Assessment of Stroke Volume and Cardiac Output in Response to Varying Heart Rates
Ориентир для пациента и семьи
Простыми словами
Автоматическая сводка по структурированным данным реестра. Она помогает сориентироваться, но не заменяет официальный протокол или оценку врача.
- Что изучают
- В протоколе указаны: Pacing.
- Кому может быть актуально
- Состояния в реестре: Vasovagal Syncope. Базовые параметры: 18 лет — 70 лет · Все.
- Что важно проверить
- Возраст, диагноз и пол — только базовые ориентиры. Предыдущее лечение, анализы и другие обязательные условия указаны ниже в критериях участия.
- Где проводится
- Канада
- Следующий шаг
- Сохраните исследование, покажите его лечащему врачу и уточните актуальный статус у исследовательского центра. Расходы, документы и поездка →
Не всё понятно в терминах? Прочитайте наш гид для пациентов →
Официальное название
Assessment of Stroke Volume and Cardiac Output in Response to Varying Heart Rates and Body Position - a Pacemaker Based Study
Обзор
The investigators will seek to determine the effects of different heart rates on both stroke volume and cardiac output using non-invasive hemodynamic assessments. In order to safely manipulate the HR, the investigators will study patients with permanent pacemakers in whom heart rate manipulation can be done in a safe and non-invasive manner.
Подробное описание
Permanent pacemakers have sometimes been used to treat patients with recurrent vasovagal syncope. This is because patients with vasovagal syncope often experience bradycardia at the time of their syncope. Unfortunately, pacemakers are often ineffective in preventing syncope.
Classical cardiovascular hemodynamics would suggest that increasing the heart rate (HR; via pacemaker) should increase the cardiac output (CO). This is because:
CO = HR x Stroke volume (SV).
The assumption is that the SV is fixed during manipulation of the HR. However, this might not be the case. As the number of beats per minute (HR) increases, the cardiac cycle length (R-R interval \[RRI\]) shortens, as a function of simple math. This means that the time in cardiac systole shortens, and the time in cardiac diastole shortens. Since cardiac diastole is when the heart fills up with blood, faster HR can be associated with decreased cardiac filling times. This, in turn, could compromise the SV. However, there is a paucity of data as to what happens to SV and CO at different HR. Further, it is possible that these effects will be different when a person is lying down supine versus when a patient is upright (when stroke volume will be lower).
The investigators will seek to determine the effects of different HR on both SV \& CO. In order to safely manipulate the HR, they will study patients with permanent pacemakers in whom HR manipulation can be done in a safe and non-invasive manner.
Вмешательства
- Устройство Pacing
Assess the non-invasively determined stroke volume and cardiac output response at different paced heart rates in patients with a cardiac pacemaker or implanted defibrillator with preserved ejection fractions (LVEF≥50%)
Первичные конечные точки
- Change in cardiac output while atrial pacing at lower and higher rates while supine [Срок оценки: 1 day]
Вторичные конечные точки (7)
- Change in cardiac output at lower and higher ventricular (VVI) paced rates while supine [Срок оценки: 1 day]
- Change of cardiac output at lower and higher atrial (AAI) paced rates while supine versus while upright [Срок оценки: 1 day]
- Change of cardiac output at lower and higher ventricular (VVI) paced rates while supine versus while upright [Срок оценки: 1 day]
- Change in stroke volume at lower and higher atrial paced rates while tilted up [Срок оценки: 1 day]
- Change in stroke volume at lower and higher ventricular (VVI) paced rates while tilted up [Срок оценки: 1 day]
- Change of stroke volume at lower and higher atrial (AAI) paced rates while supine versus while upright [Срок оценки: 1 day]
- Change of stroke volume at lower and higher ventricular (VVI) paced rates while supine versus while upright [Срок оценки: 1 day]
Критерии участия
Критерии включения
- Age 18-70 years (inclusive)
- Implanted permanent pacemaker or implanted defibrillator capable of atrial and ventricular pacing
- LV ejection fraction >50%
Критерии исключения
- Unable or unwilling to provide informed consent
- Clinical need for a cardiac resynchronization device
Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.
Здоровые добровольцы: Нет
Дизайн исследования
- Распределение
- Не применимо
- Модель
- Одна группа
- Маскирование
- Открытое
- Основная цель
- Лечение
Центры проведения
Канада · 1 центр
- University of Calgary — Calgary
Идентификаторы
NCT: NCT03446326 · REB15-2887