Anísio Pedrosa

Efficacy of Antibiotic Prophylaxis Before the Implantation of Pacemakers and Cardioverter-Defibrillators: Results of a Large, Prospective, Randomized, Double-Blinded, Placebo-Controlled Trial

Background—Although routinely administered, definitive evidence for the benefits of prophylactic antibiotics before the implantation of permanent pacemakers and implantable cardioverter-defibrillators from a large double-blinded placebo-controlled trial is lacking. The purpose of this study was to determine whether prophylactic antibiotic administration reduces the incidence of infection related to device implantation. Methods and Results—This double blinded study included 1000 consecutive patients who presented for primary device (Pacemaker and implantable cardioverter-defibrillators) implantation or generator replacement randomized in a 1:1 fashion to prophylactic antibiotics or placebo. Intravenous administration of 1 g of cefazolin (group I) or placebo (group 2) was done immediately before the procedure. Follow-up was performed 10 days, 1, 3, and 6 months after discharge. The primary end point was any evidence of infection at the surgical incision (pulse generator pocket), or systemic infection related to be procedure. The safety committee interrupted the trial after 649 patients were enrolled due to a significant difference in favor of the antibiotic arm (group I: 2 of 314 infected patients—0.63%; group II: 11 of 335 to 3.28%; RR=0.19; P=0.016). The following risk factors were positively correlated with infection by univariate analysis: nonuse of preventive antibiotic (P=0.016); implant procedures (versus generator replacement: P=0.02); presence of postoperative hematoma (P=0.03) and procedure duration (P=0.009). Multivariable analysis identified nonuse of antibiotic (P=0.037) and postoperative hematoma (P=0.023) as independent predictors of infection. Conclusions—Antibiotic prophylaxis significantly reduces infectious complications in patients undergoing implantation of pacemakers or cardioverter-defibrillators.

Biventricular Pacing Improves Clinical Behavior and Reduces Prevalence of Ventricular Arrhythmia in Patients with Heart Failure

PURPOSE To analyze the influence of biventricular pacing (BP) on clinical behavior, ventricular arrhythmia (VA) prevalence, and left ventricular ejection fraction (LV EF) by gated ventriculography. METHODS Twenty-four patients with left bundle branch block (LBBB) and NYHA class III and IV underwent pacemaker implantation and were randomized either to the conventional or BP group, all receiving BP after 6 months. RESULTS Sixteen patients were in NYHA class IV (66.6%) and 8 were in class III (33.4%). After 1-year follow-up, 14 patients were in class II (70%) and 5 were in class III (25%). Two sudden cardiac deaths occurred. A significant reduction in QRS length was found with BP (p=0.006). A significant statistical increase, from a mean of 19.13 +/- 5.19% (at baseline) to 25.33 +/- 5.90% (with BP) was observed in LVEF Premature ventricular contraction prevalence decreased from a mean of 10,670.00 +/- 12,595.39 SD or to a mean of 3,007.00 +/- 3,216.63 SD PVC/24 h with BP (p<0.05). Regarding the hospital admission rate over 1 year, we observed a significant reduction from 60. To 16 admissions with BP (p<0.05). CONCLUSION Patients with LBBB and severe heart failure experienced, with BP, a significant NYHA class and LVEF improvement. A reduction in the hospital admission rate and VA prevalence also occurred.

Cardiac Damage from Chronic Use of Chloroquine: A Case Report and Review of the Literature

Chloroquine has been widely used in rheumatological treatment, but potential severe side effects require careful follow-up. Cardiac damage is not a common consequence, but its clinical relevance has not yet been described. We report the case of a 58-year-old woman with rheumatoid arthritis, in whom chronic chloroquine use resulted in major irreversible cardiac damage. She presented with syncopal episodes due to complete atrioventricular block confirmed by electrophysiological study whose changes were concluded to be irreversible and a permanent pacemaker was indicated. Endomyocardial biopsy was also performed to search for histopathological and ultrastructural cardiac damage. We also reviewed the 22 cases of chloroquine-induced cardiopathy described to date as well as its pathophysiology.

Evidence for cardiac safety and antiarrhythmic potential of chloroquine in systemic lupus erythematosus.

AIMS To perform a comprehensive evaluation of heart rhythm disorders and the influence of disease/therapy factors in a large systemic lupus erythematosus (SLE) cohort. METHODS AND RESULTS Three hundred and seventeen consecutive patients of an ongoing electronic database protocol were evaluated by resting electrocardiogram and 142 were randomly selected for 24 h Holter monitoring for arrhythmia and conduction disturbances. The mean age was 40.2 ± 12.1 years and disease duration was 11.4 ± 8.1 years. Chloroquine (CQ) therapy was identified in 69.7% with a mean use of 8.5 ± 6.7 years. Electrocardiogram abnormalities were detected in 66 patients (20.8%): prolonged QTc/QTd (14.2%); bundle-branch block (2.5%); and atrioventricular block (AVB) (1.6%). Age was associated with AVB (P = 0.029) and prolonged QTc/QTd (P = 0.039) whereas anti-Ro/SS-A and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores were not (P > 0.05). Chloroquine was negatively associated with AVB (P = 0.01) as was its longer use (6.1 ± 6.9 vs. 1.0 ± 2.5 years, P = 0.018). Time of CQ use was related with the absence of AVB [odds ratio (OR) = 0.103; 95% confidence interval (CI) = 0.011-0.934, P = 0.043] in multiple logistic regression. Holter monitoring revealed abnormalities in 121 patients (85.2%): supraventricular ectopies (63.4%) and tachyarrhythmia (18.3%); ventricular ectopies (45.8%). Atrial tachycardia/fibrillation (AT/AF) were associated with shorter CQ duration (7.05 ± 7.99 vs. 3.63 ± 5.02 years, P = 0.043) with a trend to less CQ use (P = 0.054), and older age (P < 0.001). Predictors of AT/AF in multiple logistic regression were age (OR = 1.115; 95% CI = 1.059-1.174, P < 0.001) and anti-Ro/SS-A (OR = 0.172; 95% CI = 0.047-0.629, P = 0.008). CONCLUSIONS Chloroquine seems to play a protective role in the unexpected high rate of cardiac arrhythmias and conduction disturbances observed in SLE. Further studies are necessary to determine if this antiarrhythmic effect is due to the disease control or a direct effect of the drug.

Neurohumoral behavior in recipients of cardiac pacemakers controlled by a closed-loop autonomic nervous system-driven sensor.

The purpose of a sensor‐driven pacing system is to physiologically correct chronotropic incompetence (CI). The aim of this study was to evaluate the changes in heart rate provided by a sympathetically driven pacemaker (PM) compared with normal sinus function (NSF). Nine men and six women (age 37–80 years) with AV block and a PM controlled by a closed‐loop system were studied. Group I included eight patients with CI, and group II included seven patients with NSF. All patients underwent Valsalva maneuver and tilt table testing with measurements of plasma catecholamines and renin activity. Pacing was initially programmed in the DDDC mode at a lower rate (60 ppm) and upper rate limit (0.85 × [220 ‐ age]), then in DDDR in group I and VVIR in group II. The second phase of the study consisted of nitroglycerin and phenylephrine infusions, and the third phase of physiological provocative maneuvers. The second and third phases were performed in three patients from each group with sensor activity On and Off. In group I, heart rate changed during tilt only in the DDDR mode. In group II, heart rate changes were comparable in both modes. Catecholamine levels in group I were higher during DDDC than during DDDR pacing (P < 0.05). In group I, heart rate did not change during phases II and IV of the Valsalva maneuver in the DDDC mode, but behaved nearly physiologically after sensor activation. A late and a paradoxical response to nitroglycerin was observed in groups I and II and to phenylephrine in group I. During physiological maneuvers, significantly greater variations in heart rate were observed during DDDR than during DDDC pacing. Sympathetic SDP provides physiological modulations of the heart rate were provided by a sympathetically driven pacing system in patients with AV block and CI.

Diretriz de interpretação de eletrocardiograma de repouso

Jose Alves Pinho (BA), Mario Sergio de Carvalho Bacellar (BA),Demostenes G. Lima Ribeiro (CE), Rubens Nassar Darwich (MG),Antonio Luiz Pinho Ribeiro (MG), Marcelo Marcos Eloy Dunda (PB),Helio Germiniani (PR), Francisco Faustino Franca (PE),Laurindo Saraiva (PE), Clebia Maria Rios Ribeiro (PE),Paulo Ginefra (RJ), Iseu Gus (RS), Eney Fernandes (SC),Andres Riera (SC), Anisio Pedrosa (SP),Antonio Americo Friedman (SP), Antonio Carlos Firmiani (SP),Cesar Grupi (SP), Claudio Pinho (SP),Eduardo Vilaca Lima (SP), Elisabeth Kaiser (SP),Fabio Sandoli Brito (SP), Gilberto Luiz Castro Vinhas (SP),Helio Schwartz (SP), Jose Grindler (SP), Jose Luiz Aziz (SP),Marcio Figueiredo (SP), Marcos S. Molina (SP),Martino Martinelli (SP), Nancy Tobias (SP),Paulo Cesar R. Sanches (SP), Paulo Jorge Moffa (SP),Severino Attanes Neto (SP), Silvana Nishioka (SP)

Comportamento funcional dos portadores de marcapasso convencional submetidos a ressincronização cardíaca

BACKGROUND Cardiac resynchronization therapy (CRT) is an efficient treatment for patients with heart failure (HF), severe ventricular dysfunction and intraventricular block. Conventional pacemakers (CPM) implanted in the right ventricular apical area cause alterations in the normal sequence of cardiac activation similar to those induced by LBBB (left bundle-branch block). Therefore, patients with CPM and advanced HF could be candidates to undergo CRT, but as only small numbers of patients have been evaluated so far, definitive conclusions are lacking. OBJECTIVE To assess the clinical and functional outcome of cardiac resynchronization therapy (CRT) in patients with conventional pacemakers. METHODS Patients with CPM, who were in NYHA HF functional class III/IV class refractory to drug therapy, and left ventricular ejection fraction (LVEF) ) <35% underwent CRT. Patients clinical-functional behavior was assessed prospectively six months after the procedure. The improvement of one HF-functional class was set as an effective response to the procedure. The following was assessed: QRS duration (ECG), diastolic diameter (LVDd), left ventricular systolic diameter (LVSd) and LVEF seen on the echocardiogram. For the statistical analysis, Students paired t test and Spearmans correlation were used. RESULTS Twenty-nine patients (mean age 61.5) were evaluated. Of these, six were females, and chagasic cardiomyopathy was predominant. During the clinical follow-up of 22.7+/-13 months, 86.2% of the patients benefited from CRT. Within this group, the mean LVEF increased by 18% (p=0.013), QRS duration dropped by 11.8% (p=0.002) and no significant reduction in left ventricular intracavitary diameters was observed. CONCLUSION CRT is effective for patients with CPM and advanced HF as it yields a high rate of response (86.2%), significantly improves LVEF and reduces QRS duration.

Ativação elétrica ventricular na ressincronização cardíaca caracterizada pelo mapeamento eletrocardiográfico de superfície

OBJECTIVES: To assess cardiac electrical activation by using body surface potential mapping (BSPM), in patients with congestive heart failure (CHF) and left bundle branch block (LBBB) undergoing cardiac resynchronization therapy (CRT) with biventricular pacemaker (BIV-PM) implantation. METHODS: Mean cardiac electrical activation times were analyzed in the right ventricle (RV) (mean RV activation time = mRV), anteroseptal area (mAS), and left ventricle (mLV) of 28 patients (mean age 61.2 ± 9.5 years; NYHA class III-IV CHF; ejection fraction <40%; LBBB of mean QRS 181.2±19.4ms, SÂQRS -8.5o±68.6o), as shown in their BSPM isochronous maps, before and after implantation of atriobiventricular pacemaker, comparing those with values obtained from a control group of normal individuals [CG], in three situations: (1) native LBBB; (2) RV pacing; and (3) atriobiventricular pacing. RESULTS: Situation (1): mRV and mAS values were similar (41.0±11.8ms x 43.6±13.4ms), with delayed mLV (81.0±12.5ms, p<0.01) and asynchronous with RV and AS areas; situation (2): mRV was greater than in CG (86.8±22.9ms, p<0.001), with greater difference between mAS and mLV (63.4±20.7ms vs. 102.7±20.3ms; p<0,001); situation (3): mLV and mRV were similar (72.0±32.0ms vs. 71.6±32.3ms), mRV was greater than in CG and native LBBB (71.6±32.3ms vs. 35.1±10.9ms and 41.0±11.8ms; p<0.001), and mAS was close to CG and native LBBB values (51.3±32.8ms vs. 50.1±11.4ms and 43.6±13.4ms). CONCLUSION: The body surface potential mapping showed that RV and LV activation times which are similar, and are close to those of the AS area, suggest patterns of synchronized ventricular activation in patients with CHF and LBBB during atriobiventricular pacing.

Global and regional ventricular repolarization study by body surface potential mapping in patients with left bundle-branch block and heart failure undergoing cardiac resynchronization therapy.

Background: The controversial effects promoted by cardiac resynchronization therapy (CRT) on the ventricular repolarization (VR) have motivated VR evaluation by body surface potential mapping (BSPM) in CRT patients.

Criteria for pacemaker explant in patients without a precise indication for pacemaker implantation.

MARTINELLI, M., et al.: Criteria for Pacemaker Explant in Patients Without a Precise Indication for Pacemaker Implantation. Unnecessary pacemaker implantation may cause significant social and psychological consequences, the inconvenience of periodic office visits, and the expense of pulse generator replacement. Establishing adequate criteria for explanting pacemakers is crucial and has not yet been described. This study presents the results of a study protocol for explanting the pacemaker in patients without a clear indication for pacemaker implantation. Seventy pacemaker users without a clear reason for the implantation were included in the study conducted from August 1986 to November 1998 and were prospectively followed. The investigation consisted of clinical and neurological evaluations, echocardiogram, exercise testing, and tilt table testing. When these tests were negative, the pulse generator energy and stimulation rates were reprogrammed to the lowest values. Periodic Holter monitoring was conducted during follow‐up. When asymptomatic for 1 year, patients underwent an electrophysiological evaluation of sinus and atrioventricular junction function and ventricular vulnerability. When the electrophysiological study was negative, pacemaker explantation was performed. Of the 70 patients, 35 had their pacemaker explanted; 3 were excluded due to a positive tilt table test and electrophysiological study, and 3 are waiting for pacemaker explantation. Mean follow‐up after pacemaker explantation was 30.3 months, and all patients remained asymptomatic, except for one patient who died of a noncardiac cause. Critical analysis of pacemaker users without a well‐established indication is justified because it may allow pacemaker explant in a significant proportion of these patients, and it may bring considerable social, economic, and psychological benefits.