Silent coronary artery-left ventricular fistula: a disorder of the thebesian system?

Two cases with abnormal electrocardiogram were found to have the unusual direct communication between the coronary artery and left ventricular chamber without any manifestations of the other reported coronary arterial fistula.

A new technique: right ventriculography using a preshaped catheter

Right ventriculography with a preshaped catheter (J- or L-shaped) was evaluated in make the diagnosis of tricuspid regurgitation. Thirty normal subjects who did not have valvular disease showed no evidence of tricuspid regurgitation or premature ventricular contractions during injection except in one case. On the other hand, 24 patients with combined aortic and mitral valve disease showed mild to moderate tricuspid regurgitation in 11 patients and severe tricuspid regurgitation in eight patients. Only two patients developed frequent run of premature ventricular contraction during injection. Seven patients with severe tricuspid regurgitation were found to have severe tricuspid regurgitation during surgery. No evidence of tricuspid regurgitation was found in all six patients with isolated aortic valve disease. We can conclude that right ventriculography by the preshaped catheter improves the diagnostic accuracy of tricuspid regurgitation and a grading system of tricuspid regurgitation by angiography is proposed.

Alterations in regional cerebral hemodynamics and metabolism produced by focal cerebral ischemia

Since diffuse changes in blood flow and metabolism occur in the brain following a focal ischemic insult, changes of cerebral blood flow on the side opposite a cerebral infarction were observed. We have examined the course of the cerebral hemodynamic changes occurring in 15 patients with unilateral acute strokes. In 12 of these patients, significant blood flow changes (over 15%) occurred in the nonischemic hemisphere during the period of observation. A similar time course of change was found in the ischemic hemisphere and the flow changes in the two hemispheres appeared parallel to one another (diaschisis). Thus we have demonstrated a significant reduction in flow in the contralateral cortex following a unilateral ischemic insult. This reduction in flow was of the order of 38% from the control value which agrees quite well with the reduction in cortical glucose consumption of the order of 31%. We postulate that these changes are the hemodynamic and metabolic concomitants of diaschisis and may in part be due to a transneuronal depression of function.

Electrocardiographic changes during chest pain in unstable angina

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Effect of additional valve lesions on left ventricular ejection time in aortic stenosis

Rate-corrected left ventricular ejection time was measured from the aortic pressure tracings of 171 catheterised patients with aortic valve area less than or equal to 1.2 cm2. In 50 patients with pure aortic stenosis, left ventricular ejection time in increased with decreasing valve area and was significantly higher (468 +/- 5 ms, mean +/- SEM) than in 13 normal subjects (435 +/- 5 ms). Additional aortic regurgitation in 72 patients further increased the left ventricular ejection time to 484 +/- 4 ms. Significant mitral stenosis (mitral valve are less than or equal to 1.2 cm2) in 6 patients with aortic stenosis and 33 patients with aortic stenosis and regurgitation reduced the left ventricular ejection time to normal. Similarly, severe mitral regurgitation in 3 patients with aortic stenosis and regurgitation reduced left ventricular ejection time to normal, though slight or moderate mitral regurgitation in 4 of these patients did not. These data show that the prolonged left ventricular ejection time in aortic valve disease may be restored to normal in the presence of coexisting significant mitral disease.

Diaschisis with cerebral infarction

Fifteen patients admitted to Philadelphia General Hospital with acute strokes had repeated measurements of cerebral blood flow measured by the 133Xenon inhalation method. A progressive decline in cerebral blood flow in both hemispheres was observed during the first week after infarction in twelve of these patients. This decline could be partially explained by loss of autoregulation, but could not be correlated with level of consciousness, clinical status of PCO2. This progressive decline in flow in the non-ischemic hemisphere indicates a process more complex than a simple destruction of axonal afferants to neurons as implied by the term diaschisis. The flow changes in the non-ischemic hemisphere are likely caused by a combination of the immediate effects of decreased neuronal stimulation modified by loss of autoregulation, release of vasoactive substances, cerebral edema, and other factors.

Mean velocity of circumferential fiber shortening in prolapsed mitral leaflet syndrome

In 26 patients with mitral valve prolapse, ventricular function was evaluated by mean velocity of circumferential fiber shortening (MVCF) as measured along the basilar, middle and apical axes. Significantly increased rates of MVCF were found in patients with mitral prolapse along the basilar axis (1.75 +/- 0.23 circ/sec) and middle axis (2.09 +/- 0.34 cir/sec) (P less than 0.025 and P less than 0.05, respectively). Patients with mitral valve prolapse and regurgitation demonstrated a significant increase in MVCF along the basilar axes (1.72 +/- 0.15 cir/sec) (P less than 0.05). Asynergy apperars to have a negative effect on the MVCF along the middle axis. The MVCF was found not to be related to clinical findings, symptoms or electrocardiographic changes. The mechanism for the increase in MVCF in patients with mitral valve prolapse remains unsettled.

The relationship between prolapsing mitral leaflet syndrome and angina and normal coronary arteriograms

Patients with a prolapsing mitral leaflet frequently have chest pain while their coronary arteriograms are normal. In this regard, these patients are similar to the group of patients with angina and normal coronary arteriograms. In the present study, clinical, electrocardiographic, cardiac hemodynamic, angiographic, and metabolic findings in 20 patients with a prolapsing mitral leaflet were compared to those of 16 patients with angina and normal coronary arteriograms. Except for the presence of mitral leaflet prolapse and systolic clicks, the findings were similar in both groups. We postulate that prolapsing mitral leaflet is probably related to two different mechanisms. In one the primary pathologic change is in the mitral valve (mainly myxomatous transformation), and the abnormalities of ventricular contraction are secondary to unloading of the heart because of a volume shift into the distended and enlarged mitral leaflets. In the other group, the primary pathologic change is in the myocardium, with secondary prolapse of the mitral valve. The myocardial abnormality itself is probably related to primary underlying myocardial disease or to arteriolar pathologic changes. The latter group has probably the same pathophysiologic abnormality as patients with angina and normal coronary arteriograms.

Late thrombosis of the aortic Bjork-Shiley prosthesis. Its clinical recognition and management

Seven cases of massive thrombosis of an aortic Bjork-Shiley prosthesis were encountered among 433 valvular implants. Four patients died before treatment could be instituted, and three underwent repeat surgery successfully. Anticoagulation therapy was probably well maintained in four, and poorly maintained in three patients. These cases illustrated the need for a high index of suspicion and prompt recognition of this complication in patients with Bjork-Shiley prostheses. The diagnosis of massive thrombosis should be suspected with the rapid onset of (1) signs of congestive heart failure, (2) absence or attenuation of valvular clicks, (3) aortic regurgitation, or (4) hemolytic anemia. Salvage of these patients requires emergency replacement of the thrombosed prosthesis or removal of the thrombus.

Effect of thoracic blood volume changes on steady state cardiac output

We have investigated the extent to which shifts of blood volume out of or into the thoracic region influence the steady state cardiac output. The systemic circulation of anesthetized dogs was replaced with an artificial circuit which stimulated the pertinent mechanical characteristics of an intact circulation. As in the normal animal, the steady state venous return was proportional to the pressure gradient for venous return (i.e, mean systemic minus right atrial pressure). Cardiac function was altered either by administration of epinephrine or by changes in left ventricular afterload. At a constant mean aortic pressure of 100 mm Hg, epinephrine administration increased the steady state cardiac output by 55%. Half of this increase resulted from the lowered mean right atrial pressure (caused by improved cardiac function); the remainder resulted from an increased mean systemic pressure (caused by the volume shift to the systemic circulation). Increases in afterload transferred sufficient volume to the heart-lung compartment to reduce significantly the mean systemic pressure and, hence, the steady state venous return. Our results indicate that the heart-lung compartment contains a significant volume which is under cardiac control. In addition to being able to alter the right atrial pressure, the heart can modulate the steady state cardiac output by adjusting the mean systemic pressure. To this degree the heart can adjust its own venous return.

Spontaneous variations in atrioventricular conduction in pre-excitation

Atrial pacing in a patient with a Wolff-Parkinson-White syndrome pattern showed unusual variability in AV nodal conduction time. Changes in the AV nodal conduction time occurred predominantly at paced rates in excess of 100/min and consisted of abrupt or gradual decreases in the AH interval. Such decreases resulted in unexpected normalization of the QRS pattern. In addition, pacing also revealed evidence of block in the accessory pathway. Such changes in atrioventricular conduction may account for the known variability of the QRS pattern in patients with the WPW syndrome. Further, they may also explain the benign clinical course in this patient.

Sinus node dysfunction in acute myocardial infarction

The frequency, clinical course, and prognosis of sinus node dysfunction in 431 patients with acute myocardial infarction admitted to the coronary care unit were studied. Sinus node dysfunction occurred in 20 patients. In 13, the principal manifestation consisted of severe sinus bradycardia. In the remaining 7, periods of bradycardia alternating with episodes of supraventricular tachycardia were noted. Though several of the patients with sinus bradycardia required intravenous atropine or temporary pacing, normal sinus rhythm returned in virtually all during follow-up. The clinical course of patients with both bradycardia and tachycardia was less benign, during the acute phase and during follow-up; 5 of the 6 survivors required continued antiarrhythmic therapy or permanent pacing. The differences in the clinical course between these two groups of patients may reflect distinct underlying pathological changes. The findings in this study suggest that in contrast to sinus bradycardia, the occurrence of bradycardia-tachycardia syndrome during the acute phase of myocardial infarction may have important prognostic implications.

Myocardial metabolic studies in prolapsing mitral leaflet syndrome

Patients with prolapsing mitral leaflet syndrome (PML) frequently have chest pain of undetermined etiology. Twenty-three patients with PML underwent cardiac hemodynamic, angiographic, and metabolic studies. The latter were performed during control spontaneous heart rate and tachycardia by right atrial pacing. Myocardial supply-demand ratio (DPTI:SPTI) was estimated from the planimetric integration of the diastolic area (diastolic pressure time index = DPTI) and systolic area (systolic pressure time index = SPTI) of the central aortic pressure. Chest pain during pacing occurred in five patients. In two patients, it was associated with ST depression typical of ischemia on the electrocardiogram. Myocardial lactate abnormalities (lactate production or less than 10% extraction) occurred in seven patients during pacing tachycardia and was present in two patients during control state. DPTI:SPTI ratio during control state was 1.22 (+/- 0.07 SE) and decreased to 0.85 (+/- 0.05 SE) during pacing tachycardia. It is concluded that the myocardial lactate abnormalities in PML, which were present in approximately 30% of the patients in the present series, are most likely due to myocardial hypoxia. Whether or not the hypoxia is secondary to "small vessel disease" is not elucidated by this study.

Comparison of ejection fraction and zonal mean velocity of myocardial fiber shortening

To determine the extent of cardiac involvement until a diminished ejection fraction (EF) is present, zonal mean velocity of circumferential fiber shortening (Vcf) was measured from the left ventriculogram in 36 patients. The longitudinal axis (apex to mid-point of the aortic valve plane) in right anterior oblique view was divided into four equal parts by three perpeendicular chords. Zonal Vct and percent shortening along the proximal, middle and distal chords were measured. The results of this study indicate that a normal EF is frequently associated with a reduced Vct in one or even two zones. A reduced EF is generally accompanied by a diminished Vct in all three zones of the heart. In addition, a close correlation was found between zonal Vct and percent shortening. Hence the latter, which is much simpler to measure, can be instead of Vct Ejection fraction as a measure of myocardial performance is not as sensitive as Vct, especially in hearts with asynchrony of contraction.

Effects of epinephrine on resisitive and compliant properties of the canine vasculature

The peripheral circulation of 22 anesthetized dogs was separated into three parallel regions, where the outflow from each region could be measured and both outflow and inflow pressures could be controlled. We were thus able to estimate arterial and venous resistance and venous compliance for each region. The pressure dependency of these parameters was determined before and during continuous infusion of epinephrine (3 mug-kg-1 min-1). Epinephrine increased the arterial resistance in all regions but did so in such manner as to increase the fraction of cardiac output perfusing the splanchnic region. The venous resistances were all elevated by epinephrine and showed a greater pressure dependency than during control. Systemic venous complicance was found to be pressure dependent during both control and epinephrine administration, decreasing by nearly 50% from the lowest to the highest venous pressures (4-12 mmHg) investigated. Splanchnic compliance was found to comprise nearly half the total systemic compliance. Results were interpreted using an extension of the parallel compartment model of the peripheral circulation described by Caldini, Permutt, Waddell, and Riley (2).

Sinus and A-V nodal dysfunction following myocardial infarction

A patient in whom syncopal episodes occurred following an inferior myocardial infarction is described. Electrocardiographic monitoring revealed periods of profound sinus bradycardia and AV block during syncope. In addition, transient spontaneous prolongations of the PR interval due to AV nodal delay and episodes of atrial fibrillation also occurred. Sinus node recovery time following atrial overdrive was within normal limits. Symptoms disappeared following the insertion of a permanent, demand pacemaker. The onset of symptoms following myocardial infarction suggests that dysfunction of the sino-atrial and AV nodes may have been the result of ischemic damage during the infarction.

Iatrogenic arteriovenous fistula: a complication of percutaneous subclavian vein puncture

A case of iatrogenic subclavian arteriovenous fistula is reported. An intracath had been inserted percutaneously into the left subclavian vein to monitor the central venous pressure during aortic valve surgery. On the second postoperative day a thrill and continuous murmur were detected at the left subclavian region. Left subclavian arteriogram and catheterization studies confirmed the diagnosis of subclavian arteriovenous fistula. The lesion was treated surgically with satisfactory results.

Myocardial lactate metabolism during isometric hand grip test. Comparison with pacing tachycardia

Twenty-five patients with chest pain were studied by left ventriculography and coronary arteriography. Myocardial metabolic studies were done during control state, pacing tachycardia, isometric hand grip at 30 per cent of maximum force, and combined hand grip plus pacing tachycardia. Nine patients had myocardial lactate abnormality (group 1) as evidenced by myocardial lactate production or decreased extraction (less than 10%). Though tension time index and triple product (left ventricular ejection time times HR times systolic pressure) as determinants of myocardial oxygen consumption were highest during combined hand grip plus pacing tachycardia, myocardial lactate abnormalities were most frequent during pacing tachycardia. The present study indicates that isometric hand grip even if performed during pacing tachycardia is not a sensitive test for detection of myocardial lactate abnormalities. The rising level of arterial lactate during isometric hand grip is the most likely mechanism of positive myocardial arteriovenous lactate difference.