Patterns of ventricular contraction in patients with conduction abnormality studied by radionuclide angiocardiography.

Abstract

SUMMARY The phase image generated by radionuclide angiocardiography illustrates the regional tming of ventricular wall motion. In this study the phase image was used to investigate the patterns of ventricular contraction in 103 subjects with either normal hearts or a conduction abnormality. In 38 normal subjects the right ventricle contracted on average 7 ms after the left, and the last region to contract was the right ventricular outflow tract. In 15 subjects with left bundle branch block the left ventricle contracted 69 ms after the right, contraction spreading from the septum to the lateral wall. In 12 subjects with right bundle branch block right ventricular contraction occurred 54 ms after the left. In 11 subjects with right bundle branch block and left anterior fascicular block both right and left ventricular contraction were delayed, the right more so than the left. In three of five subjects with the Wolff-Parkinson-White syndrome and four with frequent ventricular extrasystoles areas of early contraction corresponded to areas of early depolarisation.It is concluded that ventricular contraction can be studied non-invasively and follows a pattern to be expected from the pattern of electrical depolarisation.Radionuclide angiocardiography is now firmly established in the non-invasive assessment of ventricular function. Traditionally, measurement of wall motion has been used as an index of regional contraction, but the recently introduced Fourier phase and amplitude images'-4 circumvent the problem of edge detection and provide a more complete description of wall motion. Fourier analysis quantifies the timing and magnitude of the cyclical changes in radioactive counts for each display element of the ventriculogram, and the phase and amplitude images so generated indicate the timing and magnitude of regional ventricular wall motion.The purpose of this study was to use the phase image to investigate the timing and synchronisation of left and right ventricular contraction in a variety of conduction disorders including left and right bundle branch blocks, left anterior fascicular block, the Wolff-Parkinson-White syndrome, endocardial pacing, and ventricular extrasystoles.Requests for reprints to Dr S R Underwood, Department of Cardiology, The Middlesex Hospital, Mortimer Street, London WIN 8AA.Accepted for publication 13 December 1983 Patients and methods One hundred and three subjects were studied at rest by electrocardiogram gated equilibrium radionuclide angiocardiography. Sixty-five had electrocardiographic evidence of a conduction abnormality (Table), and the phase image was used to compare the tiining of contraction in these subjects with that in the 38 whom electrical conduction was normal. All subjects had a normal ejection fraction and amplitude image for the ventricle with abnormal conduction, and the extent of ventricular contraction was therefore normal.

Left ventricle and mitral valve reverse remodeling in response to cardiac resynchronization therapy in nonischemic cardiomyopathy

“…31,32 By pacing the LV via the coronary sinus in the setting of a left bundle branch block, CRT provides a more physiologic depolarization with left to right ventricular contraction spreading from LV apex-to-base to the right ventricular outflow tract. 33 The QRS duration of CRT responders was shortened by 21 ms when compared with nonresponders, a phenomenon closely related to clinical outcomes that underscores the importance of multiparametric selection criteria. 29,30 There are important limitations to the present study and data.…”

“…In left bundle branch block, there is pre‐ejection septal contraction (also known as “septal flash”), followed by rebound septal re‐lengthening and stretch due to late posterolateral LV activation; the result is impaired septal pump function and LV ejection 31,32 . By pacing the LV via the coronary sinus in the setting of a left bundle branch block, CRT provides a more physiologic depolarization with left to right ventricular contraction spreading from LV apex‐to‐base to the right ventricular outflow tract 33 . The QRS duration of CRT responders was shortened by 21 ms when compared with nonresponders, a phenomenon closely related to clinical outcomes that underscores the importance of multiparametric selection criteria 29,30 …”

Effect of Left Bundle Branch Block on Systolic and Diastolic Function of Left Ventricle in Heart Failure

“…Ventricular hemodynamics in a small number of patients with left bundle branch block (LBBB) have previously been evaluated with phonocardiography, 1,2 echocardiography,3-6 radionuclide studies 7 or cardiac catheterization.8 It was demonstrated that altered electrical activation in patients with isolated LBBB caused global ventricular abnormalities manifested by abnormal left ventricle (LV) diastolic and systolic function.5~6 In patients with dilated cardiomyopathy, systolic function is already impaired, and this is aggravated when LBBB is present.9~lo But the effects of LBBB on systolic and diastolic LV function in heart failure (HF) (ischemic or dilated cardiomyopathy) have not been investigated in de-tail. The current study was designed to evaluate LV systolic and diastolic function in patients with isolated LBBB, and investigate whether LBBB aggravates LV systolic and diastolic functions determined by echocardiography in patients with heart failure due to different causes.…”