Electrocardiographic Changes Following Balloon Dilatation of Valvar Pulmonic Stenosis

The purpose of this paper was to study the electrocardiographic changes following balloon pulmonary valvuloplasty for pulmonic stenosis and to see if such changes reflect improvement in pulmonary valve gradient following balloon valvuloplasty. Forty-one patients, ages 7 days to 20 years, underwent balloon valvuloplasty for severe valvar pulmonic stenosis. In 35 of these patients ECGs were available 3 to 34 months (mean 11) following valvuloplasty and were compared with pre-valvu-loplasty electrocardiograms. In 30 children with excellent relief of pulmonic stenosis (group I), frontal plane mean QRS vector moved toward the left from 127 ±25° to 81 ±47°as did the horizontal plane mean QRS vector, 88 ± 36° to 27 ±51°. The amplitude of R wave in V_1, 19 ± 11.6 mm, and V₂, 19.7 ± 12.2 mm, decreased respectively to 9.5 ± 5.9 mm and 11.3 ±6.1 mm. S wave amplitude in V₅ and V₆ also decreased. The improvement in the electrocardiogram is associated with a decrease in pulmonary valve gradient from 95 ± 50 to 29 ± 23 mm Hg. In five children with significant residual pulmonary valve gradient (group II), the electrocardiograms did not show any significant change. Evaluation of the time course of ECG changes in group I revealed that recognizable electrocardiographic improvement was first observed at 6 months following successful balloon pulmonary valvuloplasty. Normal electrocardiogram suggests minimal residual pulmonary valve gradient while right ventricular hypertrophy suggests significant residual obstruction unless the electrocardiogram was recorded at or before six months following balloon valvuloplasty. These data suggest that electrocardiogram is a good indicator of improvement following balloon pulmonary valvuloplasty. (J. Interven Cardiol 1988:1:3)     

Insulin Infusion Normalizes Cardiovascular Responses and Plasma Noradrenaline after Oral Glucose in Type 1 (Insulin-dependent) Diabetes

ABSTRACT. We examined whether the abnormal regulation of the cardiovascular system and plasma noradrenaline observed after oral glucose in insulin-dependent diabetic patients could be normalized by intravenous infusion of insulin. Eight patients with type 1 (insulin-dependent) diabetes were examined after an oral glucose load with and without simultaneous infusion of insulin. Insulin infusion increased plasma insulin from 0.07 to 0.31 nmol/1. In the control experiment (glucose only), mean heart rate and mean arterial systolic blood pressure remained unchanged and plasma noradrenaline (NA) decreased (p < 0.05). After oral glucose plus intravenous insulin, mean heart rate increased by 11 % and mean systolic blood pressure by 5 % (p < 0.05, p < 0.01), whereas plasma NA did not change significantly. The present study indicates that physiologic increments in plasma insulin concentration are of importance in the regulation of the cardiovascular system and plasma NA following an oral glucose load.     

OBSERVER VARIATION IN THE SCINTIGRAPHIC DIAGNOSIS OF SOLITARY COLD THYROID LESIONS

In order to evaluate the reproducibility of the diagnosis of solitary cold thyroid lesions, two specialists in nuclear medicine and two specialists in endocrinology independently twice read 240 thyroid 99mTc pertechnetate scintigrams. No significant difference or interaction between the results obtained from the right and the left lobe was found. A solitary cold lesion was diagnosed in 100 of the 480 lobes; however, in only 30 did all four observers agree upon the diagnosis. Interobserver variation was determined by pairwise comparison of observers. The observed agreement was between 0.91 and 0.94. After adjusting for expected chance agreement, kappa values between 0.57 and 0.70 were found. Intraobserver variation was smaller than interobserver variation, revealing agreement rates of 0.93-0.96 and kappa values between 0.71 and 0.77. Agreement was related to large lesions, lesions located centrally in the lobe, and ovoid-shaped lesions. Clinicians should be aware to what extent they can rely on the information they use in their decisions. The considerable inconsistency in the evaluation of cold lesions on thyroid scintigrams should be taken into consideration, and calls in question the value of using thyroid scintigrams for deciding whether a patient should be referred for operation or biopsy.     

Sino-Atrial Dissociation: Evidence by Intracardiac Recordings in Man and by Microelectrode Studies on Isolated Rabbit Atrium

The electrophysiologic mechanisms of sinus dysfunction have recently been determined by direct recordings of the sinus node electrogram. The association of various degrees of abnormalities in the formation of the impulse within the sinus node and of sinoatrial conduction block, represents the pathophysiological substrate of the mechanism of sinus node dysfunction. The purpose of this work is to present clinical and experimental data supporting the concept of sinus node isolation. In our clinical case, the sinus node was probably intact despite aspects of sinus node dysfunction on the surface ECG. Sinus node electrograms were recorded with a sinoatrial conduction time of 100 ms (normal values in our laboratory: 83 ms +/- 38 ms). Atrial mapping demonstrated that the area depolarized by the sinus node involved a 2 cm2 zone surrounding it. This perisinusal activity could not be recorded on the surface ECG. Both exit and entry blocks in the sinus node were demonstrated. Our experimental data showed a total desynchronization between the electrical activity of the sinus node and that of the atrium under hypoxic conditions. Both types of cases demonstrated that an atrial dysrhythmia was coexisting with regular sinus activity. From these data we concluded that a sinus node free from any pathological involvement could be associated with severe symptoms of sinus node dysfunction on the surface ECG.     

Long QT Syndrome:

MILLER, R.F., et al .: Long QT Syndrome: First and Fatal Events Provoked by Hemodialysis. Long QT syndrome (LQTS) involves both congenital and acquired predispositions toward the characteristic torsades de pointes (TP) ventricular arrhythmia. Congenital long QT syndrome generally manifests with TP, syncope, or sudden death early in life. This is a documented case of previously undiagnosed congenital LQTS in a 48-year-old woman where the first and fatal episodes of TP were provoked by hemodialysis. (PACE 2003; 26[Pt. I]:103–104)     

Pituitary-Thyroid Function and Thyrotropin,Prolactin and Growth Hormone Responses to TRH in Patients with Chronic Alcoholism

ABSTRACT Basal plasma concentrations of thyroxine (T₄), 3,3′,5-triiodothyronine (T₃), free T₄ index (TF₄I), free T₃ index (FT₃I) reverse T₃, 3,3′,5-triiodothyronine (rT₃), resin T₃ uptake (TR₃U), thyroxine-binding globulin (TBG), thyrotropin (TSH), prolactin (PRL) and growth hormone (GH) as well as thyrotropin releasing hormone (TRH) stimulated TSH, PRL and GH were investigated in 31 consecutive male patients (mean age 41 years) with chronic alcoholism. According to the histology of their liver biopsies the patients were divided into three groups: patients with normal livers, steatosis and cirrhosis. The control group consisted of 30 healthy males. The patients had abstained from alcohol for at least one week when studied, and they were on a nutritionally adequate diet. All had consumed a daily minimum of 52 g ethanol for at least 5 years. None of the patients had severe or decompensated liver disease. The patients had significantly reduced T₃ and rT₃ plasma levels compared to normals. Patients with cirrhosis of the liver had increased TBG and normal RT₃U levels, while those without cirrhosis had increased RT₃U and normal TBG levels. Plasma concentrations of basal as well as TRH-stimulated TSH and PRL were unchanged in alcoholic patients, whereas basal as well as stimulated GH levels were increased in cirrhotic alcoholics. It is concluded that alcohol per se influences T₃ levels, but not the part of the hypothalamic-pituitary axis studied, and that the binding proteins are mostly determined by the degree of liver disease.