Inflammatory Asthma Phenotype Discrimination Using an Electronic Nose Breath Analyzer.

BACKGROUND AND OBJECTIVE: Patients with persistent asthma have different inflammatory phenotypes. The electronic nose is a new technology capable of distinguishing volatile organic compound (VOC) breath-prints in exhaled breath. The aim of the study was to investigate the capacity of electronic nose breath-print analysis to discriminate between different inflammatory asthma phenotypes (eosinophilic, neutrophilic, paucigranulocytic) determined by induced sputum in patients with persistent asthma. METHODS: Fifty-two patients with persistent asthma were consecutively included in a cross-sectional proof-of-concept study. Inflammatory asthma phenotypes (eosinophilic, neutrophilic and paucigranulocytic) were recognized by inflammatory cell counts in induced sputum. VOC breath-prints were analyzed using the electronic nose Cyranose 320 and assessed by discriminant analysis on principal component reduction, resulting in cross-validated accuracy values. Receiver operating characteristic (ROC) curves were calculated. RESULTS: VOC breath-prints were different in eosinophilic asthmatics compared with both neutrophilic asthmatics (accuracy 73%; P=.008; area under ROC, 0.92) and paucigranulocytic asthmatics (accuracy 74%; P=.004; area under ROC, 0.79). Likewise, neutrophilic and paucigranulocytic breath-prints were also different (accuracy 89%; P=.001; area under ROC, 0.88). CONCLUSION: An electronic nose can discriminate inflammatory phenotypes in patients with persistent asthma in a regular clinical setting. ClinicalTrials.gov identifier: NCT02026336.

[Vascular access models cause heterogeneous results in the centres of one community]. / Los modelos de atención al acceso vascular condicionan resultados heterogéneos en los centros de una misma comunidad.

INTRODUCTION: Vascular access (VA) is the main difficulty in our hemodialysis Units and there is not adequate update data in our area. PURPOSE: To describe the vascular access management models of the Autonomous Community of Madrid and to analyze the influence of the structured models in the final results. MATERIAL AND METHODS: Autonomous multicenter retrospective study. Models of VA monitoring, VA distribution 2007-2008, thrombosis rate, salvage surgery and preventive repair are reviewed. The centers are classified in three levels by the evaluation the Nephrology Departments make of their Surgery and Radiology Departments and the existence of protocols, and the ends are compared. MAIN VARIABLES: Type distribution of VA. VA thrombosis rate, preventive repair and salvage surgery. RESULTS: Data of 2.332 patients were reported from 35 out of 36 centers. Only 19 centers demonstrate database and annual evaluation of the results. Seventeen centers have multidisciplinary structured protocols. Forty-four point eight percent of the patients started dialysis by tunneled catheter (TC). Twenty-nine point five percent received dialysis by TC in December-08 vs 24.7% in December-07. Forty-four point seven percent of TC were considered final VA due to non-viable surgery, 27% are waiting for review or surgery more than 3 months. For rates study data from 27 centers (1.844 patients) were available. Native AVF and graft-AVF thrombosis rates were 10.13 and 39.91 respectively. Centers with better valued models confirmed better results in all markers: TC rates, 24.2 vs 34.1 %, p: 0.002; native AVF thrombosis rate 5.3 vs 10.7 %; native AVF preventive repair 14.5 vs 10.2%, p: 0.17; Graft- AVF thrombosis rate 19.8 vs 44.4%, p: 0.001; Graft-AVF preventive repair 83.2 vs 26.2, p < 0.001.They also have less patients with TC as a final option (32.2 vs 45.3) and less patients with TC waiting for review or surgery more than 3 months (2.8 vs 0). LIMITS: Seventy-five percent of patients were reached for the analysis of thrombosis rate. Results are not necessarily extrapolated. CONCLUSIONS: For the first time detailed data are available. TC use is elevated and increasing. Guidelines objectives are not achieved. The difference of results observed in different centers of the same public health area; make it necessary to reevaluate the various models of care and TC follow-up.

Initiating renal replacement therapy through incremental haemodialysis: Protocol for a randomized multicentre clinical trial.

BACKGROUND: Thrice-weekly haemodialysis is the usual dose when starting renal replacement therapy; however, this schedule is no longer appropriate since it does not consider residual renal function. Several reports have suggested the potential benefit of beginning haemodialysis less frequently and incrementally increasing the dose as the residual renal function decreases. However, all the data published so far are from observational studies. Thus, this clinical trial avoids any potential selection bias and will assess the possible benefits that have been observed in observational studies. METHODS/DESIGN: This report describes the study protocol of a randomized prospective multi-centre open-label clinical trial to evaluate whether starting renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than the standard thrice-weekly regimen. We also explore other clinical parameters, such as concentrations of uremic toxins, dialysis doses, control of anaemia, removal of medium-weight uremic toxins, nutritional status, quality of life, hospital admissions and mortality. Only incident haemodialysis patients who can maintain a urea clearance rate KrU ≥ 2.5 mL/min/1.73 m2 are eligible. Patient recruitment began on 1 January 2017 and will last for 2 years or until the required sample size has been recruited to ensure the established statistical power has been reached. The minimum follow-up period will be 1 year. Anuric patients with acute renal failure and patients who return to haemodialysis after a kidney transplant failure are excluded. It has been calculated that 44 patients should be recruited into each group to achieve a power of 80% in a two-sided comparison of means with a usual significance level of 0.05. A time-to-event analysis will estimate the probability of kidney function survival in both groups using the Kaplan-Meier method. Survival curves will be compared with log-rank tests. This survival analysis will be complemented with a proportional hazard model to estimate the hazard ratio of kidney function survival adjusted for any confounding factors. Analyses will be carried out in accordance with the intention-to-treat principle. DISCUSSION: The incremental initiation of dialysis may preserve residual renal function better than the conventional treatment, with similar or higher survival rates, as reported by observational studies. To our knowledge, this is the first clinical trial to evaluate whether initiating renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than beginning with the standard thrice-weekly regimen. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03302546. Registered on 5 October 2017.

[Recurrence of p-ANCA positive vasculitis with lung hemorrhage in a patient on hemodialysis]. / Recidiva de vasculitis p-ANCA positiva con hemorragia pulmonar en paciente en hemodiálisis.

Relapses of p-ANCA vasculitis during chronic dialysis treatment are infrequent. We report a patient with a pulmonary-renal syndrome and p-ANCA vasculitis who relapsed one year after starting hemodialysis treatment. Treatment with steroids and cyclosphosphamide successfully controlled the relapse, though cyclophosphamide had to be discontinued because of leucopenia. Clinical features of renal vasculitis, relapse after dialysis, the usefulness of ANCA titles as possible predictors and therapeutic options are discussed.

[The Cockcroft-Gault equation is better than MDRD equation to estimate the glomerular filtration rate in patients with advanced chronic renal failure]. / La ecuación de Cockcroft-Gault es preferible a la ecuación MDRD para medir el filtrado glomerular en la insuficiencia renal crónica avanzada.

ABSTRACT The aim of this study was to compare the accuracy of three kidney function estimating equations: classic Cockcroft-Gault (classic CG), corrected Cockcroft-Gault (corrected CG) and simplified Modification of Diet in Renal Disease (MDRD), in patients with advanced chronic renal failure. The study was made in 84 nondialyzed patients with chronic renal disease in stage 4 or 5. The glomerular filtration rate was measured on a 24-hour urine collection as the arithmetic mean of the urea and creatinine clearances (CUrCr). In each patient, the difference between each estimating equation and the measured glomerular filtration rate was calculated. The absolute difference expressed as a percentage of the measured glomerular filtration rate indicates the intermethod variability. In the total group the glomerular filtration rate measured as the CUrCr was de 13,5+/-5,1 ml/min/1.73 m(2); and the results of the estimating equations were: classic CG 14,2+/-5 (p<0,05); corrected CG 12+/-4,2 (p<0,01) and MDRD : 12,1+/-4,8 ml/min/1.73 m(2) (p<0,01). The variability of the estimating equations was 15,2+/-12,2%, 17,1+/-13,4 % and 19,3+/-13,3% (p<0,05), for classic CG, corrected CG and MDRD respectively. The percent of estimates falling within 30% above o below the measured glomerular filtration rate was 90% for CG classic, 87% for corrected CG and 79% for MDRD. The intraclass correlation coefficients respect to CUrCr were 0,86 for classic CG, 0,81 for corrected CG and 0,77 for MDRD. The MDRD variability, but not classic CG variability or corrected CG variability, showed a positive correlation with the glomerular filtration rate (r=0,25, p<0,05). In patients with chronic renal disease in stage 5, the variability of the different estimating equations was similar. We conclude that in our population with advanced chronic renal failure the classic CG equation is more accurate than the MDRD equation. Corrected CG equation has not any advantage respect to classic CG equation.

[Control of the dialysis dose by ionic dialysance and bioimpedance]. / Control de la dosis de diálisis mediante dialisancia iónica y bioimpedancia.

INTRODUCTION: The ionic dialysance monitor allows an automated measure of Kt in each dialysis session. Bioelectrical impedance analysis (BIA) determines the total body water which it is equivalent to the urea volume of distribution (V). If the Kt, determined by ionic dialysance, is divided by the V, estimated by bioelectrical impedance, a Kt/V at the end of dialysis session (Kt/VDiBi) is obtained. AIM OF THE STUDY: To evaluate the agreement between the Kt/VDiBi and the Kt/V obtained by two simplified formulas: the monocompartimental (Kt/Vm) and the equilibrated (Kt/Ve) Daugirdas equations. METHODS: The Kt/VDiBi, the Kt/Vm and the Kt/Ve were determined in 38 hemodialysis patients (27 males and 11 females) in the same hemodialysis session. The patients were on dialysis three times a week for 3.5 to 4 hours. The V was determined by monofrequency bioelectrical impedance (50 kHz) at the end of the dialysis session. RESULTS: The Kt/VDiBi, Kt/Vm and Kt/Ve were 1.29+/-0.26, 1.54+/-0.29 and 1.36+/-0.25, respectively (p<0.001 between the Kt/VDiBi and the KtVm, and p<0.001 between the KtV/DiBi and the Kt/Ve). The intraclass correlation coefficient showed better concordance between the KtV/DiBi and the Kt/Ve (coefficient 0.88) than between the Kt/VDiBi and the KtVm (coefficient 0.65). The relative difference of the Kt/VDiBi was 8.3+/-6.4% with respect to the Kt/Ve and 18.4+/-7.8 % with respect to the Kt/Vm (p<0.001). The relative difference between the Kt/VDiBi and the Kt/Ve was lower than 15% in the 84% of the patients and lower than 10% in the 64% of the patients. CONCLUSIONS: If the V obtained by bioelectrical impedance analysis is included in the ionic dialysance monitor, we can obtain a Kt/V for each patient in real time, which is similar to the equilibrated Kt/V obtained from the Daugirdas equation.

[Temperature dialysate and hemodialysis tolerance]. / Temperatura del baño y tolerancia a la hemodiálisis.

In this study, the effect of dialysate temperature on hemodynamic stability, patients' perception of dialysis discomfort and postdialysis fatigue were assessed. Thirty-one patients of the morning shift were eligible to participate in the study. Three patients refused. Patients were assessed during 6 dialysis sessions: in three sessions the dialysate temperature was normal (37 degrees C) and in other three sessions the dialysate temperature was low (35.5 degrees C). To evaluate the symptoms along the dialysis procedure and the postdialysis fatigue, specific scale questionnaires were administered in each dialysis session and respective scores were elaborated. Low temperature dialysate was associated with higher postdialysis systolic blood pressure (122 +/- 24 vs. 126 +/- 27 mmHg, p < 0.05), and lower postdialysis heart rate (82 +/- 13 vs. 78 +/- 9 beats/min, p < 0.05) with the same ultrafiltration rate. Dialysis symptoms score and postdialysis fatigue score were better with the low dialysate temperature (0.7 +/- 0.9 vs. 0.4 +/- 1 vs. p < 0.05, and 1.3 +/- 1 vs. 1 +/- 0.9 p < 0.05, respectively). Furthermore, low temperature dialysate shortened the post-dialysis fatigue period (5.4 +/- 6.3 vs. 3.1 +/- 3.3 vs. hours, p < 0.05). The clinical improvement experimented with the low temperature dialysate was not universal. A beneficial effect was exclusively observed in the patients with higher dialysis symptoms and postdialysis fatigue scores or having more than one episode of hypotension in a week. The patients were asked about their temperature preference, 7 patients (23%) request a dialysate at 37 degrees C, 19 patients (61%) prefered to be dialysed with the low temperature dialysate, and 5 patients (16%) were indifferent. The later two groups of the patients continued with the low temperature dialysate during other 4 weeks. At the end of that period, the clinical improvement remained unchanged. In summary, low temperature dialysate is particularly beneficial for highly symptomatic patients.

[Urea distribution volume calculated by ionic dialysance]. / Cálculo del volumen de distribución de la urea mediante dialisancia iónica.

BACKGROUND: Direct dialysis quantification is considered the gold standard for determining urea distribution volume, but it is impractical for routine use. So, urea distribution volume in hemodialysis patients is usually estimated from anthropometric equations. Ionic dialysance allows to calculate the urea distribution volume dividing the Kt obtained by ionic dialysance by the Kt/V obtained by a simplified formula. The aim of the present work was to analyse the concordance between the ionic dialysance and the direct dialysis quantification methods to estimate de urea distribution volume. MATERIAL AND METHODS: In 15 hemodialysis patients (10 males and 5 females), we have estimated the urea distribution volume by the direct dialysis quantification (Vurea), by the anthropometrics equations of Watson (VWatson) and Chertow (VChertow) and by the ionic dialysance method (VDI). To obtain VDI we have used two simplified Kt/V formulas: the monocompartimental and the equilibrated Daugirdas equations (VDIm and VDIe respectively). The intermethod variability was assessed by the relative difference (absolute difference between VUrea and the other methods, divided by the mean). RESULTS: VUrea (26,2 L) was statistically different from theVDIe (30,6 L, p < 0.01), VWatson 35.2 L (p < 0.001) and VChertow (38 L, p < 0.001). VDIm was 26.3 L (p = ns). VUrea represents the 42% of the body weight for the males (range 36 to 49%) and the 33% of the body weight for the female (range 28 to 38%). The intermethod variability was high for the VDIe (21.6%), VWatson (37.4%) and VChertow (48. 1%), but it was low for the VDIm (9.9%). CONCLUSIONS: Urea distribution volume calculated by the ionic dialysance method using the monocompartimental Daugirdas Kt/V equation has an acceptable agreement with the urea distribution volume calculated by the direct dialysis quantification. Anthropometry-based equations overestimate the urea distribution volume in hemodialysis patients.

Transient entrainment of bundle-branch reentry by atrial and ventricular stimulation: elucidation of the tachycardia mechanism through analysis of the surface ECG.

BACKGROUND: Different responses to entrainment have been reported in relation to the pacing site of a variety of tachycardias. However, transient entrainment of bundle-branch reentrant tachycardia (BBRT) has not been investigated systematically. METHODS AND RESULTS: We attempted entrainment of 13 BBRTs in 9 patients by pacing first the right ventricle and then the right atrium. The initial pacing cycle length (CL) was 10 ms faster than the tachycardia CL. Subsequent pacing sequences were performed with 5- to 10-ms CL decrements until tachycardia termination or loss of postatropine 1:1 AV conduction. Both full ventricular-paced and AV-conducted QRS complex references were obtained during sinus rhythm pacing from the same sites and with similar CL as during entrainment. Transient entrainment was achieved by ventricular and atrial stimulation in 11 and 8 tachycardias, respectively. Constant fusion was always present during entrainment by ventricular stimulation. There was no change in the QRS complex (orthodromically concealed fusion) during entrainment by atrial stimulation in 6 of 6 tachycardias with left bundle-branch block morphology and in 1 of 2 tachycardias with right bundle-branch block morphology. CONCLUSIONS: BBRT, especially if it has a left bundle-branch block morphology, can be differentiated from other wide-QRS-complex tachycardia mechanisms through analysis of the ECGs recorded during tachycardia entrainment by atrial and ventricular stimulation. This diagnostic approach may be especially useful when it is difficult to record a stable or sufficiently sized His bundle electrogram or when spontaneous changes in the ventricular CL precede similar changes in the His bundle CL.

Bundle-branch reentry and the postpacing interval after entrainment by right ventricular apex stimulation: a new approach to elucidate the mechanism of wide-QRS-complex tachycardia with atrioventricular dissociation.

BACKGROUND: Diagnosis of bundle-branch reentry ventricular tachycardia (BBR-VT) by the standard approach is challenging, and this may lead to nonrecognition of this tachycardia mechanism. Because the postpacing interval (PPI) after entrainment has been correlated with the distance from the pacing site to the reentrant circuit, BBR-VT entrainment by pacing from the right ventricular apex (RVA) should result in a PPI similar to the tachycardia cycle length (TCL). This factor may differentiate BBR-VT from other mechanisms of wide-QRS-complex tachycardia with AV dissociation, such as myocardial reentrant VT (MR-VT) or AV nodal reentrant tachycardia (AVNRT), in which the circuit is usually located away from the RVA. METHODS AND RESULTS: Transient entrainment by RVA pacing was attempted in 18 consecutive BBR-VTs and finally achieved in 13. Results were compared with those found in 59 consecutive MR-VTs and 50 consecutive AVNRTs. The mean PPI-TCL difference was significantly (P:<0.0001) shorter in the BBR-VT group (9+/-11 ms) than in the MR-VT (109+/-48 ms) and the AVNRT (150+/-29 ms) groups. No BBR-VT showed a PPI-TCL >30 ms (range -12 to 24 ms). Except for 2 MR-VTs, no MR-VT (range 21 to 211 ms) or AVNRT (range 100 to 215 ms) showed a PPI-TCL <30 ms. CONCLUSIONS: A PPI-TCL >30 ms, after entrainment by RVA stimulation, makes BBR-VT unlikely. Conversely, a PPI-TCL <30 ms is suggestive of BBR-VT but should lead to further investigation by use of conventional criteria.

Mechanism and location of atrial flutter in transplanted hearts: observations during transient entrainment from distant sites.

OBJECTIVES: This study was designed to elucidate the location and mechanism of typical atrial flutter in the transplanted heart. BACKGROUND: Although the F wave morphology in atrial flutter is similar in nontransplanted and transplanted hearts, the surgical incision needed for the atrial anastomosis may create a distinct electrophysiologic substrate of atrial flutter. METHODS: Entrainment from the lateral wall of the right atrium and interatrial septum was used to determine the location of atrial flutter in five patients with a transplanted heart and six patients with a nontransplanted heart. The difference between the first postpacing interval (FPPI) and the flutter cycle length (FCL) was used as an index of proximity to the circuit. RESULTS: In the transplant group, the FPPI was equal to the FCL at sites located close to the tricuspid annulus (TA); the mean differences (+/-SD) were 1 +/- 5 and -1 +/- 2 ms at the lateral wall and interatrial septum, respectively. However, from sites close to the surgical incision at the lateral wall and at the interatrial septum, these differences were significantly longer (29 +/- 12 and 27 +/- 9 ms, respectively, p < 0.05). In the nontransplant group, the FPPI was similar to the FCL at points in the lateral wall and interatrial septum close to the TA (mean difference 7 +/- 6 and 6 +/- 11 ms, respectively) and at sites close to the crista terminalis (CT) in the lateral wall (mean difference 4 +/- 4 ms). However, in sites separated from the TA at the interatrial septum the difference was markedly longer (35 +/- 11 ms, p < 0.05). CONCLUSIONS: Atrial flutter in transplanted hearts may best be explained by macroreentry around the tricuspid ring. In non-transplanted hearts a different structure (perhaps the CT?) may be the basis for atrial flutter at the lateral wall.

"Pseudodisappearance" of atrial electrogram during orthodromic tachycardia: new criteria for successful ablation of concealed left-sided accessory pathways.

OBJECTIVES: This study sought to analyze two new criteria along with other known predictors of success of radiofrequency ablation. Background. Although the overall success rate of radiofrequency ablation of accessory pathways is high, the individual predictive value of each of the established criteria is low. METHODS: We prospectively studied the local electrograms obtained before the application of radiofrequency energy in 33 patients with a left-sided concealed accessory pathway successfully ablated. Two new criteria ("pseudodisappearance" during tachycardia of a bipolar atrial electrogram visible during sinus rhythm and the presence of an "atrial notch" in the ascending limb of the unipolar ventricular electrogram during tachycardia) were studied along with other known predictors. Electrograms recorded at a total of 157 sites were analyzed (33 successful applications, 124 failures). RESULTS: Electrogram characteristics that were predictive of success during ablation on the basis of univariate analyses were a pseudodisappearance criterion (p<0.001), the presence of a Kent potential (p<0.005) and the presence of an "atrial notch" (p<0.005). After adjustment for between-patient differences, logistic regression analysis showed that only the "pseudodisappearance" criterion (odds ratio [OR] 7.2, 95% confidence interval [CI] 1.2 to 42.5, p<0.03) and the presence of a Kent potential (OR 2.4, 95% CI 1.01 to 5.79, p<0.05) had independent predictive value. CONCLUSIONS: The pseudodisappearance during tachycardia or ventricular pacing of a bipolar atrial electrogram present during sinus rhythm is associated with a good outcome during radiofrequency ablation of concealed accessory pathways. These observations may help to ablate accessory pathways and to avoid missing appropriate sites for ablation when the atrial activation is not clearly visible at the local electrogram.

Spectral analysis-based risk score enables early prediction of mortality and cerebral performance in patients undergoing therapeutic hypothermia for ventricular fibrillation and comatose status.

BACKGROUND: Early prognosis in comatose survivors after cardiac arrest due to ventricular fibrillation (VF) is unreliable, especially in patients undergoing mild hypothermia. We aimed at developing a reliable risk-score to enable early prediction of cerebral performance and survival. METHODS: Sixty-one out of 239 consecutive patients undergoing mild hypothermia after cardiac arrest, with eventual return of spontaneous circulation (ROSC), and comatose status on admission fulfilled the inclusion criteria. Background clinical variables, VF time and frequency domain fundamental variables were considered. The primary and secondary outcomes were a favorable neurological performance (FNP) during hospitalization and survival to hospital discharge, respectively. The predictive model was developed in a retrospective cohort (n = 32; September 2006-September 2011, 48.5 ± 10.5 months of follow-up) and further validated in a prospective cohort (n = 29; October 2011-July 2013, 5 ± 1.8 months of follow-up). RESULTS: FNP was present in 16 (50.0%) and 21 patients (72.4%) in the retrospective and prospective cohorts, respectively. Seventeen (53.1%) and 21 patients (72.4%), respectively, survived to hospital discharge. Both outcomes were significantly associated (p < 0.001). Retrospective multivariate analysis provided a prediction model (sensitivity = 0.94, specificity = 1) that included spectral dominant frequency, derived power density and peak ratios between high and low frequency bands, and the number of shocks delivered before ROSC. Validation on the prospective cohort showed sensitivity = 0.88 and specificity = 0.91. A model-derived risk-score properly predicted 93% of FNP. Testing the model on follow-up showed a c-statistic ≥ 0.89. CONCLUSIONS: A spectral analysis-based model reliably correlates time-dependent VF spectral changes with acute cerebral injury in comatose survivors undergoing mild hypothermia after cardiac arrest.

Evidence favoring the hypothesis that ventricular arrhythmias have prognostic significance in left ventricular hypertrophy secondary to systemic hypertension.

In the present review 6 lines of evidence will be discussed that suggest a prognostic significance for ventricular arrhythmias in patients with systemic hypertension and left ventricular hypertrophy: (1) in patients with systemic hypertension there is a statistical relation between asymptomatic ventricular arrhythmias and left ventricular hypertrophy; (2) in nonhypertensive left ventricular hypertrophy the prognostic value of ventricular arrhythmias is well known; (3) left ventricular hypertrophy is related to sudden death in patients with systemic hypertension; (4) it is generally acknowledged that ventricular arrhythmias are a frequent cause of sudden death; (5) there is experimental evidence to support the arrhythmic risk of left ventricular hypertrophy; and (6) it has been recently demonstrated that ventricular arrhythmias influence mortality in patients with left ventricular hypertrophy secondary to systemic hypertension. However, whether asymptomatic ventricular arrhythmias are specific markers for more severe sustained arrhythmias, or just markers for a more severe stage of the disease, remains to be determined.

Radiofrequency catheter ablation of ventricular tachycardia from right ventricle late after myocardial infarction.

In summary, this case illustrates how complex VT circuits may be. If the findings of this case are substantiated with additional cases, mapping and radiofrequency energy application from right ventricle would have to be considered in VT with left bundle branch blocks QRS morphology, whenever ablation from the left ventricule is ineffective.

Randomized, prospective comparison of four burst pacing algorithms for spontaneous ventricular tachycardia.

"Less aggressive" burst stimulation is more effective in terminating spontaneous monomorphic ventricular tachycardia with a lesser acceleration rate. Higher ventricular tachycardia cycle length and use of 91% coupling interval were independent predictors for pacing termination.

Successful treatment of prosthetic aortic valve mucormycosis.

Mucor endocarditis after cardiovascular surgery is rare and usually fatal. We report the first known case of prosthetic aortic valve mucormycosis in a patient without predisposing risk factors who was successfully treated using a combination of early antifungal drug therapy and surgical removal of infected material.

Mechanisms underlying ventricular arrhythmias in idiopathic dilated cardiomyopathy: implications for management.

Ventricular arrhythmias (VA) have been associated with mortality in idiopathic dilated cardiomyopathy (IDCM). All 3 main mechanisms of arrhythmogenesis - reentry, trigger activity, and automatism - have been implicated. Arrhythmogenic substrates in IDCM favor these mechanisms and are often potentiated by electrolyte imbalance secondary to diuretic treatment, by antiarrhythmic drugs, or by bradycardia, leading to polymorphic ventricular tachycardia (VT). Myocardial macroreentry is the mechanism most frequently responsible for monomorphic VT in IDCM; however, focal activation and His-Purkinje macroreentry are often responsible and, especially in the latter case, are frequently unrecognized. Clinical suspicion and final recognition by electrophysiologic testing have important therapeutic consequences, because both focal activation and His-Purkinje macroreentry can be treated effectively by catheter ablation. On the other hand, the frequent recurrences of myocardial macroreentrant VT after ablation require this therapy to be used in combination with drugs or an implantable cardioverter defibrillator (ICD). beta-Adrenoceptor antagonists (beta-blockers) have a beneficial effect for primary prevention of VA in IDCM. Type III antiarrhythmics have a neutral effect on mortality and type I antiarrhythmics should be avoided. Treatment of nonsustained VT in IDCM is controversial because it often presents without symptoms and is linked more to overall mortality than to arrhythmic mortality. Empiric treatment with amiodarone or electrophysiologically guided sotalol are preferred to the use of other drugs for secondary prevention of sustained VA. ICDs should be implanted in patients who have been resuscitated from cardiac arrest due to VA, or in those with poorly tolerated VT and severe left ventricular dysfunction. Empiric treatment with amiodarone or electrophysiologically guided class III antiarrhythmics may also be alternatives for patients with IDCM and no severe left ventricular dysfunction, especially if VT is well tolerated.

Implantable cardioverter defibrillator as therapeutic option for sudden cardiac death secondary to severe coronary vasospasm.

We report a case of a patient with angina at rest followed by sudden cardiac death secondary to ventricular fibrillation. Cardiac catheterization did not show significant coronary stenosis but after an acetylcholine test, a severe coronary spasm was induced. Despite intensive medical therapy, vasospasm was not prevented. Finally, the patient received an implantable cardioverter defibrillator (ICD) to avoid the risk of sudden cardiac death. In our opinion, ICD in addition to medical therapy may be useful in patients with sudden cardiac death secondary to coronary vasospasm.