Echocardiographic assessment of atrial function in patients with hypertrophic cardiomyopathy with and without paroxysmal atrial fibrillation.

INTRODUCTION AND OBJECTIVES: Hypertrophic cardiomyopathy (HCM) is accompanied by pathophysiological changes that predispose to the development of atrial fibrillation (AF). This arrhythmia impacts negatively on the morbidity, mortality and quality of life of these patients. Our objective was to evaluate the behavior of left atrial function, by means of atrial strain (derived from speckle tracking) and volumetric analysis by three-dimensional echocardiography, in patients with HCM with paroxysmal AF. METHOD: We analysed left atrial function in 53 patients with HCM, 25 of whom were paroxysmal AF carriers (mean age 61.7±9.9 years; 56% female) compared with 28 members of the control group (mean age 60.5±10 years; 53.6% female) who were matched especially for sex, age and other demographic data. RESULTS: It was observed that patients with HCM and a history of paroxysmal AF had lower left atrial emptying fractions than individuals in the control group; and the active atrial emptying fraction was a factor independently associated with the presence of this arrhythmia (p=0.018; odds ratio=0.93). Moreover, we found a significant reduction of the left atrial strain in all its components in the total sample of patients, with no difference between the groups. CONCLUSIONS: Measurements of atrial emptying fractions by three-dimensional echocardiography allowed differentiating patients with HCM with and without paroxysmal AF.

Echocardiographic assessment of atrial function in patients with hypertrophic cardiomyopathy with and without paroxysmal atrial fibrillation

INTRODUCTION AND OBJECTIVES: Hypertrophic cardiomyopathy (HCM) is accompanied by pathophysiological changes that predispose to the development of atrial fibrillation (AF). This arrhythmia impacts negatively on the morbidity, mortality and quality of life of these patients. Our objective was to evaluate the behavior of left atrial function, by means of atrial strain (derived from speckle tracking) and volumetric analysis by three-dimensional echocardiography, in patients with HCM with paroxysmal AF. METHOD: We analysed left atrial function in 53 patients with HCM, 25 of whom were paroxysmal AF carriers (mean age 61.7±9.9 years; 56% female) compared with 28 members of the control group (mean age 60.5±10 years; 53.6% female) who were matched especially for sex, age and other demographic data. RESULTS: It was observed that patients with HCM and a history of paroxysmal AF had lower left atrial emptying fractions than individuals in the control group; and the active atrial emptying fraction was a factor independently associated with the presence of this arrhythmia (p=0.018; odds ratio=0.93). Moreover, we found a significant reduction of the left atrial strain in all its components in the total sample of patients, with no difference between the groups. CONCLUSIONS: Measurements of atrial emptying fractions by three-dimensional echocardiography allowed differentiating patients with HCM with and without paroxysmal AF.

Relationship between ventricular repolarization parameters and the inducibility of ventricular arrhythmias during electrophysiological study in patients with coronary artery disease.

OBJECTIVE: Risk stratification of sudden cardiac death in patients with coronary artery disease is of great importance. We evaluated the association between ventricular repolarization and induction of malignant ventricular arrhythmias on electrophysiological study of patients with coronary artery disease. METHODS AND RESULTS: A total of 177 patients (65±10.1 years, 83.6% male, mean left ventricular ejection fraction [LVEF] 37.5±13.6%) were analyzed. For each 10 ms increment in the QT interval, there was a 7% increase in malignant ventricular arrhythmias inducibility; QT cutoff point of 452 ms had an accuracy of 0.611 for predicting malignant ventricular arrhythmias (p=0.011). Male gender (odds ratio [OR]=4.18, p=0.012), LVEF <35% (OR=2.32, p=0.013), amiodarone use (OR=2.01, p=0.038), and prolonged QT (OR=1.07, p=0.023) were associated with malignant ventricular arrhythmias. In patients with ventricular dysfunction, QT >452 ms was associated with significantly increased risk of malignant ventricular arrhythmias (OR=5.44, p=0.0004). In those with LVEF ³35%, QT dispersion (QTd) was significantly higher in patients with inducible malignant ventricular arrhythmias. QTd >20 ms had 0.638 accuracy and 81.3% negative predictive value in predicting malignant ventricular arrhythmias. CONCLUSION: QT interval is an independent factor associated with malignant ventricular arrhythmias in patients with coronary artery disease. The combination of ventricular dysfunction and prolonged QT interval is associated with a 5.44-fold increase of malignant ventricular arrhythmias induction. Male gender, amiodarone use, and decreased left ventricular ejection fraction are also associated with increased risk of inducibility of malignant ventricular arrhythmias on the electrophysiological study.

Relationship between ventricular repolarization parameters and the inducibility of ventricular arrhythmias during electrophysiological study in patients with coronary artery disease

OBJECTIVE: Risk stratification of sudden cardiac death in patients with coronary artery disease is of great importance. We evaluated the association between ventricular repolarization and induction of malignant ventricular arrhythmias on electrophysiological study of patients with coronary artery disease. METHODS AND RESULTS: A total of 177 patients (65±10.1 years, 83.6% male, mean left ventricular ejection fraction [LVEF] 37.5±13.6%) were analyzed. For each 10 ms increment in the QT interval, there was a 7% increase in malignant ventricular arrhythmias inducibility; QT cutoff point of 452 ms had an accuracy of 0.611 for predicting malignant ventricular arrhythmias (p=0.011). Male gender (odds ratio [OR]=4.18, p=0.012), LVEF 452 ms was associated with significantly increased risk of malignant ventricular arrhythmias (OR=5.44, p=0.0004). In those with LVEF ³35%, QT dispersion (QTd) was significantly higher in patients with inducible malignant ventricular arrhythmias. QTd >20 ms had 0.638 accuracy and 81.3% negative predictive value in predicting malignant ventricular arrhythmias. CONCLUSION: QT interval is an independent factor associated with malignant ventricular arrhythmias in patients with coronary artery disease. The combination of ventricular dysfunction and prolonged QT interval is associated with a 5.44-fold increase of malignant ventricular arrhythmias induction. Male gender, amiodarone use, and decreased left ventricular ejection fraction are also associated with increased risk of inducibility of malignant ventricular arrhythmias on the electrophysiological study.

Análise do sincronismo cardíaco pela cintilografia miocárdica em portadores de terapia de ressincronização cardíaca / Analysis of cardiac synchronism by myocardial scintigraphy in patients undergoing cardiac resynchronization therapy

INTRODUÇÃO: Sabe-se que, até 30% dos pacientes submetidos à terapia de ressincronização cardíaca (TRC) não apresentam resposta satisfatória, a partir dos critérios de seleção atuais. Informações dadas pela cintilografia de perfusão miocárdica (CPM) como sincronismo mecânico, região de última ativação mecânica (RUAM) e fibrose podem ser úteis na melhor seleção de quem realmente se beneficiaria desse dispositivo. OBJETIVO: Avaliar a presença de melhora no sincronismo mecânico do ventrículo esquerdo (VE) em portadores de TRC, através do software Synctool utilizado na técnica de CPM, bem como relacionar os dados obtidos com melhora clínica, definida por redução de pelo menos 1 classe funcional pela classificação da New York Heart Association e redução de pelo menos cinco pontos no Minessota Living With Heart Failure Questionnaire, e ainda relacionar com demais variáveis epidemiológicas, clínicas, cintilográficas e eletrocardiográficas. MÉTODOS: Trinta e um portadores de TRC realizaram CPM em dois diferentes momentos: TRC ligada e desligada. Também fora aplicado questionário sobre qualidade de vida e coletados dados clínicos acerca dos períodos antes e após implante do dispositivo. RESULTADOS: Os pacientes que apresentaram melhora da sincronia tiveram maior frequência de melhora clínica (p = 0,026) e obtiveram menores valores de volume diastólico final do VE (204,4 ± 100,4 ml vs. 304,3 ± 77,2 ml; p = 0,028) e de volume sistólico final do VE (120,2 ± 88,8 ml vs. 197,5 ± 51,6 ml; p = 0,026). Quando examinada a melhora clínica, 23 (74,1%) pacientes foram tidos como respondedores e 8 (25,9%) como não respondedores. Os respondedores apresentaram aumento significativo da fração de ejeção do VE (38,4 ± 14,1 vs.47,9 ± 15,3; p < 0,001). Os não-respondedores não apresentaram mudanças significativas em relação a volumes e função ventricular, tiveram maior média de acometimento miocárdico por fibrose (12,9 ± 5,5% vs. 5,7 ± 8,4%; p = 0,033) e maior frequência desta em parede lateral e ínfero-lateral (50% vs. 8,7%; p = 0,026), apresentaram ainda menor percentual de localização da RUAM nas paredes lateral e ínfero-lateral (12,5% vs. 56,5%; p = 0,045), assumindo assim uma posição discordante entre essa e o eletrodo de estimulação da TRC no VE. CONCLUSÃO: A TRC foi capaz de melhorar o sincronismo mecânico do VE. Melhora da sincronia mecânica está associada à melhora clínica e marcante remodelamento reverso. Presença de fibrose e RUAM nas paredes lateral e ínfero-lateral são fatores preditores de resposta à TRC.