Spontaneous T wave inversion after ventricular pacing: what is the probable mechanism?

Broken heart in elderly patients: two clinical observations

Tako-tsubo cardiomyopathy (idiopathic or transient left ventricular apical ballooning syndrome [ABS]) is a reversible condition frequently precipitated by a stressful trigger that clinically mimics an acute ST-elevation myocardial infarction. Characteristically, hypokinesis or akinesis occurs in the mid- and apical segments of the left ventricle in the absence of epicardial coronary lesions. Preserved or hyperdynamic function of the basal myocardial segments results in apical ballooning, assuming the shape of a Japanese pot used to catch octopus (a takotsubo). We report on 2 well over 70 years old women (78 and 82 years) admitted to the emergency room with chest pain. Clinical signs, ECG alterations and high troponin I in both patients imposed urgent diagnostic testing and management. The electrocardiographic findings were consistent with acute myocardial infarction and transthoracic echocardiography showed in both simultaneous apical akinesia and a hyperkinetic basal area with a moderately reduced left ventricular ejection fraction. Coronary angiography, performed on an emergency basis, in both cases revealed minimal luminal irregularities, with no evidence of plaque rupture or thrombus. The wall motion abnormality extended beyond the distribution of any single coronary artery, making it less likely that an occlusive thrombus had spontaneously dissolved or that intermittent vasospasm had occurred. Taken together, these findings were consistent with ABS, and critical observations on coronary angiography indicated the diagnosis by exclusion. The patients were seen in the clinic 4 weeks after discharge. They had had no recurrent chest pain, and had returned to the normal life they had had before the cardiovascular event. A repeat echocardiography showed a normalized estimated ejection fraction in both patients. ABS is a diagnosis of exclusion and its incidence is probably underestimated in elderly patients in whom coronary angiography is not common.

Right ventricular outflow tract pacing: relation of high to low synchronous ventricular activation with cardiac memory

Cardiac memory is usually observed after right ventricular apical pacing and considered to be related to alter asynchronous activation by apical pacing. However, it is not known whether it occurs by unaltered high to low synchronous ventricular activation by right ventricular outflow tract (RVOT) pacing. We present here a case with dual chamber pacemaker whose ventricular lead positioned in the RVOT and developed cardiac memory immediately after ventricular pacing had stopped and the underlying sinus rhythm resumed.