Impact of Pacing Mode and Diastolic Function on Cardiac Output

Impact of Pacing Mode and Diastolic Function on Cardiac Output

Background It is known from previous research that in patients with complete AV (atrioventricular) block and pacemaker stimulation stroke volume and cardiac output are higher with AV-synchronous than with AV-dyssynchronous pacing. However, the extent to which patients profited from AV-synchronous stimulation varied substantially.

Aim of the study Aim of this study is to systematically analyze the impact of diastolic function and other echo parameters on the difference of stroke volumes/cardiac output between AV-synchronous and AV-dyssynchronous pacing modes.

Methods Patients fulfilling the entry criteria will be enrolled (two-chamber pacemaker of any vendor eligible) in this monocentric, prospective, interventional study. Baseline data will be collected with a standardized questionnaire. During an echo examination, parameters of diastolic, systolic and atrial function will be assessed. Then, the stroke volume/cardiac output will be measured twice in each patient, once with AV-synchronous and once with AV-dyssynchronous pacing. Therefore, each patient will represent their own control. It will be randomized (coin tossing) which stimulation mode is first and which is second (sonographer and patient will be blinded). Descriptive statistics will be applied and regression models will be fitted to explore the data.

Inclusion Criteria:

• Patient is able and willing to give informed consent and is above the age of 18.
• Patient is implanted with a dual chamber pacemaker system for at least 6 weeks.
• Patient is in sinus rhythm on the day of recruitment.
• Patient has a ventricular pacing rate exceeding 90%.
• Upon initial device interrogation, parameters are within normal ranges.
• Calculated battery life is more than 1 year.

Exclusion Criteria:

• Patient is not in sinus rhythm on the day of echo examination.
• Intrinsic ventricular activation on the day of echo examination.
• Relevant shunt on the atrial, ventricular or pulmonary level.
• Moderate or severe heart valve dysfunction (stenosis or regurgitation).
• Presence of other medical devices that may interact with the pacemaker system.
• Women who are pregnant or breast feeding.