Single-Dose Gadoterate Meglumine for 3T Late Gadolinium Enhancement MRI for the Assessment of Chronic Myocardial Infarction: Intra-Individual Comparison with Conventional Double-Dose 1.5T MRI

OBJECTIVE: To intra-individually compare 3T magnetic resonance (MR) images obtained with one dose gadoterate meglumine to 1.5T MR using conventional double dose for assessment of chronic myocardial infarction. MATERIALS AND METHODS: Sixteen patients diagnosed with chronic myocardial infarctions were examined on single-dose 3T MR within two weeks after undergoing double-dose 1.5T MR. Representative short-axis images were acquired at three points after administration of gadoterate meglumine. Contrast-to-noise ratios between infarcted and normal myocardium (CNRinfarct-normal) and between infarct and left ventricular cavity (CNRinfarct-LVC) were calculated and compared intra-individually at each temporal scan. Additionally, two independent readers assessed relative infarct size semi-automatically and inter-observer reproducibility was evaluated using intraclass correlation coefficient. RESULTS: While higher CNRinfarct-normal was revealed at single-dose 3T at only 10 minutes scan (p = 0.047), the CNRinfarct-LVC was higher at single-dose 3T MR at each temporal scan (all, p 0.05). However, inter-observer reproducibility was higher at single-dose 3T MR (all, p < 0.05). CONCLUSION: Single-dose 3T MR is as effective as double-dose 1.5T MR for delineation of infarcted myocardium while being superior in detection of infarcted myocardium from the blood cavity, and provides better reproducibility for infarct size quantification.

Infarto miocárdico crónico como factor de riesgo de muerte súbita cardíaca / Chronic myocardial infarction as a risk factor for sudden cardiac death

INTRODUCCIÓN: el infarto miocárdico crónico constituye un factor de riesgo independiente para la muerte súbita cardiovascular. OBJETIVO: identificar la presencia de infarto miocárdico crónico en fallecidos de muerte súbita cardiovascular en un estudio poblacional. MÉTODO: se diseñó un estudio observacional, descriptivo y de corte transversal de los casos diagnosticados de forma consecutiva en 11 años, en el hospital "Julio Trigo López" en La Habana, Cuba. RESULTADOS: el infarto miocárdico crónico estuvo presente en el 24,7 % del universo analizado, con predominio en hombres (64,7 %), en edades de 60-74 años (41,3 %). La asistolia fue la arritmia documentada con mayor frecuencia en el medio extra hospitalario (51,6 %). El diagnóstico de un trombo coronario fresco y/o infarto agudo del miocardio representó la principal causa de muerte (63,5 %). CONCLUSIONES: en los pacientes con infarto miocárdico crónico, la muerte súbita constituye la causa más frecuente de muerte. Este factor de riesgo incrementa, por sí sólo, la probabilidad de ocurrencia del evento en los primeros 18 meses de ocurrida la necrosis miocárdica aguda. En la estratificación de riesgo del paciente post-infarto se hace necesaria la búsqueda de inestabilidad eléctrica, isquemia residual y disfunción ventricular izquierda como predictores para este tipo de evento.

INTRODUCTION: chronic myocardial infarction is an independent risk factor for sudden cardiovascular death. OBJECTIVE: identify the presence of chronic myocardial infarction in sudden cardiovascular death victims included in a population study. METHOD: a cross-sectional observational descriptive study was conducted of cases diagnosed consecutively in a period of 11 years at Julio Trigo López hospital in Havana, Cuba. RESULTS: chronic myocardial infarction was present in 24.7% of the study universe, with a predominance of men (64.7%) and the 60-74 age group (41.3%). Asystole was documented as the most common arrhythmia occurring in out-of-hospital conditions (51.6%). The main causes of death (63.5%) were a freshly diagnosed coronary thrombus and/or acute myocardial infarction. CONCLUSIONS: sudden death is the most common cause of death among patients with chronic myocardial infarction. This risk factor of itself increases the probability of occurrence of the event during the 18 months following the appearance of acute myocardial necrosis. Stratification of risk in post-infarction patients should include the search for electrical instability, residual ischemia and ventricular dysfunction as predictors of this type of event.