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Chapter 5 Evaluation of Systolic Function of the Left Ventricle

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Chapter 5 Evaluation of Systolic Function of the Left Ventricle

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FIGURE 5.50. M-mode echocardiogram recorded in a patient with constrictive pericarditis. Note the relatively flat motion of the posterior wall endocardium and the abnormal multipha- sic diastolic motion of the ventricular septum related to an increase in ventricular interde- pendence. PW, posterior wall.

de ection followed by varying degrees of “paradoxical” septal motion. Many of the septal motion patterns noted in constrictive pericarditis mimic right ventricular volume or pressure overload, septal pre-excitation, le bundle branch block, and, less commonly for the experienced observer, myocardial ischemia. is topic is dis- cussed further in Chapter 9. Ventricular Pre-Excitation Ventricular pre-excitation, as typi ed by the Wolf–Parkinson– White syndrome, may result in segmental wall motion abnormal- ities which are more subtle than those seen with le bundle branch block or pacing. e abnormalities seen with pre-excitation are o en in atypical locations that are not consistent with the antici- pated location of coronary artery disease. e abnormalities associ- ated with ventricular pre-excitation are highly localized and of very small magnitude and duration. ey are o en only appreciated with M-mode echocardiography, which has the ability to detect relatively small degrees of motion that occur over only a 10- or 20-ms period (Fig. 5.51). It should be emphasized that normal contraction typ- ically begins a er completion of the entire QRS. In most patients with pre-excitation, activation through the normal conduction sys- tem precedes in an orderly fashion and soon overtakes the wave of the pre-excited myocardium. Pre-excitation of the right ventricu- lar myocardium is rarely detected with echocardiography, and it is more o en the septal and posterolateral bypass pathways that are associated with visible wall motion abnormalities. Postoperative Cardiac Motion A er any form of cardiac surgery in which the pericardium is opened, there is a characteristic abnormality of cardiac motion. is was initially appreciated only as abnormal septal motion onM-mode echocardiography. Rather than being an isolated septal abnormality, this motion abnormality actually is a global phenomenon, involving exaggerated anterior motion of the entire heart within the thorax. e initial descriptions of this abnormality were in patients who had undergone valve replacement surgery. It soon became apparent that coronary artery bypass surgery also resulted in abnormal sep- tal motion. Serial echocardiography during each sequential phase of cardiac surgery has demonstrated that the abnormality develops a er any procedure in which the pericardium is opened and it may regress over 3 to 5 years. e abnormal postoperative motion on M-mode echocardiogra- phy was noted as frank paradoxical motion of the ventricular sep- tum with preserved myocardial thickening but without the initial downward de ection seen with a le bundle branch block. With two-dimensional echocardiography, it is easily appreciated that the center of the le ventricle moves anteriorly during contraction to an exaggerated degree. is has the e ect of exaggerating apparent motion of the anteroposterior and posterolateral walls and of reduc- ing the apparent motion of the anterior septum. Figure 5.52 was recorded in a patient with “paradoxical septal motion” a er cardiac

Evaluation of Systolic Function of the Left Ventricle

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FIGURE 5.51. M-mode echocardiograms recorded in two patients with ventricular pre- excitation due to the Wolff–Parkinson–White syndrome. A: A patient with a septal pathway is noted. Note the brief early downward systolic motion of the ventricular septum ( arrow ) slightly before the upstroke of the QRS. B: Note the very slight anterior motion of the poste- rior wall recorded in a patient with a posterolateral pathway due to Wolff–Parkinson–White syndrome. PW, posterior wall. surgery. Note that septal thickening is preserved and that overall cardiac motion in the thorax is abnormal. One early observation was that the absence of “paradoxical sep- tal motion” a er valve replacement surgery may be an indicator of prosthetic valve dysfunction. ere were a number of case examples in which paradoxical septal motion failed to occur in the presence of prosthetic valve dysfunction, presumably due to the concurrent vol- ume overload that mitigated against the development of abnormal motion. Reliance of this observation is obviously outmoded. Evaluation of a postoperative, le bundle branch block or paced rhythm wall motion abnormality is o en complicated by coex- istence of any of these three entities plus concurrent myocardial ischemia or infarction. Combinations of these nonischemic wall motion abnormalities, each of which can result in a wall motion abnormality, obviously makes the interpretation problematic. Even experienced observers may have di culty detecting a primary isch- emic wall motion abnormality when two or more of these other situations are present. e single best tool for separating ischemic from nonischemic abnormalities is to rely heavily on the presence or absence of systolic wall thickening. Because many of these non- ischemic abnormalities are con ned to either the early or latter half of systole, evaluating a digitized two-dimensional echocardiogram only during the rst half of systole may allow the echocardiogra- pher to identify preserved thickening and normal endocardial

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