Frequency Analysis of Ventricular Fibrillation and Resuscitation Success

SUMMARY In 56 patients, frequency analysis of the electrocardiogramof ventricular fibrillation exhibited power spectra with a distinctdominant frequency. The greatest success for resuscitation fromventricular fibrillation is recorded when ventricular fibrillationdevelops after the patient comes under coronary care. Of the41 patients in whom the onset and first 8 s of ventricular fibrillationwere artefact-free the mean dominant frequency of primary ventricularfibrillation (no cardiogenic shock or cardiac failure) in 21patients was 6.2±0.2 Hz, significantly higher than themean dominant frequency of the first 8 s of secondary ventricularfibrillation (cardiogenic shock or heart failure) (4.0±0.2Hz, 20 patients, p =0.0001). In these patients the peak-to-troughamplitude (ECG) of the first 8 s of ventricular fibrillationwas similar in both primary and secondary ventricular fibrillationas was the mean duration of ventricular fibrillation prior tothe first DC shock. There was a significantly lower successrate for resuscitation from secondary ventricular fibrillation(6 of 20 patients) compared with resuscitation from primaryventricular fibrillation (18 of 21 patients, x² 17.8, p=0.001).Of the remaining 15 patients who were collapsed between 3 and20 min before the arrival of the mobile coronary care unit,the dominant frequency of the first 8 s of ventricular fibrillationfell with increased duration of collapse (from 5.5 Hz at 3 minto a mean of 2.1 Hz at 20 min). Four of these 15 patients whosurvived the initial arrest had a mean dominant frequency of5.2±0.3 Hz, which was significantly higher than the meandominant frequency (3.1±0.3 Hz, p<0.01) of the 11patients who were not resuscitated. This study shows that low frequency ventricular fibrillationis indicative of a poor chance of successful resuscitation.Alteration of the frequency may increase resuscitation success.     

Magnetic resonance imaging in breast cancer: A literature review and future perspectives

Early detection and diagnosis of breast cancer are essential for successful treatment. Currently mammography and ultrasound are the basic imaging techniques for the detection and localization of breast tumors. The low sensitivity and specificity of these imaging tools resulted in a demand for new imaging modalities and breast magnetic resonance imaging (MRI) has become increasingly important in the detection and delineation of breast cancer in daily practice. However, the clinical benefits of the use of pre-operative MRI in women with newly diagnosed breast cancer is still a matter of debate. The main additional diagnostic value of MRI relies on specific situations such as detecting multifocal, multicentric or contralateral disease unrecognized on conventional assessment (particularly in patients diagnosed with invasive lobular carcinoma), assessing the response to neoadjuvant chemotherapy, detection of cancer in dense breast tissue, recognition of an occult primary breast cancer in patients presenting with cancer metastasis in axillary lymph nodes, among others. Nevertheless, the development of new MRI technologies such as diffusion-weighted imaging, proton spectroscopy and higher field strength 7.0 T imaging offer a new perspective in providing additional information in breast abnormalities. We conducted an expert literature review on the value of breast MRI in diagnosing and staging breast cancer, as well as the future potentials of new MRI technologies.     

Sevoflurane pharmacokinetics: effect of cardiac output

Sevoflurane uptake (Vsevo) can be predicted by the square root of time model or the four-compartment model. However, Vsevo and the effect of cardiac output on anaesthetic uptake have not been quantified clinically. After obtaining IRB approval and informed consent, 34 adult patients received closed-circuit anaesthesia with sevoflurane for 1 h. The end-expired sevoflurane concentration was maintained at 2.6% by infusion of liquid sevoflurane into the breathing system. In a subgroup of 12 patients, cardiac output was measured every 5 min by thermodilution (CO group). The effect of patient characteristics (age, height, weight, body surface area) and cardiac output on Vsevo were determined, and Vsevo was compared with the theoretical models. In the CO group, measured cardiac output was used in the formulae of these models. A two-exponential curve described average Vsevo well: Vsevo (ml liquid) = 0 + 1.62 x (1 - e(-2.3)xt) + 18.1 x (1 - e(-0.0089xt), r2 > 0.999. There was no correlation between Vsevo and patient characteristics, except that Vsevo was greater in patients with a greater cardiac output (r2 = 0.36) and cardiac index (r2 = 0.35). The rate of sevoflurane uptake decreased less than predicted by the square root of time and four-compartment models, even when measured cardiac output was used in the formulae. These findings confirm that the square root of time and four-compartment models do not accurately predict anaesthetic uptake. In addition, uptake of sevoflurane cannot be predicted by patient characteristics but was higher in patients with a higher cardiac output.      

Long-term Survival After Resuscitation From Ventricular Fibrillation Occurring Before Hospital Admission

Factors related to long-term (post-discharge) outcome followingsuccessful resuscitation from pre-hospital ventricular fibrillationby a physician-manned mobile coronary care unit were studied.Between 1 January 1966 and 31 December 1987, 190 patients wereresuscitated from pre-hospital ventricular fibrillation (158male; mean age 56 years). The aetiology of ventricular fibrillationwas acute myocardial infarction in 131 patients (69 per cent),ischaemic heart disease without infarction in 48 (25 per cent)and other or unknown in 11 (6 per cent). Predicted actuarialsurvival rates at 1, 2, 5, 10 and 20 years were 76 per cent,66 per cent, 41 per cent, 27 per cent and 12 per cent respectively.Of 128 recorded deaths over 20 years, 85 per cent were cardiacand 48 per cent were defined as sudden death outside hospital.Factors significantly associated with increased long-term mortality(p<0.05), based on analysis of 10 year actuarial life tablesusing the Lee–Desu statistic were ventricular fibrillationdue to ischaemic heart disease without infarction rather thanacute myocardial infarction, a history of previous myocardialinfarction, a history of hypertension, digoxin and diuretictherapy before ventricular fibrillation and digoxin as dischargemedication, and failure to stop smoking after discharge fromhospital by patients who had been smoking prior to ventricularfibrillation. In addition, Cox's regression analysis showedthat patient age     

Thrombolytic Therapy Within One Hour of the Onset of Acute Myocardial Infarction

Between 1986 and 1988, 239 consecutive patients with acute myocardialinfarction received thrombolytic therapy up to 285 minutes afteronset of symptoms; in 39 (17 with anterior infarction, 21 inferior,one lateral infarction) recombinant tissue plasminogen activatoror anistreplase was administered a mean of 51 minutes (range20–60 minutes) after the onset of symptoms. The patencyrates (26 of 30; 87 per cent), rapid ST segment resolution (36of 38; 95 per cent) and QRS score of 3 (28 of 38; 74 per cent)were statistically significantly higher for those seen and treatedin the first hour in comparison with those seen and treatedlater. For those treated within the first hour mean peak creatine kinasewas 1264 U/I for those with TIMI grade 2 or 3 (partial or completeperfusion) compared with 3005 U/I for those with TIMI grade0 or 1 (no perfusion or penetration without perfusion) (p=0.02):mean peak creatine kinase-MB for those with TIMI grade 2 or3 perfusion was 115 U/I compared with 312 U/I for those withTIMI grade 0 or 1 (p=0.01). Four of the 39 patients developedventricular fibrillation following thrombolytic therapy, threewithin 24 hours of infarction and one following reinfarctionon day 15. There were no significant bleeding complications.One patient died. Thrombolytic therapy within 1 hour of the onset of symptomsled to a very high angiographic patency rate, rapid ST segmentresolution with preservation of left ventricular function. Thistherapy is without significant complications.     

Out-of-hospital Ventricular Fibrillation in Patients Under the Age of 40 Years and the Long-term Prognosis

SUMMARY Among patients with ventricular fibrillation outside hospitalseen by our mobile coronary care unit between 1967 and 1988,28 were aged less than 40 years (range 12–39, mean 28).Coronary artery disease was present in 11 (39 per cent) andwas the most common single cause, although none of these patientswas aged less than 28 years. Of 15 patients with cardiac disease,only four (27 per cent) had previously sought medical advice.Nineteen patients (68 per cent) collapsed without precedingsymptoms. Survival to reach hospital was significantly associatedwith bystander cardiopulmonary resuscitation and early defibrillation.Eleven patients (39 per cent) survived to hospital discharge,of whom seven remain alive after 2 to 21 years, five withoutsymptoms. Thus, as demonstrated for older patients, coronaryartery disease is an important cause of sudden death in thisage group, and bystander cardiopulmonary resuscitation and earlydefibrillation are important for survival. Most of these patientscollapse without warning and are not already known to have cardiacdisease.     

Holmium-166 radioembolization for the treatment of patients with liver metastases: design of the phase I HEPAR trial

Background

Intra-arterial radioembolization with yttrium-90 microspheres ( ⁹⁰Y-RE) is an increasingly used therapy for patients with unresectable liver malignancies. Over the last decade, radioactive holmium-166 poly(L-lactic acid) microspheres ( ¹⁶⁶Ho-PLLA-MS) have been developed as a possible alternative to ⁹⁰Y-RE. Next to high-energy beta-radiation, ¹⁶⁶Ho also emits gamma-radiation, which allows for imaging by gamma scintigraphy. In addition, Ho is a highly paramagnetic element and can therefore be visualized by MRI. These imaging modalities are useful for assessment of the biodistribution, and allow dosimetry through quantitative analysis of the scintigraphic and MR images. Previous studies have demonstrated the safety of ¹⁶⁶Ho-PLLA-MS radioembolization ( ¹⁶⁶Ho-RE) in animals. The aim of this phase I trial is to assess the safety and toxicity profile of ¹⁶⁶Ho-RE in patients with liver metastases.

Methods

The HEPAR study (Holmium Embolization Particles for Arterial Radiotherapy) is a non-randomized, open label, safety study. We aim to include 15 to 24 patients with liver metastases of any origin, who have chemotherapy-refractory disease and who are not amenable to surgical resection. Prior to treatment, in addition to the standard technetium-99m labelled macroaggregated albumin ( ^99mTc-MAA) dose, a low radioactive safety dose of 60-mg ¹⁶⁶Ho-PLLA-MS will be administered. Patients are treated in 4 cohorts of 3-6 patients, according to a standard dose escalation protocol (20 Gy, 40 Gy, 60 Gy, and 80 Gy, respectively). The primary objective will be to establish the maximum tolerated radiation dose of ¹⁶⁶Ho-PLLA-MS. Secondary objectives are to assess tumour response, biodistribution, performance status, quality of life, and to compare the ¹⁶⁶Ho-PLLA-MS safety dose and the ^99mTc-MAA dose distributions with respect to the ability to accurately predict microsphere distribution.

Discussion

This will be the first clinical study on ¹⁶⁶Ho-RE. Based on preclinical studies, it is expected that ¹⁶⁶Ho-RE has a safety and toxicity profile comparable to that of ⁹⁰Y-RE. The biochemical and radionuclide characteristics of ¹⁶⁶Ho-PLLA-MS that enable accurate dosimetry calculations and biodistribution assessment may however improve the overall safety of the procedure.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01031784","term_id":"NCT01031784"}}NCT01031784