Exclusion of atrial thrombus by transesophageal echocardiography does not preclude embolism after cardioversion of atrial fibrillation. A multicenter study

BACKGROUND

Transesophageal echocardiography (TEE) has been used recently to detect atrial thrombi before cardioversion of atrial arrhythmias. It has been assumed that embolic events after cardioversion result from embolism of preexisting atrial thrombi that are accurately detected by TEE. This study examined the clinical and echocardiographic findings in patients with embolism after cardioversion of atrial fibrillation despite exclusion of atrial thrombi by TEE.

METHODS AND RESULTS

Clinical and echocardiographic data in 17 patients with embolic events after TEE-guided electrical (n = 16) or pharmacological (n = 1) cardioversion were analyzed. All 17 patients had nonvalvular atrial fibrillation, including four patients with lone atrial fibrillation. TEE before cardioversion showed left atrial spontaneous echo contrast in five patients and did not show atrial thrombus in any patient. Cardioversion resulted in return to sinus rhythm without immediate complication in all patients. Thirteen patients had cerebral embolic events and four patients had peripheral embolism occurring 2 hours to 7 days after cardioversion. None of the patients were therapeutically anticoagulated at the time of embolism. New or increased left atrial spontaneous echo contrast was detected in four of the five patients undergoing repeat TEE after cardioversion including one patient with a new left atrial appendage thrombus.

CONCLUSIONS

Embolism may occur after cardioversion of atrial fibrillation in inadequately anticoagulated patients despite apparent exclusion of preexisting atrial thrombus by TEE. These findings suggest de novo atrial thrombosis after cardioversion or imperfect sensitivity of TEE for atrial thrombi and suggest that screening by TEE does not obviate the requirement for anticoagulant therapy at the time of and after cardioversion. A randomized clinical trial is needed to compare conventional anticoagulant management with a TEE-guided strategy including anticoagulation after cardioversion.

Estimation of left ventricular filling pressures using two-dimensional and Doppler echocardiography in adult patients with cardiac disease. Additional value of analyzing left atrial size, left atrial ejection fraction and the difference in duration of pulmonary venous and mitral flow velocity at atrial contraction

OBJECTIVES

The purpose of this study was to determine whether left atrial size and ejection fraction are related to left ventricular filling pressures in patients with coronary artery disease.

BACKGROUND

In patients with coronary artery disease, left ventricular filling pressures can be estimated by using Doppler mitral and pulmonary venous flow velocity variables. However, because these flow velocities are age dependent, additional variables that indicate elevated left ventricular filling pressures are needed to increase diagnostic accuracy.

METHODS

Echocardiographic left atrial and Doppler mitral and pulmonary venous flow velocity variables were correlated with left ventricular filling pressures in 70 patients undergoing cardiac catheterization.

RESULTS

Left atrial size and volumes were larger and left atrial ejection fractions were lower in patients with elevated left ventricular filling pressures. Mean pulmonary wedge pressure was related to mitral E/A wave velocity ratio (r = 0.72), left atrial minimal volume (r = 0.70), left atrial ejection fraction (r = -0.66) and atrial filling fraction (r = -0.66). Left ventricular end-diastolic and A wave pressures were related to the difference in pulmonary venous and mitral A wave duration (both r = 0.77). By stepwise multilinear regression analysis, the ratio of mitral E to A wave velocity was the most important determinant of pulmonary wedge (r = 0.63) and left ventricular pre-A wave (r = 0.75) pressures, whereas the difference in pulmonary venous and mitral A wave duration was the most important variable for both left ventricular A wave (r = 0.75) and left ventricular end-diastolic (r = 0.80) pressures. The sensitivity of a left atrial minimal volume > 40 cm3 for identifying a mean pulmonary wedge pressure > 12 mm Hg was 82%, with a specificity of 98%.

CONCLUSIONS

Left atrial size, left atrial ejection fraction and the difference between mitral and pulmonary venous flow duration at atrial contraction are independent determinants of left ventricular filling pressures in patients with coronary artery disease. The additive value of left atrial size and Doppler variables in estimating filling pressures and the possibility that left atrial size may be less age dependent than other mitral and pulmonary venous flow velocity variables merit further investigation.

A laser-induced scar at the cardia increases the yield pressure of the lower esophageal sphincter

Low yield pressure of the lower esophageal sphincter is associated with esophageal reflux, and fundoplication must increase yield pressure if it is to prevent reflux. We attempted to increase yield pressure endoscopically in the dog by using the Nd:YAG laser to produce a fibrous scar at the cardia in the approximate line of the gastric sling fibers. Ten beagle dogs were studied. In a pilot study with two dogs, 15 watts for 4.2 sec were found to produce a scar deep into the muscle coat of the stomach. Three configurations of scar were used. One produced significant rises in yield pressure in all four of the dogs treated, the second produced a significant rise in one of the two dogs treated, and the third caused a significant drop in yield pressure in the one dog treated. One dog died of gastric perforation 10 days after lasering, but no other animal experienced any ill effects. These findings may have therapeutic implications for the management of esophageal reflux.

Outpatient arteriography--a safe and practical proposition?

Ninety-five patients, who underwent fine catheter peripheral angiography as outpatients, were followed up and assessed to determine the safety of this procedure. No patients reported any major side effects and in particular no patients experienced a rebleed from the arterial puncture site. This procedure could be safely adopted in any radiology department.

Pathogenesis of venous ulceration in relation to the calf muscle pump function

Air plethysmography has been used to quantitate venous reflux by measuring the average filling rate of the veins (venous filling index; in milliliters per second) on standing from the supine position, the ejection fraction of the calf muscle pump as a result of one tip-toe movement, and the residual volume fraction after 10 tip-toe movements. Thirty normal limbs, 110 limbs with primary varicose veins, 34 limbs with reflux in the deep veins but without occlusion, and 31 limbs with deep venous occlusion, with or without reflux, have been studied. An increase in the incidence of ulceration occurred with increasing values of reflux and decreasing values of the calf muscle pump ejection fraction. A poor ejection fraction was the primary cause of venous ulceration in limbs with minimal reflux. A good ejection fraction, however, significantly reduced the incidence of ulceration in limbs with marked reflux (p less than 0.05). The residual volume fraction, which expresses the combined effect of venous reflux and ejection fraction with rhythmic exercise, showed a good correlation with the incidence of ulceration and the measurements of ambulatory venous pressure (r = 0.81). The air-plethysmographic measurements completely assess the calf muscle pump function and provide an accurate method to identify the predominant hemodynamic factor (ejection fraction, reflux, or both) responsible for the clinical picture of the patient.

Is yield pressure at the cardia increased by effective fundoplication?

Yield pressure at the cardia was measured before and after fundoplication in 10 patients; five had a Nissen fundoplication and five a Belsey mark IV procedure. Surgery was considered successful if oesophagitis healed or if 24 hour pH monitoring returned to normal. There was a marked rise in yield pressure in all eight patients with a successful operation. Yield pressure remained low in two patients in whom oesophagitis persisted.

A perioperative technique for detection of retained valve cusps in the in situ vein graft

A problem of the in situ vein bypass technique is the retained value cusp. To ensure that maximum flow has been obtained through the vein graft after valvotomy, a simple perioperative technique has been developed. This consists of infusing normal saline solution into the vein and comparing the distal to proximal (antegrade) flow with the proximal to distal (retrograde) flow under the same conditions. Twelve consecutive in situ vein grafts have been assessed. Antegrade and retrograde flow measurements were similar in four of the grafts but different in eight (40% to 80% reduced retrograde flow). Valvotomy was repeated and subsequent measurements of retrograde flow were similar or greater than the antegrade. The technique described is simple, reproducible, inexpensive, and may prove useful for routine intraoperative evaluation of valvotomy of in situ vein grafts.

Objective noninvasive evaluation of venous surgical results

The hemodynamic effect of conventional surgery for varicose veins has been evaluated with a new method of air-plethysmography. The functional venous volume of the leg, venous reflux, and calf muscle pump-ejecting capacity have been measured in 42 legs with primary varicose veins. The patients were studied clinically, with Doppler ultrasound, duplex scanning, and phlebography preoperatively. Doppler ultrasound was repeated postoperatively. Air-plethysmography was performed one day before surgery and 8 to 10 days after surgery. A decrease of the functional venous volume of 16% has been observed (p less than 0.001). The abolition of venous reflux has been shown in all the patients. An improvement in the calf muscle pump-ejecting capacity has also been shown, with a 30% increase of the ejection fraction of the calf muscle pump and with a 43% decrease of the residual volume fraction after 10 tiptoe movements (p less than 0.001). The results indicate that this new method of air-plethysmography apart from its diagnostic value offers a new and unique technique for a noninvasive, objective, and quantitative evaluation of the results of established and experimental venous surgery.

Does measurement of yield pressure at the cardia during endoscopy provide information on the function of the lower oesophageal sphincter mechanism?

We describe a technique for measuring the yield pressure at the cardia during upper gastrointestinal endoscopy. The test was applied to 47 patients with macroscopic oesophagitis and nine patients with achalasia. Controls were 123 patients from the routine endoscopy list in whom no abnormality was found and 21 healthy volunteers. Yield pressure was similar in both control groups, but was significantly higher in achalasia (p less than 0.001) and lower in oesophagitis (p less than 0.001). Yield pressures fell dramatically after pneumatic dilatation in the achalasia patients. The test was reproducible and yield pressure was not affected by age, sex, weight, or sedation. Measurement of yield pressure during endoscopy provides information which may reflect the function of the whole antireflux mechanism, and not just the lower oesophageal sphincter.

Increased respiratory chemosensitivity induced by oral almitrine in healthy man

Cardiorespiratory effects of 50 mg and 100 mg doses of almitrine and placebo given orally on separate test days to twelve healthy volunteers were assessed in a double-blind crossover study. The drug caused no significant changes in ventilation, mixed venous CO2 tension, metabolic rate, heart rate or blood pressure while they were resting and breathing room air. With progressive hypercapnia, however, the ventilatory response increased by 5% after the 50 mg dose (NS) and by 27% after the 100 mg dose (P less than 0.05). There were greater increases in the response to progressive hypoxia by 78% after 50 mg of almitrine (P less than 0.01) and by 120% after 100 mg (P less than 0.01), which was also significantly greater than the increase after the 50 mg dose (P less than 0.01). In contrast there were only minor and inconsistent changes in chemosensitivity after administering placebo. The findings are consistent with an agonist action of almitrine in the peripheral chemoreceptors and suggest that it may have clinical value in managing respiratory failure due to hypoventilation.

Increased respiratory chemosensitivity induced by infusing almitrine intravenously in healthy man

The respiratory effects of intravenously infused almitrine were evaluated in healthy volunteers. In the dose range 0.25-1.0 mg/kg/hour it caused large and dose-dependent increases in hypoxic chemosensitivity, which were longlasting and more persistent than the drug's retention in the plasma. Increases in sensitivity to hypercapnia were much less and were detected only when the plasma almitrine exceeded 200 ng/ml. Small increases in resting ventilation and metabolic rate with a decrease in mixed venous carbon dioxide tension occurred only at the highest infusion rate. The findings accord with an action of almitrine in the peripheral chemoreceptors, which may be of therapeutic value in managing some cases of respiratory failure.

Cystic adventitial disease of the popliteal artery

A 62-year-old man with intermittent claudication but normal foot pulses at rest had no atheroma shown on femoral arteriography. There was evidence of external compression of the artery at the level of a popliteal cyst which was demonstrated by arthrography on films taken after sufficient exercise to be in communication with the knee joint. At operation the cyst was continuous with changes of cystic adventitial disease of the popliteal artery. Both the main cyst and th cystic changes in the artery were removed. Postoperatively the patient's claudication disappeared. Evidence is presented that synovial cysts play a part in the production of arterial cystic adventitial disease.

Haemorrhagic shock in early acute pancreatitis. A rare but significant event

Serious haemorrhage late in the course of severe acute pancreatitis is an uncommon but wellrecognized condition. Massive intraperitoneal bleeding as a presenting symptom is extremely rare and has not previously been recorded. A case where bleeding occurred from the left gastric artery is presented. Attention is drawn to the need for laparotomy or paracentesis in the profoundly shocked patient with pancreatitis who fails to respond to conservative care, for in such cases the haemorrhage may readily be arrested and a fatal outcome averted.

An experimental evaluation of the optimal method of use of streptokinase in venous thrombosis

Experiments have been carried out in dogs to determine the optimal method of use of streptokinase in venous thrombosis.

The experiments show that:– High-dose regional infusion is the most efficient system of producing thrombolysis.Occlusive thrombi are readily removed by this system.Low-dose regional infusions and high-dose systemic infusions are much less efficient but, in general, regional delivery is preferable when possible.

As a result of these experimental conclusions a number of patients have been successfully treated with high-dose regional infusions of streptokinase (Mavor, Bennett, Galloway, and Karmody, 1969; Mavor, Galloway, and Karmody, 1970).

The surgical aspects of deep vein thrombosis

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