Anatomic characteristics of the left atrium in subjects undergoing radiofrequency ablation for atrial fibrillation.

OBJECTIVE: To analyze the anatomic characteristics of the left atrium and pulmonary veins in individuals undergoing ablation for atrial fibrillation and to identify possible anatomic factors related with recurrence. MATERIAL AND METHODS: We retrospectively reviewed the CT angiography studies done to plan radiofrequency ablation for atrial fibrillation in 95 patients (57 men; mean age, 65 ±â€¯10 y). We reviewed the anatomy of the pulmonary veins and recorded the diameters of their ostia as well as the diameter and volume of the left atrium. We analyzed these parameters according to the type of arrhythmia and the response to treatment. RESULTS: In 71 (74.7%) patients, the anatomy of the pulmonary veins was normal (i.e., two right pulmonary veins and two left pulmonary veins). Compared to patients with paroxysmal atrial fibrillation, patients with persistent atrial fibrillation had slightly larger diameter of the left pulmonary veins (left superior pulmonary vein 17.9 ±â€¯2.6 mm vs. 16.7 ±â€¯2.2 mm, p = 0.04; left inferior pulmonary vein 15.3 ± 2 mm vs. 13.8 ±â€¯2.2 mm, p = 0.009) and larger left atrial volume (91.9 ±â€¯24.9 cm3 vs. 70.7 ±â€¯20.3 mm3, p = 0.001). After 22.1 ±â€¯12.1 months' mean follow-up, 41 patients had sinus rhythm. Compared to patients in whom the sinus rhythm was restored, patients with recurrence had greater left atrial volume (81.4 ±â€¯23.0 mm3 vs. 71.1 ±â€¯23.2 mm3, p = 0.03). No significant differences in pulmonary vein diameters or clinical parameters were observed between patients with recurrence and those without. CONCLUSION: The volume of the left atrium is greater in patients with persistent atrial fibrillation and in those who do not respond to ablation.

Valoración del índice de reserva de perfusión miocárdica por resonancia magnética en pacientes con trasplante cardíaco / Cardiac magnetic resonance imaging myocardial perfusion reserve index in heart transplant patients

OBJETIVO: Comparar el índice de reserva de perfusión miocárdica (IRPM) medido por resonancia magnética cardíaca de estrés (RMC-estrés) con regadenosón en sujetos trasplantados frente a no trasplantados. MATERIAL Y MÉTODOS: Se compararon, de forma retrospectiva, 20 trasplantados cardíacos consecutivos, asintomáticos y sin sospecha clínica de enfermedad microvascular, a quienes se realizó RMC-estrés con regadenosón y coronariografía por TC (CTC) para descartar enfermedad vascular del injerto (EVI) respecto a 16 sujetos no trasplantados, con RMC-estrés realizada por indicación clínica, negativa para isquemia y sin signos de cardiopatía estructural. El IRPM se estimó de forma semicuantitativa tras calcular el valor de la pendiente durante la perfusión de primer paso y dividir el valor obtenido en estrés respecto al reposo. Se comparó IRPM en ambos grupos. Los pacientes con RMC-estrés positiva para isquemia o CTC con estenosis coronaria significativa fueron derivados a coronariografía convencional. RESULTADOS: Más de la mitad de los sujetos permanecieron asintomáticos durante la prueba de estrés. La RMC-estrés resultó positiva para isquemia en dos trasplantados, que se confirmó mediante CTC y coronariografía convencional. Los pacientes trasplantados presentaron menor volumen telediastólico indexado (59,3 ±15,2 ml/m2 frente a 71,4±15,9 ml/m2, p = 0,03), menor IRPM (1,35±0,19 vs. 1,6±0,28, p = 0,003 y menor respuesta hemodinámica al regadenosón que los no trasplantados (incremento medio de la frecuencia cardíaca de 13,1±5,4 lpm frente a 28,5±8,9 lpm, p < 0,001). CONCLUSIÓN: La RMC-estrés con regadenosón es una técnica segura. En ausencia de enfermedad coronaria epicárdica significativa, los trasplantados presentan menor IRPM que los no trasplantados, lo que sugiere enfermedad microvascular. En pacientes trasplantados, la respuesta hemodinámica esperable al regadenosón es menor que en no trasplantados

OBJECTIVE: To compare the myocardial perfusion reserve index (MPRI) measured during stress cardiac magnetic resonance imaging (MRI) with regadenoson in patients with heart transplants versus in patients without heart transplants. MATERIAL AND METHODS: We retrospectively compared 20 consecutive asymptomatic heart transplant patients without suspicion of microvascular disease who underwent stress cardiac MRI with regadenoson and coronary computed tomography angiography (CTA) to rule out cardiac allograft vasculopathy versus 16 patients without transplants who underwent clinically indicated stress cardiac MRI who were negative for ischemia and had no signs of structural heart disease. We estimated MPRI semiquantitatively after calculating the up-slope of the first-pass enhancement curve and dividing the value obtained during stress by the value obtained at rest. We compared MPRI in the two groups. Patients with positive findings for ischemia on stress cardiac MRI or significant coronary stenosis on coronary CTA were referred for conventional coronary angiography. RESULTS: More than half the patients remained asymptomatic during the stress test. Stress cardiac MRI was positive for ischemia in two heart transplant patients; these findings were confirmed at coronary CTA and at conventional coronary angiography. Patients with transplants had lower end-diastolic volume index (59.3±15.2 ml/m2 vs. 71.4±15.9 ml/m2 in those without transplants, p = 0.03), lower MPRI (1.35±0.19 vs. 1.6±0.28 in those without transplants, p = 0.003), and a less pronounced hemodynamic response to regadenoson (mean increase in heart rate 13.1±5.4 bpm vs. 28.5±8.9 bpm in those without transplants, p <0.001). CONCLUSION: Stress cardiac MRI with regadenoson is safe. In the absence of epicardial coronary artery disease, patients with heart transplants have lower MPRI than patients without transplants, suggesting microvascular disease. The hemodynamic response to regadenoson is less pronounced in patients with heart transplants than in patients without heart transplants

Seguridad del empleo de regadenosón como fármaco vasodilatador en resonancia magnética cardíaca de estrés / Safety of regadenoson for vasodilation in cardiac MRI stress tests

OBJETIVO: Describir la seguridad del regadenosón como fármaco vasodilatador en estudios de resonancia magnética cardíaca (RMC) de estrés realizados para detectar isquemia miocárdica. MATERIAL Y MÉTODOS: Se analizaron de manera retrospectiva los estudios de 120 pacientes (88 varones, edad media 67 ±11,6 años) con sospecha de cardiopatía isquémica o con enfermedad coronaria conocida e indicación clínica para RMC de estrés. Los estudios se realizaron en un equipo de 1,5 Tesla (MAGNETOM Aera, Siemens Healthineers) empleando regadenosón (5ml, 0,4mg) como agente vasodilatador. En todos los pacientes se recogieron los factores de riesgo cardiovascular, fármacos que tomaban e indicación de la prueba, además de las constantes vitales en situación de reposo y bajo estrés y los síntomas y efectos adversos inducidos por el fármaco. RESULTADOS: El 52,6% de los pacientes permanecieron asintomáticos. Los síntomas más frecuentes fueron la opresión centrotorácica (25%) y la disnea (12%). Durante el pico de estrés, el incremento medio de la frecuencia cardíaca fue de 23,9±11,4 lpm y el descenso medio de la presión arterial sistólica y diastólica de 7,1±18,8mmHg y 5,3±9,2mmHg, respectivamente (p < 0,001). En pacientes obesos y diabéticos se objetivó menor respuesta hemodinámica al regadenosón, mientras que los pacientes sintomáticos presentaron mayor incremento de la frecuencia cardíaca (27,4±11,2 lpm frente a 20,6±10,7 lpm, p = 0,001). No se evidenció ningún efecto adverso grave. CONCLUSIÓN: El regadenosón es un fármaco bien tolerado que se puede utilizar con seguridad en RMC de estrés

OBJECTIVE: To determine the safety of regadenoson for vasodilation in cardiac MRI stress tests to detect myocardial ischemia. MATERIAL AND METHODS: We retrospectively analyzed cardiac MRI studies done in 120 patients (mean age, 67±11.6 years; 88 men) with suspected ischemic heart disease or known coronary disease who had clinical indications for cardiac MRI stress tests. All studies were done on a 1.5 T scanner (MAGNETOM Aera, Siemens Healthineers) using regadenoson (5ml, 0.4mg) for vasodilation. We recorded cardiovascular risk factors, medications, and indications for the test as well as vital signs at rest and under stress and the symptoms and adverse effects induced by the drug. RESULTS: No symptoms developed in 52.6% of patients. The most common symptoms were central chest pain (25%) and dyspnea (12%). At peak stress, the mean increase in heart rate was 23.9±11.4 beats per minute and the mean decreases in systolic and diastolic blood pressure were 7.1±18.8mmHg and 5.3±9.2mmHg, respectively (p <0.001). The response to regadenoson was less pronounced in obese and diabetic patients. The increase in heart rate was greater in symptomatic patients (27.4±11.2 bpm vs. 20.6±10.7 bpm in asymptomatic patients, p = 0.001). No severe adverse effects were observed. CONCLUSION: Regadenoson is well tolerated and can be safely used for cardiac MRI stress tests

Cardiac magnetic resonance imaging myocardial perfusion reserve index in heart transplant patients. / Valoración del índice de reserva de perfusión miocárdica por resonancia magnética en pacientes con trasplante cardíaco.

OBJECTIVE: To compare the myocardial perfusion reserve index (MPRI) measured during stress cardiac magnetic resonance imaging (MRI) with regadenoson in patients with heart transplants versus in patients without heart transplants. MATERIAL AND METHODS: We retrospectively compared 20 consecutive asymptomatic heart transplant patients without suspicion of microvascular disease who underwent stress cardiac MRI with regadenoson and coronary computed tomography angiography (CTA) to rule out cardiac allograft vasculopathy versus 16 patients without transplants who underwent clinically indicated stress cardiac MRI who were negative for ischemia and had no signs of structural heart disease. We estimated MPRI semiquantitatively after calculating the up-slope of the first-pass enhancement curve and dividing the value obtained during stress by the value obtained at rest. We compared MPRI in the two groups. Patients with positive findings for ischemia on stress cardiac MRI or significant coronary stenosis on coronary CTA were referred for conventional coronary angiography. RESULTS: More than half the patients remained asymptomatic during the stress test. Stress cardiac MRI was positive for ischemia in two heart transplant patients; these findings were confirmed at coronary CTA and at conventional coronary angiography. Patients with transplants had lower end-diastolic volume index (59.3±15.2 ml/m2 vs. 71.4±15.9 ml/m2 in those without transplants, p=0.03), lower MPRI (1.35±0.19 vs. 1.6±0.28 in those without transplants, p=0.003), and a less pronounced hemodynamic response to regadenoson (mean increase in heart rate 13.1±5.4 bpm vs. 28.5±8.9 bpm in those without transplants, p <0.001). CONCLUSION: Stress cardiac MRI with regadenoson is safe. In the absence of epicardial coronary artery disease, patients with heart transplants have lower MPRI than patients without transplants, suggesting microvascular disease. The hemodynamic response to regadenoson is less pronounced in patients with heart transplants than in patients without heart transplants.

Safety of regadenoson for vasodilation in cardiac MRI stress tests. / Seguridad del empleo de regadenosón como fármaco vasodilatador en resonancia magnética cardíaca de estrés.

OBJECTIVE: To determine the safety of regadenoson for vasodilation in cardiac MRI stress tests to detect myocardial ischemia. MATERIAL AND METHODS: We retrospectively analyzed cardiac MRI studies done in 120 patients (mean age, 67±11.6 years; 88 men) with suspected ischemic heart disease or known coronary disease who had clinical indications for cardiac MRI stress tests. All studies were done on a 1.5 T scanner (MAGNETOM Aera, Siemens Healthineers) using regadenoson (5ml, 0.4mg) for vasodilation. We recorded cardiovascular risk factors, medications, and indications for the test as well as vital signs at rest and under stress and the symptoms and adverse effects induced by the drug. RESULTS: No symptoms developed in 52.6% of patients. The most common symptoms were central chest pain (25%) and dyspnea (12%). At peak stress, the mean increase in heart rate was 23.9±11.4 beats per minute and the mean decreases in systolic and diastolic blood pressure were 7.1±18.8mmHg and 5.3±9.2mmHg, respectively (p <0.001). The response to regadenoson was less pronounced in obese and diabetic patients. The increase in heart rate was greater in symptomatic patients (27.4±11.2 bpm vs. 20.6±10.7 bpm in asymptomatic patients, p=0.001). No severe adverse effects were observed. CONCLUSION: Regadenoson is well tolerated and can be safely used for cardiac MRI stress tests.