Pacing stress echocardiography

Abstract

BackgroundHigh-rate pacing is a valid stress test to be used in conjunction with echocardiography; it is independent of physical exercise and does not require drug administration. There are two main applications of pacing stress in the echo lab: the noninvasive detection of coronary artery disease through induction of a regional transient dysfunction; and the assessment of contractile reserve through peak systolic pressure/ end-systolic volume relationship at increasing heart rates to assess global left ventricular contractility.MethodsThe pathophysiologic rationale of pacing stress for noninvasive detection of coronary artery disease is obvious, with the stress determined by a controlled increase in heart rate, which is a major determinant of myocardial oxygen demand, and thereby tachycardia may exceed a fixed coronary flow reserve in the presence of hemodynamically significant coronary artery disease. The use of pacing stress echo to assess left ventricular contractile reserve is less established, but promising. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon). To build the force-frequency relationship, the force is determined at different heart rate steps as the ratio of the systolic pressure (cuff sphygmomanometer)/end-systolic volume index (biplane Simpson rule). The heart rate is determined from ECG.ConclusionTwo-dimensional echocardiography during pacing is a useful tool in the detection of coronary artery disease. Because of its safety and ease of repeatability noninvasive pacing stress echo can be the first-line stress test in patients with permanent pacemaker.The force-frequency can be defined as up- sloping (normal) when the peak stress pacing systolic pressure/end-systolic volume index is higher than baseline and intermediate stress values, biphasic with an initial up- sloping followed by a later down-sloping trend, or flat or negative when peak stress pacing systolic pressure/end-systolic volume index is equal or lower than baseline stress values. This approach is certainly highly feasible and allows a conceptually immaculate definition of contractility with prognostic usefulness, but its therapeutic implications remains to be established. Bowditch treppe, assessed with pacing stress, can be used to assess the optimal stimulation frequency and to optimise the patient's chronotropic response in programming rate-adaptive pacemakers.

Diagnostic and Prognostic Value of Rapid Pacing Stress Echocardiography for the Detection of Coronary Artery Disease: Influence of Pacing Mode and Concomitant Antiischemic Therapy (Final Results of Multicenter Study Pol‐RAPSE)

“…In the article by Plonska 5 AAI pacing mode was exclusively used and higher specificity was obtained comparing to this study. Right ventricular pacing causes dyssynchrony of the apical septum, 8–10 hampering the correct interpretation of wall motion. In such case the motion analysis should be focused on myocardial thickening rather than on inward endocardial motion.…”

KCNQ potassium channel mutations cause cardiac arrhythmias in Drosophila that mimic the effects of aging

“…In humans, the effects of loss of function mutations in the KCNQ gene are more pronounced under conditions of physical or emotional stress (23,24). To gage cardiac performance in Drosophila, we used an external electrical pacing paradigm to physically stress the fly heart (17,25).…”

Provocative Tests for Myocardial Ischemia in Patients with Implantable Electronic Cardiac Devices

“…It was initially performed by transvenous pacemaker implantation and right atrial stimulation or transthoracic or transesophageal echocardiography methods combined with transesophageal atrial stress induced by stimulation of the left atrium through a catheter for nasal or oral transesophageal stimulation. There are variations of protocols referred to in the literature [5][6][7][8][9][10][11][12] which consist of elevation of the stimulation HR in stages of 1 to 3 minutes until reaching the submaximal HR and, if tolerated, the maximum HR. Stress with atrial stimulation through transesophageal echocardiography allows HR to increase rapidly, seeking an ischemic response, with practically spontaneous recovery after the cessation of artificial stimulation, avoiding a prolonged state of ischemia.…”