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Biomedical subjects

J V Messer

Publications and source records attributed to J V Messer.

At least 37 records · Page 2Linked to original sources
PubMed1982

Sequence and timing of ventricular wall motion in patients with bundle branch block. Assessment by radionuclide cineangiography.

We determined the sequence and timing of inward ventricular wall motion by least-square phase analysis of radionuclide cineangiograms in 10 patients with left bundle branch block (LBBB), five patients with right bundle branch block (RBBB) and 11 patients with normal conduction. All LBBB and RBBB patients had normal coronary arteries and no segmental wall motion abnormalities. The left ventricle (LV) was divided into eight segments and the right ventricle (RV) into three; sequence and timing were scored by three observers. In normal subjects, wall motion begins in either or both ventricles and ends in the LV or both ventricles. In patients with LBBB it begins in the RV and ends in the LV; in patients with RBBB is begins in the LV and ends in the RV or both ventricles. The intraventricular wall motion is also altered in the ventricle ipsilateral to a bundle branch block. In LBBB, the mean time of onset of LV wall motion is delayed 1.9 frames (38 msec), whereas RV wall motion is normal. In RBBB, the onset of RV wall motion is delayed 1.3 frames (26 msec), whereas LV wall motion is not delayed.

Adult↗
PubMed1981

Clinical significance and characteristics of exercise-induced ventricular tachycardia.

Forty-seven patients (0.08%) from a total of 5,730 consecutive patients undergoing treadmill stress tests developed one or more episodes of ventricular tachycardia. Forty patients had heart disease, coronary artery disease being the leading cause. Rest ECG was normal in 12 patients and showed long QTc (greater than 440 msec) in 16 patients. Ventricular tachycardia was brief and self-terminating, requiring D/C cardioversion in only one patient. "Exertional hypotension" preceded ventricular tachycardia in 16 of 34 patients. There was poor correlation (r = 0.16) between the rate of ventricular tachycardia (VT) and the underlying heart rate. Only four episodes of VT were initiated by R on T premature ventricular beats. In summary, exercise-induced ventricular tachycardia 1) is a rare complication of treadmill stress test and occurs in patients with heart disease; 2) is frequently preceded by "exertional hypotension," and 3) is not related to the R on T phenomenon. The high incidence of prolonged QT may indicate a role for the automatic nervous system in its pathogenesis.

Adult↗
PubMed1981

Efficacy of coronary bypass grafting in exercise-induced ventricular tachycardia.

The effects of coronary bypass grafting on ventricular tachycardia induced by treadmill stress testing (TST) were analyzed in nine patients by repeating the test an average of 5 months after operation. Preoperatively, eight patients experienced pain and all had ischemic ST-segment depression during exercise. Six patients had a single episode and two patients had multiple episodes of ventricular tachycardia; in one patient ventricular tachycardia degenerated into ventricular flutter necessitating direct-current cardioversion. Postoperatively, time of exercise and double product were significantly higher during TST. Electrocardiographic ischemic changes were present in only two patients and ventricular tachycardia was not observed. All patients are alive and average of 24 months after the operation, and eight of them are asymptomatic. In conclusion, among patients with coronary artery disease who have exercise-induced ventricular arrhythmias, myocardial revascularization is associated with improvement of exercise capacity and suppression of arrhythmias.

Adult↗
PubMed1979

Myocardial imaging with 134mCesium. Comparison of scintigraphic and cineradiographic results.

Thirty-four patients had noninvasive myocardial perfusion imaging at rest using 134mCs. The results were compared with the results of coronary cineangiography and left ventriculography. All 21 patients who had abnormal left ventriculograms had corresponding myocardial imaging defects. This group included 14 patients with electrocardiographic evidence of either an old inferior, anteroseptal, anterior, or anterolateral myocardial infarction. Thirteen patients had normal left ventriculograms: this group included 6 patients with 75% or greater obstruction of one or more coronary arteries and 7 patients with normal or insignificantly diseased vessels. Only 2 of these patients had abnormal myocardial images: both had severe obstruction of the proximal left anterior descending artery without collateral filling of this vessel. In the resting patient who has 134mCs myocardial imaging, we concluded that we primarily are visualizing varying degrees of scarred myocardium rather than reversibly ischemic myocardium.

Adult↗
PubMed1979

Value and limitations of technetium-99m stannous pyrophosphate in the detection of acute myocardial infarction.

Technetium-99m stannous pyrophosphate (99mTc-PYP) myocardial imaging was performed in 436 consecutive patients for the evaluation of chest pain and suspected acute myocardial infarction (AMI). Scintigrams were assessed independently by three observers with a 90% interobserver agreement. In 134 patients with documented AMI (97 TRANSMURAL, 37 NONTRANSMURAL), THE SENSITIVITY OF 99MTc-PYP imaging was significantly lower in patients with nontransmural AMI (41%) than in patients with transmural AMI (78%), 99mTc-PYP imaging correctly localized the site of transmural infarction in 53 patients (70%). A diffuse 99mTc-PYP uptake was found in nine (10%) of 91 patients with positive scintigrams: six of these had a transmural AMI and three nontransmural AMI. In 226 patients without AMI, the specificity of infarct imaging was 95%. A false-positive scintigram was found in 0%, 8%, 9%, and 2% of patients with unstable angina, progressive angina, stable angina, and noncardiac chest pain, respectively. A diffuse uptake was found in six (54%) of 11 patients with false-positive scintigrams. No patient with the clinical diagnosis of noncardiac chest pain showed discrete uptake. In 76 patients with uncertain diagnosis for AMI, 99Tc-PYP imaging was considered of value in 11 patients with ventricular conduction defects (two patients with WPW syndrome, nine patients with LBBB). These data suggest that: 1. 99mTc-PYP imaging is moderately sensitive in detecting and localizing transmural AMI and is insensitive in detecting nontransmural AMI; 2. A discrete 99mTc-PYP uptake is highly specific for AMI; 3. a diffuse uptake is neither sensitive to, nor specific for AMI. Myocardial imaging with 99m-Tc-PYP is of clinical value when the standard electrocardiographic and enzymatic techniques are inadequate for an accurate diagnosis of AMI.

Acute Disease↗
PubMed1979

Occlusive disease confined to the right coronary artery: clinical features, surgical treatment and long-term follow-up in 124 patients.

The clinical presentation and surgical results in 124 consecutive patients who underwent aorta to right coronary arterial bypass surgery from January 1970 through June 1977 were reviewed. Preoperatively, 75 percent of the patients were in New York Heart Association functional class III or IV, 9 percent presented with unstable angina and 5 percent had life-threatening ventricular arrhythmias. All patients had high grade occlusive disease confined to the right coronary artery; 34 percent of the patients had associated nonsignificant disease (less than 50 percent intraluminal narrowing) of the left anterior descending or circumflex artery. Left ventricular function was normal in 63 percent and minimally impaired in 37 percent. The operative mortality rate was 1.6 percent. The course of the 122 survivors was followed up for 3.7 years. There were four late deaths, and the 5 year mortality rate was 4.0 percent. Eight patients were reoperated on because of recurrence of symptoms and occlusion of the graft or progression of occlusive disease of the other major coronary arteries, or both. Of the remaining 110 patients, 98 are either in functional class I or II, 60 are taking no cardiovascular medications, 52 are working full time without angina nad 73 are asymptomatic. In summary, bypass surgery for isolated right coronary artery disease has a low mortality rate and results in excellent long-term symptomatic improvement.

Adult↗
PubMed1977

Myocardial mechanics and energetics in experimental iron-deficiency anemia.

The effect of iron-deficiency anemia on myocardial mechanics and energetics was studied in 10 anesthetized bealge puppies. Nine littermates served as controls. Left ventricular/body weight ratio was increased 14.2% (P less than 0.05) and cardiac index 36.5% (P less than 0.02) in the anemic puppies. Heart rate, mean systolic pressure, myocardial lactate extraction coefficient, and lactic dehydrogenase isozymes were similar in both groups. Contractile state measured in vivo (pressure-velocity curves) and in isolated muscles (isotonic force-velocity curves) was virtually identical in the littermate groups. Despite markedly increased coronary blood flow in the anemia animals, oxygen consumption per unit weight of myocardium was the same in both groups. Contractile element efficiency averaged 18.3% in 10 adult mongrel dogs studied in a similar fashion and was 27.1% and 39.8% in the normal puppies and anemic puppies, respectively. The oxygen cost of internal or force-generating work was similar among the three groups of dogs. It is concluded that the volume load produced by iron-deficiency anemia was associated with a normal contractile state, normal unit myocardial oxygen consumption, no evidence of chronic anaerobiosis, and a high contractile element efficiency, perhaps as a consequence of increased diastolic fiber stretch.

Anemia, Hypochromic↗
PubMed1976

Mechanical properties of rat cardiac muscle during experimental thiamine deficiency.

The intrinsic contractile properties of isolated left ventricular trabecular periods of 24, 40, and 53 days were compared with those from 35 weight-matched food-deprived animals and 25 ad libitum fed controls. Contraction mechanics were measured for each muscle when stretched to the peak of its length tension curve at 28 degrees C in oxygenated Krebs-Henseleit solution. Although both thiamine-deficient and food-deprived groups had a marked diminution in body and left ventricular weight in comparison to ad libitum fed controls, no differences in left ventricular weights from thiamine-deficient and food-deprived rats were observed. In comparison to ad libitum fed control animals, food-deprived rats exhibited a prolongation in the duration of muscle contraction and an augmentation of tension development after 40 days. Upon appearance of neurological signs at an average of 53 days of a thiamine-deficient rats exhibited a decrease in performance associated with a decrease in the duration of contraction and rate of tension development.

Animals↗
PubMed1975

Internal mammary arteriovenous malformation with communication to the pulmonary vessels.

A 25 year old asymptomatic man with a past history of pulmonary tuberculosis presented with a continuous murmur. Selective arteriography revealed a left internal mammary arteriovenous malformation in communication with vessels in the left upper pulmonary lobe. No significant hemodynamic abnormalities were detected. This is the 26th reported case of internal mammary arteriovenous fistula and the 6th with a pulmonary communication. Review of the data in previous cases suggests that surgical indications are limited to symptomatic relief, heart failure during infancy or the possible risk of endarteritis, proximal arterial degeneration or rupture.

Adult↗
PubMed1975

Effects of hypoxia, cyanide, and ischaemia on myocardial contraction: observations in isolated muscle and intact heart.

Using potassium cyanide (KCN) to stimulate hypoxia, the effects of intracoronary injections of KCN were compared with total occlusions of the same vessel. Imparied contraction as measured by segment length gauges was of equally abrupt onset following both interventions. The magnitude of systolic expansion at one minute was more marked following total occlusion than after KCN administration.

Animals↗
PubMed1975

Regional myocardial metabolism during subtotal and total coronary artery occlusion.

Regional myocardial metabolism was examined by means of coronary venous sampling in dogs having acute nonsimultaneous occlusions of the left anterior descending (LAD) and circumflex (CIRC) coronary arteries. Regional coronary venous metabolic sampling was not found to separate ischemic from nonischemic myocardium in LAD occlusion and did so imperfectly in isolated CIRC occlusion. Myocardial metabolic consequences of subtotal and total coronary artery occlusion were compared in dogs during LAD and CIRC occlusion and in human subjects with subtotal and total anterior coronary artery occlusion. In spite of ECG evidence of greater myocardial ischemia during total coronary artery occlusion in the dog, transmyocardial metabolic changes were more consistent during subtotal occlusion. Human subjects stressed during cardiac catheterization exhibited a similar apparent paradox. This suggests variable coronary venous washout from ischemic myocardium during total coronary artery occlusion and, in humans, may also reflect the presence of scar tissue. Caution is advised when interpreting myocardial metabolic information in the presence of total coronary artery occlusion, since underestimation of the extent of myocardial ischemia is more likely than with an occlusion of lesser degree.

Animals↗
PubMed1973

Heart muscle viability following hypoxia: protective effect of acidosis.

The mechanical performance of hypoxic heart muscle is further depressed by an acid pH. In contrast to preparations at normal or alkaline pH. however, hypoxic preparations at acid pH do not develop contracture and exhibit full recovery of mechanical activity upon reoxygenation.

Acid-Base Equilibrium↗