K. Joseph Elsperger

Two-dimensional echocardiographic identification of complicated aortic root endocarditis: implications for surgery

Two-dimensional echocardiography successfully displayed the location and extent of aortic root complications, annular abscess or mycotic aneurysm in nine patients with aortic valve endocarditis. Five of the nine patients had prosthetic valve endocarditis and four had native valve endocarditis. The infective process extended into the paravalvular structures, including the interventricular septum (seven patients), right ventricular outflow tract (three patients), interatrial septum (one patient) and anterior mitral valve leaflet (four patients). The amount of aorto-left ventricular discontinuity caused by these complications was quantitated in degrees of annular circumference on the parasternal short axis image and in distance on the parasternal long axis image. The echocardiographic findings were confirmed at surgery and were helpful in the preoperative anticipation of the type of surgical procedure required: aortic valve replacement or composite aortic valve and root replacement. Five patients had prosthetic valve endocarditis with calculated aorto-left ventricular discontinuity of 173 +/- 55 degrees on parasternal short axis images and 1.36 +/- 0.72 cm on parasternal long axis images. Initial surgical repair included three composite aortic root-valve prosthesis implants, one reconstructive procedure with valve replacement and one simple aortic valve replacement. During a follow-up period of 18 months (range 1 to 35), a second reparative procedure was required for only one patient to repair an aortic conduit to coronary artery venous bypass graft. Four patients had native valve endocarditis with calculated aorto-left ventricular discontinuity of 100 +/- 17 degrees on parasternal short axis images and 0.88 +/- 63 cm on parasternal long axis images. Initial surgical repair included two reconstructive procedures with valve replacement and two simple aortic valve replacements. During a follow-up period of 30 months (range 16 to 42), three of these four patients required a second reparative procedure: one each for repair of a paraprosthetic leak, a ventricular septal defect and persistent aorto-left ventricular discontinuity. Two-dimensional echocardiography accurately detected aortic annular abscess and mycotic aneurysm complicating aortic valve endocarditis and the resultant degree of aorto-left ventricular discontinuity. Circumferential aorto-left ventricular discontinuity with these complications is greater for prosthetic than native valve endocarditis and predicts a more extensive surgical repair.(ABSTRACT TRUNCATED AT 400 WORDS)

Two-dimensional echocardiographic detection of right-sided cardiac intracavitary thromboembolus with pulmonary embolism

Five patients with pulmonary embolism, in whom right-sided intracardiac thromboembolus was detected by echocardiography and confirmed by either angiography, surgery or postmortem examination, are described. One of these patients died from massive pulmonary embolism after right heart catheterization. In two patients treated medically, either partial or total lysis of the thromboembolus was demonstrated echocardiographically; in another two patients, the right atrial thromboembolus was successfully removed surgically. Typical locations and echocardiographic characteristics of right-sided thromboemboli are described. The potential usefulness of two-dimensional echocardiography in both the diagnosis and the management of patients with right-sided intracardiac thromboembolism is discussed.

Tissue acoustic properties of fresh left ventricular thrombi and visualization by two dimensional echocardiography: Experimental observations

Abstract Although two dimensional echocardiography can detect left ventricular thrombi In certain cardiovascular disease states, there Is theoretical concern that the acoustic Impedance properties of recently formed fresh thrombi may not allow their echocardiographic visualization. If such were the case, false negative studies might occur even with technically adequate echocardiographic examinations. To determine if the tissue acoustic properties of acute thrombi allow their visualization and differentiation from surrounding intracavitary blood and adjacent myocardium with two dimensional echocardiography, an in vivo canine model of acute left ventricular thrombus was studied. In 10 dogs left ventricular thrombus was induced using coronary ligation and subendocardial injection of a sclerosing agent, sodium rlclnoleate. Acoustically distinct left ventricular thrombi were imaged by two dimensional echocardiography within hours (mean ± standard deviation 121 ± 40 minutes, range 45 to 180), and the thrombi could easily be differentiated from surrounding blood and adjacent myocardium. Thrombi with a maximal dimension as small as 0.6 cm at autopsy were highly reflective and could be imaged with echocardiography. Histologic examination of the thrombi showed characteristic features of early thrombosis. In six dogs, echocardiographic imaging revealed two acoustically distinct areas of thrombi. Gross and microscopic examination of the thrombi in these animals confirmed two distinct types of thrombus with differing histologie features. Although technical aspects of the echocardiographic examination or certain biologic features of thrombi such as thrombus size may limit the detection of thrombi by echocardiography in certain situations, our data indicate that the tissue acoustic properties of recently formed thrombi are not a primary limitation to their echocardiographic detection. These findings support the use of two dimensional echocardiography in the investigation of the natural history, prevention and therapy of left ventricular thrombus in patients during the early course of acute myocardial Infarction.

Serum potassium, calcium and magnesium after resuscitation from ventricular fibrillation: a canine study.

Serum electrolytes were measured before and sequentially for 3 hours after resuscitation from ventricular fibrillation in a canine model that was designed to approximate the human cardiac arrest and resuscitation process. Twenty anesthetized dogs were resuscitated from ventricular fibrillation; 7 required epinephrine during resuscitation and 13 did not. To control for the effects of anesthesia, 10 dogs were anesthetized and instrumented, but ventricular fibrillation was not induced. Serum potassium decreased from 3.7 +/- 0.3 mmol/liter at baseline to 3.2 +/- 0.4 mmol/liter 45 minutes after resuscitation in the experimental dogs resuscitated without epinephrine, as compared with 3.6 +/- 0.3 to 3.4 +/- 0.2 mmol/liter in control dogs (p = 0.07 versus control dogs by two-way analysis of variance) and returned toward baseline at the end of 3 hours. Serum calcium decreased from 9.6 +/- 0.6 mg/dl at baseline to 8.9 +/- 0.9 mg/dl at 5 minutes after resuscitation as compared with 9.4 +/- 0.7 to 9.5 +/- 0.7 mg/dl in control dogs (p less than 0.05 versus control dogs) and returned to baseline by 3 hours. Serum magnesium decreased from 1.5 +/- 0.1 to 1.3 +/- 0.2 mEq/dl by 3 hours in resuscitated dogs as compared with 1.6 +/- 0.2 to 1.5 +/- 0.2 mEq/dl in control dogs (p = 0.06 versus control dogs). These changes in serum potassium, calcium and magnesium were independent of the administration of epinephrine during the resuscitation process. Changes in potassium were independent of arterial pH or bicarbonate therapy. Serum glucose increased after ventricular fibrillation but not in control dogs (p less than 0.0005 versus control). No changes in other electrolytes were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Serial changes in left ventricular wall motion by two-dimensional echocardiography following anterior myocardial infarction

To evaluate the time course of spontaneous changes in wall motion following anterior infarction, we prospectively performed serial apical four-chamber two-dimensional echocardiography on 45 consecutive long-term survivors of initial transmural anterior infarction. Studies were performed on admission (1 +/- 1 days), 1 week after admission (6 +/- 2 days), at discharge (15 +/- 8 days), and at long-term follow-up (235 +/- 186 days). Ventricular size was expressed as end-diastolic area in square centimeters. Wall motion for this tomographic section was evaluated as the percent change in left ventricular area from end diastole to end systole (% LVA). Patients were grouped on the basis of significant differences for %LVA between the first and fourth studies. Group I (n = 14) had improved wall motion (23 +/- 5% to 38 +/- 9%); group II (n = 23) did not change (22 +/- 9% to 23 +/- 11%); and group III (n = 8) had worsened wall motion (28 +/- 6% to 18 +/- 7%). End-diastolic area did not change over the study period for groups I and II but increased significantly for group III (30 +/- 6 to 35 +/- 4 cm2, p less than 0.05). Most of the increase in end-diastolic area for group III was between the third and fourth study. The percent improvement (%IMP) in wall motion for patients in group I who did not have ventricular fibrillation outside the hospital expressed in days (t) following infarction fit an exponential curve (%IMP = 100-100e-(.108t) that predicts that 70% of eventual recovery will occur in the first 15 days post-infarction. We conclude that changes in left ventricular size and wall motion occur following anterior infarction with improvement or worsening occurring spontaneously in some patients. If improvement occurs, it should be evident within 2 weeks of infarction; infarct expansion in this select group of long-term survivors occurred primarily after discharge.

Postresuscitation electrolyte changes: role of arrhythmia and resuscitation efforts in their genesis

Hypokalemia frequently occurs after resuscitation from ventricular fibrillation (VF) in man. To test the casual roles of VF and resuscitation variables in this electrolyte change, we studied six groups of dogs: VF with CPR and electrical cardioversion (n = 9), control dogs with no intervention (n = 9), CPR without arrhythmia (n = 5), electrical cardioversion without arrhythmia (n = 5), CPR and cardioversion without arrhythmia (n = 5), and rapid right ventricular pacing (n = 5) (pacing rate 374 +/- 68 beat/min; BP 79/52 mm Hg during pacing). Blood for K, Ca, Mg, and glucose analysis was collected before each intervention (or at baseline in control animals) and sequentially for 3 hr. Mg had a maximum change of 0.3 mEq/L in the VF group 7 min after resuscitation, but did not change in the other groups (p less than .005). Glucose had a maximum change of 79 mg/dl in the VF group 7 min after resuscitation but did not change in the other groups (p less than .005). Ca had a maximum decrease of 0.4 mg/dl in the VF group 15 min after resuscitation but did not decrease in the other groups (p less than .005). K had a maximum decrease of 0.8 mEq/L in the VF group 60 min after resuscitation, whereas decreases were less in the other groups (p less than .005). Thus, VF caused a rapid rise in Mg and glucose followed by a fall in Ca and K. These changes were independent of resuscitation efforts as well as the moderate hypotension induced by rapid right ventricular pacing.(ABSTRACT TRUNCATED AT 250 WORDS)

The Cardiac Electrophysiology of Postresuscitation Hypokalemia in Dogs

Hypokalemia has been observed in man after out‐of‐hospital ventricular fibrillation and after cardiover‐sion from ventricular tachycardia in the electrophysiology laboratory, and also in dogs following ventricular fibrillation (maximal effect 45–60 minutes after resuscitation). Since the electrophysiological effects of postresuscitation hypokalemia are unknown, we evaluated the effects of this hypokalemia on ventricular fibrillation thresholds (group 1) and on right ventricular effective refractory periods (group 2). In both groups, anesthetized dogs with normal hearts were divided into experimental animals that had 2 minutes of ventricular fibrillation followed by cardioversion without medications and control animals without ventricular fibrillation. In group 1, we measured serum potassium before ventricular fibrillation (or time 0 in control dogs) and then measured potassium and ventricular fibrillation threshold at 45, 60, 75, and 90 minutes after baseline. In group 2 animals we measured right ventricular effective refractory periods and serum potassium at baseline and sequentially from 7 to 180 minutes after resuscitation. In group 1, the maximum change in potassium from baseline was ‐0.8 ± 0.3 mEq/L at 60 minutes after resuscitation as compared to ‐0.1 ± 0.3 mEq/L in control animals at 60 minutes (P < 0.01). At 60 minutes, ventricular fibrillation threshold was 8 ± 3 mA in ventricuJar fibrillation animals and 7 ± 3 mA in control animals (P = NS). In group 2 animals, the maximum change in serum potassium also occurred 60 minutes after resuscitation and was ‐0.8 ± 0.3 mEq/L as compared to ‐0.2 ± 0.2 mEq/L in control animals (P < 0.001). Right ventricular effective refractory periods after an 8‐beat drive at 200 msec were 121 ± 35 msec in the resuscitated animals versus 123 ± 19 msec in control animals 60 minutes after baseline (P = NS). In conclusion, postresuscitation hypokalemia had no effect on the ventricular fibrillation threshold or right ventricular effective refractory period in anesthetized dogs with structurally normal hearts prior to arrest.

Two-dimensional echocardiographic detection of left ventricular posterior wall motion abnormalities using an inferior angulation view

Two-dimensional echocardiography is frequently used to detect left ventricular (LV) wall motion abnormalities. Modification of the apical 4-chamber view by inferior angulation of the transducer provides a superior image for detection of regional wall motion abnormalities of the LV posterior wall. The inferior angulation image was prospectively compared with the standard parasternal short-axis image for detection of posterior LV wall motion abnormalities as defined by contrast left ventriculography in 63 consecutive patients. Posterior wall akinesia was present on the contrast left ventriculogram in 22 of the 63 patients. The parasternal short-axis image was judged technically inadequate for interpretation in 7 patients (11%). The inferior angulation image was technically adequate for interpretation in all patients. The sensitivity, specificity and accuracy of the inferior angulation image for detection of LV posterior wall motion abnormality was 91%, 80% and 84%, respectively, vs 67%, 71% and 70% for the parasternal short-axis image. The differences between the sensitivity, specificity and accuracy for the 2 views were not statistically significant. These observations indicate that the inferior angulation image provides a useful plane for routine echocardiographic analysis of regional LV wall motion either as a primary method to detect posterior wall motion abnormality or as a confirmatory view to document posterior wall motion abnormality.