Simon Meij

Left ventricular performance, regional blood flow, wall motion, and lactate metabolism during transluminal angioplasty.

The response of left ventricular function, coronary blood flow, and myocardial lactate metabolism during percutaneous transluminal coronary angioplasty (PTCA) was studied in a series of patients undergoing the procedure. From four to six balloon inflation procedures per patient were performed with an average duration per occlusion of 51 +/- 12 sec (mean +/- SD) and a total occlusion time of 252 +/- 140 sec. Analysis of left ventricular hemodynamics in 19 patients showed that the relaxation parameters, peak negative rate of change in pressure, and early time constants of relaxation, responded earliest to short-term coronary occlusion (peak effect at 17 +/- 7 sec) while other parameters, such as peak pressure, left ventricular end-diastolic pressure, and peak positive rate of change in pressure, responded more gradually, suggesting a progressive depression of myocardial mechanics throughout the procedure. Left ventricular angiograms, available for 14 patients, indicated an early onset of asynchronous relaxation concurrent with the early response in peak negative dP/dt and the time constant of early relaxation. All hemodynamic functions fully recovered within minutes after the end of PTCA. Mean blood flow in the great cardiac vein and proximal coronary sinus and the hyperemic response were measured in 20 patients. Before PTCA mean flow in the great cardiac vein was 69 +/- 17 ml/min and in the coronary sinus it was 129 +/- 34 ml/min. Reactive hyperemia (great cardiac vein) was 55% after the first PTCA and 91% after the third. A more pronounced reaction was observed when the residual functional coronary stenosis was reduced in subsequent dilatations. Arteriovenous lactate difference appeared constant during the first two occlusions (control +0.11 mmol/liter, first PTCA -0.87 mmol/liter, and second PTCA -0.82 mmol/liter) and did not increase during subsequent occlusions. Within minutes after the procedure lactate balance was again positive, demonstrating the reversibility of the metabolic disturbances after repeated ischemia. The results of this study indicate that there is no permanent dysfunction of global or regional myocardial mechanics, myocardial blood flow, or lactate metabolism after PTCA with four to six coronary occlusions of 40 to 60 sec.

High-Dose β-Blockers and Tight Heart Rate Control Reduce Myocardial Ischemia and Troponin T Release in Vascular Surgery Patients

Background— Adverse perioperative cardiac events occur frequently despite the use of beta (&bgr;)-blockers. We examined whether higher doses of &bgr;-blockers and tight heart rate control were associated with reduced perioperative myocardial ischemia and troponin T release and improved long-term outcome. Methods and Results— In an observational cohort study, 272 vascular surgery patients were preoperatively screened for cardiac risk factors and &bgr;-blocker dose. Beta-blocker dose was converted to a percentage of maximum recommended therapeutic dose. Heart rate and ischemic episodes were recorded by continuous 12-lead electrocardiography, starting 1 day before to 2 days after surgery. Serial troponin T levels were measured after surgery. All-cause mortality was noted during follow-up. Myocardial ischemia was detected in 85 of 272 (31%) patients and troponin T release in 44 of 272 (16.2%). Long-term mortality occurred in 66 of 272 (24.2%) patients. In multivariate analysis, higher &bgr;-blocker doses (per 10% increase) were significantly associated with a lower incidence of myocardial ischemia (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.51 to 0.75), troponin T release (HR, 0.63; 95% CI, 0.49 to 0.80), and long-term mortality (HR, 0.86; 95% CI, 0.76 to 0.97). Higher heart rates during electrocardiographic monitoring (per 10-bpm increase) were significantly associated with an increased incidence of myocardial ischemia (HR, 2.49; 95% CI, 1.79 to 3.48), troponin T release (HR, 1.53; 95% CI, 1.16 to 2.03), and long-term mortality (HR, 1.42; 95% CI, 1.14 to 1.76). Conclusion— This study showed that higher doses of &bgr;-blockers and tight heart rate control are associated with reduced perioperative myocardial ischemia and troponin T release and improved long-term outcome in vascular surgery patients.

Reduction of Recurrent Ischemia With Abciximab During Continuous ECG-Ischemia Monitoring in Patients With Unstable Angina Refractory to Standard Treatment (CAPTURE)

BACKGROUND In the CAPTURE (c7E3 Fab Anti Platelet Therapy in Unstable REfractory angina) trial, 1265 patients with refractory unstable angina were treated with abciximab or placebo, in addition to standard treatment from 16 to 24 hours preceding coronary intervention through 1 hour after intervention. To investigate the incidence of recurrent ischemia and the ischemic burden, a subset of 332 patients (26%) underwent continuous vector-derived 12-lead ECG-ischemia monitoring. METHODS AND RESULTS Patients were monitored from start of treatment through 6 hours after coronary intervention. Ischemic episodes were detected in 31 (18%) of the 169 abciximab and in 37 (23%) of the 163 placebo patients (NS). Only 9 (5%) of abciximab versus 22 (14%) of placebo patients had >/=2 ST episodes (P<0.01). In patients with ischemia, abciximab significantly reduced total ischemic burden (P<0.02), which was calculated alternatively as the total duration of ST episodes per patient, the area under the curve of the ST vector magnitude during episodes, or the sum of the areas under the curves of 12 leads during episodes. Twenty-one patients (6%) suffered a myocardial infarction (MI) (18) or died (3) within 5 days of treatment. The presence of asymptomatic and symptomatic ST episodes during the monitoring period preceding coronary intervention was associated with an increased relative risk of these events of 3.2 (95% CI 1.4, 7.4) and 4.1 (95% CI 1.4, 12.2), respectively. CONCLUSIONS Recurrent ischemia predicts MI or death within 5 days of follow-up. Treatment with abciximab is associated with a reduction of frequent ischemia and a reduction of total ischemic burden in patients with refractory unstable angina. As such, patients with ischemia derive particularly high benefit from abciximab.

Criteria for early extubation after intracardiac surgery in adults.

Of 142 adult patients undergoing open-heart surgery, 123 were extubated either in the operating room or within 3 hours after admission to the recovery room, to avoid the discomfort and risks of prolonged mechanical ventilation. The remaining 19 patients, who had impaired cardiac function, were mechanically ventilated for 1 to 7 days postoperatively. The most important criteria for cardiopulmonary malfunction indicating the need for continued mechanical ventilation were a low mixed venous O2 saturation (S−VO2.) of < 60% and a high left atrial pressure (>20 torr). Of the 123 patients, 118 had an uneventful postoperative recovery and 5 needed reintubation, 2 because of low S−VO2 and 3 because of complications unrelated to respiratory management.Most adult patients can spontaneously breathe adequately immediately after or within 3 hours of completed open-heart surgery, but a thorough physiologic and clinical evaluation should precede extubation, to identify those who need prolonged mechanical ventilation in the postoperative phase. Criteria for selection of patients for early extubation are presented.

The Electrical T-Axis and the Spatial QRS-T Angle Are Independent Predictors of Long-Term Mortality in Patients Admitted with Acute Ischemic Chest Pain

Objective: To investigate whether the orientation of the electrical T-axis and the spatial QRS-T angle provide independent diagnostic and prognostic information in patients presenting with acute chest pain. Methods: Patients with symptoms suggestive of acute cardiac pathology, who were seen by a general practitioner and for whom a prehospital electrocardiogram (ECG) was recorded by the ambulance service between 1992 and 1994 were investigated. The ECGs (n = 2,261) for our study population were stored for off-line analysis by the Modular ECG Analysis System. QRS- and T-axes were computed from the reconstructed vectorcardiographic X, Y and Z leads. During the year 2000, a follow-up of the entire cohort was performed, and the vital status of the patients was determined via the civil registrar’s office. Cox multivariable regression analyses were performed to evaluate the relation between the orientation of the T-axis, the spatial QRS-T angle and long-term mortality. Results: An abnormal orientation of the T-axis and the spatial QRS-T angle were associated with an increased likelihood of cardiac diseases and an increased risk of all-cause mortality during short- and long-term follow-up. Conclusions: We conclude that the frontal T-axis and the spatial QRS-T angle are important determinants of diagnosis and prognosis in patients presenting with acute chest pain. The reintroduction of vectorcardiography in routine clinical practice might therefore be reconsidered.

Cardiorespiratory and metabolic effects of profound hypothermia.

At operation the body temperature of mechanically ventilated infants was initially decreased to 25--22 degrees C with surface cooling and further lowered to 16 degrees C by total body perfusion. During circulatory arrest, averaging 40 min, repair of complex intracardiac deformities was carried out. Rewarming to 36 degrees C was achieved by 35--65 min of total body perfusion. Of 29 infants, 23 under 10 kg survived their correction; normothermic ventilation without added CO2 was given throughout the cooling period. The following measurements were made: gas exchange, lung mechanics, heart rate, arterial pressure, right atrial pressure, cardiac output (Qt), ECG, core and nasopharyngeal temperature, as well as biochemical determinations. During surface cooling O2 consumption (VO2), CO2 production (VCO2), endtidal CO2 (PETCO2) and PaCO2 decreased proportionally and linearly with body temperature. Inspiratory resistance, total compliance, physiological dead space (VD/VT), and the single breath CO2 curve did not reveal disturbed lung function. Mean arterial pressure was 98, 90, and 70 mm Hg and heart rate was 141, 107, and 76 beat/min, at temperature 35, 30, and 25 degrees C, respectively. Cardiac index was 2.2 +/- 0.2 liter/min/m2 (mean +/- SEM, n = 25) 2 hours after surgery. Arterial lactate reached peak values of 4.1 +/- 0.3 mM/liter (n = 17), during rewarming but returned to normal. Respiratory alkalosis caused by hyperventilation during cooling caused no apparent harm. No neurological damage was observed. It is concluded that surface cooling performed with normothermic ventilation under guidance of core temperature, VO2, PETCO2, and VCO2, is a safe method.

Epicardial wall motion and left ventricular function during coronary graft angioplasty in humans

Epicardial wall motion and left ventricular function changes during temporary coronary artery occlusion were assessed in a patient at the time of percutaneous transluminal angioplasty performed on a previously placed stenotic coronary artery bypass graft. Epicardial wall motion was analyzed using biplane cineradiography with frame to frame measurements of distances between pairs of radiopaque epicardial markers placed at the time of previous cardiac surgery. Bypass graft occlusion after initial dilation led to the early onset of a biphasic epicardial late systolic lengthening and early diastolic shortening similar to the regional wall motion abnormality preceding the procedure.

Continuous ST-segment monitoring associated with infarct size and left ventricular function in the GUSTO-I trial.

BACKGROUND The aim of this study was to evaluate whether in patients with myocardial infarction, the intensity and duration of myocardial ischemia as measured by continuous ST monitoring are associated with infarct size and residual left ventricular function. METHODS AND RESULTS The analyses included patients with myocardial infarction, receiving thrombolytic therapy, who were enrolled in the electrocardiographic substudy of GUSTO-I, monitored by a vector-derived 12-lead electrocardiographic recording system, and in whom either infarct size (defined as cumulative release of alpha-hydroxybutyrate dehydrogenase activity per liter of plasma over a 72-hour period [Q(72)]) or left ventricular ejection fraction (LVEF) was determined. With the use of linear regression analysis, we investigated the association of various ST-trend characteristics with Q(72) (206 patients) and with LVEF (180 patients). A higher area under the ST trend since thrombolysis until 50% ST recovery and a higher area under recurrent ischemic episodes (ST reelevations) were significantly associated with a higher Q(72), whereas only a higher area under recurrent ischemic episodes was significantly associated with a lower LVEF. These associations remained after adjusting for other patient characteristics such as age, sex, infarct location, and time to treatment. CONCLUSIONS These findings support the physiologic hypothesis that both the intensity and duration of myocardial ischemia (both reflected by the estimated areas under the ST-trend curve) determine myocardial damage and thus are associated with infarct size and ejection fraction in patients with acute myocardial infarction who receive thrombolytic therapy.

Haemodynamic and biochemical variables after induction of anaesthesia with fentanyl and nitrous oxide in patients undergoing coronary artery by-pass surgery

The effects on the haemodynamic and biochemical parameters of three different anaesthetic induction regimes, namely fentanyl (4.1 μg · kg-1 or 15 μg · kg-1) plus 60 percent nitrous oxide with oxygen and fentanyl 15 μg · kg-1 plus 60 per cent nitrogen with oxygen, were studied in patients undergoing coronary artery surgery. Fentanyl 15 μg · kg-1 with nitrous oxide and oxygen produced simultaneous reductions in oxygen uptake, cardiac index and left ventricular stroke work with an unaltered oxygen extraction. Diastolic blood pressure (an index of coronary artery perfusion) was only slightly reduced, and there were no changes in arterial lactate, glucose and free fatty acids. The lower dose of fentanyl (4.1 μg · kg-1) with nitrous oxide produced no haemodynamic changes but decreased the oxygen uptake and extraction. The patients receiving fentanyl 15 μg · kg-1 with nitrogen and oxygen showed increases in heart rate, blood pressure, cardiac index and left ventricular stroke work, together with a significant fall in oxygen extraction. Moreover, in the patients who received fentanyl 4.1 μg · kg-1 with nitrous oxide and oxygen and fentanyl 15 μg · kg-1 with nitrogen and oxygen there were significant increases in blood lactate, glucose and free fatty acids, indicating increased sympathetic activity. We conclude that fentanyl 15 μg · kg-1, together with 60 per cent nitrous oxide with oxygen provides a satisfactory haemodynamic and biochemical state during induction of anaesthesia in patients with myocardial function prejudiced by coronary artery insufficiency.RésuméLes auteurs ont comparé les modifications de paramètres hémodynamiques et biologiques amenées par trois techniques ďinduction ďanesthésie dans des cas de pontages aortocoronariens. Les patients ďun premier groupe ont reçu une dose de 4.1 μg · kg-1 de fentanyl et ont été ventilés avec un mélange de protoxyde ďazote et ďoxygène dans des proportions de 60 et de 40 pour cent; ceux ďun second groupe recevaient 15 μg · kg-1 de fentanyl avec le même mélange de protoxyde; enfin, dans un troisième cas, une dose de 15 μg · kg-1 était administrée et les patients étaient ventilés avec un mélange ďazote et ďoxygène dans un rapport 60/40. Le fentanyl à la dose de 15 μg · kg-1 avec une ventilation au protoxyde ďazote amenait une diminution simultanée de la consommation ďoxygène, de ľindex cardiaque, du travail ďéjection ventriculaire gauche avec extraction ďoxygène diminuée. La pression diastolique (témoin de la perfusion coronarienne) n’était que peu diminuée et ľon n’a pas observé de modification des lactates, du glucose et des acides gras libres artériels. Les doses inférieures de fentanyl avec le protoxyde n’amenaient pas de modifications hémodynamiques mais diminuaient la consommation et ľextraction ďoxygène.D’autre part, les patients qui ont reçu les doses de 15 μg · kg-1 de fentanyl avec une ventilation à ľazote-oxygène, ont présenté des élévations de la fréquence cardiaque, de la pression artérielle, de ľindex cardiaque et du travail ďéjection ventriculaire gauche en même temps qu’une diminution significative de ľextraction ďoxygène.Chez les malades ayant reçu 4.1 μg · kg-1 de fentanyl avec protoxyde, ainsi que chez ceux ayant reçu 15 μg · kg-1 avec le mélange azote-oxygène, on a trouvé des augmentations significatives des lactates, du glucose et des acides gras libres, témoin ďune augmentation de ľactivité sympathique.Nous concluons que le fentanyl à la dose de 15 μg · kg-1 associé à une ventilation avec un mélange de 60 pour cent de protoxyde ďazote et ďoxygène, produit une induction satisfaisante au point de vue hémodynamique et biochimique chez les coronariens.

A microcomputer based charting system for documentation of circulatory, respiratory and pharmacological data during anesthesia

SummaryA system for the on-line production of anaesthetic records with a microcomputer is described. The requirements of the system are a keyboard, a video display unit and a colour plotter. The system requires no programming expertise from anaesthetists and nurses. The records have improved information display, patient care and reduced time spent in administration effort. Disadvantages are the relatively high cost and requirement of preprocessing of haemodynamic and respiratory parameters.