Fernando Eugênio dos Santos Cruz Filho

Electrical behavior of T-wave polarity alternans in patients with congenital long QT syndrome.

OBJECTIVES This study was designed to evaluate the incidence and characteristics of onset of T-wave polarity alternans (TWPA) in patients with long QT syndrome. BACKGROUND The T-wave alternans is a phenomenon that consists of beat-to-beat variability in the amplitude, morphology, and sometimes polarity of the T-wave, and it may trigger life-threatening arrhythmias. METHODS The 24-h Holter recordings of 11 patients with congenital long QT syndrome were studied. Episodes of TWPA with 10 or more consecutive cycles were selected and analyzed as follows: 1) mean cycle length (MCL) and QTc interval duration (QTcI) of the episodes of TWPA and the 10 cycles preceding and succeeding the TWPA; 2) MCL and QTcI of the third, second, and first minute before onset (Mn_3, Mn_2, Mn_1); 3) MCL and QTcI from the tenth to the first cycle immediately preceding the onset of TWPA (R_10 to R_1); 4) MCL and QTcI from the first to the fourteenth cycle during alternans (R0 to R14); 5) MCL and QTcI from the first to the tenth cycle immediately succeeding TWPA (R+1 to R+10); 6) linear correlation (Lnc) between QT interval and cycle length (CL) (LncQT/CL) during alternans and for the 10 preceding cycles; 7) Lnc between the first three alternans cycles and episode duration (Lnc 3CL/EpD); and 8) difference between the longest and shortest QTc interval. We also selected episodes consisting of four or more consecutive cycles in order to analyze daily rhythms of the phenomenon. RESULTS The TWPA was observed in 5 (45%) out of the 11 patients studied. The alternans process is initiated by a sudden shortening of the first alternans cycle without previous heart rate changes and ends at the moment when prolongation of the cycle tends to occur. LncQT/ CL-alternans: r = 0.38 +/- 0.2 (p = 0.20); without alternans: r = 0.81 +/- 0.06 (p = 0.01). Lnc 3CL/EpD: r = 0.002 (p = 0.992). The QTc difference during alternans: 312.0 +/- 52.1 ms; without alternans: 86.0 +/- 36.4 ms (p = 0.001). Daily rhythm: 71% of the episodes occurred between 8 AM and 8 PM, with higher incidence during the morning. CONCLUSIONS The TWPA was dependent on the cardiac CL; there was loss of the LncQT/CL and an increase in the QT interval variability. Like other biological variables, T-wave polarity alternans has a higher density during the morning.

Signal-averaged P wave in patients with wolff-parkinson-white syndrome after successful radiofrequency catheter ablation

OBJECTIVES We attempted to establish a relation between the atrial conduction time assessed by the signal-averaged P wave electrocardiogram and episodes of paroxysmal atrial fibrillation in patients with the Wolff-Parkinson-White syndrome. BACKGROUND The incidence of paroxysmal atrial fibrillation is higher in patients with the Wolff-Parkinson-White syndrome than in normal persons. However, the role of intraatrial conduction delay in precipitating the disorganization of atrial rhythm is not completely understood. METHODS The total duration of the signal-averaged P wave and the P wave in standard lead II was evaluated after successful radiofrequency catheter ablation in 28 patients with the Wolff-Parkinson-White syndrome. The data obtained from 17 patients (61%) with a documented history of prior paroxysmal atrial fibrillation (group I) were compared with those obtained from 11 patients (39%) without a history of atrial fibrillation (group 2). Both groups were further compared with a normal control population. RESULTS The mean +/- SD signal-averaged P wave duration in group 1 was 141.94 +/- 9.47 ms (range 130.0 to 171.0). Fourteen patients (82%) in this group showed a P wave duration > 135.0 ms. In group 2, the signal-averaged P wave duration was 126.64 +/- 8.72 ms (range 111.0 to 136.0). Only one patient in this group (9%) showed a P wave duration > 135.0 ms (p < 0.000, group 1 vs. group 2). The signal-averaged P wave duration in the control group was 124.46 +/- 4.49 ms (range 115.0 to 129.5; p < 0.000, group 1 vs. the control group; p < 0.454, group 2 vs. the control group). The P wave duration in lead II was 92.06 +/- 8.85 ms in group 1 and 92.27 +/- 7.86 ms in group 2 (p < 0.949). Using a cutoff value of < 135.0 ms for a normal signal-averaged P wave duration, the method had a sensitivity and specificity and positive and negative predictive values of 82%, 91%, 93% and 77%, respectively, for identifying patients with clinical paroxysmal atrial fibrillation. CONCLUSIONS In the current study, the signal-averaged P wave showed a prolonged intraatrial conduction time in patients with the Wolff-Parkinson-White syndrome and paroxysmal atrial fibrillation. These patients can be differentiated from those with the pre-excitation syndrome without clinical atrial fibrillation as well as from normal subjects. The prolonged intraatrial conduction time may serve as an atrial substratum for development and maintenance of the fibrillatory state.

Tratamento cirúrgico de fibrilação atrial utilizando ablação com radiofrequência bipolar em doença mitral reumática

OBJECTIVE: To analyze the effectiveness of surgical treatment of atrial fibrillation (AF) using bipolar radiofrequency ablation during mitral valve procedures of rheumatic etiology in heart surgery. METHODS: We retrospectively reviewed medical registries of 53 patients submitted to atrial ablation with bipolar radiofrequency energy during mitral valve surgery. Thirty four (64%) patients were women and the age varied from 27 to 72 years old (average: 49.3 ± 10.7 years). Aortic and/or tricuspid procedures were also present in 36 (68%) patients. Average time of reported atrial fibrillation was 41 months (from 3 to 192 months). Type of AF was classified as: paroxysmal in 8 patients, persistent in 3, permanent in 42. Left atrium had an average size of 52.9 ± 8.5 mm. The surgeries in these series were: 47 mitral valve replacements and 6 mitral valve repairs. Eletrocardiografic follow up was 83% complete in 14 months. Data from 24h Holter were explored. RESULTS: Seven (13%) perioperative deaths were observed and survival after 14 months was 87%. Observed heart rhythm after 1 year of surgery was sinus rhythm in 25 (66%) patients, AF in 7 (18%), flutter in 7 (13%), junctional in 1 (3%). CONCLUSION: Bipolar radiofrequency ablation in patients submitted to mitral valve surgery of rheumatic etiology is effective in converting to sinus rhythm in 68% of patients after 14 months.

Uso da radiofrequência bipolar para o tratamento da fibrilação atrial durante cirurgia cardíaca

FUNDAMENTO: O tratamento da fibrilacao atrial com dispositivo de ablacao de tecidos por radiofrequencia bipolar em concomitância a cirurgia cardiaca tem se mostrado metodo eficaz no tratamento desta arritmia. OBJETIVO: Descrever a experiencia inicial do Instituto Nacional de Cardiologia no tratamento cirurgico da fibrilacao atrial com uso de dispositivo de radiofrequencia bipolar em pacientes submetidos a cirurgia cardiaca, relatando o resultado de acompanhamento pos-operatorio de um ano. METODOS: Entre janeiro de 2008 e marco de 2009, 47 pacientes (36 mulheres) consecutivos, com idade media de 53,7 ± 10,6 anos, apresentando fibrilacao atrial por um periodo medio de 34,6 meses (3 a 192 meses) foram submetidos a ablacao cirurgica desta arritmia, por radiofrequencia bipolar, durante o procedimento que motivou a indicacao da cirurgia. Oito apresentavam fibrilacao atrial intermitente e 39, continua. Oitenta e um por cento foram submetidos a cirurgia valvar como procedimento principal. Esta e uma analise retrospectiva, observacional, com avaliacao de um ano de pos-operatorio das variaveis clinicas e de Holter 24 h. RESULTADOS: Dos 47 pacientes, 40 sobreviveram um ano. Desses, 33 foram submetidos a Holter 24 h, em um intervalo medio de 401 dias apos a cirurgia. Encontrou-se a seguinte distribuicao de ritmos: 24 (73%) sinusal, 5 (15%) fibrilacao atrial, tres (9%) Flutter atrial e um (3%) ritmo juncional. Foram observados dois acidentes vasculares encefalicos, sendo um associado a arritmia supraventricular. CONCLUSAO: A ablacao cirurgica de fibrilacao atrial com dispositivo de radiofrequencia bipolar concomitante a cirurgia cardiaca e metodo eficaz para o tratamento desta arritmia.BACKGROUND Atrial fibrillation with tissue ablation device through bipolar radiofrequency in conjunction with cardiac surgery has proven to be an effective method to treat this arrhythmia. OBJECTIVE Describe the initial experience of the Instituto Nacional de Cardiologia in the surgical treatment of atrial fibrillation using bipolar radiofrequency device in patients undergoing cardiac surgery, reporting the results of postoperative follow-up of one year. METHODS Between January 2008 and March 2009, 47 consecutive patients (36 women), with mean age of 53.7 ± 10.6 years, with atrial fibrillation for a mean period of 34.6 months (3-192 months) underwent surgical ablation of this arrhythmia, through bipolar radiofrequency during the procedure which led to the indication of surgery. Eight of them showed intermittent atrial fibrillation and 39, continued. Eighty-one percent underwent valve surgery as the main procedure. This is a one-year postoperative retrospective, observational evaluation of clinical variables and 24-h Holter. RESULTS Out of the 47 patients, 40 survived one year. Out of these, 33 underwent 24 h Holter, at an average interval of 401 days after the surgery. The following rhythm distribution was found: 24 (73.0%) sinus, five (15.0%) atrial fibrillation, three (9.0%) atrial Flutter and one (3.0%) junctional rhythm. Two cerebrovascular accidents were observed, one of which was associated with supraventricular arrhythmia. CONCLUSION Surgical ablation of atrial fibrillation with bipolar radiofrequency device concomitant with cardiac surgery is an effective method for treating this arrhythmia.

Videothoracoscopy for isolated atrial fibrillation ablation through bipolar radiofrequency

BACKGROUND The prevalence of atrial fibrillation, expenses with the healthcare system and the associated high morbidity and mortality have justified the search for new therapeutic approaches. OBJECTIVE To evaluate the reproducibility of the surgical technique, its safety and the initial outcome of the video-assisted surgery for the isolated atrial fibrillation ablation with bipolar radiofrequency. METHODS Ten patients (90% men) with symptomatic atrial fibrillation (50% paroxystic type) that was refractory to drug therapy, with no heart disease that required concomitant surgical treatment, were submitted to arrhythmia ablation guided by thoracoscopy from May 2007 to May 2008. Clinical, laboratory and image variables were prospectively collected before, during surgery and at the postoperative follow-up. RESULTS The surgery was carried out as planned in all patients. There was no intra-thoracic structure iatrogenic lesion or deaths. At the mean 6-month follow-up, 80% of the patients were free of atrial fibrillation. There was a significant improvement in the symptoms of New York Heart Association Functional Class heart failure (2.4 + or - 0.5 to 1.6 + or - 0.7; p = 0.011). There was no evidence of pulmonary vein stenosis at the angiotomography in this series. CONCLUSION The video-assisted surgery for the treatment of atrial fibrillation is reproducible and safe. There is a heart failure symptom evolution improvement after the surgery.FUNDAMENTO: A prevalencia da fibrilacao atrial, os gastos com o sistema de saude e a elevada morbidade e mortalidade associadas a ela, tem justificado a procura por novas abordagens terapeuticas. OBJETIVO: Avaliar a reprodutibilidade da tecnica cirurgica, a seguranca e os resultados inicias da cirurgia video-assistida para a ablacao da fibrilacao atrial isolada com radiofrequencia bipolar. METODOS: Dez pacientes (90% homens) com fibrilacao atrial (50% paroxistica) sintomatica e refrataria a terapia medicamentosa, sem doenca cardiaca que requeresse cirurgia concomitante, foram submetidos a ablacao da arritmia guiada por toracoscopia, no periodo de maio de 2007 a maio de 2008. Variaveis clinicas, laboratoriais e de imagem foram prospectivamente coletadas antes, durante e no seguimento pos-operatorio. RESULTADOS: A cirurgia foi realizada conforme o planejado em todos os pacientes. Nao houve lesao iatrogenica de estruturas intratoracicas ou obitos. No seguimento medio de seis meses, 80% dos pacientes estao livres de fibrilacao atrial. Houve melhora significativa dos sintomas de insuficiencia cardiaca classe funcional New York Heart Association (2,4 ± 0,5 para 1,6 ± 0,7; p = 0,011). Nao houve evidencia de estenose de veias pulmonares a angiotomografia, nesta serie. CONCLUSAO: A cirurgia video-assistida para o tratamento da fibrilacao atrial e reprodutivel e segura. Ha melhora evolutiva dos sintomas de insuficiencia cardiaca apos a cirurgia.

Cirurgia vídeo-assistida para a ablação da fibrilação atrial isolada por radiofrequência bipolar

BACKGROUND The prevalence of atrial fibrillation, expenses with the healthcare system and the associated high morbidity and mortality have justified the search for new therapeutic approaches. OBJECTIVE To evaluate the reproducibility of the surgical technique, its safety and the initial outcome of the video-assisted surgery for the isolated atrial fibrillation ablation with bipolar radiofrequency. METHODS Ten patients (90% men) with symptomatic atrial fibrillation (50% paroxystic type) that was refractory to drug therapy, with no heart disease that required concomitant surgical treatment, were submitted to arrhythmia ablation guided by thoracoscopy from May 2007 to May 2008. Clinical, laboratory and image variables were prospectively collected before, during surgery and at the postoperative follow-up. RESULTS The surgery was carried out as planned in all patients. There was no intra-thoracic structure iatrogenic lesion or deaths. At the mean 6-month follow-up, 80% of the patients were free of atrial fibrillation. There was a significant improvement in the symptoms of New York Heart Association Functional Class heart failure (2.4 + or - 0.5 to 1.6 + or - 0.7; p = 0.011). There was no evidence of pulmonary vein stenosis at the angiotomography in this series. CONCLUSION The video-assisted surgery for the treatment of atrial fibrillation is reproducible and safe. There is a heart failure symptom evolution improvement after the surgery.FUNDAMENTO: A prevalencia da fibrilacao atrial, os gastos com o sistema de saude e a elevada morbidade e mortalidade associadas a ela, tem justificado a procura por novas abordagens terapeuticas. OBJETIVO: Avaliar a reprodutibilidade da tecnica cirurgica, a seguranca e os resultados inicias da cirurgia video-assistida para a ablacao da fibrilacao atrial isolada com radiofrequencia bipolar. METODOS: Dez pacientes (90% homens) com fibrilacao atrial (50% paroxistica) sintomatica e refrataria a terapia medicamentosa, sem doenca cardiaca que requeresse cirurgia concomitante, foram submetidos a ablacao da arritmia guiada por toracoscopia, no periodo de maio de 2007 a maio de 2008. Variaveis clinicas, laboratoriais e de imagem foram prospectivamente coletadas antes, durante e no seguimento pos-operatorio. RESULTADOS: A cirurgia foi realizada conforme o planejado em todos os pacientes. Nao houve lesao iatrogenica de estruturas intratoracicas ou obitos. No seguimento medio de seis meses, 80% dos pacientes estao livres de fibrilacao atrial. Houve melhora significativa dos sintomas de insuficiencia cardiaca classe funcional New York Heart Association (2,4 ± 0,5 para 1,6 ± 0,7; p = 0,011). Nao houve evidencia de estenose de veias pulmonares a angiotomografia, nesta serie. CONCLUSAO: A cirurgia video-assistida para o tratamento da fibrilacao atrial e reprodutivel e segura. Ha melhora evolutiva dos sintomas de insuficiencia cardiaca apos a cirurgia.

Use of bipolar radiofrequency for the treatment of atrial fibrillation during cardiac surgery

FUNDAMENTO: O tratamento da fibrilacao atrial com dispositivo de ablacao de tecidos por radiofrequencia bipolar em concomitância a cirurgia cardiaca tem se mostrado metodo eficaz no tratamento desta arritmia. OBJETIVO: Descrever a experiencia inicial do Instituto Nacional de Cardiologia no tratamento cirurgico da fibrilacao atrial com uso de dispositivo de radiofrequencia bipolar em pacientes submetidos a cirurgia cardiaca, relatando o resultado de acompanhamento pos-operatorio de um ano. METODOS: Entre janeiro de 2008 e marco de 2009, 47 pacientes (36 mulheres) consecutivos, com idade media de 53,7 ± 10,6 anos, apresentando fibrilacao atrial por um periodo medio de 34,6 meses (3 a 192 meses) foram submetidos a ablacao cirurgica desta arritmia, por radiofrequencia bipolar, durante o procedimento que motivou a indicacao da cirurgia. Oito apresentavam fibrilacao atrial intermitente e 39, continua. Oitenta e um por cento foram submetidos a cirurgia valvar como procedimento principal. Esta e uma analise retrospectiva, observacional, com avaliacao de um ano de pos-operatorio das variaveis clinicas e de Holter 24 h. RESULTADOS: Dos 47 pacientes, 40 sobreviveram um ano. Desses, 33 foram submetidos a Holter 24 h, em um intervalo medio de 401 dias apos a cirurgia. Encontrou-se a seguinte distribuicao de ritmos: 24 (73%) sinusal, 5 (15%) fibrilacao atrial, tres (9%) Flutter atrial e um (3%) ritmo juncional. Foram observados dois acidentes vasculares encefalicos, sendo um associado a arritmia supraventricular. CONCLUSAO: A ablacao cirurgica de fibrilacao atrial com dispositivo de radiofrequencia bipolar concomitante a cirurgia cardiaca e metodo eficaz para o tratamento desta arritmia.BACKGROUND Atrial fibrillation with tissue ablation device through bipolar radiofrequency in conjunction with cardiac surgery has proven to be an effective method to treat this arrhythmia. OBJECTIVE Describe the initial experience of the Instituto Nacional de Cardiologia in the surgical treatment of atrial fibrillation using bipolar radiofrequency device in patients undergoing cardiac surgery, reporting the results of postoperative follow-up of one year. METHODS Between January 2008 and March 2009, 47 consecutive patients (36 women), with mean age of 53.7 ± 10.6 years, with atrial fibrillation for a mean period of 34.6 months (3-192 months) underwent surgical ablation of this arrhythmia, through bipolar radiofrequency during the procedure which led to the indication of surgery. Eight of them showed intermittent atrial fibrillation and 39, continued. Eighty-one percent underwent valve surgery as the main procedure. This is a one-year postoperative retrospective, observational evaluation of clinical variables and 24-h Holter. RESULTS Out of the 47 patients, 40 survived one year. Out of these, 33 underwent 24 h Holter, at an average interval of 401 days after the surgery. The following rhythm distribution was found: 24 (73.0%) sinus, five (15.0%) atrial fibrillation, three (9.0%) atrial Flutter and one (3.0%) junctional rhythm. Two cerebrovascular accidents were observed, one of which was associated with supraventricular arrhythmia. CONCLUSION Surgical ablation of atrial fibrillation with bipolar radiofrequency device concomitant with cardiac surgery is an effective method for treating this arrhythmia.

Contribution of the electrophysiological and anatomical analysis of the atypical atrioventricular nodal tachycardia circuit

OBJECTIVES To analyze retrograde conduction during junctional ectopic tachycardia (JET) episodes and investigate the existence of a relationship between the presence of a retrograde block and the risk of atrioventricular block (AVB) development during radiofrequency ablation procedures in patients with nodal atrioventricular tachycardia (NAVT). METHODS 145 male and female patients aged 16-84 years, with NAVT who had undergone radiofrequency catheter ablation in the posteroseptal region of the right atrium were studied. Evaluation criteria were anatomical location and electrophysiological behavior of retrograde conduction during NAVT, in order to understand the nodal reentrant circuit (classifying the tachycardia as typical or atypical), and monitoring of retrograde conduction during JET episodes for risk-predicting AVB events. RESULTS Of the 145 patients studied, 132 (91%) met electrophysiological and anatomical criteria of the typical form of NAVT, and 13 (9%) of atypical form. During the ablation, 5.3% with the typical form and 30.8% of the atypical form presented risk events for AVB. After the ablation, complications were a total AVB episode in one patient and a first-degree AVB episode in another in the typical group, and one first-degree AVB in the atypical group. All three episodes were preceded by risk events and resulted in permanent nodal injury. CONCLUSION Patients with atypical NAVT presented higher percentages of risk events for atrioventricular block than did patients with the typical form (p=0.021).A careful observation of retrograde conduction during JET episodes is vital in order to avoid permanent damage in AV nodal conduction, such as TAVB, after the ablation procedure.

Improvement in left ventricular dysfunction after surgical correction of mitral regurgitation

OBJECTIVE To evaluate whether left ventricular end-systolic (ESD) diameters < or = 51mm in patients (pt) with severe chronic mitral regurgitation (MR) are predictors of a poor prognosis after mitral valve surgery (MVS). METHODS Eleven pt (aged 36 +/- 13 years) were studied in the preoperative period (pre), median of 36 days; in the early postoperative period (post1), median of 9 days; and in the late postoperative period (post2), mean of 38.5 +/- 37.6 months. Clinical and echocardiographic data were gathered from each pt with MR and systolic diameter > or = 51 mm (mean = 57 +/- 4mm) to evaluate the result of MVS. Ten patients were in NYHA Class III/IV. RESULTS All but 2 pt improved in functional class. Two pt died from heart failure and infectious endocarditis 14 and 11 months, respectively, after valve replacement. According to ejection fraction (EF) in post2, we identified 2 groups: group 1 (n=6), whose EF decreased in post1, but increased in post2 (p=0.01) and group 2 (n=5), whose EF decreased progressively from post1 to post2 (p=0.10). All pt with symptoms lasting < or = 48 months had improvement in EF in post2 (p=0.01). CONCLUSION ESD > or = 51 mm are not always associated with a poor prognosis after MVS in patients with MR. Symptoms lasting up to 48 months are associated with improvement in left ventricular function.

Myosin-binding Protein C Compound Heterozygous Variant Effect on the Phenotypic Expression of Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic disease caused by mutations in genes encoding sarcomere proteins. It is the major cause of sudden cardiac death in young high-level athletes. Studies have demonstrated a poorer prognosis when associated with specific mutations. The association between HCM genotype and phenotype has been the subject of several studies since the discovery of the genetic nature of the disease. This study shows the effect of a MYBPC3 compound variant on the phenotypic HCM expression. A family in which a young man had a clinical diagnosis of HCM underwent clinical and genetic investigations. The coding regions of the MYH7, MYBPC3 and TNNT2 genes were sequenced and analyzed. The proband present a malignant manifestation of the disease, and is the only one to express HCM in his family. The genetic analysis through direct sequencing of the three main genes related to this disease identified a compound heterozygous variant (p.E542Q and p.D610H) in MYBPC3. A family analysis indicated that the p.E542Q and p.D610H alleles have paternal and maternal origin, respectively. No family member carrier of one of the variant alleles manifested clinical signs of HCM. We suggest that the MYBPC3-biallelic heterozygous expression of p.E542Q and p.D610H may cause the severe disease phenotype seen in the proband.