EPM algorithm: A stepwise approach to accessory pathway localization in ventricular pre-excitation.

BACKGROUND: Accurate estimation of accessory pathway (AP) localization in patients with ventricular pre-excitation or Wolff-Parkinson-White (WPW) syndrome remains a diagnostic challenge. Existing algorithms have contributed significantly to this area, but alternative algorithms can offer additional perspectives and approaches to AP localization. OBJECTIVE: This study introduces and evaluates the diagnostic accuracy of the EPM algorithm in AP localization, comparing it with established algorithms Arruda and EASY. METHODS: A retrospective analysis was conducted on 138 patients from Hospital São Paulo who underwent catheter ablation. Three blinded examiners assessed the EPM algorithm's diagnostic accuracy against the Arruda and EASY algorithms. The gold standard for comparison was the radioscopic position of the AP where radiofrequency ablation led to pre-excitation disappearance on the ECG. RESULTS: EPM showed a diagnostic accuracy of 51.45%, closely aligning with Arruda (53.29%) and EASY (44.69%). Adjacency accuracy for EPM was 70.67%, with Arruda at 66.18% and EASY at 72.22%. Sensitivity for EPM in distinguishing left vs. right APs was 95.73%, with a specificity of 74.33%. For identifying septal vs. lateral right APs, EPM sensitivity was 82.79% with a specificity of 46.15%. These measures were comparable to those of Arruda and EASY. Inter-observer variability was excellent for EPM, with Kappa statistics over 0.9. CONCLUSION: The EPM algorithm emerges as a reliable tool for AP localization, offering a systematic approach beneficial for therapeutic decision-making in electrophysiology. Its comparable diagnostic accuracy and excellent inter-observer variability underscore its potential clinical applicability. Future research may further validate its efficacy in a broader clinical setting.

Long-term clinical outcomes of patients with nonsignificant transplanted renal artery stenosis.

BACKGROUND: Transplant renal artery stenosis (TRAS) is the main vascular complication of kidney transplantation. For research and treatment purposes, several authors consider critical renal artery stenosis to be greater than 50%, and percutaneous intervention is indicated in this scenario. However, there are no reports in the current literature on the evolution of patients with less than 50% stenosis. METHOD: This retrospective study included data from all patients who underwent kidney transplantation and were suspected of having TRAS after transplantation with stenosis under 50% independent of age and were referred for angiography at a single centre between January 2007 and December 2014. RESULTS: During this period, 6,829 kidney transplants were performed at Hospital do Rim, 313 of whom had a clinical suspicion of TRAS, and 54 of whom presented no significant stenosis. The average age was 35.93 years old, the predominant sex was male, and most individuals (94.4%) underwent dialysis before transplantation. In most cases in this group, transplants occurred from a deceased donor (66.7%). The time between transplantation and angiography was less than one year in 79.6% of patients, and all presented nonsignificant TRAS. Creatinine levels, systolic blood pressure, diastolic blood pressure and glomerular filtration rate improved over the long term. The outcomes found were death and allograft loss. CONCLUSION: Age, sex and ethnic group of patients were factors that did not interfere with the frequency of renal artery stenosis. The outcomes showed that in the long term, most patients evolve well and have improved quality of life and kidney function, although there are cases of death and kidney loss.

Pacemaker lead-related macroreentrant atrial tachycardia.

Macroreentrant atrial circuits are frequently associated with scarring. Previous reports have shown the possible development of scar tissue that is adjacent to pacemaker (PM) leads. However, reports of PM lead-related reentrant tachycardia are scarce. We report the case of a 63-year-old woman who presented with macroreentrant atrial tachycardia (MAT), related to the atrial trajectory of an old single-lead ventricular PM, that was successfully treated with radiofrequency ablation after a conventional electrophysiological study ruled out isthmus-dependent atrial flutter and provided sufficient data to confirm this diagnosis. This report presents a case of MAT originating around the trajectory of a PM lead, probably because of scar tissue that developed adjacent to the lead. Experimental studies have already shown that interstitial atrial fibrosis may develop adjacent to a ventricular single-lead. This finding suggests that MAT develops in patients with this specific condition. Recognizing this condition is important for managing these arrhythmias and performing safe ablation with the preservation of PM lead integrity.

Impact of severe OSA on pharmacoinvasive treatment in ST elevation myocardial infarction patients.

PURPOSE: The negative association between obstructive sleep apnea (OSA) and adverse cardiovascular outcomes in patients undergoing percutaneous coronary intervention (PCI) is well documented. However, little is known about the influence of OSA on fibrinolytic therapy. The aim of this study was to evaluate the impact of severe OSA on pharmacoinvasive treatment in ST elevation myocardial infarction (STEMI) patients. METHODS: We enrolled consecutive STEMI patients without previous vascular disease, heart failure, or OSA diagnosis. All patients underwent either a pharmacoinvasive therapy or primary PCI. Syntax score (SS) was calculated for all patients, and a full bedside polysomnography was performed in the first 72 h of admission. In-hospital events and 30 days readmissions were analyzed. RESULTS: The sample included 116 patients, 87 men. Patients with severe OSA were older (p = 0.01), had higher neck and abdominal circumferences (p < 0.01), and had higher BMI (p < 0.01). They also had lower reperfusion rates post-fibrinolysis (20 vs. 65%; p = 0.001), higher SS (20.2 ± 11.2 vs. 14.6 ± 10.6; p = 0.03), lower left ventricle ejection fraction (45 ± 8 vs. 51 ± 10%; p = 0.02), and a higher incidence of atrial arrhythmias (4 vs. 21%; p = 0.02). STEMI patients with severe OSA presented with threefold increase in the risk for at least one adverse outcome. Regression analysis showed that both severe OSA and hypertension were independent predictors of higher SS. CONCLUSION: Severe OSA was associated with a poor outcome after pharmacoinvasive treatment in STEMI patients.

Ventricular arrhythmias in the Chagas disease are not random phenomena: Long-term monitoring in Chagas arrhythmias.

BACKGROUND: Variability of ventricular arrhythmias among days in patients with Chagas disease is not detected by 24 hours of Holter monitoring. OBJECTIVE: To analyze whether ventricular arrhythmias are a random phenomenon or have a reproducible behavior in patients with Chagas cardiomyopathy. METHOD: Holter monitoring was recorded in 16 subjects with a mean age of 52 ± 8 years. They were clinically stable and had ventricular couplets, isolated premature ventricular contractions (PVCs), and nonsustained ventricular tachycardia (NSVT). The recordings occurred for 7 days. Hurst exponent (HE) evaluated randomness and predictability index (PI) and repeated analysis of variance (ANOVA) assessed reproducibility. RESULTS: The HE was significantly greater than 0.5 in all 16 patients, which confirms the nonrandomness of arrhythmias in this Chagas sample. The PI for ventricular couplets and isolated PVCs was, on average, 38% and 54%, respectively. ANOVA with repeated measurement showed significant differences in the daily frequency of ventricular couplets (n = 15, P ≤ .05), isolated PVC (n = 12, P ≤ .05), and NSVT (n = 7, P ≤ .05). CONCLUSION: Ventricular arrhythmias in Chagas cardiomyopathy are not random. Dissimilarities in arrhythmias frequency make unlikely that 24 hours of Holter recording can capture this variability.

Clinical value of myocardial performance index in patients with isolated diastolic dysfunction.

AIMS: The Doppler-derived myocardial performance index (MPI) has been considered as a diagnostic and prognostic Doppler marker for many different clinical conditions. The purpose of this study was to determine the diagnostic accuracy of traditional Pulsed-wave Doppler (PWD-MPI) and Pulsed-wave tissue Doppler imaging (TDI-MPI) and the degree of agreement between these methods in patients with grade-I diastolic dysfunction (DDI) and a normal ejection fraction. METHODS: Forty-seven consecutive ambulatory patients with DDI were compared to 51 healthy subjects with normal echocardiograms. All subjects underwent measurement of time intervals and MPI with PWD and pulsed TDI. RESULTS: TDI-MPI and PWD-MPI were significantly higher in patients with DDI than in control subjects: 0.49 ± 0.14 vs. 0.40 ± 0.09 (P < 0.001) and 0.45 ± 0.11 vs. 0.37 ± 0.08 (P < 0.001), respectively. Cutoff values of TDI-MPI > 0.42 and PWD-MPI > 0.40 identified DDI subjects, with sensitivities of 74 and 64%; specificities of 61 and 69%; positive likelihood ratios of 1.9 and 2.0; and negative likelihood ratios of 0.42 and 0.53, respectively; no significant difference was noted between the areas under the ROC curves of TDI-MPI and PWD-MPI (P = 0.77). Bland-Altman plots showed wide limits of agreement between these indices: - 0.17 to 0.23 in healthy subjects and - 0.24 to 0.32 in DDI patients. CONCLUSION: PWD-MPI and TDI-MPI showed poor clinical agreement and were not reliable parameters for the assessment of left ventricular diastolic function.

Catheter entrapment in Chiari network: Extraction with radiofrequency.

We report a challenging case of a duodecapolar mapping catheter entrapment in Chiari network and its release by radiofrequency energy application with an ablation catheter.

Radiofrequency ablation of a middle cardiac vein inserted accessory pathway resulting in posterolateral coronary artery occlusion: A case report.

INTRODUCTION: Posteroseptal accessory pathways account for 34.5% of the total. Of these, 36% are located within the coronary sinus (CS). Its ablation requires technical alternatives to avoid damage to surrounding tissues, especially branches of the right coronary artery. CASE REPORT: A 22-year-old man was referred for re-do ablation of an accessory left septal-septal (PSE) pathway. Inside the CS, a precocity of 25 ms was found in the region of the median cardiac vein (VCM) (Fig. 2, panel A). Radiofrequency (RF) was administered with a non-irrigated bidirectional catheter within this vessel with resolution of the pre-excitation after 5 seconds. Immediately after, the patient presented chest pain and revealed a ST segment elevation of 1 mm in the inferior leads of ECG. Coronary angiography showed occlusion of the middle third of the posterior ventricular branch of the right coronary artery, with no signs of thrombus or dissection. Arterial angioplasty was performed with a bare metal stent, followed by TIMI III distal flow. Retrograde aortic mapping was performed and a precocity of 20 ms was found in the PSE region. The RF was applied followed by loss of pre-excitation after 1.5 seconds of application. CONCLUSION: This case demonstrates the risks involving delivering radiofrequency within the coronary sinus. We discuss some strategy that could help electrophysiologists in similar cases.

Objective Evaluation of Gastroesophageal Reflux Disease in Patients with Paroxysmal Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Some evidence shows that gastroesophageal reflux disease (GERD) may be a trigger for paroxysmal AF (PAF). Most of the previous studies that correlated GERD and AF used questionnaires to diagnose GERD, not an objective evaluation. This study aims to evaluate in patients with PAF: (a) accuracy of symptoms to diagnose GERD; (b) prevalence of GERD; and (c) temporal correlation between cardiac arrhythmia and reflux. METHODS: Twenty-two patients (59% females, mean age 68 years) with PAF underwent esophageal manometry followed by ambulatory pH monitoring and concurrent Holter. Eight (36%) patients had GERD symptoms. Patients were grouped as GERD+ or GERD- based on the DeMeester score. Temporal correlation between arrhythmia and reflux was recorded. RESULTS: Six (27%) patients were GERD+. Symptoms had sensitivity and specificity of 50 and 70%, respectively, for the diagnosis of GERD. Episodic AF occurred in one patient only (GERD-). There were 23 episodes of AF during the test with 14% correlation with reflux. Persistent AF during the period of the test was found in five patients (60% GERD+). CONCLUSIONS: Our results show: (a) Symptoms have a low accuracy for the diagnosis of GERD; (b) the prevalence of GERD in patients with PAF is low; and

'Choosing Wisely' culture among Brazilian cardiologists.

OBJECTIVE: (i) To describe how aligned the 'Choosing Wisely' concept is with the medical culture among Brazilian cardiologists and (ii) to identify predictors for physicians' preference for avoiding wasteful care. DESIGN: Cross-sectional study. SETTING: Brazilian Society of Cardiology. PARTICIPANTS: Cardiologists who agree to fill a web questionary. INTERVENTION: A task force of 12 Brazilian cardiologists prepared a list of 13 'do not do' recommendations, which were made available on the Brazilian Society of Cardiology website for affiliates to assign a supported score of 1 to 10 to each recommendation. MAIN OUTCOME MEASUREMENT: Score average for supporting recommendations. RESULTS: Of 14 579 Brazilian cardiologists, 621 (4.3%) answered the questionnaire. The top recommendation was 'do not perform routine percutaneous coronary intervention in asymptomatic individuals' (mean score = 8.0 ± 2.9) while the one with the lowest support was 'do not use an intra-aortic balloon pump in infarction with cardiogenic shock' (5.8 ± 3.2). None of the 13 recommendations presented a mean grade >9 (strong support); 7 recommendations averaged 7-8 (moderate support) followed by 6 recommendations with an average of 5-7 (modest support). Multivariate analysis independently identified predictors of the score attributed to the top recommendation; being an interventionist and time since graduation were both negatively associated with support. CONCLUSIONS: (i) The support of Brazilian cardiologists for the 'Choosing Wisely' concept is modest to moderate, and (ii) older generations and enthusiasm towards the procedure one performs may be factors against the 'Choosing Wisely' philosophy.

Rationale and design of the First Brazilian Cardiovascular Registry of Atrial Fibrillation: The RECALL study.

BACKGROUND: Atrial fibrillation (AF) is an important and growing public health problem worldwide, but data about its actual prevalence, therapeutic management, and clinical outcomes in middle- to low-income countries are scarce. DESIGN: The First Brazilian Cardiovascular Registry of Atrial Fibrillation (the RECALL study) will assess demographic characteristics and evidence-based practice of a representative sample of patients with AF in Brazil. The prospective, multicenter registry has a planned sample size of around 5,000 patients at approximately 80 sites. Eligibility criteria include age >18 years and permanent, paroxysmal, or persistent AF documented by electrocardiogram, 24-hour Holter monitoring, or device interrogation. Patients will be followed up through 1 year after enrollment. Information on laboratory tests, echocardiographic data, medication use, and clinical outcomes will be obtained. Various aspects of the population will be described, including demographic characteristics; antithrombotic therapies; antiarrhythmic agents; level of control of international normalized ratio (by average time within the therapeutic range) among patients using vitamin K antagonists; rates of warfarin discontinuation; outcomes such as death, stroke, systemic embolism, and major bleeding within 1 year after enrollment in the study; and rates of electrical cardioversion, percutaneous ablation of AF, ablation of the atrioventricular junction, and pacemaker/cardioverter-defibrillator implantation. SUMMARY: RECALL is the first prospective, multicenter registry of AF in Brazil. This study will provide important information about demographics, practice patterns, treatments, and associated outcomes in patients with AF. The results of this registry will also allow Brazilian data to be put in perspective with other AF registries across the world and provide opportunities to improve care of patients with AF in Brazil.

Training Program for Cardiology Residents to Perform Focused Cardiac Ultrasound Examination with Portable Device.

INTRODUCTION: Training requirements for general cardiologists without echocardiographic expertise to perform focused cardiac ultrasound (FCU) with portable devices have not yet been defined. The objective of this study was to evaluate a training program to instruct cardiology residents to perform FCU with a hand-carried device (HCD) in different clinical settings. METHODS: Twelve cardiology residents were subjected to a 50-question test, 4 lectures on basic echocardiography and imaging interpretation, the supervised interpretation of 50 echocardiograms and performance of 30 exams using HCD. After this period, they repeated the written test and were administered a practical test comprising 30 exams each (360 patients) in different clinical settings. They reported on 15 parameters and a final diagnosis; their findings were compared to the HCD exam of a specialist in echocardiography. RESULTS: The proportion of correct answers on the theoretical test was higher after training (86%) than before (51%; P = 0.001). The agreement was substantial among the 15 parameters analyzed (kappa ranging from 0.615 to 0.891; P < 0.001). The percentage of correct interpretation was lower for abnormal (75%) than normal (95%) items, for valve abnormalities (85%) compared to other items (92%) and for graded scale (87%) than for dichotomous (95%) items (P < 0.0001, for all). For the final diagnoses, the kappa value was higher than 0.941 (P < 0.001; 95% CI [0.914, 0.955]). CONCLUSION: The training proposed enabled residents to perform FCU with HCD, and their findings were in good agreement with those of a cardiologist specialized in echocardiography.

Ventricular arrhythmias are not a short-term reproducible phenomenon--why long recording monitoring is necessary.

BACKGROUND: The variability of ventricular arrhythmias (VA) among different days of the week is not well detected by one-day Holter monitoring. AIMS: To evaluate whether there are differences in VA distribution pattern during long recording period. METHODS: The EKG was recorded for 14 h per day during 7 days by Holter system in 34 consecutive pat ventricular couplets and non-sustained ventricular tachycardia (NSVT) recording from patients provided graphic data. We applied the Hurst method (H Coefficient) which evaluates whether a repetitive phenomenon is random or not. When the H is >0.5 and <1 means it is not random and implies a long-term memory effect. Considering the arrhythmic variability, the data were also analyzed by repetitive ANOVA comparing incidence of arrhythmias among the days. RESULTS: Isolated PVCs and ventricular couplets during 98 h recording provided graphic of the occurrence. A trend of increasing and decreasing of arrhythmias was observed which looks erratic. The H coefficient, however, was significantly >0.5 for all patients. Repeated ANOVA showed statistic difference among days in 31 patients with isolated PVCs; in 26 with ventricular couplets and 19 with NSVT when analyzed per hour during week days (p < 0.05). CONCLUSION: PVCs, ventricular couplets and NSVT are not a random phenomenon. Our data suggest the occurrence of ventricular arrhythmias had no similarity among the days, making unlikely that a single Holter recording for 24h may capture this phenomenon.

CHronic use of Amiodarone aGAinSt Implantable cardioverter-defibrillator therapy for primary prevention of death in patients with Chagas cardiomyopathy Study: rationale and design of a randomized clinical trial.

BACKGROUND: The implantable cardioverter defibrillator (ICD) is better than antiarrhythmic drug therapy for the primary and secondary prevention of all-cause mortality and sudden cardiac death in patients with either coronary artery disease or idiopathic dilated cardiomyopathy. This study aims to assess whether the ICD also has this effect for primary prevention in chronic Chagas cardiomyopathy (CCC). METHODS: In this randomized (concealed allocation) open-label trial, we aim to enroll up to 1,100 patients with CCC, a Rassi risk score for death prediction of ≥10 points, and at least 1 episode of nonsustained ventricular tachycardia on a 24-hour Holter monitoring. Patients from 28 centers in Brazil will be randomly assigned in a 1:1 ratio to receive an ICD or amiodarone (600 mg/d for 10 days, then 200-400 mg/d until the end of the study). The randomization sequence will be generated by computer, and the members of the committees responsible for end point validation and data analysis will be blinded to study assignment. The primary end point is all-cause death, and enrolment will continue until 256 patients have reached this end point. Key secondary end points include cardiovascular death, sudden cardiac death, hospitalization for heart failure, and quality of life. We expect follow-up to last 3 to 6 years, and data analysis will be done on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov number NCT01722942. CONCLUSION: CHAGASICS is the first large-scale trial to assess the benefit of ICD therapy for the primary prevention of death in patients with CCC and nonsustained ventricular tachycardia, who have a moderate to high risk of death.

The impact of sleep duration in obstructive sleep apnea patients.

PURPOSE: Obstructive sleep apnea (OSA) is a risk factor for cardiovascular disease. Strong associations have been reported among sleep duration, hypertension, obesity, and cardiovascular mortality. The authors hypothesize that sleep duration may play a role in OSA severity. The aim of this study is to analyze sleep duration in OSA patients. METHODS: Patients who underwent overnight polysomnography were consecutively selected from the Sleep Clinic of Universidade Federal de São Paulo database between March 2009 and December 2010. All subjects were asked to come to the Sleep Clinic at 8:00 a.m. for a clinical evaluation and actigraphy. Anthropometric parameters such as weight, height, hip circumference, abdominal circumference, and neck circumference were also measured. RESULTS: One hundred thirty-three patients were divided into four groups based on total sleep time, sleep efficiency, sleep latency, and wake after sleep onset: very short sleepers (n = 11), short sleepers (n = 21), intermediate sleepers (n = 56), and sufficient sleepers (n = 45). Apnea-hypopnea index (AHI) was higher in very short sleepers (50.18 ± 30.86 events/h) compared with intermediate sleepers (20.36 ± 14.68 events/h; p = 0.007) and sufficient sleepers (23.21 ± 20.45 events/h; p = 0.02). Minimal and mean arterial oxygen saturation and time spent below 90 % oxygen saturation exhibited worse values in very short sleepers. After adjustment for gender, age, AHI, and body mass index, mean oxygen saturation was significantly associated to total sleep time (p = 0.01). CONCLUSIONS: In conclusion, the present study suggests that sleep duration may be associated to low mean oxygen saturation in OSA patients.

Impact of prophylactic corticosteroids on systemic inflammation after extensive atrial ablation in pigs.

AIMS: Prophylactic corticosteroids have been reported to attenuate the increase in C-reactive protein (CRP) and the incidence of atrial fibrillation (AF) both after heart surgery and AF ablation. We tested the impact of a single prophylactic corticosteroid dose on ultrasensitive CRP 24 h and 14 days after extensive linear atrial ablation (8 mm or 3.5 irrigated tip) guided by electroanatomical mapping (NavX) in pigs with normal hearts. METHODS AND RESULTS: Pigs (n = 19; 35 kg) were divided into three groups: corticoid (n = 7), atrial ablation with administration of 500 mg methylprednisolone intravenous at anaesthetic induction; control (n = 7), atrial ablation only; and sham (n = 5), surgical procedure without ablation. Troponin and CRP were measured before, 24 h and 14 days after the procedure. After sacrifice, lesions were analysed macroscopically and histologically. Linear lesions were created in the right (n = 23) and left (n = 21) atrium of 14 animals, with no difference between groups. In all groups there was elevation of troponin and CRP 24 h after ablation, with a return to baseline values after 14 days. However, CRP levels of the control, corticoid, and sham groups were similar at all three time points analysed (baseline P = 0.52, 24 h P = 0.21, 14 days P = 0.66). Histological analysis did not show any difference between corticoid and control groups. CONCLUSION: In this model, extensive biatrial RF ablation, per se, does not promote systemic inflammation. The use of a prophylactic single corticoid dose before ablation did not prevent systemic inflammation or alter the healing of the lesions.

Radiofrequency ablation does not induce apoptosis in the rat myocardium.

BACKGROUND: The mechanisms implicated in the genesis of delayed radiofrequency (RF) effects remain unclear, but may be related to extension of the lesion beyond the region of coagulative necrosis. The role of apoptosis in this process has not been previously reported. We assessed whether RF promotes apoptosis in the region surrounding acute ablation lesions in a rat model. METHODS: Wistar rats (n=30; weight 300 g) were anesthesized, the chest was opened, and the heart was exposed. A modified unipolar RF ablation (custom catheter 4.5-mm-tip diameter, 12 Watts, 10 seconds) was undertaken on the left ventricular anterolateral epicardial surface and the chest was closed. After 2 hours, animals were killed for histological (hematoxylin and eosin, TdT-mediated dUTP Nick End-Labeling [TUNEL] assay) and immunohistochemical (anti-BAD and anti-caspase 3 antibodies) analysis (n=18). Additional animals (n=12) were sacrificed at 2 (n=3), 24 (n=3), 48 (n=3), and 72 hours (n=3) after ablation exclusively for anti-BAD Western Blotting analysis. RESULTS: Lesions were characterized by well-defined regions of coagulative necrosis. In 18/18 (100%) animals, TUNEL assay revealed positive luminescent reaction cells in the region surrounding the lesion, extending up to 2 mm from the border zone. However, microscopic evaluation of the nuclei and immunohistochemical and anti-BAD Western Blotting analysis were negative in all (100%) rats. Thus, positive TUNEL reaction in the periphery of the ablation lesion likely reflects nonspecific DNA damage. CONCLUSION: RF ablation does not promote apoptosis in the periphery of the myocardial lesion. This finding may have implications for the elucidation of late lesion extension following RF ablation.

Volume-time curve: an alternative for endotracheal tube cuff management.

BACKGROUND: Despite numerous studies on endotracheal tube cuff pressure (CP) management, the literature has yet to establish a technique capable of adequately filling the cuff with an appropriate volume of air while generating low CP in a less subjective way. The purpose of this prospective study was to evaluate and compare the CP levels and air volume required to fill the endotracheal tubes cuff using 2 different techniques (volume-time curve versus minimal occlusive volume) in the immediate postoperative period after coronary artery bypass grafting. METHODS: A total of 267 subjects were analyzed. After the surgery, the lungs were ventilated using pressure controlled continuous mandatory ventilation, and the same ventilatory parameters were adjusted. Upon arrival in the ICU, the cuff was completely deflated and re-inflated, and at this point the volume of air to fill the cuff was adjusted using one of 2 randomly selected techniques: volume-time curve and minimal occlusive volume. We measured the volume of air injected into the cuff, the CP, and the expired tidal volume of the mechanical ventilation after the application of each technique. RESULTS: The volume-time curve technique demonstrated a significantly lower CP and a lower volume of air injected into the cuff, compared to the minimal occlusive volume technique (P < .001). No significant difference was observed in the expired tidal volume between the 2 techniques (P = .052). However, when the subjects were submitted to the minimal occlusive volume technique, 17% (n = 47) experienced air leakage as observed by the volume-time graph. CONCLUSIONS: The volume-time curve technique was associated with a lower CP and a lower volume of air injected into the cuff, when compared to the minimal occlusive volume technique in the immediate postoperative period after coronary artery bypass grafting. Therefore, the volume-time curve may be a more reliable alternative for endotracheal tube cuff management.

Epicardial and Endocardial Ablation Based on Channel Mapping in Patients With Ventricular Tachycardia and Chronic Chagasic Cardiomyopathy: Importance of Late Potential Mapping During Sinus Rhythm to Recognize the Critical Substrate.

Background Ventricular tachycardia (VT) in patients with chronic chagasic cardiomyopathy (CCC) is associated with considerable morbidity and mortality. Catheter ablation of VT in patients with CCC is very complex and challenging. The main goal of this work was to assess the efficacy of VT catheter ablation guided by late potentials (LPs) in patients with CCC. Methods and Results Seventeen consecutive patients with refractory VT and CCC were prospectively included in the study. Combined endo-epicardial voltage and late activation mapping were obtained during baseline rhythm to define scarred and LP areas, respectively. The end point of the ablation procedure was the elimination of all identified LPs. Epicardial and endocardial dense scars (<0.5 mV) were detected in 17/17 and 15/17 patients, respectively. LPs were detected in the epicardial scars of 16/17 patients and in the endocardial scars of 14/15 patients. A total of 63 VTs were induced in 17 patients; 22/63 (33%) were stable and entrained, presenting LPs recorded in the isthmus sites. The end point of ablation was achieved in 15 of 17 patients. Ablation was not completed in 2 patients because of cardiac tamponade or vicinity of the phrenic nerve and circumflex artery. Three patients (2 with unsuccessful ablation) had VT recurrence during follow-up (39 months). Conclusions Endo-epicardial LP mapping allows us to identify the putative isthmuses of different VTs and effectively perform catheter ablation in patients with CCC and drug-refractory VTs.