Regional QT Interval Dispersion as an Early Predictor of Reperfusion in Patients with Acute Myocardial Infarction after Fibrinolytic Therapy / A Dispersão do Intervalo QT Regional como Preditor Precoce de Reperfusão em Pacientes com Infarto Agudo do Miocárdio Pós-terapia Fibrinolítica

Abstract Background: Patients with ST-elevation acute myocardial infarction attending primary care centers, treated with pharmaco-invasive strategy, are submitted to coronary angiography within 2-24 hours of fibrinolytic treatment. In this context, the knowledge about biomarkers of reperfusion, such as 50% ST-segment resolution is crucial. Objective: To evaluate the performance of QT interval dispersion in addition to other classical criteria, as an early marker of reperfusion after thrombolytic therapy. Methods: Observational study including 104 patients treated with tenecteplase (TNK), referred for a tertiary hospital. Electrocardiographic analysis consisted of measurements of the QT interval and QT dispersion in the 12 leads or in the ST-segment elevation area prior to and 60 minutes after TNK administration. All patients underwent angiography, with determination of TIMI flow and Blush grade in the culprit artery. P-values < 0.05 were considered statistically significant. Results: We found an increase in regional dispersion of the QT interval, corrected for heart rate (regional QTcD) 60 minutes after thrombolysis (p = 0.06) in anterior wall infarction in patients with TIMI flow 3 and Blush grade 3 [T3B3(+)]. When regional QTcD was added to the electrocardiographic criteria for reperfusion (i.e., > 50% ST-segment resolution), the area under the curve increased to 0.87 [(0.78-0.96). 95% IC. p < 0.001] in patients with coronary flow of T3B3(+). In patients with ST-segment resolution >50% and regional QTcD > 13 ms, we found a 93% sensitivity and 71% specificity for reperfusion in T3B3(+), and 6% of patients with successful reperfusion were reclassified. Conclusion: Our data suggest that regional QTcD is a promising non-invasive instrument for detection of reperfusion in the culprit artery 60 minutes after thrombolysis.

Resumo Fundamento: Pacientes com infarto do miocárdico com elevação do segmento-ST atendidos em centros de atendimento primário e tratados de acordo com a estratégia fármaco-invasiva são submetidos à fibrinólise seguida de coronariografia em período de 2-24h. Neste cenário, o conhecimento de marcadores de reperfusão como a redução em 50% do segmento-ST é fundamental. Objetivo: Analisar o desempenho da dispersão do intervalo QT em adição aos critérios clássicos, como marcador precoce de reperfusão pós-terapia trombolítica. Métodos: Estudo observacional com a inclusão de 104 pacientes tratados com tenecteplase (TNKase) e referenciados a hospital de atendimento terciário. A análise dos eletrocardiogramas (ECG) consistiu em mensuração do intervalo QT e sua dispersão nas 12 derivações, e também apenas na região com supradesnivelamento-ST antes e 60min pós-TNKase. A angiografia foi realizada em todos os pacientes com obtenção do fluxo TIMI e Blush da artéria culpada. Foram considerados significantes valores de p < 0,05. Resultados: Observamos aumento da dispersão do intervalo QT, corrigido pela frequência cardíaca, regional (dQTcR) 60min pós-lise (p = 0,006) em infartos de parede anterior nos casos com fluxo TIMI 3 e Blush 3 [T3B3(+)]. Adicionando a dQTcR ao critério ECG (redução do ST > 50%) de reperfusão, a área sob a curva aumentou para 0,87 [(0,78-0,96), IC95%, p < 0,001] em pacientes com fluxo coronário T3B3(+). Nos pacientes com critério de ECG para reperfusão e dQTcR > 13 ms a sensibilidade e especificidade foram 93% e 71%, respectivamente, para reperfusão em T3B3(+), possibilitando reclassificar 6% dos pacientes com sucesso de reperfusão. Conclusão: Os dados sugerem a dQTcR como instrumento promissor na identificação não invasiva de reperfusão na artéria coronária culpada, 60min pós-trombólise.

Regional QT Interval Dispersion as an Early Predictor of Reperfusion in Patients with Acute Myocardial Infarction after Fibrinolytic Therapy.

BACKGROUND: Patients with ST-elevation acute myocardial infarction attending primary care centers, treated with pharmaco-invasive strategy, are submitted to coronary angiography within 2-24 hours of fibrinolytic treatment. In this context, the knowledge about biomarkers of reperfusion, such as 50% ST-segment resolution is crucial. OBJECTIVE: To evaluate the performance of QT interval dispersion in addition to other classical criteria, as an early marker of reperfusion after thrombolytic therapy. METHODS: Observational study including 104 patients treated with tenecteplase (TNK), referred for a tertiary hospital. Electrocardiographic analysis consisted of measurements of the QT interval and QT dispersion in the 12 leads or in the ST-segment elevation area prior to and 60 minutes after TNK administration. All patients underwent angiography, with determination of TIMI flow and Blush grade in the culprit artery. P-values < 0.05 were considered statistically significant. RESULTS: We found an increase in regional dispersion of the QT interval, corrected for heart rate (regional QTcD) 60 minutes after thrombolysis (p = 0.06) in anterior wall infarction in patients with TIMI flow 3 and Blush grade 3 [T3B3(+)]. When regional QTcD was added to the electrocardiographic criteria for reperfusion (i.e., > 50% ST-segment resolution), the area under the curve increased to 0.87 [(0.78-0.96). 95% IC. p < 0.001] in patients with coronary flow of T3B3(+). In patients with ST-segment resolution >50% and regional QTcD > 13 ms, we found a 93% sensitivity and 71% specificity for reperfusion in T3B3(+), and 6% of patients with successful reperfusion were reclassified. CONCLUSION: Our data suggest that regional QTcD is a promising non-invasive instrument for detection of reperfusion in the culprit artery 60 minutes after thrombolysis.

Athlete's heart in a Brazilian paralympic judo team. Case series study.

BACKGROUND: Athlete's heart is a term describing the cardiovascular effects of long-term conditioning among highly trained athletes. It is a variation of normal standards. DESIGN AND SETTING: Case series study at the cardiology division of a public university hospital. METHODS: We studied 14 visually handicapped paralympic athletes (8 men) in the national judo team. They were 26.3 ± 6.4 years old, with body mass index 25 ± 14, and had been practicing judo for 9.2 ± 7.9 years. Clinical evaluations, electrocardiograms, exercise testing and echocardiograms were performed by independent observers. RESULTS: Signs of athlete's heart were found in all athletes, comprising left ventricular hypertrophy (5 cases), sinus bradycardia (5), T-wave juvenile pattern (3), T wave juvenile pattern (3), left atrial hypertrophy (2) and increased left ventricular volume (9 cases; 62.22 ± 6.46 ml/m2). There were very strong correlations between left ventricular mass/body surface and endurance time (r: 0.91) and estimated peak oxygen uptake (r: 0.8). The correlations between left ventricular internal diastolic dimension and endurance time (r: 0.91) and estimated peak oxygen uptake (r: 0.8) were strong. Despite increased left ventricular dimensions (4 cases), atrial dimensions (1) and relative wall thickness (4), all athletes had normal left ventricular mass/body surface (89.98 ± 21.93 g/m²). The exercise testing was normal: exercise duration 706 ± 45 seconds and estimated peak oxygen uptake 62.70 ± 9.99 mlO2/min. CONCLUSIONS: Signs of athlete's heart were seen frequently in the paralympic judo team. These demonstrated the presence of mild cardiac adaptations to training.

Athlete's heart in a Brazilian paralympic judo team. Case series study

ABSTRACT BACKGROUND: Athlete's heart is a term describing the cardiovascular effects of long-term conditioning among highly trained athletes. It is a variation of normal standards. DESIGN AND SETTING: Case series study at the cardiology division of a public university hospital. METHODS: We studied 14 visually handicapped paralympic athletes (8 men) in the national judo team. They were 26.3 ± 6.4 years old, with body mass index 25 ± 14, and had been practicing judo for 9.2 ± 7.9 years. Clinical evaluations, electrocardiograms, exercise testing and echocardiograms were performed by independent observers. RESULTS: Signs of athlete's heart were found in all athletes, comprising left ventricular hypertrophy (5 cases), sinus bradycardia (5), T-wave juvenile pattern (3), T wave juvenile pattern (3), left atrial hypertrophy (2) and increased left ventricular volume (9 cases; 62.22 ± 6.46 ml/m2). There were very strong correlations between left ventricular mass/body surface and endurance time (r: 0.91) and estimated peak oxygen uptake (r: 0.8). The correlations between left ventricular internal diastolic dimension and endurance time (r: 0.91) and estimated peak oxygen uptake (r: 0.8) were strong. Despite increased left ventricular dimensions (4 cases), atrial dimensions (1) and relative wall thickness (4), all athletes had normal left ventricular mass/body surface (89.98 ± 21.93 g/m²). The exercise testing was normal: exercise duration 706 ± 45 seconds and estimated peak oxygen uptake 62.70 ± 9.99 mlO2/min. CONCLUSIONS: Signs of athlete's heart were seen frequently in the paralympic judo team. These demonstrated the presence of mild cardiac adaptations to training.