Impacto a largo plazo del tratamiento con presión positiva continua en la vía aérea superior sobre la incidencia de arritmias y la variabilidad de frecuencia cardiaca en pacientes con apnea del sueño / Long-term Impact of Continuous Positive Airway Pressure Therapy on Arrhythmia and Heart Rate Variability in Patients With Sleep Apnea

Introducción: La disfunción del sistema nervioso autonómico produce alteraciones en la variabilidad de la frecuencia cardiaca y aumenta la incidencia de arritmias. Analizamos este fenómeno fisiopatológico en pacientes con síndrome de apnea/hipoapnea del sueño severo y el impacto sobre el mismo del tratamiento con presión positiva continua en la vía aérea (CPAP). Métodos: Pacientes consecutivos con síndrome de apnea/hipoapnea del sueño severo de reciente diagnóstico fueron prospectivamente considerados para inclusión. Se analizó la incidencia de arritmias y la variabilidad de la frecuencia cardiaca (obtenidos mediante registro Holter de 24 horas) antes de iniciarse tratamiento con CPAP y tras un año del mismo. Resultados: Se incluyeron 26 pacientes. El tiempo de uso de CPAP durante el registro Holter fue de 6,6 ± 1,8 horas. Tras inicio de CPAP, se apreció una reducción marginalmente significativa en la FC media (80 ± 9 a 77 ± 11 lpm, p = 0,05). El uso de CPAP se asoció a una modulación parcial y exclusivamente en horas de vigilia de los parámetros de modulación parasimpáticar-MSSD (p = 0,047) y HF (p = 0,025) y de modulación simpática LF (p = 0,049). Ninguno de estos revirtió completamente a la normalidad (p < 0,001). Se observó una reducción de los episodios no sostenidos de taquicardia auricular (p = 0,024), sin efecto demostrativo sobre otras arritmias. Conclusiones: El tratamiento con CPAP se asocia a una mejora solo parcial y diurna de la variabilidad de la frecuencia cardiaca y disminuye la incidencia de taquicardia auricular. Ambos efectos podrían influir en la morbimortalidad cardiovascular de los pacientes con síndrome de apnea/hipoapnea del sueño

Introduction: Autonomic dysfunction can alter heart rate variability and increase the incidence of arrhythmia. We analyzed the impact of continuous positive airway pressure (CPAP) on this pathophysiological phenomenon in patients with severe sleep apnea-hypopnea syndrome. Methods: Consecutive patients with recently diagnosed severe sleep apnea-hypopnea syndrome were prospectively considered for inclusion. Incidence of arrhythmia and heart rate variability (recorded on a 24-hour Holter monitoring device) were analyzed before starting CPAP therapy and 1 year thereafter. Results: A total of 26 patients were included in the study. CPAP was administered for 6.6 ± 1.8 hours during Holter monitoring. After starting CPAP, we observed a marginally significant reduction in mean HR (80 ± 9 to 77 ± 11 bpm, p = .05). CPAP was associated with partial modulation (only during waking hours) of r-MSSD (p = .047) and HF (p = .025) parasympathetic parameters and LF (p = .049) sympathetic modulation parameters. None of these parameters returned completely to normal levels (p < .001). The number of unsustained episodes of atrial tachycardia diminished (p = .024), but no clear effect on other arrhythmias was observed. Conclusions: CPAP therapy only partially improves heart rate variability, and exclusively during waking hours, and reduces incidence of atrial tachycardia, both of which can influence cardiovascular morbidity and mortality in sleep apnea-hypopnea syndrome patients

Long-term Impact of Continuous Positive Airway Pressure Therapy on Arrhythmia and Heart Rate Variability in Patients With Sleep Apnea.

INTRODUCTION: Autonomic dysfunction can alter heart rate variability and increase the incidence of arrhythmia. We analyzed the impact of continuous positive airway pressure (CPAP) on this pathophysiological phenomenon in patients with severe sleep apnea-hypopnea syndrome. METHODS: Consecutive patients with recently diagnosed severe sleep apnea-hypopnea syndrome were prospectively considered for inclusion. Incidence of arrhythmia and heart rate variability (recorded on a 24-hour Holter monitoring device) were analyzed before starting CPAP therapy and 1 year thereafter. RESULTS: A total of 26 patients were included in the study. CPAP was administered for 6.6 ± 1.8 hours during Holter monitoring. After starting CPAP, we observed a marginally significant reduction in mean HR (80 ± 9 to 77 ± 11 bpm, p=.05). CPAP was associated with partial modulation (only during waking hours) of r-MSSD (p=.047) and HF (p=.025) parasympathetic parameters and LF (p=.049) sympathetic modulation parameters. None of these parameters returned completely to normal levels (p<.001). The number of unsustained episodes of atrial tachycardia diminished (p=.024), but no clear effect on other arrhythmias was observed. CONCLUSIONS: CPAP therapy only partially improves heart rate variability, and exclusively during waking hours, and reduces incidence of atrial tachycardia, both of which can influence cardiovascular morbidity and mortality in sleep apnea-hypopnea syndrome patients.

Caracterización de la vía lenta nodular en pacientes con taquicardia por reentrada nodular: implicaciones clínicas para guiar la ablación / Characterization of the nodal slow pathway in patients with nodal reentrant tachycardia: clinical implications for guiding ablation

Introducción y objetivos La ablación de vía lenta nodular es el tratamiento de elección de la taquicardia por reentrada nodular. No hay descritas variables demográficas, anatómicas ni electrofisiológicas que predigan una localización exacta de la vía lenta dentro del nódulo auriculoventricular ni su proximidad a la vía rápida. El objetivo es estudiar estas variables. Métodos Se incluyó prospectivamente a 54 pacientes (17 varones; media de edad, 55 ± 16 años) sometidos a ablación efectiva de vía lenta. Se midieron los periodos refractarios de ambas vías y su tiempo de conducción diferencial. Se calculó las distancias desde la región hisiana (correspondiente a la localización de la vía rápida) hasta el ostium del seno coronario (con lo que se obtuvo una estimación de la longitud anteroposterior del triángulo de Koch) y también hasta la zona de la vía lenta. Resultados El tiempo de conducción diferencial (139 ± 98 ms) no se correlacionó con las distancias His-seno coronario (19 ± 6 mm; p = 0,6) ni His-vía lenta (14 ± 4 mm; p = 0,4). A mayor distancia His-seno coronario, se estableció mayor distancia His-vía lenta (r = 0,652; p < 0,01) y se confirmó la correlación anatómica entre las dimensiones del triángulo y la separación entre ambas vías. En los pacientes mayores de 70 años, se observaron menor tamaño del triángulo y menor distancia entre ambas vías (p < 0,001). Conclusiones Una mayor dimensión anteroposterior del triángulo de Koch se asocia a una localización de vía lenta más alejada de la rápida, encontrándose ambas más próximas entre sí (mayor riesgo de bloqueo auriculoventricular) en los pacientes de edad avanzada (AU)

Introduction and objectives: Nodal slow pathway ablation is the treatment of choice for nodal reentrant tachycardia. No demographic, anatomic, or electrophysiologic variables have been reported to predict an exact location of the slow pathway in the atrioventricular node or its proximity to the fast pathway. The purpose of this study was to analyze these variables. Methods: The study prospectively included 54 patients (17 men; mean age, 55 [16] years) who had undergone successful slow pathway ablation. The refractory periods of both pathways and their differential conduction time were measured, and calculations were performed to obtain the distance from the His-bundle region (location of the fast pathway) to the coronary sinus ostium (to estimate the anteroposterior length of the triangle of Koch) and to the slow pathway area. Results: The differential conduction time (139 [98] ms) did not correlate with the His-coronary sinus distance (19 [6] mm; P = .6) or the His-slow pathway distance (14 [4] mm; P = .4). When the Hiscoronary sinus distance was larger, the His-slow pathway distance was also larger (r = 0.652; P < .01) and the anatomic correlation between the triangle dimensions and the separation between the two pathways was confirmed. In patients older than 70 years, smaller triangle sizes and a shorter distance between both pathways were observed (P < .001). Conclusions: A greater anteroposterior dimension of the triangle of Koch is associated with a slow pathway location farther from the fast pathway. In elderly patients the two pathways are closer together (higher risk of atrioventricular block) (AU)

Characterization of the nodal slow pathway in patients with nodal reentrant tachycardia: clinical implications for guiding ablation.

INTRODUCTION AND OBJECTIVES: Nodal slow pathway ablation is the treatment of choice for nodal reentrant tachycardia. No demographic, anatomic, or electrophysiologic variables have been reported to predict an exact location of the slow pathway in the atrioventricular node or its proximity to the fast pathway. The purpose of this study was to analyze these variables. METHODS: The study prospectively included 54 patients (17 men; mean age, 55 [16] years) who had undergone successful slow pathway ablation. The refractory periods of both pathways and their differential conduction time were measured, and calculations were performed to obtain the distance from the His-bundle region (location of the fast pathway) to the coronary sinus ostium (to estimate the anteroposterior length of the triangle of Koch) and to the slow pathway area. RESULTS: The differential conduction time (139 [98] ms) did not correlate with the His-coronary sinus distance (19 [6] mm; P=.6) or the His-slow pathway distance (14 [4] mm; P=.4). When the His-coronary sinus distance was larger, the His-slow pathway distance was also larger (r=0.652; P<.01) and the anatomic correlation between the triangle dimensions and the separation between the two pathways was confirmed. In patients older than 70 years, smaller triangle sizes and a shorter distance between both pathways were observed (P<.001). CONCLUSIONS: A greater anteroposterior dimension of the triangle of Koch is associated with a slow-pathway location farther from the fast pathway. In elderly patients the two pathways are closer together (higher risk of atrioventricular block).

Resultados a largo plazo de la crioablación con balón para el tratamiento de la fibrilación auricular en un centro de bajo volumen / Long-term outcome of cryoballoon ablation of atrial fibrillation in a low-volume center

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Pulmonary hemorrhage after cryoballoon ablation for pulmonary vein isolation in the treatment of atrial fibrillation.

Pulmonary vein isolation has evolved over the past years as an alternative for the treatment of symptomatic recurrences of atrial fibrillation refractory to antiarrhythmic drug treatment. Both radiofrequency energy and cryoballoon ablation have proven useful in this setting. We present the case of a 55-year-old male patient undergoing cryoballoon ablation complicated with pulmonary hemorrhage. The cause of this rare complication may be found in the damage of vascular venous structures near the ablation zone or, alternatively, in hemorrhagic damage of the pulmonary vein surrounding tissue (or less probably to direct injury of the lingular bronchus). The extremely low temperatures achieved in this case (which are often associated with deep balloon position inside the veins) are alarming and should alert the physician about the possibility of an excessively intrapulmonary vein deployment of the cryoablation balloon.

Infarto de miocardio en inmigrantes del sur de Asia en Cataluña. Resultados del Estudio ASIAM / Myocardial infarction in south asian immigrants in Catalonia. Results from the ASIAM study

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Obstructive sleep apnea in patients with typical atrial flutter: prevalence and impact on arrhythmia control outcome.

BACKGROUND: The clinical yield of cavotricuspid isthmus (CTI) radiofrequency ablation of atrial flutter (AF) is limited by a high incidence of atrial fibrillation (AFib) in the long term. Among other acknowledged variables, the association of obstructive sleep apnea (OSA) could favor incomplete arrhythmia control in this setting. We assessed the impact of CPAP in reducing the occurrence of AFib after CTI ablation. METHODS: Consecutive patients with AF who were undergoing CTI ablation were screened for OSA. Relationship of the following variables with the occurrence of AFib during follow-up (12 months) was investigated: CPAP initiation, hypertension, BMI, underlying structural heart disease, left atrial diameter, and AFib documentation prior to ablation. RESULTS: We prospectively included 56 patients (mean age: 66 (± 11) years; 12 female patients), of whom 46 (82%) had OSA and 25 (45%) had severe OSA. Twenty-one patients (38%) had AFib during follow-up after CTI ablation. Both freedom from AFib prior to ablation and CPAP initiation in those patients without previously documented AFib at inclusion were associated with a reduction of AFib episodes during follow-up (P = .019 and P = .025, respectively). Inversely, CPAP was not protective from AFib recurrence when this arrhythmia was documented prior to ablation (P = .25). CONCLUSIONS: OSA is a prevalent condition in patients with AF. Treatment with CPAP is associated with a lower incidence of newly diagnosed AFib after CTI ablation. Screening for OSA in patients with AF appears to be a reasonable clinical strategy.

Punto de corte óptimo de NT-proBNP para el diagnóstico de insuficiencia cardiaca mediante un test de determinación rápida en atención primaria / Rapid point-of-care NT-proBNP optimal cut-off point for heart failure diagnosis in primary care

Introducción y objetivos. La determinación de péptidos natriuréticos puede estar recomendada como paso previo al ecocardiograma ante la sospecha de insuficiencia cardiaca. El punto de corte óptimo para el diagnóstico de insuficiencia cardiaca en atención primaria no está completamente definido. El objetivo es determinar dicho punto de corte. Métodos. Es un estudio prospectivo para evaluar un test rápido local de fracción N-terminal del péptido natriurético tipo B en atención primaria. Se incluyó a pacientes con solicitud de ecocardiograma realizada por un médico de familia ante la sospecha clínica de insuficiencia cardiaca. Se realizó historia clínica y exploración física basadas en los criterios de Framingham, electrocardiograma, radiografía de tórax, determinación de fracción N-terminal del péptido natriurético tipo B y ecocardiograma. El diagnóstico de insuficiencia cardiaca fue establecido por un cardiólogo ciego al valor de fracción N-terminal del péptido natriurético tipo B, utilizando los criterios de la Sociedad Europea de Cardiología (clínica y confirmación ecocardiográfica). Resultados. Se evaluó a 220 pacientes (el 65,5% mujeres) con una mediana [intervalo intercuartílico] de edad de 74 [67-81] años. El diagnóstico de insuficiencia cardiaca se confirmó en 52 (23,6%), 16 con fracción de eyección del ventrículo izquierdo < 50% (39,6 ± 5,1%). Los valores de fracción N-terminal del péptido natriurético tipo B fueron 715 [510,5-1.575] y 77,5 [58-179,75] pg/ml para pacientes con y sin insuficiencia cardiaca respectivamente. El mejor punto de corte fue 280 pg/ml, con un área bajo la curva receiver operating characteristic de 0,94 (intervalo de confianza del 95%, 0,91-0,97). Seis pacientes diagnosticados de insuficiencia cardiaca (11,5%) tuvieron valores de fracción N-terminal del péptido natriurético tipo B < 400 pg/ml. La incorporación de los péptidos habría evitado el 67% de los ecocardiogramas solicitados. Conclusiones. En una población ambulatoria atendida en atención primaria, el mejor punto de corte de fracción N-terminal del péptido natriurético tipo B para descartar insuficiencia cardiaca fue 280 pg/ml. La determinación de fracción N-terminal del péptido natriurético tipo B mejora los procesos diagnósticos y podría ser coste-efectiva (AU)

Introduction and objectives. Measurement of natriuretic peptides may be recommended prior to echocardiography in patients with suspected heart failure. Cut-off point for heart failure diagnosis in primary care is not well established. We aimed to assess the optimal diagnostic cut-off value of N-terminal pro-B-type natriuretic peptide on a community population attended in primary care. Methods. Prospective diagnostic accuracy study of a rapid point-of-care N-terminal pro-B-type natriuretic peptide test in a primary healthcare centre. Consecutive patients referred by their general practitioners to echocardiography due to suspected heart failure were included. Clinical history and physical examination based on Framingham criteria, electrocardiogram, chest X-ray, N-terminal pro-B-type natriuretic peptide measurement and echocardiogram were performed. Heart failure diagnosis was made by a cardiologist blinded to N-terminal pro-B-type natriuretic peptide value, using the European Society of Cardiology diagnosis criteria (clinical and echocardiographic data). Results. Of 220 patients evaluated (65.5% women; median 74 years [interquartile range 67-81]). Heart failure diagnosis was confirmed in 52 patients (23.6%), 16 (30.8%) with left ventricular ejection fraction <50% (39.6 [5.1]%). Median values of N-terminal pro-B-type natriuretic peptide were 715 pg/mL [interquartile range 510.5-1575] and 77.5 pg/mL [interquartile range 58-179.75] for patients with and without heart failure respectively. The best cut-off point was 280 pg/mL, with a receiver operating characteristic curve of 0.94 (95% confidence interval, 0.91-0.97). Six patients with heart failure diagnosis (11.5%) had N-terminal pro-B-type natriuretic peptide values <400 pg/mL. Measurement of natriuretic peptides would avoid 67% of requested echocardiograms. Conclusions. In a community population attended in primary care, the best cut-off point of N-terminal pro-B-type natriuretic peptide to rule out heart failure was 280 pg/mL. N-terminal pro-B-type natriuretic peptide measurement improve work-out diagnosys and could be cost-effectiveness (AU)

Rapid point-of-care NT-proBNP optimal cut-off point for heart failure diagnosis in primary care.

INTRODUCTION AND OBJECTIVES: Measurement of natriuretic peptides may be recommended prior to echocardiography in patients with suspected heart failure. Cut-off point for heart failure diagnosis in primary care is not well established. We aimed to assess the optimal diagnostic cut-off value of N-terminal pro-B-type natriuretic peptide on a community population attended in primary care. METHODS: Prospective diagnostic accuracy study of a rapid point-of-care N-terminal pro-B-type natriuretic peptide test in a primary healthcare centre. Consecutive patients referred by their general practitioners to echocardiography due to suspected heart failure were included. Clinical history and physical examination based on Framingham criteria, electrocardiogram, chest X-ray, N-terminal pro-B-type natriuretic peptide measurement and echocardiogram were performed. Heart failure diagnosis was made by a cardiologist blinded to N-terminal pro-B-type natriuretic peptide value, using the European Society of Cardiology diagnosis criteria (clinical and echocardiographic data). RESULTS: Of 220 patients evaluated (65.5% women; median 74 years [interquartile range 67-81]). Heart failure diagnosis was confirmed in 52 patients (23.6%), 16 (30.8%) with left ventricular ejection fraction <50% (39.6 [5.1]%). Median values of N-terminal pro-B-type natriuretic peptide were 715 pg/mL [interquartile range 510.5-1575] and 77.5 pg/mL [interquartile range 58-179.75] for patients with and without heart failure respectively. The best cut-off point was 280 pg/mL, with a receiver operating characteristic curve of 0.94 (95% confidence interval, 0.91-0.97). Six patients with heart failure diagnosis (11.5%) had N-terminal pro-B-type natriuretic peptide values <400 pg/mL. Measurement of natriuretic peptides would avoid 67% of requested echocardiograms. CONCLUSIONS: In a community population attended in primary care, the best cut-off point of N-terminal pro-B-type natriuretic peptide to rule out heart failure was 280 pg/mL. N-terminal pro-B-type natriuretic peptide measurement improve work-out diagnoses and could be cost-effectiveness.

Diagnostic and prognostic value of electrophysiologic study in patients with nondocumented palpitations.

The 12-lead electrocardiogram helps to define the arrhythmic mechanism in patients with palpitations. However, in the setting of nondocumented palpitations the value of the electrophysiologic study (EPS) needs additional investigation. We investigated the utility of the EPS in patients with nondocumented palpitations. A total of 172 patients with normal electrocardiographic findings and nondocumented palpitations underwent an EPS. The clinical and electrophysiologic characteristics were assessed. The symptoms were long-lasting (>5 minutes) in 56%. Sudden onset was present in 99%, and termination was rapid in 65%. Neck palpitations were reported in 36%. The EPS findings were normal in 86 patients (50%); atrioventricular nodal reentrant tachycardia was induced in 43, orthodromic reentrant tachycardia in 9, and nonsustained atrial tachycardia/fibrillation (AT/AF) in 34. Long-lasting episodes, sudden termination, and neck palpitations predicted positive EPS findings and were associated with reentrant supraventricular tachycardia (p<0.001). The induction of AT/AF was associated with age >50 years and structural heart disease (p<0.001). After 53 ± 36 months of follow-up, 92% of patients with negative EPS findings were symptom free. Only 32% of patients with induced AT/AF remained free of symptoms (p<0.001). The recurrence of palpitations was more prevalent among patients with structural heart disease and aged >50 years (p<0.001). In conclusion, 50% of patients with nondocumented palpitations had positive EPS findings. A long duration, sudden termination, and neck palpitations, together with structural heart disease and age >50 years, predicted tachycardia inducibility and recurrence and could help in selecting patients suitable for EPS and ablation.

Taquicardia auricular de vena pulmonar: características clínicas, electrocardiográficas y electrofisiológicas diferenciales / Atrial tachycardia originating from the pulmonary vein: clinical, electrocardiographic, and differential electrophysiologic characteristics

Introducción y objetivos. Las venas pulmonares (VP) son un origen frecuente de taquicardias auriculares (TA) ocasionalmente difícil de reconocer en el ECG. Analizamos las características diferenciales clínicas y electrofisiológicas, incluidas la duración y la presencia de melladura en la onda P sinusal, asociadas a las TA-VP. Métodos. Ochenta y siete pacientes sometidos a ablación de TA fueron incluidos y agrupados: TA-VP (grupo 1, n = 25), TA-VP asociada a fibrilación auricular (grupo 2, n = 18), otras TA izquierdas (grupo 3, n = 7) y TA derechas (grupo 4, n = 37). Resultados. El grupo 1 presentó edad media más joven (44 ± 14 años) que los grupos 2 a 4 (57 ± 9, 58 ± 12 y 53 ± 16 años, respectivamente; p < 0,05) y menor diámetro auricular izquierdo que otras TA izquierdas (grupos 2 y 3): 38 ± 4 vs. 48 ± 7 y 49 ± 5 mm, respectivamente (p < 0,05). Las TA-VP fueron debidas más frecuentemente a automatismo anormal/actividad desencadenada (p < 0,05) y presentaron ciclo auricular corto: 289 ± 45 y 280 ± 48 (grupos 1-2) vs. 392 ± 106 y 407 ± 87 ms (grupos 3-4; p < 0,05). La identificación de una onda P sinusal con duración ≥ 110 ms (sensibilidad/especificidad, 68%/69%) y melladura (79%/70%) en menores de 50 años con TA sin cardiopatía de base se asoció a TAVP (p < 0,05). Conclusiones. Una P sinusal prolongada y mellada en pacientes jóvenes con TA rápidas y sin cardiopatía predice un origen en VP (AU)

Introduction and objectives. Although atrial tachycardia (AT) frequently originates in the pulmonary vein, pulmonary vein atrial tachycardia (PV-AT) can be difficult to recognize on an ECG. The aim of this study was to identify clinical and electrophysiologic characteristics specific to PV-AT, including sinus P-wave duration and notching. Methods. The study included 87 patients who underwent AT ablation, divided into four groups: those with PV-AT alone (Group 1, n=25), those with PV-AT associated with atrial fibrillation (Group 2, n=18), and those with other forms of left AT (Group 3, n=7) and right AT (Group 4, n =37). Results. The mean age of patients in Group 1, at 44±14 years, was less than in Groups 2, 3 and 4, at 57±9, 58±12 and 53±16 years, respectively (P < .05) and the left atrial diameter, at 38±4 mm, was less than in the other left AT groups: 48±7 mm in Group 2 and 49±5 mm in Group 3 (P < .05). Overall, PV-AT was most frequently due to abnormal automaticity or triggered activity (P < .05) and presented with a short cycle length: 289±45 ms and 280±48 ms in Groups 1 and 2, respectively, versus 392±106 ms and 407 ± 87 ms in Groups 3 and 4, respectively (P < .05). In patients aged <50 years with at and no underlying heart disease pv-at was significantly p <.05) associated with a P-wave duration ≥110 ms (sensitivity 68%, specificity 69%) and P-wave notching (sensitivity 79%, specificity 70%). Conclusions. Sinus P-wave prolongation and notching in young patients with a rapid AT but without heart disease predicted an origin in the pulmonary vein (AU)

Atrial tachycardia originating from the pulmonary vein: clinical, electrocardiographic, and differential electrophysiologic characteristics.

INTRODUCTION AND OBJECTIVES: Although atrial tachycardia (AT) frequently originates in the pulmonary vein, pulmonary vein atrial tachycardia (PV-AT) can be difficult to recognize on an ECG. The aim of this study was to identify clinical and electrophysiologic characteristics specific to PV-AT, including sinus P-wave duration and notching. METHODS: The study included 87 patients who underwent AT ablation, divided into four groups: those with PV-AT alone (Group 1, n=25), those with PV-AT associated with atrial fibrillation (Group 2, n=18), and those with other forms of left AT (Group 3, n=7) and right AT (Group 4, n=37). RESULTS: The mean age of patients in Group 1, at 44 + or - 14 years, was less than in Groups 2, 3 and 4, at 57 + or - 9, 58 + or - 12 and 53 + or - 16 years, respectively (P< .05) and the left atrial diameter, at 38 + or - 4 mm, was less than in the other left AT groups: 48 + or - 7 mm in Group 2 and 49 + or - 5 mm in Group 3 (P< .05). Overall, PV-AT was most frequently due to abnormal automaticity or triggered activity (P< .05) and presented with a short cycle length: 289 + or - 45 ms and 280 + or - 48 ms in Groups 1 and 2, respectively, versus 392 + or - 106 ms and 407 + or - 87 ms in Groups 3 and 4, respectively (P< .05). In patients aged <50 years with AT and no underlying heart disease, PV-AT was significantly (P< .05) associated with a P-wave duration > or = 110 ms (sensitivity 68%, specificity 69%) and P-wave notching (sensitivity 79%, specificity 70%). CONCLUSIONS: Sinus P-wave prolongation and notching in young patients with a rapid AT but without heart disease predicted an origin in the pulmonary vein.

Role of heart rate in cardiovascular diseases: how the results of the BEAUTIFUL study change clinical practice.

The BEAUTIFUL (morBidity-mortality EvAlUaTion of the If inhibitor ivabradine in patients with coronary artery disease and left ventricULar systolic dysfunction) study assessed the morbidity and mortality benefits of the HR-lowering agent ivabradine. The placebo arm of the BEAUTIFUL trial was a large cohort of patients with stable coronary artery disease (CAD) and left ventricular systolic dysfunction. A subanalysis in the placebo group tested the hypothesis that elevated resting HR at baseline was a marker for subsequent cardiovascular death and morbidity. The primary aim of the study was to test whether lowering the HR with ivabradine reduced cardiovascular death and morbidity in patients with CAD and left ventricular systolic dysfunction. In the overall analysis, reduction in HR with ivabradine did not improve cardiac outcomes compared with placebo. The most important finding of the study was that patients with high baseline HR had an increase in serious cardiovascular events including death (34%), hospital admission secondary to congestive heart failure (53%), acute myocardial infarction (46%), or revascularization procedure (38%). In addition, in the subset analysis focusing on patients with baseline HR > or =70 bpm and left ventricular ejection fraction <40% the agent resulted in a 36% decrease in hospital admissions secondary to fatal and nonfatal myocardial infarction and a 30% decrease in coronary revascularization. The first practical implication from the study includes that baseline HR should be recorded in addition to other risk factors such as BP and lipid profile, in the follow-up of patients with CAD. Attempts should be made to achieve HR <70 bpm by cardiac rehabilitation and routine use of appropriately dosed beta-blockers. Despite the neutral results obtained in the BEAUTIFUL study, ivabradine could be administered to the subgroup of patients in whom HR <70 bpm is not achieved despite proper dosing of beta-blockers and in those in whom beta-blockers are contraindicated. Furthermore, in clinical practice, ivabradine may be helpful for patients with stable CAD who have a high HR while receiving beta-blockers. Future studies are needed to confirm the hypothesis that single reduction of HR can improve cardiovascular prognosis.

Long-term mortality predictors in patients with chronic bifascicular block.

AIMS: To evaluate the long-term mortality rate and to determine independent mortality risk factors in patients with bifascicular block (BFB). Patients with BFB are known to have a higher mortality risk than the general population, not only related to progression to atrio-ventricular block but also due to the presence of malignant ventricular arrhythmias. Previous observational and epidemiological studies including a high proportion of patients with structural heart disease have shown an important cardiac mortality rate and may not reflect the real outcome of patients with BFB. METHODS AND RESULTS: From March 1998 until December 2006, we prospectively studied 259 consecutive BFB patients, 213 (82%) of whom presenting with syncope/pre-syncope, undergoing electrophysiological study. After a median follow-up of 4.5 years (P25:2.16-P75:6.41), 53 patients (20.1%) died, 19 (7%) of whom due to cardiac aetiology. Independent total mortality predictors were age [hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01-1.09], NYHA class>or=II (HR 2.17, 95% CI 1.05-4.5), atrial fibrillation (HR 2.96, 95% CI 1.1-7.92), and renal dysfunction (HR 4.26, 95% CI 2.04-9.01). An NYHA class of >or=II (HR 5.45, 95% CI 2.01-14.82) and renal failure (HR 3.82, 95% CI 1.21-12.06) were independent predictors of cardiac mortality. No independent predictors of arrhythmic death were found. CONCLUSION: Total mortality, especially of cardiac cause, is lower than previously described in BFB patients. Advanced NYHA class and renal failure are predictors of cardiac mortality.

Entrainment from the para-Hisian region for differentiating atrioventricular node reentrant tachycardia from orthodromic atrioventricular reentrant tachycardia.

AIMS: The difference between the stimulus-atrial and ventriculo-atrial intervals (SA-VA) and between the post-pacing interval and the tachycardia cycle length (PPI-TCL) during entrainment from the right ventricular apex distinguishes atrioventricular node reentrant (AVNRT) from orthodromic atrioventricular reentrant tachycardia (AVRT). We hypothesized that these features still apply when entrainment is performed from the para-Hisian region. METHODS AND RESULTS: Forty-seven supraventricular tachycardias (34 AVNRT/13 AVRT) were included. The SA-VA and PPI-TCL were obtained in all patients by using two right-sided diagnostic catheters. In 24 of them, these measurements were also performed upon His-bundle capture during entrainment. A paced QRS widening of >or=40 ms during entrainment, when compared with the tachycardia QRS width, identified absence of His-bundle capture, P < 0.001. A SA-VA >75 ms distinguished AVNRT from AVRT, P < 0.001 (sensitivity/specificity 97%/100%). A PPI-TCL >100 ms was diagnostic of AVNRT, P < 0.001 (sensitivity/specificity 97%/92%). Upon His-bundle capture, the SA-VA and PPI-TCL shortened in AVNRT (121 +/- 23 to 66 +/- 24 ms; 139 +/- 30 to 85 +/- 31 ms, respectively, P < 0.001) and no longer differentiated AVNRT from AVRT. CONCLUSION: Para-Hisian entrainment without His-bundle capture distinguishes AVNRT from AVRT with the advantage of using only two diagnostic catheters.

Eficacia antianginosa de la ivabradina. Mecanismos de acción diferenciales con otros fármacos antianginosos / The antianginal effects of ivabradine. Its mechanism of action differentiates it from other antianginal drugs

La reducción de la frecuencia cardiaca es un instrumento básico en el tratamiento de la angina crónica estable, con efectos tanto en los síntomas como en el pronóstico. Los bloqueadores beta, y en menor medida los calcioantagonistas no dihidropiridínicos, ejercen parte de su eficacia antianginosa por este mecanismo. La ivabradina inhibe de forma selectiva la corriente If en las células del nodo sinusal y logra una marcada prolongación del tiempo de despolarización diastólica espontánea y, con ello, una significativa reducción de la frecuencia cardiaca, tanto en reposo como durante el ejercicio, sin otros efectos hemodinámicos, a diferencia de los antagonistas del calcio o los bloqueadores beta, y con potencia similar a la de éstos. Los estudios en voluntarios sanos y en angina de esfuerzo crónica estable limitante han demostrado la eficacia frente a placebo con diferentes dosis. En comparación con los bloqueadores beta o antagonistas del calcio, o combinada con ellos, también se ha objetivado una franca mejoría de los síntomas anginosos y una mayor tolerancia al esfuerzo (AU)

Reducing the heart rate is one of the basic aims of treatment for chronic stable angina; it has an influence on both symptoms and prognosis. Beta-blockers, and to a lesser extent non-dihydropyridine calcium channel blockers, derive part of their antianginal effect from this mechanism. Ivabradine, a selective inhibitor of the If current in sinus node cells, markedly prolongs the spontaneous diastolic depolarization time and, thereby, significantly reduces the heart rate, both at rest and during exercise. Moreover, the drug has no other hemodynamic effects, unlike beta-blockers and calcium channel blockers, which have a similar effect on the heart rate. Studies in healthy volunteers and patients with chronic, stable, lifestyle-limiting exercise-induced angina have demonstrated ivabradine’s effectiveness at different doses compared with placebo. Moreover, compared with beta-blockers, calcium channel blockers and their combination, the drug has also been shown to result in a clear improvement in anginal symptoms and in increased exercise tolerance (AU)