = 0.79) and perioperative mortality (5.4% versus 7.9%, p = 1.0) in the bicaval versus biatrial groups. Temporary (13.5% versus 39.4%, p = 0.15) and permanent pacing (0 versus 3 patients) tended to be less frequent and central venous pressure measured at 1-week was lower in the bicaval group (mean 13.8 +/- 6cm versus 14.9 +/- 5.4cm, p = 0.42), but not attaining statistical significance. Severe tricuspid regurgitation was seen in one bicaval versus five biatrial patients at follow-up. Though bicaval group tended to require less pacing, had less tricuspid regurgitation and had lower central venous pressures, these did not attain statistical significance. There were otherwise no obvious differences in outcome. SHORT ABSTRACT: Seventy five consecutive orthotopic heart transplantations done during the period 1996-2001 by bicaval or biatrial surgical technique were compared. There was no difference in low cardiac output, intraaortic balloon pump insertion and mortality but the bicaval patients tended to have less pacing and diuretic requirements and lower central venous pressures, though not attaining statistical significance.
... Canfield, DE, and Raiswell, R., 1991, Pyrite for-mation and fossil preservation, in Allison, ... more ... Canfield, DE, and Raiswell, R., 1991, Pyrite for-mation and fossil preservation, in Allison, PA, and Briggs, DEG, eds., Taphonomy: Releasing the ... Goldenville-Halifax transition, Mahone Bay, Nova Scotia: Rela-tive sea-level rise in the Meguma source ter-rane: Canadian Journal ...
Coronary revascularization surgery does not traditionally employ angiography to assess procedural... more Coronary revascularization surgery does not traditionally employ angiography to assess procedural success. Early graft failure is reported up to 30% in one year (JAMA Nov 2005) may relate to technical errors or conduit problems. We hypothesize that intra-operative assessment of graft by angiography identifies graft defects and may improve the long term graft survival.
Background: Traumatic injury to the aorta and great vessels is a surgical emergency with survivor... more Background: Traumatic injury to the aorta and great vessels is a surgical emergency with survivors who reach hospital typically having suffered multiple injuries. There are several diagnostic and treatment options available, with new modalities emerging to challenge the gold standards. A review of recent trends in management of these injuries in Auckland, New Zealand was carried out and patient outcomes assessed. Methods: The charts of patients admitted to Auckland and Green Lane Hospital's cardiothoracic intensive care unit, with a diagnosis of injury to the thoracic aorta or great vessels since 1995 were retrospectively reviewed. Imaging techniques, injury types and treatment methods were analysed along with survival and neurological morbidity. Results: In the study period our unit operated on 29 cases of traumatic rupture of the thoracic aorta or great vessels. Digital subtraction angiography and more recently, multidetector computed tomography scanning have been used to diagnose the injury. Twenty-seven injuries were to the aorta and two to the innominate artery. The 30-day survival rate of those reaching the operating theatre was 90%. There was one case of postoperative hemiparesis and five cases of recurrent laryngeal nerve injury, but none of spinal cord ischaemic injury. Endoluminal stent grafting was carried out for one patient, without complication. Conclusions: Good survival rates exist for those who reach surgery for traumatic rupture of the aorta or great vessels. Multidetector computed tomography scanning is an alternative to digital subtraction angiography, potentially reducing treatment delay. In addition endoluminal grafting as opposed to open repair has been reported as a safe technique. The injury remains a surgical emergency requiring urgent diagnosis and transfer to an equipped cardiothoracic unit for definitive treatment.
Acute ischaemic ventricular septal defect (VSD) is a severe complication of acute myocardial infa... more Acute ischaemic ventricular septal defect (VSD) is a severe complication of acute myocardial infarction. We present the unusual case of a 66-year-old man with a haemodynamically stable acute posterior basal ischemic VSD, who was managed successfully with hybrid primary coronary artery bypass grafting followed by delayed percutaneous VSD closure, with an excellent intermediate-term outcome. We feel this management strategy should be considered in selected patients with acute posterior VSDs and stable clinical status.
Small scale cycles deposited over 10–100 kyr are a common component of Phanerozoic shelfal deposi... more Small scale cycles deposited over 10–100 kyr are a common component of Phanerozoic shelfal deposits. A combination of detailed outcrop analysis and data-mining from published literature of cycles largely deposited in greenhouse regimes reveals a series of recurring sedimentological, paleoecological, and taphonomic motifs. In general, each cycle is composed of three to four components:(a) a basal skeleton-rich bed with evidence of condensation and, in some cases mineralization;(b) a medium-dark gray siliciclastic ...
Tsunamis are frequent events in modern marine environments but evidence of their passing in subti... more Tsunamis are frequent events in modern marine environments but evidence of their passing in subtidal ancient epicontinental sea deposits is elusive. It has been suggested that this is due to mis-identification or poor preservation potential. Herein a numerical modelling approach is used to show that tsunami propagation in one large ancient epicontinental sea was hindered by the damping effect of shallow bathymetries and reflection, refraction and diffraction from emergent landmasses. The Imperial College Ocean Model (ICOM) is used for this study and is first validated against data from the Sumatra-Andaman Tsunami of December 2004. A palaeobathymetric dataset is then presented for the Hettangian (Lower Jurassic) Laurasian Seaway with idealised tsunami sources situated on the continental shelf and within the adjacent oceanic basin. Results show that tsunamis forced from within ocean basins adjacent to the epicontinental sea are rapidly attenuated over the continental slope and fail to propagate great distances onto the shelf. Similarly, the sedimentological effect of tsunamis forced from within the epicontinental sea is also restricted. It is concluded that tsunami deposits in ancient epicontinental seas are most likely to occur in relative proximity to the source region and this must contribute to their scarcity in the geological record.
The rhythmically bedded limestone-marl-shale succession of the Blue Lias Formation (Lias Group, E... more The rhythmically bedded limestone-marl-shale succession of the Blue Lias Formation (Lias Group, Early Jurassic age) of Kilve in Somerset (SW England) preserves a suite of large conical concretions that formed around methane seeps. These are 1-2 m high, and elliptical in plan (axes 2-4 m), with an outer limestone shell forming the flanks of the cone. The cone flank is composed of micritic carbonate (20-30 cm thick), which locally includes sheets and pods of intraclasts and bioclasts. The cycle-forming limestone beds of the host strata are composed of dark grey micrite with carbon-isotope values (δ 13 C = 0.6 to 0.8‰) consistent with carbon sourced from a mixture of seawater and by sulphate reduction, and oxygen-isotope values (δ 18 O = −6‰) suggesting some degree of later diagenesis. The pale grey micrite that forms the sides of the mounds includes three-dimensional ammonites and intraclasts, and thus cemented close to the sedimentwater interface prior to compaction. The mound-forming carbonate is markedly isotopically light with respect to carbon, but not with respect to oxygen (δ 13 C = − 24.3 to −26.4; δ 18 O = −2 to −3.5‰). The isotope signature indicates that cements were probably derived from a mixture of sources that included biogenic methane. The intraclasts within the limestone suggest that syn-depositional physical brecciation and mixing of cements had occurred, and thus mixing of methane rich-fluids with the overlying surface waters is likely also to have occurred. The relatively heavy oxygen-isotope values may be indicative of anaerobic oxidation of methane. The mound-bearing interval of the Blue Lias Formation is benthos-poor and comprises predominantly laminated black shales, characteristic of poor bottom water oxygenation. The largest of the mounds is however, capped with fossiliferous breccias. Thus the mounds either formed benthic islands that elevated the biota into an oxic zone or, alternatively, they may have supported a chemotrophic community. Although cold seep deposits have been documented previously they are still comparatively rare. This example is one of the oldest in Europe, and is unusual amongst described ancient seeps in preserving relief that extended above the ancient seafloor.
More than two thirds of beds in the lowest Jurassic, Blue Lias Formation lack ammonites, which ar... more More than two thirds of beds in the lowest Jurassic, Blue Lias Formation lack ammonites, which are commonly preserved in irregular or planar-bedded, bioturbated limestones, very rarely in laminated limestones and almost never in laminated black shales. Ammonites are preserved in 3D in nodular and planar-bedded limestones and at any orientation to bedding. Co-occurrence with macrobenthos and absence from beds without benthos suggest that Blue Lias ammonites were nektobenthonic. Scour structures and imbrication of ammonites in the Best Bed imply presence of traction currents. Lack of epifauna on large cephalopod shells (and other fossils) implies rapid deposition in event beds. Blue Lias deposition was episodic, not slow and continuous as the fine grain size implies. Undistorted trace fossils, uncrushed ammonites and stable isotope values all suggest early cementation of limestone beds from pore waters of a similar composition to contemporary Jurassic sea water. A clear diagenetic trend exists, with limestones having least, and laminated black shales most, modified stable isotope values. Contrast between trace fossil fills and host sediment demonstrates that Blue Lias rhythms are primary, but limestone beds have been diagenetically cemented.
Traumatic aortic arch rupture is associated with a high mortality rate. Historically, the mainsta... more Traumatic aortic arch rupture is associated with a high mortality rate. Historically, the mainstay of treatment has been emergency open repair with cardiopulmonary bypass. This has had significant associated mortality and morbidity in a group of patients who often have multiple injuries.
Background: To evaluate our surgical results for Acute Ischaemic Ventricular Septal Defect and su... more Background: To evaluate our surgical results for Acute Ischaemic Ventricular Septal Defect and suggest practice guidelines.
Gorham's ... more Gorham's disease is a very rare disorder of uncertain aetiology, characterised by non-neoplastic proliferation of vascular or lymphatic channels within bone leading to resorption and replacement of osseous matrix with angiomatous tissue. Fewer than 200 cases have been reported in the literature. The complication of chylothorax is associated with a high morbidity and mortality. We present the case of a 17-year-old male with Gorham's disease of the sternum, clavicle and rib, complicated by bilateral chylothorax. Despite thoracic duct ligation and radiotherapy, the patient progressively deteriorated and died 36 weeks following initial presentation.
sented in cardiogenic shock; 6/14 suffered anterior STEMI. Overall, median time to reperfusion (d... more sented in cardiogenic shock; 6/14 suffered anterior STEMI. Overall, median time to reperfusion (door-toballoon or aspiration) was 122 minutes (range 84-166). For the six patients presenting within working hours (weekdays 8 am to 5 pm), the median reperfusion time was 125 minutes (range 84-154 minutes), compared with 112 minutes (range 92-166 minutes) in the eight patients presenting outside working hours. Only one patient achieved reperfusion within 90 minutes from presentation. Twelve of fourteen patients achieved TIMI 3 flow in the culprit vessel after PCI. Two patients required nonemergency surgical revascularisation during the same admission and one patient underwent a later staged PCI in another vessel. All patients survived to hospital discharge, as did 12/13 followed to 30 day follow-up. Conclusion: Helicopter transfer for PPCI from Whangarei to Auckland Hospital is a feasible treatment strategy for patients presenting with STEMI. Improvements are required if the full benefits of this strategy are to be realised.
Orthotopic heart transplantation was done by the biatrial technique initially and the bicaval tec... more Orthotopic heart transplantation was done by the biatrial technique initially and the bicaval technique has become popular recently. This study aims to determine if bicaval technique is advantageous. Consecutive transplants performed between 1996 and 2001 were divided into two groups-37 patients done by bicaval and 38 by biatrial technique. Data accumulation was by retrospective study of patient charts. Both groups had similar preoperative variables. There were no differences in low cardiac output (18.9% versus 26.3%, p = 0.62), intraaortic balloon pump insertion (16.2% versus 15.7%, p = 1.0), re-exploration (13.5% versus 18.4%, p = 0.79) and perioperative mortality (5.4% versus 7.9%, p = 1.0) in the bicaval versus biatrial groups. Temporary (13.5% versus 39.4%, p = 0.15) and permanent pacing (0 versus 3 patients) tended to be less frequent and central venous pressure measured at 1-week was lower in the bicaval group (mean 13.8 +/- 6cm versus 14.9 +/- 5.4cm, p = 0.42), but not attaining statistical significance. Severe tricuspid regurgitation was seen in one bicaval versus five biatrial patients at follow-up. Though bicaval group tended to require less pacing, had less tricuspid regurgitation and had lower central venous pressures, these did not attain statistical significance. There were otherwise no obvious differences in outcome. SHORT ABSTRACT: Seventy five consecutive orthotopic heart transplantations done during the period 1996-2001 by bicaval or biatrial surgical technique were compared. There was no difference in low cardiac output, intraaortic balloon pump insertion and mortality but the bicaval patients tended to have less pacing and diuretic requirements and lower central venous pressures, though not attaining statistical significance.
... Canfield, DE, and Raiswell, R., 1991, Pyrite for-mation and fossil preservation, in Allison, ... more ... Canfield, DE, and Raiswell, R., 1991, Pyrite for-mation and fossil preservation, in Allison, PA, and Briggs, DEG, eds., Taphonomy: Releasing the ... Goldenville-Halifax transition, Mahone Bay, Nova Scotia: Rela-tive sea-level rise in the Meguma source ter-rane: Canadian Journal ...
Coronary revascularization surgery does not traditionally employ angiography to assess procedural... more Coronary revascularization surgery does not traditionally employ angiography to assess procedural success. Early graft failure is reported up to 30% in one year (JAMA Nov 2005) may relate to technical errors or conduit problems. We hypothesize that intra-operative assessment of graft by angiography identifies graft defects and may improve the long term graft survival.
Background: Traumatic injury to the aorta and great vessels is a surgical emergency with survivor... more Background: Traumatic injury to the aorta and great vessels is a surgical emergency with survivors who reach hospital typically having suffered multiple injuries. There are several diagnostic and treatment options available, with new modalities emerging to challenge the gold standards. A review of recent trends in management of these injuries in Auckland, New Zealand was carried out and patient outcomes assessed. Methods: The charts of patients admitted to Auckland and Green Lane Hospital's cardiothoracic intensive care unit, with a diagnosis of injury to the thoracic aorta or great vessels since 1995 were retrospectively reviewed. Imaging techniques, injury types and treatment methods were analysed along with survival and neurological morbidity. Results: In the study period our unit operated on 29 cases of traumatic rupture of the thoracic aorta or great vessels. Digital subtraction angiography and more recently, multidetector computed tomography scanning have been used to diagnose the injury. Twenty-seven injuries were to the aorta and two to the innominate artery. The 30-day survival rate of those reaching the operating theatre was 90%. There was one case of postoperative hemiparesis and five cases of recurrent laryngeal nerve injury, but none of spinal cord ischaemic injury. Endoluminal stent grafting was carried out for one patient, without complication. Conclusions: Good survival rates exist for those who reach surgery for traumatic rupture of the aorta or great vessels. Multidetector computed tomography scanning is an alternative to digital subtraction angiography, potentially reducing treatment delay. In addition endoluminal grafting as opposed to open repair has been reported as a safe technique. The injury remains a surgical emergency requiring urgent diagnosis and transfer to an equipped cardiothoracic unit for definitive treatment.
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