The relationship of myocardial contraction and electrical excitation—the correlation between scintigraphic phase image analysis and electrophysiologic mapping

Division of Heart Failure and Pulmonary Hypertension, Alta Bates Hospital, Berkeley, CA, USA.
Journal of Nuclear Cardiology (Impact Factor: 2.65). 08/2009; 16(5):792-800. DOI: 10.1007/s12350-009-9114-9
Source: PubMed

ABSTRACT Phase imaging derived from equilibrium radionuclide angiography presents the ventricular contraction sequence. It has been widely but only indirectly correlated with the sequence of electrical myocardial activation.
We sought to determine the specific relationship between the sequence of phase progression and the sequence of myocardial activation, contraction and conduction, in order to document a noninvasive method that could monitor both.
In 7 normal and 9 infarcted dogs, the sequence of phase angle was correlated with the epicardial activation map in 126 episodes of sinus rhythm and pacing from three ventricular sites.
In each episode, the site of earliest phase angle was identical to the focus of initial epicardial activation. Similarly, the serial contraction pattern by phase image analysis matched the electrical epicardial activation sequence completely or demonstrated good agreement in approximately 85% of pacing episodes, without differences between normal or infarct groups.
A noninvasive method to accurately determine the sequence of contraction may serve as a surrogate for the associated electrical activation sequence or be applied to identify their differences.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The heart's structure-function relationships explain normal cardiac dynamics and clarify how they are disrupted by disease. For 500 years, anatomists described circumferential and helical cardiac fibres, yet disagreed about their relationships. One current model is attributed to Torrent Guasp who described functional pathways, the helical ventricular myocardial band (HVMB) with two interconnected loops: an outer basal loop with transverse fibres surrounds an inner apical helical loop that is composed of oblique descending and ascending segments that create a conical apical vortex. This review addresses the potential role of the HVMB in explaining the mechanics of isovolumic contraction, ejection, post-ejection isovolumic interval, rapid filling, torsion and recoiling. During the post-ejection isovolumic interval, a ∼90-ms hiatus exists between the end of contraction of the descending and the ascending segments. Compromise of this hiatus by disease disturbs the interdependence between torsion and 'untwisting' and impairs cardiac function. The validity of conventional expressions such as isovolumic relaxation, hyperechogenic septal line, untwisting and mitral valve opening will be revisited.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 08/2014; 47(4). DOI:10.1093/ejcts/ezu278 · 2.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Normal cardiac function of the left and right ventricles, together with the septum, is related to form/function interactions within the helical ventricular myocardial band. This knowledge is a prerequisite to understanding form/function interactions in diseases and for planning new treatments. Topics discussed include congestive heart failure in dilated hearts of ischaemic, valvar or nonischaemic origin as well as diastolic dysfunction. Similar thinking underlies novel treatments for dyssynchrony in pacing, together with focusing upon varying global left or right ventricular anatomy to correct mitral and tricuspid insufficiency caused by tethering of the leaflets. The septum is the lion of the right ventricle and insight is provided into offsetting septal damage during cardiac surgery, rebuilding its anatomical structure in post-tetralogy pulmonary insufficiency, as well as rectifying its dysfunction by decompression in patients with a left ventricular assist device.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 07/2014; DOI:10.1093/ejcts/ezu279 · 2.81 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A growing body of evidence suggests that the arrhythmogenic substrate underlying Brugada syndrome (BrS) is located in the right ventricular outflow tract (RVOT), and electrophysiological abnormalities recently evidenced most commonly concur in conduction slowing. Also, imaging studies reported wall motion abnormalities of the RVOT in patients with BrS, with a various extent of RV remodeling. However, there are no data regarding a potential relationship between electrophysiological alterations and contraction abnormalities in BrS. We aimed to assess (1) the potential relationship between contraction delays of the RV quantified by phase analysis of equilibrium radionuclide angiography (ERNA), and the spontaneous ST-segment elevation pattern; and (2) to evidence RV remodeling in patients with BrS. Seventy patients with BrS and 18 control subjects were included in the study. For the purpose of the study, the spontaneous ST-segment elevation pattern was graded simultaneously to ERNA acquisition. RV contraction delays and amplitude were assessed using multiharmonic phase analysis of ERNA, and ventricular volumes and ejection fraction were assessed using gated blood-pool single photon emission computed tomography. RVOT contraction was delayed in patients with BrS, and RV contraction heterogeneity increased according to the pattern of ST-segment elevation, without impairment of the amplitude of contraction. RV volumes were greater in patients with BrS compared with control subjects, without impairment of the ejection fraction, whatever the ST-segment elevation pattern or the magnitude of contraction heterogeneity. In patients with BrS, we found a relationship between RV contraction heterogeneity and ST-segment pattern, providing evidence of a functional modulation of the arrhythmogenic substrate.
    Heart rhythm: the official journal of the Heart Rhythm Society 07/2011; 8(12):1905-12. DOI:10.1016/j.hrthm.2011.07.026 · 4.92 Impact Factor

Preview (2 Sources)

Available from