Gustavo Glotz de Lima

Randomized study of propofol effect on electrophysiological properties of the atrioventricular node in patients with nodal reentrant tachycardia.

Background: Atrioventricular nodal reentrant tachycardia (AVNRT) is probably the most common form of paroxysmal supraventricular tachycardia. Percutaneous catheter ablation is a technique to interrupt cardiac conduction pathways selectively. The anesthetist is challenged to provide a safe anesthetic which takes into account the electrophysiologists requirements for minimal cardiac conduction interference. Propofol is an ideal drug. However, previous studies have shown that the infusion of propofol has sometimes been associated with bradyarrhythmias or conversion of arrhythmias to sinusal rhythm. The purpose of this report is to verify the interferences of propofol in the electrophysiological properties of the atrioventricular (AV) node conduction system in patients with AVNRT.

Effects of Propofol on the Cardiac Conduction System

BACKGROUND AND OBJECTIVES Some studies have demonstrated that the use of propofol is occasionally associated with bradyarrhythmias or reversion of arrhythmias to sinus rhythm. This property of propofol suggests interference with the Cardiac Conduction System (CCS). CONTENTS A review of the main contemporary articles on the use of propofol in the presence of cardiac arrhythmias was undertaken. The authors describe pathophysiological mechanisms of supraventricular tachyarrhythmias (SVT) and occasional interferences caused by propofol on the CCS. CONCLUSIONS The studies undertaken so far seem to indicate that propofol probably interferes in automatic SVT (at least in children), but not in reentrant tachyarrhythmias.

One‐to‐Two Atrioventricular Conduction Causing Nonreentrant Tachycardia: Successful Treatment with Radiofrequency Ablation

The anatomical substrate for AV nodal reentrant tachycardia (AVNRT) is well known and is due to anterograde conduction through a siow conducting pathway and retrograde conduction using a fast conducting path way. In this report, we describe a patient with AVNRT who also presented with frequent episodes of paroxysmal nonreentrant tachycardia due to the occurrence of two conducted ventricular beats for each sinus depolarization. Palpitations and arrhythmias were abolished after radiofrequency ablation of the slow pathway.

Marca-passo permanente após implante percutâneo valvular aórtico: a necessidade é maior que imaginávamos?

ABSTRACT Permanent Pacemaker After Percutaneous AorticValve Implantation: Is the Need Greater thanWe Had Anticipated? Background: Percutaneous aortic valve implantation (PAVI)is a promising alternative treatment for severe aorticstenosis in high surgical risk patients. However, part ofthese patients may develop electrical conduction systemdisturbances and require permanent pacemaker implan-tation. The mechanism of such electrical conduction systemdisturbances has not been totally elucidated. Our objectiveis to assess the frequency and factors related to the needof a permanent pacemaker (PPM) in this scenario. Method: A series of cases describing absolute and relative variablesassociated to PPM implantation in patients submitted toPAVI at Instituto de Cardiologia do Rio Grande do Sul. Results: Between November 2008 and November 2009,ten patients were submitted to PAVI using the CoreValve TM prosthesis. Two patients who died due to complicationsnot associated to the conduction system disturbances we-re excluded. The procedure was successfully carried outin the eight remaining patients, with gradient reductionbetween the left ventricle and aorta and symptomaticrelief. Most of the patients were women (75%) and meanage was 86 years. PPM was required in six patients (75%)after PAVI. The single procedure related event was thedevelopment of left bundle branch block (LBBB). Duringclinical follow-up, one patient resumed sinus rhythm,two alternated their own rhythm with the pacemakerrhythm and three remain totally dependent of artificialstimulus.

CHA2 DS2 VASc Score as a Predictor of Cardiovascular Events in Ambulatory Patients without Atrial Fibrillation.

New evidence suggests that the CHA2DS2VASc (congestive heart failure, hypertension [HTN], age, diabetes, stroke, vascular disease, and female gender) score may be a reliable tool to predict the risk of thromboembolic events in patients without documented atrial fibrillation (AF).

Struck by Lightning A Case of Nature-Induced Pre-excited Atrial Fibrillation

A 28-year-old man, with no previous medical history, was brought to the emergency department after being struck by a lightning bolt while working in an open field during a storm. He immediately received bystander cardiopulmonary resuscitation and was conscious at the time of arrival at the hospital. An initial evaluation revealed the presence of an electric burn at the entry site near the right elbow and exit wounds (punctate burns) on both feet (Figure 1A and 1B). Signs of hemodynamic compromise (blood pressure, 90/40 mm Hg; heart rate, 160 beats per minute) were also observed. His ECG revealed an irregular wide complex tachycardia with …

Risk of ionizing radiation in women of childbearing age undergoing radiofrequency ablation.

Background The International Commission of Radiology recommends a pregnancy screening test to all female patients of childbearing age who will undergo a radiological study. Radiation is known to be teratogenic and its effect is cumulative. The teratogenic potential starts at doses close to those used during these procedures. The prevalence of positive pregnancy tests in patients undergoing electrophysiological studies and/or catheter ablation in our midst is unknown. Objective To evaluate the prevalence of positive pregnancy tests in female patients referred for electrophysiological study and/or radiofrequency ablation. Methods Cross-sectional study analyzing 2,966 patients undergoing electrophysiological study and/or catheter ablation, from June 1997 to February 2013, in the Institute of Cardiology of Rio Grande do Sul. A total of 1490 procedures were performed in women, of whom 769 were of childbearing age. All patients were screened with a pregnancy test on the day before the procedure. Results Three patients tested positive, and were therefore unable to undergo the procedure. The prevalence observed was 3.9 cases per 1,000 women of childbearing age. Conclusion Because of their safety and low cost, pregnancy screening tests are indicated for all women of childbearing age undergoing radiological studies, since the degree of ionizing radiation needed for these procedures is very close to the threshold for teratogenicity, especially in the first trimester, when the signs of pregnancy are not evident.

Catheter ablation of arrhythmias exclusively using electroanatomic mapping: a series of cases.

Background Catheter ablation is a treatment that can cure various cardiac arrhythmias. Fluoroscopy is used to locate and direct catheters to areas that cause arrhythmias. However, fluoroscopy has several risks. Electroanatomic mapping (EAM) facilitates three-dimensional imaging without X-rays, which reduces risks associated with fluoroscopy. Objective We describe a series of patient cases wherein cardiac arrhythmia ablation was exclusively performed using EAM. Methods Patients who presented with cardiac arrhythmias that were unresponsive to pharmacological therapy were prospectively selected between March 2011 and March 2012 for arrhythmia ablation exclusively through EAM. Patients with indications for a diagnostic electrophysiology study and ablation of atrial fibrillation, left atrial tachyarrhythmias as well as hemodynamically unstable ventricular arrhythmia were excluded. We documented the procedure time, success rate and complications as well as whether fluoroscopy was necessary during the procedure. Results In total, 11 patients were enrolled in the study, including seven female patients (63%). The mean age of the patients was 50 years (SD ±16.5). Indications for the investigated procedures included four cases (35%) of atrial flutter, three cases (27%) of pre-excitation syndrome, two cases (19%) of paroxysmal supraventricular tachycardia and two cases (19%) of ventricular extrasystoles. The mean procedure duration was 86.6 min (SD ± 26 min). Immediate success (at discharge) of the procedure was evident for nine patients (81%). There were no complications during the procedures. Conclusion This study demonstrates the feasibility of performing an arrhythmia ablation exclusively using EAM with satisfactory results.

Chronotropic response to exercise after pulmonary veins isolation or Cox-maze operation

OBJECTIVE To evaluate the chronotropic response to exercise during immediate and late postoperative period after atrial fibrillation and mitral valve surgical treatment by different techniques. METHODS Prospective controlled clinical study of 42 patients presenting chronic AF associated mitral valve disease, who underwent surgery by the techniques of pulmonary veins isolation (n=16), Modified Cox-maze procedure, without cryoablation (n=13), both with isolated mitral valve repair (n=13). The preoperative clinical characteristics, surgical indications, kind and aetiology of valve lesion were similar between groups. The patients were outpatient followed-up and underwent series of ergometric tests. RESULTS In the immediate postoperative period, chronotropic response was similar in the 3 groups with mean of 73.6 +/- 12.3% of maximal calculated heart rate. In the surgical pulmonary veins isolation group, there was an increment of heart rate, from 64.4 +/- 12.4% of maximal heart rate in the immediate postoperative period to 78.9 +/- 10.5% in the 12th month (P=0.012) of postoperative. In the Cox-maze group, heart rate varied, respectively, from 73.9 +/- 11.14% to 78.8 +/- 15.2% (P=1.000) and in the control group (only mitral valve surgery), from 67.2 +/- 14.3% to 71.9 +/- 12.9% (P=0.889). CONCLUSION An attenuation of immediate postoperative chronotropic response to exercise was similar in the postoperative in the three different surgical techniques. There was a significant improvement in this response concerning to postoperative outcome in the pulmonary veins isolation group. These results suggest that simple surgical pulmonary veins isolation may be related to a better preservation of atrial chronotropism.

Relationship between silent atrial fibrillation and the maximum heart rate in the 24-hour Holter: cross-sectional study

CONTEXT AND OBJECTIVE Occurrences of asymptomatic atrial fibrillation (AF) are common. It is important to identify AF because it increases morbidity and mortality. 24-hour Holter has been used to detect paroxysmal AF (PAF). The objective of this study was to investigate the relationship between occurrence of PAF in 24-hour Holter and the symptoms of the population studied. DESIGN AND SETTING Cross-sectional study conducted at a cardiology hospital. METHODS 11,321 consecutive 24-hour Holter tests performed at a referral service were analyzed. Patients with pacemakers or with AF throughout the recording were excluded. RESULTS There were 75 tests (0.67%) with PAF. The mean age was 67 ± 13 years and 45% were female. The heart rate (HR) over the 24 hours was a minimum of 45 ± 8 bpm, mean of 74 ± 17 bpm and maximum of 151 ± 32 bpm. Among the tests showing PAF, only 26% had symptoms. The only factor tested that showed a correlation with symptomatic AF was maximum HR (165 ± 34 versus 147 ± 30 bpm) (P = 0.03). Use of beta blockers had a protective effect against occurrence of PAF symptoms (odds ratio: 0.24, P = 0.031). CONCLUSIONS PAF is a rare event in 24-hour Holter. The maximum HR during the 24 hours was the only factor correlated with symptomatic AF, and use of beta blockers had a protective effect against AF symptom occurrence.