First-in-human experience of preload regulation with percutaneous transluminal caval flow regulation in heart failure with reduced ejection fraction patients.

AIMS: This study aims to investigate the acute haemodynamic effects of percutaneous transluminal flow regulation (PTCR®) with an inferior vena cava regulator balloon in heart failure patients. Preload reduction in heart failure has been achieved with high potency diuretics. However, no study has been conducted in humans to assess the effect of inferior vena cava intermittent occlusion for preload reduction. METHODS AND RESULTS: Six patients were included in the study: four men (55 ± 6 years old) and two women (63 ± 4 years old). Baseline evaluations included Doppler echocardiogram, coronary angiogram, and right heart catheterization. Caval balloon was kept inflated for 30 min, and right catheterization and control echocardiogram were performed while the balloon was still inflated. The balloon was then deflated and removed. Right haemodynamic variables were evaluated before balloon insertion and with the inflated balloon. The mean right atrial pressure decreased by 42.59% (P = 0.005); systolic right ventricular pressure decreased by 30.19% (P < 0.003); mean pulmonary arterial pressure decreased by 25.33% (P < 0.043); mean pulmonary capillary wedge pressure decreased by 31.37% (P > 0.016); and cardiac output increased by 9.92% (P < 0.175). CONCLUSIONS: The haemodynamic and echocardiographic changes obtained in our study using PTCR® suggest that this innovative approach can play a beneficial role in the heart failure treatment.

Time-weighted vs. conventional quantification of 24-h average systolic and diastolic ambulatory blood pressures.

BACKGROUND: Conventional calculation of mean 24-h ambulatory blood pressure (BP), SBP and DBP based on the average of all BP readings disregards the fact that a larger number of measurements is usually scheduled during the daytime than at night, an imbalance possibly leading to an overestimation of 24-h average BP. The aim of our study was to quantify this possible bias and to explore its determinants. METHODS: Four hundred and fifty untreated individuals were subdivided into three groups (150 individuals each) with three different ambulatory blood pressure measurement schedules for day/night: group I, four (day)/two (night) readings/h; group II, four (day)/three (night) readings/h; and group III, with BP readings every 30 min throughout 24 h. Hourly and 24-h averages were computed. The conventional 24-h averages of all SBP and DBP values were compared with the averages of hourly SBP and DBP mean values (time-weighted quantification). The difference between 24-h conventional and 24-h time-weighted BP was computed in each group and related to the degree of nocturnal BP dip and to the ratio between the number of readings of day and night. RESULT: In the three groups, 24-h conventional and 24-h time-weighted BP values were highly correlated (r > 0.99), 24-h conventional SBP and DBP being significantly higher (P < 0.01) than the corresponding 24-h time-weighted values in groups I and II but not in group III (Bland-Altman analysis). The bias magnitude was related to the day/night ratio in number of readings and to nocturnal BP dip in groups I and II (P < 0.01) but not in group III. CONCLUSION: The higher number of readings/h during daytime leads to an overestimation of conventional 24-h average BP, particularly in individuals with preserved nocturnal BP dipping. This can be avoided either by scheduling the same number of readings/h throughout 24 h or by performing a time-weighted quantification of 24-h BP. The clinical implications of these different approaches deserve further investigation.

El asesoramiento cardiológico a través de la telemedicina: experiencia en el estado Lara-Venezuela / Cardiologic support by telemedicine: experience in Lara State-Venezuela

La transmisión de electrocardiogramas por vía telefónica es una técnica ampliamente difundida en el mundo. Se describe la experiencia de 17 meses (marzo 2006-agosto 2007) de utilización de un sistema de transmisión de electrocardiogramas, desde 23 centros urbanos y suburbanos ubicados en el Estado Lara. Los electrocardiogramas son tomados y transmitidos por los médicos generales mediante equipos Aerotel ®, ubicados en los hospitales o ambulatorios, a la central de llamadas ubicada en Caracas. El cardiólogo de guardia transmite el electrocardiograma el cual es recibido e interpretado por el especialista de guardia de telemedicina. El trazo electrocardiográfico, interpretado es enviado en pocos minutos al médico referente vía Fax. Se realizaron 3.690 electrocardiogramas a 3.104 pacientes. El motivo de la realización del electrocardiograma fue en la mayoría de los casos, dolor torácico (25 por ciento) o hipertensión arterial (26 por ciento). Los electrocardiogramas con anormalidades alcanzaron el 65 por ciento. Los trastornos isquémicos representaron el porcentaje mayor de anormalidades (32 por ciento). De las arritmias, la de mayor frecuencia la fibrilación y el “flutter”auricular (43 por ciento). Los trastornos de conducción el bloqueo de rama derecha y el hemibloqueo anterior izquierdo ocuparon la mayor frecuencia (23 por ciento y 35 por ciento respectivamente). Los electrocardiogramas cuyo diagnóstico requirió una conducta inmediata alcanzaron a 428 electrocardiogramas, siendo los más frecuentes la fibrilación auricular y la lesión subepicárdica: 203 (47 por ciento) y 161 (38 por ciento respectivamente. Este estudio muestra la utilidad de un sistema de tele-electrocardiografía, que presta asesoramiento cardiológico a centros urbanos y suburbanos en los cuales no existen especialistas de manera permanente.

Telephone transmission of electrocardiograms is widely practiced around the world. This study describes the experience with a tele-electrocardiography system, over 17 months (March, 2006-August, 2007), in 23 urban and suburban centers located in Lara State. Electrocardiograms were obtained by general practitioners using Aerotel® devices located in clinics and hospitals and transmitted to a call center located in Caracas. There a receiving cardiologist interpreted the tracings. Within a few minutes the interpretation was sent back to the referring physician. A total of 3,690 electrocardiograms were obtained from 3,104 patients. The reason for obtaining an electrocardiogram in these patients was, in most cases, a presenting history of chest pain (25%) or a finding of arterial hypertension (26%). An abnormality was found in 65% of the tracings. Conduction disturbances accounted for the highest percentage (32%). Among rhythm disturbances, atrial fibrillation and flutter were present in 43% of the electrocardiograms. Right bund le branch block and left anterior hemiblock were the most frequent conduction abnormalities (23% and 35% respectively). There were 428 electrocardiographic diagnoses, resulting in an immediate intervention, of which atrial fibrillation and a subepicardial lesion accounted for 203 (47%) and 161 (38%) cases respectively. This study shows the utility of a tele-electrocardiography system, which provides cardiologic support to urban and suburban centers, where specialists arenot available.

[Circadian profiles of heart rate and its instantaneous variability in patients with chronic Chagas' disease]. / Perfiles circadianos de la frecuencia cardíaca y de su variabilidad instantánea en una población de pacients con infección chagásica crónica.

INTRODUCTION AND OBJECTIVES: Impairment of the autonomous nervous system in early stages of Chagas' disease is still a matter of debate, although multiple approaches (including heart rate response to orthostatism and the Valsalva maneuver, and spontaneous variability) have been used to ascertain its occurrence. The circadian profile of heart rate and its variability have not been investigated in patients with Chagas' disease. PATIENTS AND METHOD: We analyzed the 24-hour heart rate by Holter recordings in 63 patients with and without ECG alterations, who had positive serological findings for Chagas' disease. These results were compared with those in 22 healthy subjects matched for sex and age. Mean 24-hour heart rate and its circadian amplitude were analyzed with Cusum analysis and nocturnal dip. In a subgroup of 45 subjects (30 with Chagas' disease and 15 healthy controls), heart rate instantaneous variability (24-hour pNN50 and r-MSSD) and circadian amplitude were also calculated by Cusum analysis. RESULTS: 24-hour and diurnal heart rates were lower in patients with Chagas' disease than in healthy subjects (P<.05). Circadian amplitude and dip were lower in patients, but these differences did not reach statistical significance. In the subgroup of 45 subjects, the reductions in instantaneous heart rate variability (pNN50 and r-MSSD) in Chagasic patients were small, and circadian amplitudes were preserved, when compared with healthy subjects. CONCLUSIONS: The lower heart rate in patients with Chagas' disease occurred only during diurnal activity, and instantaneous heart rate variability was preserved. These findings suggest an alteration in the sympathetic branch of the autonomous nervous system. The circadian heart rate profile, which has not been studied previously in patients with Chagas' disease, does not seem appreciably blunted in this stage of the disease.

Angiografia no tromboembolismo pulmonar: aspectos atuais / Angiography in pulmonary embolism: update

A técnica empregada nos casos de tromboemolismo pulmonar consiste na introduçäo de um cateter pela veia antecubital, reposicionamento do mesmo em tronco da artéria pulmonar e injeçäo de contraste. Esta técnica é isenta de arritmias importantes e/ou acidentes angiográficos. A contraindicaçäo absoluta ao procedimento, consiste na reaçäo alércia aos contrastes iodados e as relativas säo o infarto do miocárdio recente e a presença de arritmias cardíacas graves. A angiografia pulmonar é portanto o meio diagnóstico definitivo da embolia pulmonar e ajuda na melhor forma de terapêutica a ser efetuada, principalmente em pacientes de alto risco, com a probabilidade de uso empírico de anticoagulantes. O achado mais importante é a visualizaçäo do embolo intraarterial, com um defeito de enchimento da artéria (cut-off) e oclusäo de múltiplos ramos arteriais pequenos em uma área circunscrita (prunning ou podamento). Quando os sinais angiográficos säo discutíveis, o tratamento deve ser elaborado com base nos achados clínicos. A cintilografia prévia ao exame, poderá elucidar acometimento de artérias de calibre menor que o detectado pela técnica radiológica