Inhibition of demand pacemakers by myopotentials.

The inhibition of unipolar demand pacemakers by myopotentials was studied in 215 paced patients with or without symptoms and in steady pacing rhythm. ECG recordings were taken of all patients at rest and during effort in which maximal muscular strength from the pectoralis major (PM) and rectus abdominis (RA) muscles was required. In 75 patients (34.

Global and segmental left ventricular function in beta-thalassemia.

The systolic and diastolic left ventricular (LV) function was studied by M-mode echocardiography in 60 patients with beta-thalassemia (mean age +/- SD, 17.1 +/- 7.5 years) and 30 healthy controls (15.

Iron overload and left ventricular performance in beta thalassemia.

The effect of iron overload on left ventricular (LV) performance was studied in 60 patients with beta-thalassemia. Patients were divided into 3 groups according to the number of blood units (BU) received. Clinically, 14 patients were in advanced classes (III and IV) of congestive heart failure (CHF).

Cardiac arrhythmias in chronic renal failure? Holter monitoring during dialysis and everyday activity at home.

25 patients undergoing regular haemodialysis for chronic renal failure underwent Holter ECG monitoring for a continuous 48-hour period covering dialysis and the intermediate period of everyday activity at home. A low dialysate potassium concentration (1.7 mEq/l) was used.

Autonomic neuropathy in leprosy.

The integrity of the autonomic control of the cardiovascular system was studied in 21 patients with lepromatous leprosy and in ten normal people using several simple tests based on cardiovascular reflexes. Impairment of both parasympathetic and sympathetic function was demonstrated in the lepromatous patients.

Rectus abdominis as a source of myopotentials inhibiting demand pacemakers.

We examined four patients with a demand pacemaker who exhibited transient symptoms of vertigo while trying to rise from the supine position. In two of these there was an epicardial pacing system with the pacemaker in the abdominal wall superficial to the rectus abdominis muscle; in the other two cases the pacing system was transvenous with the pacemaker superficial to the right pectoralis major muscle. It was found that the "pseudovertigo" was due to pacemaker inhibition caused by rectus abdominis myopotentials in all four patients.

Sinus node coronary arteries studied with angiography.

Coronary angiograms of 309 consecutive patients undergoing coronary angiography were reviewed to investigate the blood supply to the sinus node area. Blood was supplied from the right coronary artery in 59% of cases, from the left coronary artery in 38%, and from both coronary arteries in 3%. The posterior sinus node artery was demonstrated in 32 patients (27% of the 119 patients with the sinus node artery originating from the left circumflex and 10.

Peripheral venous contrast echocardiography. A study of a new technique of injection in vitro and in vivo.

A new technique of peripheral venous contrast echocardiography is described which uses a special type of injection catheter to achieve a much greater density of image of the cardiac cavities. The multi-hole catheter gave consistently better results than the conventional single hole catheter under trials both in vitro and vivo.

The importance of the sinus node artery in the blood supply of the atrial myocardium. An anatomical study of 360 cases.

The sinus node artery (SNA) and its contribution to the blood supply of the atrial myocardium (AM) were studied using X-rays and corrosion casting in a series of 360 human hearts. In 68 cases (19%) the SNA supplied the right atrium and part of the atrial septum (group A), in 211 cases (59%) it supplied the myocardium of one atrium (right or left), the atrial septum and part of the other atrium (group B), and in 81 cases (22%) the SNA supplied almost the entire AM (group C). In 133 cases (37%) the vessel supplying the sinus node (SN) was not the main continuation of the SNA, contrary to what is generally accepted.

False echocardiographic diagnosis of aortic root dissection in case of abdominal aortic dissection.

A patient with strong clinical and radiological indications of dissection involving the ascending aorta had this "confirmed" on an echocardiogram which showed a typical pattern of double lumen. At necropsy there was dissection of the abdominal aorta but the heavily calcified thoracic aorta was free of dissection. Echocardiography may be useful but not entirely reliable in the diagnosis of dissection even in the presence of a typical clinical picture.

An S-shaped atrial artery supplying the sinus node area. An anatomical study.

An S-shaped sinus node artery (SSNA), originating in the posterolateral part of the left circumflex artery (LCir) below or behind the left auricle, is described in detail. The coronary vessels were studied in 300 human hearts by x-ray films or by casting of the vessels, and the SSNA was found in 24 (21.5 percent) of the 111 cases where the sinus node artery (SNA) arose from the LCir, (ie, 8 percent of all the hearts).

Double diastolic murmur in mitral stenosis with atrial fibrillation and complete heart block.

A double diastolic murmur was heard in a patient with mitral stenosis, atrial fibrillation, and complete heart block. Echo-phonocardiographic examination showed two separate opening and closing movements of the mitral valve in the same long diastole. A clear time relation was observed between the valve closing movements and the separate diastolic murmurs, giving support to the theory that the backward motion of the mitral valve against the forward blood flow through the valve is responsible for the production of these murmurs.

Early diastole in mitral valve disease.

Noninvasive findings from the study of early diastole in patients with mitral stenosis or mitral regurgitation are reported. Isovolumic relaxation time and the opening phase of the mitral valve are the main subintervals of early diastole. In mitral stenosis, a 3rd subinterval, the ECHO X-E phase, is described.

Effects of oxyfedrin: a beta-adrenoreceptor stimulant, on infarct size following acute coronary artery ligation.

Regional left ventricular blood flow and the extent of myocardial ischaemia were studied after acute coronary artery occlusion in open-chest dogs before and after infusion of oxyfedrin, a beta-adrenergic stimulant. Regional blood flow was measured with radioactive tracer microspheres and local tissue injury was estimated by the S-T segment elevation in epicardial electrocardiograms. Animals receiving oxyfedrin were divided into two groups: 1 and 2.

Noninvasive study of early diastole in mitral stenosis.

Cardiac events of early diastole were studied in 50 normal subjects and 46 patients with mitral stenosis (MS) by simultaneous recordings of the mitral valve echogram (MVE), phonocardiogram, and apexcardiogram (ACG). Left ventricular isovolumic relaxation time (IRT), measured between A2 and onset of the MVE opening motion, had almost the same values in normals 54 +/- 7 msec, and MS 51 +/- 16 msec. The interval between A2 and the ACG "O" point was approximately double that of IRT: 99 +/- 11 msec in normal subjects, 109 +/- 20 msec in MS.

Extent of the inferior myocardial infarction assessed by the frontal plane of the vectorcardiogram.

A correlation was made between the vectorcardiographic changes and the peak value of the L.D.H.

End-diastolic amplitude of mitral valve echogram in mitral stenosis.

By using simultaneous recordings of the mitral valve echogram and apex cardiogram, the mitral echogram amplitude was measured at the onset of left ventricular isovolumic contraction (MAIC). Twenty normal subjects and 68 patients with a reduced diastolic closure rate in the mitral valve echogram were studied. Of these patients, 53 had mitral stenosis, 6 aortic valvar stenosis, and 9 hypertrophic obstructive cardiomyopathy.

Rocking motion of the right cardiac cavities in Ebstein's anomaly. A specific cineangiographic sign.

In 7 cases of Ebstein's anomaly the right cineangiogram disclosed a big right atrium, the tricuspid valve positioned to the left of the spine and tricuspid regurgitation. The right atrial appendage was nearing the outflow tract of the right ventricle and the pulmonary artery so as the normal U appearance of the right aniograms was abolished. In addition to these signs a very characteristics and almost pathognomonic rocking motion of the radiopaque material, moving from the right atrium towards the right ventricle during ventricular diastole and backwards to the atrium during the next ventricular systole was observed.

Re-entry ectopic ventricular rhythm caused by artificial pacing.

Two cases with coupled ectopic ventricular rhythm associated with artificial pacing are presented. The premature ventricular beats appeared at a fixed distance from the R of the previous electrical stimulus complex and when pacing was stopped ventricular arrest occurred. This provides strong evidence that the ectopic ventricular beats were dependent on the electrical stimulus and therefore that they were produced by its re-entry.

Length of main left coronary artery in relation to atherosclerosis of its branches. A coronary arteriographic study.

The relation between the length of the main left coronary artery and the presence of atherosclerosis in its branches or the presence of complete left bundle-branch block was studied by selective coronary arteriography in 43 persons. The length of the main left coronary artery was found to be significantly shorter in patients with coronary atherosclerosis than in subjects without angiographic evidence of coronary artery disease. In patients with electrocardiographic evidence of complete left bundle-branch block, the length of the left main coronary artery was significantly shorter than that in both previous groups.

Mechanical alterations of the left ventricle during right atrial pacing.

The effect of increasing heart rate by right atrial pacing on the peak value of the first derivative of left ventricular (LV) pressure(dp/dt) and the maximal velocity of the contractile element (KVmax) was studied in 12 cases. Peak dp/dt was poor as regards its sensitivity in reflecting the changes of contractility, due to its strong dependence on LV end-diastolic (EDP) and systolic pressure. KVmax increased constantly in the 4 normals and in 2 cases of ischaemic heart disease which did not develop angina; the increase exceeded 90 ml sec-1 in the former and one of the latter cases in which resting LV function was normal.