NAT2 phenotype alters pharmacokinetics of rivaroxaban in healthy volunteers

Rivaroxaban is a direct inhibitor of factor Xa, a member of direct oral anticoagulant group of drugs (DOACs). Despite being a widely extended alternative to vitamin K antagonists (i.e., acenocoumarol, warfarin) the interindividual variability of DOACs is significant, and may be related to adverse drug reaction occurrence or drug inefficacy, namely hemorrhagic or thromboembolic events. Since there is not a consistent analytic practice to monitor the anticoagulant activity of DOACs, previously reported polymorphisms in genes coding for proteins responsible for the activation, transport, or metabolism of DOACs were studied. The study population comprised 60 healthy volunteers, who completed two randomized, crossover bioequivalence clinical trials between two different rivaroxaban formulations. The effect of food, sex, biogeographical origin and 55 variants (8 phenotypes and 47 single nucleotide polymorphisms) in drug metabolizing enzyme genes (such as CYP2D6, CYP2C9, NAT2) and transporters (namely, ABCB1, ABCG2) on rivaroxaban pharmacokinetics was tested. Individuals dosed under fasting conditions presented lower tmax (2.21 h vs 2.88 h, β = 1.19, R2 =0.342, p = 0.012) compared to fed volunteers. NAT2 slow acetylators presented higher AUC∞ corrected by dose/weight (AUC∞/DW; 8243.90 vs 7698.20 and 7161.25 h*ng*mg /ml*kg, β = 0.154, R2 =0.250, p = 0.044), higher Cmax/DW (1070.99 vs 834.81 and 803.36 ng*mg /ml*kg, β = 0.245, R2 =0.320, p = 0.002), and lower tmax (2.63 vs 3.19 and 4.15 h, β = -0.346, R2 =0.282, p = 0.047) than NAT2 rapid and intermediate acetylators. No other association was statistically significant. Thus, slow NAT2 appear to have altered rivaroxaban pharmacokinetics, increasing AUC∞ and Cmax. Nonetheless, further research should be conducted to verify NAT2 involvement on rivaroxaban pharmacokinetics and to determine its clinical significance.

Genetic Variation in CYP2D6 and SLC22A1 Affects Amlodipine Pharmacokinetics and Safety

Amlodipine is an antihypertensive drug with unknown pharmacogenetic biomarkers. This research is a candidate gene study that looked for associations between amlodipine pharmacokinetics and safety and pharmacogenes. Pharmacokinetic and safety data were taken from 160 volunteers from eight bioequivalence trials. In the exploratory step, 70 volunteers were genotyped for 44 polymorphisms in different pharmacogenes. CYP2D6 poor metabolizers (PMs) showed higher half-life (t1/2) (univariate p-value (puv) = 0.039, multivariate p-value (pmv) = 0.013, β = -5.31, R2 = 0.176) compared to ultrarapid (UMs), normal (NMs) and intermediate metabolizers (IMs). SLC22A1 rs34059508 G/A genotype was associated with higher dose/weight-corrected area under the curve (AUC72/DW) (puv = 0.025; pmv = 0.026, β = 578.90, R2 = 0.060) compared to the G/G genotype. In the confirmatory step, the cohort was increased to 160 volunteers, who were genotyped for CYP2D6, SLC22A1 and CYP3A4. In addition to the previous associations, CYP2D6 UMs showed a lower AUC72/DW (puv = 0.046, pmv = 0.049, β = -68.80, R2 = 0.073) compared to NMs, IMs and PMs and the SLC22A1 rs34059508 G/A genotype was associated with thoracic pain (puv = 0.038) and dizziness (puv = 0.038, pmv = 0.014, log OR = 10.975). To our knowledge, this is the first work to report a strong relationship between amlodipine and CYP2D6 and SLC22A1. Further research is needed to gather more evidence before its application in clinical practice.

Association between CYP2C19 and CYP2B6 phenotypes and the pharmacokinetics and safety of diazepam

Diazepam is a benzodiazepine (BZD) used worldwide for a variety of conditions. Long-term use of diazepam increases the risk for developing tolerance and dependence and for the occurrence of adverse drug reactions (ADRs). CYP3A4 and CYP2C19 mainly metabolize diazepam and are therefore the primary pharmacogenetic candidate biomarkers. In this work, we aimed to explore the impact of CYP3A4 and CYP2C19 phenotypes and of 99 additional variants in other 31 pharmacogenes (including other CYP, UGT, NAT2 and CES enzymes, ABC and SLC transporters) on diazepam pharmacokinetic variability and safety. 30 healthy volunteers that had participated in a single-dose bioequivalence clinical trial of two diazepam formulations were enrolled in the present candidate gene pharmacogenetic study. CYP2C19 poor metabolizers (PMs) showed an almost 2-fold increase in AUC_0-∞/DW compared to rapid (RMs) or normal (NM) metabolizers, and a 1.46-fold increase compared to intermediate metabolizers (IMs). CYP2B6 PMs showed a 2,74-fold higher AUC_0-∞/DW compared to RMs, and 2.10-fold compared to NMs (p < 0.007). A dose reduction of 25-50 % may be appropriate for CYP2C19 or CYP2B6 PMs to avoid ADRs, dependence and tolerance. Combined CYP2C19 +CYP2B6 PMs may not use diazepam or sharper dose adjustments (e.g., a dose reduction of 50-70 %) may be advisable. To our knowledge, this is the first work to report a strong relationship between CYP2B6 phenotype and diazepam pharmacokinetics. Additional nominal associations (i.e., 0.007 <p < 0.05) between ABCG2, ABCB1, NAT2 and UGT1A4 polymorphisms and pharmacokinetic variability were observed; further research should elaborate on the clinical relevance of the described associations.

The Connection Between Stress and Immune Status in Pigs: A First Salivary Analytical Panel for Disease Differentiation

This paper analyzes the association between stress and immune response activations in different diseases, based on the salivary analytics. Moreover, a first attempt to discriminate between diseases was performed by principal component analysis. The salivary analytics consisted of the measurement of psychosocial stress (cortisol and salivary alpha-amylase) indicators, innate (acute phase proteins: C-reactive protein and haptoglobin), and adaptive immune (adenosine deaminase, Cu and Zn) markers and oxidative stress parameters (antioxidant capacity and oxidative status). A total of 107 commercial growing pigs in the field were divided into six groups according to the signs of disease after proper veterinary clinical examination, especially, healthy pigs, pigs with rectal prolapse, tail-biting lesions, diarrhea, lameness, or dyspnea. Associations between stress and immune markers were observed with different intensities. High associations (r = 0.61) were observed between oxidative stress markers and adaptive immune markers. On the other hand, moderate associations (r = 0.31–0.48) between psychosocial stress markers with both innate and adaptive immune markers were observed. All pathological conditions showed statistically significant differences in at least 4 out of the 11 salivary markers studied, with no individual marker dysregulated in all the diseases. Moreover, each disease condition showed differences in the degree of activation of the analyzed systems which could be used to create different salivary profiles. A total of two dimensions were selected through the principal component analysis to explain the 48.3% of the variance of our data. Lameness and rectal prolapse were the two pathological conditions most distant from the healthy condition followed by dyspnea. Tail-biting lesions and diarrhea were also far from the other diseases but near to healthy animals. There is still room for improvements, but these preliminary results displayed a great potential for disease detection and characterization using salivary biomarkers profiling in the near future.

[Lisfranc lesions: clinical-functional repercussion]

OBJECTIVE

Clinical and functional evaluation of patients with Lisfranc lesion without work or sport cause and treated in our center.

MATERIAL AND METHODS

Thirteen patients with Lisfranc lesion without occupational or sports causes were divided into two groups, high-energy and low-energy injuries. Were analyzed the return to work and sports activity prior to the injury and the use of footwear and insoles after the injury. Also were assessed AOFAS and EVA postoperative score and posterior complications after lesion recovery.

RESULTS

High-energy group included 7 patients who underwent surgery on an average of 7.3 days. Of the total of patients, 4 presented post-surgical sequelae. Of these patients, one patient was unable to return to their previous work activity and two patients were unable to practice the usual sports activity. The AOFAS was 79.4 and EVA 2.8. In the low energy group, we found six patients operated on 5.6 days on average. All of them were able to return to their previous work and sports activity. The AOFAS were 84.8 and the EVA 1.6. Statistically significant differences were not observed in any of the variables studied.

CONCLUSION

Patients with Lisfranc injury out of laboral or sports background present good clinical and functional results.

How to interpret elevated plasmatic level of high-sensitive troponin T in newborns and infants?

Research and clinical implications on novel cardiac biomarkers has intensified significantly in the past few years. The high-sensitive troponin T (hscTnT) assay plays a dominant role in diagnostic algorithm regarding myocardial injury in adults. Despite generally accepted use of hscTnT there are no data about physiological concentrations and cut-off limits in neonates and infants to date. The aim of this study is to assess hscTnT levels in healthy newborns and infants. Consecutively 454 healthy full termed newborns and 40 healthy infants were enrolled in the study. Samples of cord or venous blood were drawn and tested for hscTnT concentrations with high-sensitive TnT assay (Roche Cobas e602 immunochemical analyzer). The 97.5 percentile of hscTnT concentration was assessed and correlation analysis was performed in neonates. Two hundred and thirteen samples (47 %) were excluded due to blood hemolysis of various degrees in neonates. Finally, the group of 241 healthy newborns was statistically analyzed. The median concentration of hscTnT was 38.2 ng/ml, 97.5 percentile reached 83.0 ng/l (confidential interval 74.1 to 106.9 ng/l). HscTnT concentrations were statistically decreased in hemolytic samples when compared to non-hemolytic samples (34.3 ng/l [26.7 to 42.0 ng/l] and 37.1 ng/l [30.5 to 47.9 ng/l], respectively, p=0.003). Elevated plasma concentrations of hscTnT decreased to adult level within six months. This study has confirmed the higher reference levels of hscTnT in neonates and young infants when compared with adult population. Many extracardiac factors as hemolysis and age may affect the hscTnT level. Based on presented results, a careful clinical interpretation of hscTnT is recommended.

[Arterial hypertension and stenosis of the accessory renal artery]

We present the case of a 45 year old patient with severe hypertension refractory to medical treatment who was diagnosed a significant stenosis of an accessory renal artery whilst the main renal arteries were normal. The arterial dilatation through angioplasty of the accessory artery improved dramatically the control of his hypertension.

Prevalence of HFE C282Y and H63D in Jewish populations and clinical implications of H63D homozygosity

The frequencies of C282Y and H63D mutations of the HFE gene vary between different populations. A previous study showed an unexpectedly high H63D frequency in Chuetas (a population of Jewish descent). The present study addressed the question of the distribution of these mutations in Jewish populations from different origins and studied the possible causes of the high H63D frequency in Chuetas. Moreover, to improve the understanding of the controversial relationship between H63D homozygosity and iron overload, a group of patients with altered iron metabolism were studied. The high frequency of H63D mutation in Chuetas is not due to a high prevalence of this mutation in Sephardic Jews. Jewish populations have low C282Y and moderate H63D frequencies, suggesting slight gene flow from their surrounding populations. In accordance with historical and demographic data, genetic drift is the most probable cause for the singular H63D frequency in Chuetas. Clinically, this study of H63D homozygotes supports the conclusion that this genotype must be taken into account, because it confers an increased risk of iron overload and therefore genetic susceptibility to developing hereditary hemochromatosis or to aggravating other diseases.

Haemodynamic Strategy for Treatment of Diastolic Anterograde Giacomini Varicose Veins

OBJECTIVES

To assess the diagnosis and outcome of a haemodynamic strategy for the treatment of primary varicose veins associated with anterograde diastolic flow (ADF) in the Giacomini vein (GV).

METHODS

ADF in the GV, with the escape point located at the saphenopopliteal junction, was demonstrated in 15 patients (15 limbs) by duplex ultrasound. No other escape points were seen in this group. ADF was defined as the flow present in the relaxing phase after isometric contraction of the lower limb, measured in the standing position. Duplex and clinical follow-up was performed prospectively at 1 week, at 1, 3, 6, and 12 months and once per year thereafter, between 1998 and 2001. Surgery consisted of flush division of the GV from the small saphenous vein (SSV) and division of the incompetent collateral veins from the GV.

RESULTS

GV diameter showed an average reduction from 6 to 4 mm 33 months after surgery. Fourteen patients (93%) showed no symptoms or varicose veins. GV reconnection and recurrent ADF was demonstrated in two patients (13%).

CONCLUSIONS

ADF is a rare condition associated with primary varicose veins. ADF occurs when there is a closed venovenous shunt with recirculation in the muscular diastole. This implies that, although a part of the circuit is ascendant, the re-entry point must be located downstream to the escape point. Accurate duplex assessment is required to distinguish this atypical haemodynamic condition from an abnormal systolic circuit bypassing a deep vein obstruction. Interruption of the GV above its junction with the SSV abolished ADF with an acceptable rate of recurrences.

[Sterile maggots as adjuvant procedure for local treatment in a patient with proximal calciphylaxis]

Proximal calciphylaxis with skin ulcerations has a very poor survival and infection is the main cause of the high mortality rate. We present the case of a diabetic obese hemodialysis woman diagnosed of severe calciphylaxis with extensive ulcers in the abdomen and left thigh. After a first ineffective debridement attempt, systemic medical treatment was associated with daily wet cures with enzymatic ointments and maggot therapy resulting in spectacular granulation and healing of these ulcers. We want to underline the great properties of sterile maggots to selectively dissolve necrotic tissue, to disinfect the wound and to stimulate healing. Thus, sterile-maggot debridement may constitute a very good adjuvant treatment even in proximal ulcers of calciphylaxis, preventing systemic infection.

[Acute bilateral visual loss in a hemodialysed patient]

We report the case of a regular hemodialysis patient that presented with bilateral visual lost without other concomitant symptoms, that was consquence of an acute ischemic optic neuropathy. We describe the characteristics of this uncommon pathology and rewiew the relation to optic neuropathy and chronic renal failure.

Durability of reflux-elimination by a minimal invasive CHIVA procedure on patients with varicose veins. A 3-year prospective case study

OBJECTIVES

to assess the outcome of a conservative and haemodynamic method for insufficient veins on an ambulatory basis (French acronym, "CHIVA") with preservation of the greater saphenous vein (GSV) for treatment of primary varicose veins.

METHODS

duplex incompetence of the sapheno-femoral junction (SFJ) and the GSV trunk, with the re-entry perforating point located on a GSV tributary was demonstrated in 58 patients with varices (58 limbs). The re-entry point was defined as the perforator, whose compression of the superficial vein above its opening eliminates reflux in the GSV. Duplex scanning was performed preoperatively and at 7 days, and patients were followed prospectively at 1, 3, 6, 12, 24, and 36 months after CHIVA. Operation consisted in flush ligation and division from the GSV of the tributary containing the re-entry perforating vein (no additional high ligation is included). If reflux returned, SFJ interruption was performed in a second surgical procedure.

RESULTS

the GSV diameter showed an average reduction from 6.6 to 3.9 mm 36 months after surgery. Reflux in the GSV system was demonstrated in all but five (8%) patients. Of the 53 patients with recurrent reflux, 46 underwent SFJ interruption.

CONCLUSIONS

elimination of reflux in the GSV after the interruption of insufficient collaterals is only temporary.

Low recurrence of syncope in patients with inducible sustained ventricular tachyarrhythmias treated with an implantable cardioverter-defibrillator

AIMS

To determine the effectiveness of the implantable cardioverter defibrillator (ICD) in preventing recurrence of syncope in patients with structural heart disease, previously unexplained syncope and inducible ventricular arrhythmias.

METHODS

Thirty-eight patients with syncope, structural heart disease and inducible arrhythmias had an ICD implanted. All ICDs delivered antitachycardia pacing and shocks of adjusted energy. Detection and therapy were programmed according to uniform criteria.

RESULTS

The mean age of the patients was 63+/-11 years and most of them were male (36/38). After a mean follow-up of 28+/-15 (4-61) months, six patients died and one underwent heart transplantation. Syncope recurred in three patients, but in none of them was it caused by an arrhythmic event. In 18 patients, 113 episodes of ventricular tachycardia/ventricular fibrillation were detected and appropriately treated by the ICD. The mean time from implant until first appropriate therapy was 18+/-14 months. The actuarial probability of receiving appropriate therapy was 20% and 42% at 12 and 24 months, respectively.

CONCLUSIONS

In patients with unexplained syncope, structural heart disease and inducible arrhythmias, ICD prevents syncope associated with arrhythmic events. Frequent effective use of antitachycardia pacing and shocks of adjusted energy seem essential to this aim.

Factors increasing the mortality rate for patients with ruptured abdominal aortic aneurysms

The objective of this report was to analyze the current surgical results of operative treatment in patients suffering ruptured AAA (abdominal aortic aneurysms) and to define those independent predictive factors for mortality. During a period of 2 years, from January 1996 to December 1997, 144 patients operated on for ruptured AAA in 10 hospitals were included in a multicenter retrospective study. Among the collected variables concerning each patient, those with potential relation to surgical mortality were studied: gender, age, diabetes, hypertension, cardiopathy, pulmonary obstructive disease, preoperative renal dysfunction, symptomatic cerebrovascular disease, peripheral vascular disease, hematocrit on admission, preoperative hypotension < 80 mmHg, loss of consciousness, cardiac arrest, aortic aneurysm location (infrarenal versus non-infrarenal), iliac involvement, aneurysm size, type of rupture, left renal vein ligature, ligature of a patent inferior mesenteric artery, place of aortic cross-clamping, type of grafting, exclusion of both hypogastric arteries, venous technical complications, associated surgery, use of cell saver, intraoperative blood loss, and postoperative complications (renal failure, sepsis, coagulopathy, cardiac complications, pulmonary complications, colon ischemia, prosthetic graft complications, and need for reoperation). Those variables with statistical significance in the univariate analysis were introduced into a multivariate logistic regression model to determine the independent predictors of death. From our results we concluded that surgery for ruptured abdominal aortic aneurysms continues to have an excessively high mortality rate. Even though some preoperative variables could be identified as predictors of mortality, an absolute mortality risk has not yet been determined and the decision to negate surgery should be individualized rather than taken on that basis only. Early diagnosis and treatment of symptomatic aneurysms would improve mortality figures and selective screening should be contemplated.

Comparison of clinical outcome of stripping and CHIVA for treatment of varicose veins in the lower extremities

The purpose of this nonrandomized case-review study was to compare the outcome of stripping and CHIVA for treatment of varicose veins in the lower extremities in our department. Outcome was evaluated by independent physicians. A total of 85 patients underwent saphenous vein stripping in association with phlebectomy and 90 patients underwent CHIVA cure. The duration of follow-up was 3 years. Study criteria were (1) presence of varicose veins as a cause of failure (1.1% in the CHIVA group vs. 15.3% in the stripping group), (2) appearance of telangiectasia (8.9% in the CHIVA group vs. 65.9% in the stripping group), (3) patient dissatisfaction rate (3.3% in the CHIVA group vs. 16.5% in the stripping group), (4) postoperative symptoms as a cause of failure (1.1% in the CHIVA group vs. 21.2% in the stripping group), and (5) saphenous nerve injury (1 patient in the CHIVA group vs. 16 in the stripping group). Differences between all five criteria were significantly in favor of the CHIVA group as compared to saphenous vein stripping with phlebectomy. Clinical results at 3 years are better for patients treated with CHIVA than stripping with regard to presence of varicose veins, clinical symptoms, presence of telangiectasia, cosmetic satisfaction, and neurologic complications. Data in our series of CHIVA treatments are comparable to those reported in the literature and better than those described in three series of stripping procedures with 3-year follow-up. A prospective randomized study is now underway to confirm these findings.

[Mobile carotid plaque]

INTRODUCTION

In the literature only seven cases have been published describing a mobile carotid plaque, and lack of precise description makes it difficult to differentiate these lesions from mobile thrombotic lesions. The natural history of these lesions is not known and their treatment is controversial, although there is a tendency to choose the type of treatment to be given according to the embologenic potential of the lesion.

CLINICAL CASES

We report two cases with mobile carotid plaques. In both cases diagnosis was made on ultrasound Doppler. The first patient had neurological symptoms and a mobile plaque associated with stenosis of over 70%. Surgical treatment was indicated. The second patient had no neurological symptoms. On ultrasound Doppler studies there was a fragment of mobile plaque in the common carotid artery, in the region of the carotid sinus with stenosis of 30 50%. Distal to this zone, in the bulb of the internal carotid artery there was stenosis of >70%. In this case medical treatment was given in view of deterioration in the patient s general state. Both patients improved.

CONCLUSIONS

Including our second case, three patients with mobile carotid plaques (neurologically asymptomatic) have now been reported to have made good progress with medical treatment. Until there is more data regarding the natural history of these lesions, they should not be considered to be in themselves sufficient reason for carrying out carotid endarterectomy. The possibility of indicating surgical treatment depends on the degree of carotid stenosis.

[Indications for carotid endarterectomy without arteriography. A validation study using eco-Doppler]

INTRODUCTION

The possibility of diagnosing carotid stenosis and carrying out surgery without arteriography has increased with the use of different diagnostic methods. The eco-Doppler has been shown to be a useful method, although it requires previous individualised validation.

OBJECTIVE

We aim to validate our Vascular Diagnostic Laboratory in the diagnosis of stenosis of the carotid bifurcation using eco-Doppler as compared with angiography, and the therapeutic indication thus obtained.

PATIENTS AND METHODS

We made a prospective study for one year of 62 consecutive patients diagnosed on eco-Doppler as having carotid stenosis of over 70% and subsequent carotid arteriography. The treatment indicated is given, without waiting for the result of the angiography, on clinical evaluation, computerized tomography or cranial magnetic resonance and eco-Doppler, and subsequently on angiography. The degree of correlation of both methods, both for the therapeutic indication and for the degree of stenosis was determined.

RESULTS

In five cases there was discrepancy and the therapeutic indication was different. Three of these were related to the diagnosis of carotid occlusion and in the other two cases there were bilateral lesions of over 50% on eco-Doppler, which were classified as minor on angiographic study. In the group with stenosis of over 70% with < 50% contralateral stenosis, eco-Doppler showed sensitivity and specificity of 100%, with a kappa correlation index = 1.

CONCLUSION

It is possible to indicate carotid endarterectomy in patients with unilateral stenosis greater than 70% and contralateral stenosis < 50%, based on the eco-Doppler studies done in our Vascular Diagnostic Laboratory.

Radiofrequency ablation of a posteroseptal atrioventricular accessory pathway in a left-sided tricuspid ring with Ebsteinlike anomaly in a patient with congenitally corrected transposition of the great arteries

Radiofrequency ablation successfully eliminated a posteroseptal accessory pathway in a left-sided tricuspid ring with Ebsteinlike anomaly in a patient with a congenitally corrected transposition of the great arteries.

[Arrhythmia recurrence in patients with an old myocardial infarct treated by implantable defibrillator: an analysis according to the initial clinical presentation]

INTRODUCTION AND OBJECTIVES

The importance of the clinical presentation in the frequency and type of recurrences of ventricular arrhythmias in patients that received an automatic implantable defibrillator is not well known. The purpose of this study was to analyze the frequency and type of recurrences in patients with an old myocardial infarction that received an automatic implantable defibrillator with electrogram recording.

METHODS AND RESULTS

We analyzed 100 patients classified in 3 groups according to their clinical presentation: Sustained Monomorphic Ventricular Tachycardia (VT Group n = 65), Cardiac Arrest (CA Group = 19), and Syncope (Syncope Group n = 16). There were no significant differences in the clinical variables among the different groups, nor in the inducibility of arrhythmia at the electrophysiologic study. In a follow-up 27 +/- 14 months, 54% of patients presented at last one episode of sustained ventricular arrhythmia. All recurrences except one were as sustained monomorphic ventricular tachycardia (776 episodes). 81% of episodes of sustained monomorphic ventricular tachycardia (630) were treated with antitachycardia pacing with an effectiveness of 89%. There were no differences in the probability of arrhythmic recurrence among groups but death probability was higher in the ventricular fibrillation group at 36 follow-up months (38% vs 7% and 12% in the sustained monomorphic ventricular tachycardia and syncope groups respectively, p = 0.0113).

CONCLUSIONS

In the patients with an old myocardial infarction and malignant ventricular arrhythmias, most of recurrences are due to sustained monomorphic ventricular tachycardia independently of the clinical presentation. The antitachycardia pacing is not only effective in patients with documented sustained monomorphic ventricular tachycardia but also in those that are presented as cardiac arrest or syncope.

[Analysis of local electrograms and characteristics of the ablation procedure in left-sided accessory pathways that required five or more pulses of radiofrequency]

INTRODUCTION AND OBJECTIVES

Radiofrequency ablation of left sided accessory pathways requires multiple pulses in some patients due to different factors such as inadequate mapping, inappropriate tissue electrode contact and particular anatomic factors. However these characteristics have not been specifically analyzed.

METHODS

We have studied a prospective ablative series of 65 consecutive patients with left-sided pathways submitted to radiofrequency ablation by a simplified technique. In every application point, we analyzed the electrogram features, application point, impedance, potency and temperature.

RESULTS

52 patients (80%) required less than 5 radiofrequency pulses (group A) and 13 (20%) required > or = than 5 pulses (group B). The presence of a suggestive potential accessory pathway in local electrogram was similar in both groups and there were no differences in the local A-V or V-A intervals. However, in patients with pre-excitation the Delta-V interval was shorter in group A than in group B (8 ms vs 15 ms; p < 0.001). Furthermore, the impedance observed from the ablation point in group A was lower (108 +/- 12 vs 121 +/- 22 ohms; p < 0.001), and the maximum watts required to reach the predetermined temperature was higher in group A (42 +/- 16 vs 31 +/- 18 watts; p < 0.001). Final success of the procedure was 100%.

CONCLUSIONS

Patients requiring more than 5 radiofrequency pulses had electrograms and tissue contact equal or better than those requiring less than 5 pulses. This suggests that difficulties encountered in some procedures can be due to anatomical factors rather than inaccurate mapping or insufficient tissue contact.

Arrhythmia recurrence in patients with a healed myocardial infarction who received an implantable defibrillator: analysis according to the clinical presentation

OBJECTIVES

The purpose of this study was to analyze the type of arrhythmia recurrence, based on stored electrograms, in patients with a healed myocardial infarction (MI) who received an implantable defibrillator.

BACKGROUND

Previous studies suggest that patients presenting with cardiac arrest (CA) tend to recur as ventricular fibrillation (VF), whereas those suffering sustained monomorphic ventricular tachycardia (SMVT) tend to recur as SMVT. However, these data have not been confirmed in a homogeneous population of patients with MI.

METHODS

A total of 88 patients was divided into three groups according to their clinical presentation: SMVT (n = 57), CA (n = 16) or syncope (n = 15).

RESULTS

There were no significant differences in clinical characteristics among groups. In the electrophysiologic study SMVT was induced in 93%, 94% and 80% of patients, respectively (p = NS). During the follow-up period, 52% of patients presented a total of 671 episodes of ventricular arrhythmia treated by the defibrillator. All recurrences were as SMVT except for one VF. There were 610 episodes of SMVT treated with antitachycardia pacing, with an effectiveness of 96%. A total of 61 episodes was treated initially with cardioversion. No differences in the probability of recurrence were observed among groups, although the statistical power was low (50%).

CONCLUSIONS

In patients with an old infarction and malignant ventricular arrhythmias, the majority of recurrences are due to SMVT independently of the clinical presentation (SMVT, CA or syncope) or the induced arrhythmia at the electrophysiologic study. The programming of an antitachycardia zone seems to be appropriate also for patients who present with CA or syncope.

[Patients with structural heart disease, syncope of unknown etiology and inducible ventricular arrhythmias treated with implantable defibrillators]

OBJECTIVES

This study evaluates the hypothesis that in patients with syncope of unknown origin and heart anomalies, inducible ventricular arrhythmias are specific arrhythmias and therefore should be treated as such.

BACKGROUND

Although syncope is a frequent clinical entity, the evaluation and treatment of patients with syncope without a clear etiology still remains undefined. Many patients with syncope of undetermined origin undergo invasive electrophysiologic evaluation. Abnormalities of the sinus node, prolongation of conduction times or inducible arrhythmias found during these evaluations are usually assumed to be the cause of syncope, and are consequently treated. However, whether tachyarrhythmias are truly the cause of syncope, and whether treatment of these tachyarrhythmias can prevent recurrent syncope and arrhythmic death, is unknown.

PATIENTS AND METHODS

An electrophysiological study was performed on 160 patients with structural heart disease and syncope of unknown origin. In 23 out of the 160 patients (16%), programmed electrical stimulation induced sustained ventricular arrhythmias. In 18 out of the 23 patients an automatic defibrillator was implanted and they form the study group.

RESULTS

In these 18 patients, programmed ventricular stimulation induced sustained monomorphic ventricular tachycardia in 12, sustained polymorphic ventricular tachycardia in 2 and ventricular fibrillation in 4. During a mean follow-up of 14 months, 9 patients received 81 appropriate therapies from the device (53 because of ventricular tachycardia and 23 because of ventricular fibrillation). The probability of appropriate therapy was 100% at 1 year follow-up. There were no episodes of sudden death and 1 patient died of congestive heart failure.

CONCLUSIONS

In patients with syncope of undetermined origin, heart disease and inducible ventricular tachyarrhythmias treated with a implantable cardioverter defibrillator, there is a high incidence of appropriate therapies. Our results support the practice of using implantable cardioverter defibrillators in patients with syncope of unknown origin, heart disease and inducible ventricular arrhythmias.

[Radiofrequency ablation of multiple atrioventricular accessory pathways in a patient with syncope, atrial fibrillation and fasciculoventricular fibers]

Multiple accessory pathways in patients with the Wolff-Parkinson-White syndrome are infrequent and are associated with a higher risk of ventricular fibrillation. We present an exceptional case of a patient with four accessory pathways with anterograde conduction and a fasciculo-ventricular fiber in whom we performed a radiofrequency ablation. A 20 year old healthy male patient was seen at the emergency room after suffering syncope. The electrocardiogram showed atrial fibrillation with wide QRS complex suggestive of preexcitation. The electrophysiologic study demonstrated the presence of four atrio-ventricular accessory pathways with antegrade conduction (left lateral, right posteroseptal, right midseptal and right posterolateral). After ablation of the fourth accessory pathway, the electrocardiogram showed a persistent delta wave with a short HV interval. Atrial stimulation demonstrated decremental conduction, progressive lengthening of the AH interval and no modification in the HV interval nor in the preexcitation pattern, suggestive of the presence of a fasciculo-ventricular fiber. This exceptional case report is demonstrative of the complexity of the Wolff-Parkinson-White syndrome, and the feasibility and efficacy of radiofrequency catheter ablation in a single procedure.

[Long-term follow up of patients with nodal reentry tachycardia who had undergone radiofrequency ablation]

INTRODUCTION

The aim of this study was to assess the long term results (minimum of 3 years) of radiofrequency catheter ablation in patients with common (slow-fast) atrioventricular nodal reentrant tachycardia.

PATIENTS AND METHODS

Sixty consecutive patients (mean age 56 +/- 16 years, range 14 to 83, 16 men and 44 women) underwent slow pathway (n = 51, Group A) or fast pathway (n = 9, Group B) radiofrequency catheter ablation between January 1992 and March 1994. All patients were followed at 1, 3, 6 and 12 months after ablation with serial examinations and electrocardiograms and the last follow-up was made on April 1997.

RESULTS

During a mean follow-up period of 48 +/- 7 months (range 38 to 63) all evaluated patients remained asymptomatic. Eight recurrences were observed at a mean of 1 +/- 2 months (range, 0.5 to 7) after a successful ablation procedure. A second procedure was effective in eliminating the dual atrioventricular nodal pathway in each of them. In Group A patients, the pre-ablation PR interval, at 12 months after ablation and at last follow-up were 122 +/- 11, 124 +/- 13 and 124 +/- 15 ms, respectively. In Group B patients, the pre-ablation PR interval, at 12 months after ablation and at last follow-up were 130 +/- 24, 200 +/- 12, 200 +/- 24 ms, respectively. No significant atrioventricular conduction disturbances in any patient were observed. One patient developed a new onset left bundle branch block and 4 patients died of noncardiac causes.

CONCLUSIONS

In patients with atrioventricular nodal reentrant tachycardia, radiofrequency catheter ablation is a safe and effective therapy, with substantial good results that persist during long term follow-up, with a low recurrence rate and without complications during short and long term outcome.

[Hemodynamic deterioration in patients submitted to ablation of the atrioventricular node]

INTRODUCTION

Radiofrequency ablation of the atrioventricular conduction system has become an established therapy for patients with drug-refractory atrial fibrillation. We observed 14 patients with hemodynamic deterioration related to worsening of mitral regurgitation after the procedure.

PATIENTS AND METHODS

We retrospectively evaluated 256 consecutive patients with drug-refractory atrial fibrillation referred for radiofrequency ablation of the AV node and implantation of a pacemaker. Because we found hemodynamic deterioration related to worsening mitral regurgitation, we compared the clinical history, electrophysiologic and echocardiographic data from the patients with hemodynamic deterioration and worsening mitral regurgitation (group A) with those without hemodynamic deterioration (group B).

RESULTS

Fourteen out of 256 patients (group A) undergoing ablation of the atrioventricular conduction system deteriorated with acute pulmonary edema (3 patients) or congestive heart failure (11 patients) at a mean of 6 weeks after the ablation procedure. Four of these patients were referred for mitral valve surgery. The length of the procedure and the number of applications during ablation were similar in both groups. Compared with group B patients, group A patients had significantly higher left ventricular end-diastolic diameters (64 +/- 6 mm vs 56 +/- 9 mm; p < 0.05) at baseline despite similar left ventricular end-systolic diameters, fractional shortening and grade of mitral regurgitation (1.15 +/- 1.05 vs 1.11 +/- 0.97). Moreover, whereas no change was observed in left ventricular end-diastolic diameter, left ventricular end-systolic diameter, fractional shortening and grade of mitral regurgitation in group B patients after ablation, group A patients experienced a significant increase in left ventricular end-diastolic diameter (64 +/- 6 mm vs 72 +/- 9 mm; p < 0.01) and grade of mitral regurgitation (1.15 +/- 1.05 vs 2.90 +/- 1.15; p < 0.01). In patients operated on no ablation related structural damage to the mitral valve apparatus could be detected. The worsening of the mitral regurgitation was related to dilation of the mitral valve annulus.

CONCLUSIONS

Hemodynamic deterioration together with progression of mitral regurgitation is a potential complication of ablation of the atrioventricular conduction system.

Radiofrequency ablation of anteroseptal, para-Hisian, and mid-septal accessory pathways using a simplified femoral approach

Feasibility of RF ablation using a simplified two-catheter technique from a femoral approach was studied in 97 consecutive patients with a manifest or concealed accessory pathway located at the anteroseptal, mid-septal, and para-Hisian areas. RF was applied at the site with the shortest V-delta interval or the earliest retrograde atrial activation during orthodromic tachycardia or right ventricular pacing. Ablation was initially successful in 88 of 97 patients (91%). Success rate was 94% (16/17) for anteroseptal, 94% (39/43) for para-Hisian, and 89% (33/37) for mid-septal accessory pathways, without differences between manifest and concealed pathways for any of the locations. Mean number of RF pulses was 8 +/- 5 for anteroseptal, 6 +/- 6 for mid-septal, and 12 +/- 13 for para-Hisian accessory pathways. Two patients (2%) required implantation of a permanent pacemaker for complete AV block. At a mean follow-up of 27 +/- 14 months, four patients with previous manifest preexcitation experienced resumption of intermittent preexcitation, but only one required a second successful procedure for recurrence of palpitations. RF ablation can be used effectively and without impairment of normal AV conduction in the majority of patients with anteroseptal, para-Hisian, and mid-septal accessory pathways using a simplified two-catheter technique from a femoral approach.

[Long term follow-up in patients with the permanent form of junctional reciprocating tachycardia treated with radiofrequency ablation]

OBJECTIVES

This study sought to determine the long-term follow-up, safety and efficacy of radiofrequency catheter ablation in patients with the permanent form of junctional reciprocating tachycardia. We assessed the reversibility of tachycardia-related left ventricular dysfunction and we detailed the location and electrophysiologic characteristics of these atrioventricular decremental pathways.

BACKGROUND

Permanent junctional reciprocating tachycardia is an infrequent form on reciprocating tachycardia, commonly incessant and usually drug-refractory. The electrocardiographic hallmarks include an RP interval > PR with inverted P waves in leads II, III, aVF and V3-V6. During tachycardia, retrograde ventriculo-atrial conduction occurs over an accessory pathway with decremental conduction properties, located predominantly in the posteroseptal zone. It is known that long lasting and incessant tachycardia may result in tachycardia-related severe ventricular dysfunction, the so called tachycardiomyopathy.

PATIENTS AND METHODS

We included 24 patients (9 males, 15 females; mean age 42 +/- 22 years) with the diagnosis of permanent junctional reciprocating tachycardia at electrophysiologic study. Six patients had tachycardia-related left ventricular dysfunction. Radiofrequency energy was delivered at the site of earliest retrograde atrial activation during reciprocating tachycardia (n = 22) or ventricular pacing (n = 2). All patients were followed at the outpatient clinic and serial echocardiograms were performed in those who presented depressed left ventricular function.

RESULTS

Radiofrequency catheter ablation was performed in 24 decremental accessory pathways. Earliest retrograde atrial activation was right posteroseptal in 22 patients (92%), right midseptal in 1 (4%) and right posterolateral in 1 (4%). Twenty-three accessory pathways were successfully ablated with a mean of 5 +/- 3 (median, 4) radiofrequency applications of a mean duration of 48 +/- 13 s. Only the midseptal accessory pathway could not be ablated. After a mean follow-up of 21 +/- 16 months (median, 15; range 2 to 64) 22 patients remain asymptomatic. There were recurrences in 4 patients after the initial successful ablation (three during the first month and one during the second month after the procedure), two were ablated in a second ablation procedure, one patient required a third procedure and one required a fourth. All patients with left ventricular dysfunction experienced an improvement after ablation. Mean preablation left ventricular ejection fraction in patients with tachycardiomyopathy was 28 +/- 6% (median, 27) and raised to 51 +/- 16% (median, 47) after ablation (p < 0.02).

CONCLUSIONS

Our study supports the concept that radiofrequency catheter ablation is a safe and useful treatment for patients with permanent junctional reciprocating tachycardia. Radiofrequency current should be the treatment of choice in these patients because this arrhythmia is usually drug-refractory. The majority of accessory pathways with decremental conduction properties are localized in the posteroseptal zone. Cessation of the arrhythmia after successful ablation results in recovery of left ventricular dysfunction.

Enhanced detection criteria in implantable defibrillators

INTRODUCTION

Enhanced detection criteria in third-generation implantable defibrillators have been implemented to avoid inappropriate therapy of fast supraventricular arrhythmias. We prospectively analyzed the use of these criteria in patients with an implantable defibrillator with electrogram storing capability.

METHODS AND RESULTS

In 82 consecutive patients with a Guidant-CPI implantable defibrillator, sudden onset > 9% and stability < 40 msec were systematically programmed in zone 1 of therapy together with a sustained rate duration security mechanism. All detected tachycardia episodes were analyzed. The study population consisted of 59 patients who had at least one episode of tachycardia detected in zone 1 during follow-up. The tachycardia rate in zone 1 never exceeded 210 beats/min. Twenty patients had no episodes during follow-up, and three patients had episodes detected exclusively in zone 2 of therapy. Supraventricular arrhythmias were detected frequently in the ventricular tachycardia zone (193 of 690 tachycardia episodes in 23 of 59 patients). Use of sudden onset was very effective in detecting sinus tachycardias (65 of 67 episodes), and stability was very useful in detecting atrial fibrillation (31 of 32 episodes). However, sensitivity in detecting ventricular tachycardia was only 90% (451 of 497 episodes). Application of the sustained rate duration criterion allowed appropriate treatment of all ventricular tachycardia episodes, increasing sensitivity to 100%; however, specificity in appropriate nontreatment of supraventricular decreased from 96% to 83%. Subsequent analysis of different algorithms applied to our data showed that sudden onset > 9% and stability < 40 msec was the algorithm with the best specificity and sensitivity.

CONCLUSION

Programming sudden onset and stability detection criteria with a sustained rate duration safety net for triggering tachycardia therapy results in appropriate device management in most patients with supraventricular and slow (< 210 beats/min) ventricular tachycardias.

Radiofrequency ablation of concealed left free-wall accessory pathways without coronary sinus catheterization: results in 100 consecutive patients

INTRODUCTION

Feasibility of radiofrequency (RF) ablation using a two-catheter technique without coronary sinus catheterization was studied in 100 consecutive patients with a single concealed left free-wall accessory pathway.

METHODS AND RESULTS

Tachycardia was induced by electrical stimulation in the right atrium/right ventricle, and the presence of a concealed left free-wall accessory pathway was suggested electrocardiographically (negative P wave in leads I and/or aVL during orthodromic tachycardia) or by earlier atrial activation in the pulmonary artery compared to the high right atrium. Mapping of the mitral annulus was performed during right ventricular pacing or orthodromic tachycardia, and RF energy was applied at the site with the earliest retrograde atrial activation. Ablation was considered effective if tachycardia could not be induced, and if VA dissociation or exclusive retrograde nodal conduction was observed. Ablation was initially successful in 98 of 100 patients. Mean number of radiofrequency pulses were 3.2 +/- 2. Mean fluoroscopy time and total procedure time was 14 +/- 9 and 107 +/- 32 minutes, respectively. There were no complications related to the procedure. At a mean follow-up of 22 +/- 13 months, two patients experienced tachycardia recurrence and required a second procedure, which was successful.

CONCLUSIONS

Our results suggest that RF catheter ablation of concealed left free-wall accessory pathways can be safely, effectively, and rapidly performed using a simplified two-catheter technique with no need for coronary sinus catheterization.

Atrial fibrillation induced by atrioventricular nodal reentrant tachycardia

In 4 patients with recurrent episodes of paroxysmal atrial fibrillation as the only documented arrhythmia, electrophysiologic study showed that atrial fibrillation originated after a very fast transition from atrioventricular nodal reentrant tachycardia. Recognition of atrioventricular nodal reentrant tachycardia as the triggering factor for atrial fibrillation has important therapeutic consequences.

[Radiofrequency ablation of occult left accessory pathways without catheterization of the coronary sinus]

BACKGROUND

Radiofrequency catheter ablation of concealed left-sided accessory pathways conventionally implies the introduction of several catheters for the assessment of electrophysiological properties as well as for the localization of the accessory pathways.

PATIENTS AND METHODS

Feasibility of radiofrequency ablation using a simplified two-catheter technique without coronary sinus catheterization was prospectively studied in 95 consecutive patients with a single concealed left free-wall accessory pathway. A 6F quadripolar catheter was introduced into the right atrium/right ventricle and tachycardia was induced by electrical stimulation. The presence of a concealed left-sided accessory pathway was suggested electrocardiographically (negative P wave in I and/or aVL during orthodromic tachycardia) or by earlier atrial activation in the pulmonary artery compared to the right atrium. Mapping of the mitral annulus and ablation were performed during orthodromic tachycardia or ventricular pacing using a 7F steerable catheter. Radiofrequency energy was applied at sites with the shortest VA interval. The procedure was considered effective if tachycardia could not be induced and if VA dissociation or exclusive nodal VA conduction were observed.

RESULTS

The procedure was initially successful in 93 out of 95 patients (98%). Mean number of applications were 3.2 +/- 2. Mean fluoroscopy time and total procedure duration were 14 +/- 9 and 108 +/- 33 minutes respectively. At a mean follow-up of 21 +/- 13 months, 2 patients required a second session because of tachycardia recurrence.

CONCLUSIONS

Radiofrequency catheter ablation of concealed left-sided accessory pathways can be safely, effectively and rapidly performed using a two-catheter technique without coronary sinus catheterization.

[One thousand consecutive radiofrequency ablation procedures. Indications, results, and complications]

INTRODUCTION

Radiofrequency ablation has become the treatment of choice in the majority of patients suffering from cardiac arrhythmias. In this study we present our experience in a large group of patients treated using this procedure.

METHODS

Between January 1992 and February 1996, we performed 1000 consecutive ablation procedures in 938 patients with different cardiac arrhythmias. The indication for ablation were: tachycardias due to the presence of an accessory pathway (n = 487), atrio-ventricular nodal reentrant tachycardia (n = 284), atrio-ventricular nodal ablation (n = 104), atrial tachycardia (n = 42), atrial flutter (n = 41) and ventricular tachycardia (n = 42).

RESULTS

Radiofrequency ablation was initially effective in 908 out of the 938 patients (97%). Effectiveness ranged from 100% in atrio-ventricular nodal ablation to 83% in atrial tachycardia. During follow-up, a total of 45 recurrences of the arrhythmia were documented (5%) ranging from 2% in atrial tachycardia to 28% in atrial flutter. In 40 out of the 45 patients a second procedure was performed, being effective in 34 of them. Finally, radiofrequency ablation was effective in 896 out of the 938 patients (96%). A total of 13 significative complications were observed (1.3%). Of them, 10 occurred during the 250 initial procedures (4%) and 3 in the remaining 750 procedures (0.4%).

CONCLUSIONS

In centers performing a large number of procedures, radiofrequency ablation is a safe and effective method for the treatment of the majority of cardiac arrhythmias.

[Heart block caused by hyperkalemia as a complication of ureteroileostomy]

Report case of a patient who, after an ureteroileostomy, developed complete atrioventricular block secondary to severe hyperkaliemia, a condition for which no references have been found in the literature. Special mention is made of the mechanisms which trigger the electrolytic changes in these by-pass techniques.

Radiofrequency catheter ablation of atriofascicular accessory pathways guided by discrete electrical potentials recorded at the tricuspid annulus

BACKGROUND

The purpose of this study was to test the feasibility of using the recording of discrete electrical potentials to guide radiofrequency catheter ablation of atriofascicular accessory pathways with Mahaim-like properties.

METHODS AND RESULTS

Four patients (3 females, 1 male) who fulfilled criteria for having atriofascicular accessory pathways with Mahaim-like properties and preexcited reciprocating tachycardia underwent radiofrequency catheter ablation. The mean age was 35 years (range 27-47). Symptoms were present for a mean of 10.5 years (range 6-18). Recording of discrete electrical potentials of the atriofascicular pathway was attempted by mapping the tricuspid annulus in sinus rhythm, during atrial pacing, and during reciprocating tachycardia. During atrial pacing, a mean of seven radiofrequency pulses (range 1-14), delivered to the tricuspid annulus at the area where electrical potentials were recorded, eliminated conduction through the atriofascicular accessory pathway in all patients. No complications occurred. Tachycardia did not reoccur during a mean follow-up of 5 months (range 3-9).

CONCLUSIONS

Recording of discrete electrical potentials at the tricuspid annulus identifies an optimal ablation site where radiofrequency current can safely eliminate conduction through atriofascicular accessory pathways with Mahaim-like properties.

A five year review of youth suicide in Manitoba

Suicide is the second leading cause of death in adolescents. The suicide rate in the 15 to 24 year old age group has increased at a faster rate than in any other age group. This study is a descriptive and retrospective investigation of 204 files from the Chief Medical Examiner's office of all youths aged 24 years and less in the province of Manitoba who committed suicide between 1984 and 1988. The study found a high male to female ratio, a large number of younger adolescents and a suicide rate in the Native population which was ten times that of non-Natives. The method of suicide varied by gender and race. Males more often used hanging and guns; females were more likely to overdose. Natives tended to hang themselves more than non-Natives, while non-Natives more often used guns. The highest percentage of Native suicides occurred in urban areas. Depression and substance abuse were identified as risk factors. A number of recommendations regarding information gathering post-suicide, as well as prevention and intervention programs are proposed.

[Radiofrequency ablation of the slow nodal pathway in cases of paroxysmal nodal reentry tachycardia]

INTRODUCTION

We describe our experience in the treatment of supraventricular tachycardia due to atrioventricular nodal reentry by radiofrequency catheter ablation of the slow pathway.

PATIENTS AND METHODS

Thirty-four patients (mean age 52 +/- 13 years) with recurrent drug refractory atrioventricular nodal reentrant tachycardia underwent radiofrequency catheter ablation of slow-pathway as the first procedure. Maximal energy used was 28 +/- 8 W, mean time was 4.4 +/- 2.8 min, and a mean number of 13 +/- 9 discharges per patient.

RESULTS

Of the 34 patients 14 were successfully treated (no slow-pathway conduction, no AV nodal reentrant echo complexes, no inducible tachycardia), 11 were considered as partially successful (no inducible tachycardia, with slow-pathway conduction or echoes) and 9 patients were unsuccessfully treated (all of them underwent fast-pathway ablation with a successful outcome). Eight recurrences were observed during a mean follow-up period of 7 +/- 4 months: One in a patient with previously successful ablation (remained asymptomatic while taking beta-blockers), 6 in patients with first procedure partially successful (all of them underwent effective second slow-pathway ablation) and 1 in a patient with an unsuccessful procedure that underwent fast pathway ablation. A repeated procedure was successful in ablating the slow pathway. None of our patients developed complete atrio-ventricular block. One patient developed cardiac tamponade that needed surgical drainage. At last follow-up all patients are free from tachycardias.

CONCLUSION

Slow pathway ablation is an effective method of treatment in patients with atrio-ventricular nodal reentrant tachycardia. Long term success is related to complete abolition of slow pathway conduction.