bluuebunny/crossref_metadata_2025 huggingface dataset:
Serial electrophysiologic studies in patients with chronic bundle branch block.
Authors: Peters R W , Scheinman M M , Dhingra R , Rosen K , McAnulty J , Rahimtoola S H , Modin G
Published: June 2011

Serial His bundle recordings were obtained during 1:1 atrioventricular (AV) conduction in 90 patients with chronic bundle branch block over a mean interval of 30 months. Atrioventricular conduction time (AH) increased greater than or equal to 10 msec in 25 (28%) and infranodal conduction time (HV) increased greater than or equal to 8 msec in 29 (32%), but only 10 patients had parallel increases in AH and HV intervals. Increases in conduction times were independent of age, time interval between studies, cause of heart disease or initial AH or HV intervals. Women were significantly more likely than men to show an increased HV interval and spontaneous trifascicular block. Spontaneous progression to second- or third-degree AV block occurred at the AV node in seven patients and below the node in 12 patients. The initial AH interval was prolonged in five of seven patients (71%) with AV nodal block and had increased further in only two at restudy. The initial HV interval was abnormal in eight of 12 patients (67%) who progressed to infranodal block and was prolonged further in eight at restudy. We conclude that in patients with chronic bundle branch block, (1) approximately 33% show progressive AV conduction system disease and AV nodal and infranodal disease progress independently; (2) progression of infranodal disease is more common in women; (3) AV nodal disease progress independently; (2) progression of infranodal disease is more common in women; (3) AV nodal disease is a common cause of AV block and can occur without further prolongation of the AH interval once a critical level of disease is attained, whereas infranodal block is usually accompanied by progressive lengthening of the HV interval; and (4) progression of AV conduction disease is not readily predictable from clinical and electrophysiologic variables.
Unstable angina pectoris: management based on available information.
Authors: Russell R O , Rackley C E , Kouchoukos N T
Published: June 2011

Several prospective randomized studies of medical or surgical therapy have not shown that either form of management alone is uniformly superior with respect to mortality for unstable angina pectoris. Patients managed medically have a greater incidence of angina pectoris. Earlier studies indicated a higher rate of nonfatal myocardial infarction with urgent surgery. Present management includes hospitalization and early intensive medical therapy with nitrates and, usually, beta-blocking agents. Coronary arteriography is advised within a few days. If the patient has left main coronary artery disease or three-vessel disease, early coronary artery bypass graft surgery within days to a couple of weeks is advised. Otherwise, medical management is advised and elective surgery can be performed if the patient remains symptomatic.
Effects of exercise training on ventricular function in patients with recent myocardial infarction.
Authors: Cobb F R , Williams R S , McEwan P , Jones R H , Coleman R E , Wallace A G
Published: June 2011

We evaluated the effects of 6 months of exercise training (bicycle ergometry, walking and jogging) on exercise performance and ventricular function in patients with recent myocardial infarction. Fifteen patients were selected on the basis of myocardial infarction at least 6 weeks but not more than 6 months before the study and age younger than 65 years. The patients were evaluated by maximal treadmill exercise testing and radionuclide angiography at rest and exercise before and after training. Before exercise training, maximal treadmill exercise time ranged from 1.5 to 11 minutes, ejection fraction at rest from 18% and 67% and end-diastolic volume from 108 to 208 ml. The mean EF was 48 +/- 5% (+/- SD) at rest and did not change at maximal exercise (48.5 +/- 5%). All 11 patients who completed the exercise training program achieved a significant training effect, as defined by a reduction in heart rate at 50% maximal pretraining effort or an increase in maximal treadmill time. The mean ejection fraction and end-diastolic volume and wall motion abnormalities at rest and at comparable pretraining exercise work loads and heart rates were not significantly different after training. Despite a wide range of rest and exercise ventricular function, patients with recent uncomplicated myocardial infarcts significantly increased their exercise performance. Because rest and exercise ventricular function were comparable before and after training, improvement in exercise performance probably resulted from training effects on the peripheral vasculature.
Normal exercise capacity in patients with severe left ventricular dysfunction: compensatory mechanisms.
Authors: Litchfield R L , Kerber R E , Benge J W , Mark A L , Sopko J , Bhatnagar R K , Marcus M L
Published: June 2011

About one-third of patients who have severe left ventricular dysfunction can achieve normal levels of exercise. To elucidate the mechanisms that permit this to occur, we studied six patients with severe left ventricular dysfunction (average left ventricular ejection fraction 17 +/- 2.5% [mean +/- SEM]) who achieved nearly normal levels of exercise tolerance (greater than 11 minutes of treadmill exercise, Sheffield protocol). All patients had normal pulmonary function at rest and during exercise. Hemodynamics were measured at rest and during supine and upright exercise. The major mechanisms of the preserved exercise capacity in these patients were chronotropic competence, ability to tolerate elevated wedge pressures (33 +/- 3 mm Hg) without dyspnea, ventricular dilation, and increased levels of plasma norepinephrine at rest and during exercise. Also, whereas peripheral vascular resistance was unchanged during supine exercise, it decreased by 50% during similar levels of upright exercise. As a consequence, increases in cardiac output from rest to exercise were greater during upright than supine exercise (100% vs 50%, respectively) (p less than 0.05), and pulmonary wedge pressures were lower during upright than supine exercise (21 +/- 5 mm Hg vs 33 +/- 3 mm Hg). Thus, multiple mechanisms permit some patients with severe left ventricular dysfunction to achieve normal levels of exercise. These studies emphasize that left ventricular function must be assessed by direct means rather than inferring function of the left ventricle from the results of an exercise tolerance test.
Increased exercise tolerance and reduced electrocardiographic ischemia with diltiazem in patients with stable angina pectoris.
Authors: Wagniart P , Ferguson R J , Chaitman B R , Achard F , Benacerraf A , Delanguenhagen B , Morin B , Pasternac A , Bourassa M G
Published: June 2011

Diltiazem is a calcium slow-channel blocking drug that may be effective in the treatment of chronic stable angina pectoris. To evaluate the therapeutic efficacy 3 hours after a single oral dose of 120 mg, 12 men with chronic stable angina pectoris performed a maximal exercise test on a bicycle ergometer after ingesting either placebo or diltiazem administered in a double-blind fashion. During submaximal exercise at a fixed work load, diltiazem decreased the average heart rate response from 119 +/- 17 to 107 +/- 14 beats/min (p less than 0.01), systolic blood pressure from 182 +/- 15 to 175 +/- 15 mm Hg (p less than 0.05) and the rate-pressure product from 21.8 +/- 4.2 to 18.8 +/- 3.2 x 10(-3) units (p less than 0.01). The average submaximal work load at which significant ST-segment depression (0.1 mV) first appeared was increased from 355 +/- 142 to 525 +/- 143 seconds (p less than 0.01) after diltiazem. At peak exercise after diltiazem, the average depth of ST-segment depression in any one lead and the extent of myocardial ischemia observed in all 12 ECG leads were decreased (p less than 0.01), even though the average work load was increased by 29% (p less than 0.01). Peak heart rate, systolic blood pressure and rate-pressure product were similar with placebo and diltiazem. The plasma diltiazem concentration was 13.9 +/- 29 ng/ml 3 hours after ingestion and was significantly (p less than 0.05) related to the increased time to the onset of important ST-segment depression (r = 0.65) and to the decrease in the extent of myocardial ischemia observed in all 12 ECG leads (r = -0.61) compared with placebo. Thus, diltiazem is effective in treating chronic stable angina pectoris. It decreases myocardial oxygen requirements during upright exercise and appears to increase myocardial oxygen delivery.
Platelet function in coronary artery disease: effects of coronary surgery and sulfinpyrazone.
Authors: Cade J F , Doyle D J , Chesterman C N , Morgan F J , Rennie G C
Published: June 2011

Platelet survival and plasma concentrations of beta thromboglobulin and platelet factor 4 were measured in 44 patients before and 6 months after coronary artery bypass grafting. Postoperatively, patients were randomized to receive sulfinpyrazone, 800 mg/day, or placebo. Preoperatively, platelet survival was significantly shorter than normal, and plasma concentrations of both platelet-specific proteins were significantly elevated. Postoperatively, all three indexes of platelet function tended to become normal, but these changes were statistically significant only in patients treated with sulfinpyrazone. Postoperative exercise testing correlated significantly with plasma concentrations of beta thromboglobulin and platelet factor 4 measured preoperative and postoperative. These results are consistent with reports of the effects of sulfinpyrazine on platelet involvement in other conditions, and suggest that the drug reduces platelet activation and inhibits actual destruction. The results also show a relationship between abnormalities of platelet function and an index of postoperative myocardial ischemia.
Borderline hypertension and obesity: two prehypertensive states with elevated cardiac output.
Authors: Messerli F H , Ventura H O , Reisin E , Dreslinski G R , Dunn F G , MacPhee A A , Frohlich E D
Published: June 2011

Systemic, renal and splanchnic hemodynamics, intravascular volume, circulating catecholamine levels and plasma renin activity were compared in 39 patients with borderline hypertension and 28 normotensive subjects, who were less than 5% (n = 42, lean patients) or more than 40% overweight (n = 25, obese patients). Lean borderline hypertensive patients had greater cardiac output (p less than 0.05), heart rate (p less than 0.01) and renal blood flow (p less than 0.05); cardiopulmonary redistribution of intravascular volume (p less than 0.05); and higher circulating norepinephrine levels (p less than 0.05). Obese normotensive subjects also showed an increased cardiac output (p less than 0.005), stroke volume (p less than 0.01), left ventricular stroke work (p less than 0.05), and renal blood flow (p less than 0.05) (but not respective indexes), but intravascular volume was expanded (p less than 0.05) without redistribution and circulating catecholamine levels were normal. Obese borderline hypertensive patients had hemodynamic characteristics similar to those of obese normotensive subjects except for an increased peripheral resistance (p less than 0.05). The data indicate that although both populations have an increased cardiac output, the lean borderline hypertensive patients have signs of enhanced adrenergic activity as evidenced by higher circulating catecholamine levels and heart rate with blood volume translocation to the cardiopulmonary circulation. In contrast, the obese subjects (whether normotensive or borderline hypertensive), who also have increased cardiac output, seem to have normal adrenergic activity and an expanded intravascular volume without cardiopulmonary redistribution.
Effects of alcohol use and other aspects of lifestyle on blood pressure levels and prevalence of hypertension in a working population.
Authors: Arkwright P D , Beilin L J , Rouse I , Armstrong B K , Vandongen R
Published: June 2011

The relationship between alcohol consumption and blood pressure was studied in 491 males, ages 20-45 years, who volunteered to complete a health questionnaire and submit to standardized measurements of blood pressure, heart rate and body size. Average weekly alcohol consumption correlated with systolic pressure (r = 0.18) but not diastolic pressure. Systolic pressure increased progressively with increasing alcohol consumption, with no obvious threshold effect. In moderate and heavy drinkers (53% of the population studied), the prevalence of systolic hypertension (greater than or equal to 140 mm Hg) was four times that of teetotalers. The effect of alcohol on systolic blood pressure was independent of the effects of age, obesity, cigarette smoking and physical activity. Ex-heavy drinkers had blood pressures similar to those of teetotalers, suggesting that the effect of alcohol is reversible. Cigarette smokers had lower diastolic pressures than nonsmokers, an effect independent of obesity. The linear correlation between alcohol consumption and systolic blood pressure and the lower blood pressures in exdrinkers suggest a cause-and-effect relationship. The results indicate that alcohol ranks close to obesity as a potentially preventable cause of hypertension in the community.
Comparison of amount of extent of coronary narrowing by atherosclerotic plaque and of myocardial scarring at necropsy in anterior and posterior healed transmural myocardial infarction.
Authors: Cabin H S , Roberts W C
Published: June 2011

The amount of cross-sectional area narrowing by atherosclerotic plaque in each 5-mm-long segment from the entire lengths of the right, left main, left anterior descending and left circumflex coronary arteries and the size, predominant location and extent of myocardial scarring were determined in 59 necropsy patients with a healed transmural myocardial infarct (MI). The mean number of the four major epicardial coronary arteries narrowed severely (76-100% in cross-sectional area) was 3.0 in the 37 patients with posterior MI and 2.6 in the 22 patients with anterior MI (p less than .025). The mean percent of severely narrowed 5-mm segments from all four major coronary arteries was similar in the anterior and posterior MI groups, 38% vs 46%. The patients with anterior MI, however, had a higher percentage of severely narrowed 5-mm segments of the left anterior descending than of the left circumflex but not the right coronary artery, 46% vs 25% (p less than 0.001) and 40% (NS). The patients with posterior MI had a higher percentage of severely narrowed segments of the right and left circumflex coronary arteries than of the left anterior descending artery, 55% and 51% vs 32% (p less than 0.05). The anterior MI group had, on the average, larger left ventricular scars than the posterior MI group (20% vs 9%, p greater than 0.002) and more frequent scarring of the ventricular septum, 16 patients (73%) vs six patients (16%) (p less than 0.001).
Prevention of lipid accumulation in experimental vein bypass grafts by antiplatelet therapy.
Authors: Bonchek L I , Boerboom L E , Olinger G N , Pepper J R , Munns J , Hutchinson L , Kissebah A H
Published: June 2011

The ameliorative effect of antiplatelet therapy on atherogenesis of vein grafts was assessed in autologous cephalic veins grafted into femoral arteries of 16 normolipemic and 11 hyperlipemic stump-tailed macaque monkeys. Before grafting, one half of each vein was distended at high pressure (700 mm Hg) and the other half at low pressure (350 mm Hg). Eight normolipemic monkeys were treated with aspirin, 80 mg/day, and dipyridamole, 50 mg/day, and eight were controls. When grafts were harvested at 12 weeks, tissue cholesterol and beta-apoprotein content in grafts from untreated monkeys were significantly higher than in ungrafted, uninjured veins. Antiplatelet therapy eliminated the increase in lipid content of vein segments distended at low pressure, and significantly lowered lipid content of segments distended at high pressure, though not to be control levels of ungrafted veins. Seven of the 11 hyperlipemic monkeys received antiplatelet drugs and four did not. The lipid content of all graft segments was significantly higher than in grafted or ungrafted veins from normolipemic monkeys. Antiplatelet therapy again significantly reduced the lipid content in vein segments distended at both levels of pressure, and also reduced the elevated cholesterol content in ungrafted veins. Although this animal preparation differs in many ways from human coronary bypass operations, these observations may be pertinent to the prevention of atherosclerosis in human vein bypass grafts.
Improved electrocardiographic criteria for the diagnosis of inferior myocardial infarction.
Authors: Warner R , Hill N E , Sheehe P R , Mookherjee S , Fruehan C T , Smulyan H
Published: June 2011

New electrocardiographic (ECG) criteria for the diagnosis of inferior myocardial infarction (IMI) are proposed. The criteria are based upon the relationships between portions of the vectorcardiographic (VCG) QRS loop in the frontal plane and the corresponding portions of the ECG QRS complexes recorded in leads II and III. The application of the proposed criteria requires that the tracings be obtained with three-channel ECG machines so that the temporal relationships between the QRS complexes in lead II and those in simultaneously recorded lead III can be inspected. This type of analysis of the ECG permits important features of the contour of the VCG QRS loop to be predicted. The proposed ECG criteria for the diagnosis of IMI are: in the absence of counterclockwise rotation in the frontal plane, (1) Q waves of 30 msec or longer in lead II or (2) regression of initial inferior forces from lead III to lead II. The proposed ECG criteria were evaluated in an initial series of 333 patients and, using a blind experimental design, in a confirmatory series of 94 patients. The performance of the proposed criteria was statistically superior to that of two sets of ECG Q-wave criteria and comparable to that of the VCG criteria of Starr et al.
Modulation of parasystolic activity by nonparasystolic beats.
Authors: Nau G J , Aldariz A E , Acunzo R S , Halpern M S , Davidenko J M , Elizari M V , Rosenbaum M B
Published: June 2011

We studied 12 patients with ventricular parasystole in whom pacemaker activity could be modulated by nonparasystolic beats (NPBs). In six patients (group 1) in whom the intrinsic parasystolic cycle length (XX interval) was obtained without interposed NPBs, we found that NPBs falling during the first half of the cycle prolonged the XRX interval (containing one NPB) and that NPBs falling during the second half of the cycle abbreviated the XRX interval; both effects were maximal when NPBs fell close to the middle of the cycle and were separated by a reversal point. However, because of mutual interference between parasystolic beats and NPBs, only 13.2-43.4% of the parasystolic cycle could be effectively scanned. We also found that the XRX and RX intervals were linearly related. This relationship served to establish that in six patients in whom the XX interval was not obtained (group 2), modulation showed a similar behavior, although neither the reversal point nor the sense of the modulation could be determined. In this report, we suggest diagnostic criteria of parasystolic modulation.
Lipomatous hypertrophy of the interatrial septum: in vivo diagnosis.
Authors: Isner J M , Swan C S , Mikus J P , Carter B L
Published: June 2011

Lipomatous hypertrophy of the interatrial septum (LHIS), a finding associated with obesity and advancing age, consists of the accumulation of adipose tissue, including fetal adipose tissue, in the interatrial septum cephalad and caudad to the fossa ovalis. Previous descriptions of this entity have been limited to autopsy examination. We report a patient in whom the diagnosis of LHIS was established during life by the use of computed tomographic cardiac imaging. As is often the case in patients discovered at autopsy to have LHIS, this patient had atrial fibrillation and, while in normal sinus rhythm, an abnormal P-wave morphology. This patient represents the first patient in whom the diagnosis of LHIS has been established during life. LHIS should be considered in the differential diagnosis of atrial fibrillation and other supraventricular rhythm/conduction disturbances, particularly in obese, elderly patients.
Dietary intake and serum total cholesterol level: their relationship to different lifestyles in several Japanese populations.
Authors: Ueshima H , Iida M , Shimamoto T , Konishi M , Tanigaki M , Doi M , Nakanishi N , Takayama Y , Ozawa H , Komachi Y
Published: June 2011

Serum total cholesterol level and dietary intake were surveyed 1975--1977 in six Japanese population groups with different lifestyles, including groups in both rural (Akita and Kochi) and urban (Osaka) areas. Clerical workers in Osaka, who had the most westernized lifestyle of all the study groups, had the highest mean serum total cholesterol level (202 mg/dl for men ages 40--49 and 50--59 years), while farmers in Akita had the lowest mean serum total cholesterol level (163 mg/dl for men 40--49 years old, 159 mg/dl for men 50--59 years old, 165 mg/dl for men 60--69 years old). Nutrient intake data for mean ages 40--59 years showed 23% of calories from fat for clerical workers in Osaka, the highest among the study groups, whereas farmers in Akita showed a low level of 14%. The ratio of dietary polyunsaturated to saturated fatty acids was over 1.1 for all groups. Cholesterol intake was 339--487 mg/day. Total carbohydrate as a percentage of calories was 53--65%; 75--80% of carbohydrate energy was ingested from cereals. Sugar accounted for less than 3.5% of total calories. In the cross-group correlation analysis between dietary lipid intake and serum total cholesterol, a significant strong positive correlation was found between the dietary lipid factor (phi) of Keys et al. and the mean serum total cholesterol level. A weak but significant correlation was observed between the dietary lipid factor and serum total cholesterol for individual inhabitants of Osaka.
Left ventricular myocardial blood flow in multivessel coronary artery disease.
Authors: Chen P H , Nichols A B , Weiss M B , Sciacca R R , Walter P D , Cannon P J
Published: June 2011

The relationship between resting left ventricular (LV) myocardial blood flow (MBF) and hemodynamic determinants of myocardial oxygen consumption was investigated in 15 patients with multivessel coronary artery disease (CAD) and in 10 patients with normal coronary arteriograms. Mean LV MBF per unit mass of tissue was measured with a multicrystal scintillation camera from the regional clearance rates of xenon-133 injected into the left main coronary artery. Peak LV wall stress, mean velocity of circumferential fiber shortening (Vcf), rate of ejection during the first third of systole (1/3 SV), LV ejection fraction (EF), and the ratio of peak LV systolic pressure to LV end-systolic volume were measured by contrast left ventriculography. Mean LV MBF per unit mass was significantly reduced (48 +/- 11 vs 67 +/- 12 ml/100 g.min; p less than 0.01) in patients with multivessel CAD. However, none of the patients with CAD experienced chest pain or had electrocardiographic evidence of myocardial ischemia during the resting MBF measurements. Ejection phase indexes were lower in the patients with CAD: LVEF (56 +/- 10% vs 64 +/- 7%, p less than 0.05); 1/3 SV (35 +/- 3 vs 44 +/- 4%, p less than 0.05); and mean Vcf (1.05 +/- 0.30 vs 1.19 +/- 0.27 circ/sec, NS). LV wall thickness (9.8 +/- 1.9 vs 7.5 +/- 1.4 mm, p less than 0.01) and LV mass index (94 +/- 32 vs 64 +/- 17 g/m2, p less than 0.05) were significantly increased in the patients with CAD, accounting for the reduction in peak LV wall stress (276 +/- 73 vs 373 +/- 91 dyn-cm-2 x 10(-3), p less than 0.05) observed in these patients. Multiple regression analysis indicated that indexes of three of the major determinants of myocardial oxygen consumption explained 65% of the variation in MBF in patients with CAD: peak LV stress, mean Vcf and heart rate. After adjustment for these three indexes, the average LV MBF rates were not significantly different in the two patient groups (54.8 +/- 1.8 vs 57.6 +/- 2.3 ml/100 g.min). In both groups, resting LV MBF/beat correlated most highly with peak LV wall stress (r = 0.79). Thus, the reduction in LV MBF per unit mass observed in patients with multivessel CAD at rest is related to lower levels of hemodynamic variables that determine myocardial oxygen consumption. Peak LV wall stress is the most important hemodynamic variable determining the level of resting MBF in patients with and without CAD.
Effect of exercise on erythrocyte count and blood activity concentration after technetium-99m in vivo red blood cell labeling.
Authors: Konstam M A , Tu'meh S , Wynne J , Beck J R , Kozlowski J , Holman B L
Published: June 2011

We studied the effect of exercise on blood radiotracer concentration after technetium-99m in vivo red blood cell labeling. After red blood cell labeling, 13 subjects underwent maximal supine bicycle exercise. Radioactivity, analyzed with a well counter, was measured in heparinized venous blood samples drawn at rest and during peak exercise. Changes in activity were compared with changes in erythrocyte count. Activity and erythrocyte counts increased during exercise in all 13 subjects. Percent increase in activity correlated with percent increase in erythrocyte count (r = -0.78), but did not correlate with either duration of exercise or maximal heart rate. Twenty minutes after termination of exercise, activity and erythrocyte count had decreased from peak exercise values but remained higher than preexercise values. In nine nonexercised control subjects, samples drawn 20 minutes apart showed no change in activity or in erythrocyte count. We conclude that exercise increases blood activity, primarily because of an increase in erythrocyte count. During radionuclide ventriculography, blood activity must be measured before and after any intervention, particularly exercise, before a change in left ventricular activity can be attributed to a change in left ventricular volume.
Ejection fraction response to exercise in patients with chest pain, coronary artery disease and normal resting ventricular function.
Authors: Gibbons R J , Lee K L , Cobb F R , Coleman R E , Jones R H
Published: June 2011

We studied the ejection fraction (EF) response to upright exercise using first-pass radionuclide angiography (RNA) in 281 patients with chest pain, significant coronary artery disease and normal resting ventricular function. A wide range of resting function (heart rate and EF) and exercise function (heart rate, EF and peak work load) was measured in this population. The EF response to exercise (delta EF) varied widely, ranging from a decrease of 36% to an increase of 26%. Twenty-eight clinical, catheterization and RNA variables were examined to determine their relationship to delta EF. Considered individually, the variables showing the strongest relationship were resting pulse pressure, positive exercise ECG changes and adequate exercise. Multivariable analysis identified resting pulse pressure, adequate exercise, resting EF, the change in end-diastolic volume index with exercise, positive exercise ECG changes and, to a lesser degree, the number of diseased vessels as variables that were significant independent predictors of delta EF. These observations indicate that delta EF is a complex response that is influenced by many pathophysiologic variables in the presence of coronary artery disease. Several of these variables are not related to the extent of coronary artery disease.
Percutaneous transluminal coronary angioplasty in patients with variant angina.
Authors: David P R , Waters D D , Scholl J M , Crépeau J , Szlachcic J , Lespérance J , Hudon G , Bourassa M G
Published: June 2011

Among the first 83 patients treated with percutaneous transluminal coronary angioplasty (PTCA) at our institution, typical variant angina was recognized beforehand in five cases and was discovered within 4 months of PTCA in six others. All patients had a 65-95% proximal left anterior descending coronary artery stenosis and only one had a coronary lesion greater than 50% in other coronary arteries. Before PTCA, all patients were premedicated with calcium-antagonist drugs. Thirteen of 15 PTCAs, including three of four repeat PTCAs, were technically successful. However, variant angina recurred after successful PTCA in three of the five patients in whom it was documented beforehand and in an additional two of two patients with variant angina before a successful repeat PTCA. Overall, among the nine patients with variant angina after successful PTCA, five had restenosis at the site of PTCA and two others developed severe lesions adjacent to the site of PTCA within 4 months of the procedure. The three patients without restenosis have been treated with calcium-antagonist drugs from soon after PTCA and have remained angina-free. These results suggest that PTCA is technically feasible in patients with variant angina who have organic lesions, but symptoms due to coronary spasm usually persist or recur, often with restenosis.
Evidence of a shared mechanism of vasoconstriction in pulmonary and systemic circulation in hypertension: a possible role of intracellular calcium.
Authors: Guazzi M D , Polese A , Bartorelli A , Loaldi A , Fiorentini C
Published: June 2011

We investigated the hemodynamics of the greater and lesser circulation in 35 patients with primary hypertension, as well as the effects of calcium-channel blockade, to test whether a common factor may account for the excessive vascular resistance in the two circuits and whether intracellular calcium concentration ([Ca++]i) may be involved. We proved that (1) elevated pulmonary arteriolar resistance (PAR) is not related to pulmonary blood flow and volume, pleural pressure, arterial oxygen or carbon dioxide tension and pH, left ventricular filling pressure and function; (2) systemic vascular resistance (SVR) significantly correlates with PAR; (3) calcium-channel blockade with nifedipine reduces systemic and pulmonary arterial pressures toward normal and significantly lowers both SVR and PAR; (4) the percent decrease in vascular resistance after nifedipine is related to the baseline level of resistance in both the greater and the lesser circulations. Failure of the mechanisms currently indicated as responsible for pulmonary vasoconstriction to explain convincingly the increased PAR, the correlation between SVR and PAR, as well as the qualitatively similar response to calcium-channel blockade suggest that a common factor produces vasoconstriction in the two circuits. A pathogenetic role of a primary disorder in [Ca++]i cannot be excluded, but remains to be proved.
Carcinoid heart disease: diagnosis by two-dimensional echocardiography.
Authors: Howard R J , Drobac M , Rider W D , Keane T J , Finlayson J , Silver M D , Wigle E D , Rakowski H
Published: June 2011

We prospectively studied 14 patients with the carcinoid syndrome to determine if two-dimensional echocardiography could detect the nature and extent of valvular abnormalities. Eight of the 14 patients had definite abnormalities of the right-sided cardiac valves. The tricuspid valve had a characteristic appearance, similar to previously described pathologic findings. The leaflets appeared diffusely thickened, shortened and stiff without evidence of commissural fusion. Saline contrast studies demonstrated tricuspid regurgitation, which corresponded to the severity of the tricuspid valve involvement. The pulmonary valve could only be adequately assessed in seven of 14 patients, and morphologic abnormalities similar to those in the tricuspid valve were found. Follow-up studies have shown progression of cardiac disease in six of eight patients. We conclude that two-dimensional echocardiography can detect the characteristic cardiac abnormalities in the carcinoid syndrome and may be a useful tool for following their progression.
Cross-sectional echocardiographic diagnosis and subclassification of univentricular hearts: imaging studies of atrioventricular valves, septal structures and rudimentary outflow chambers.
Authors: Sahn D J , Harder J R , Freedom R M , Duncan W J , Rowe R D , Allen H D , Valdes-Cruz L , Goldberg S J
Published: June 2011

We reviewed anatomic observations (surgical or autopsy), angiograms and echocardiograms from 44 patients with documented univentricular hearts. Thirty-three patients had univentricular heart of left ventricular type with an outflow or rudimentary chamber. Five had univentricular heart of right ventricular type, and six had univentricular heart of indeterminate types without a rudimentary chamber. Univentricular heart was correctly diagnosed by two-dimensional echocardiography in all but two of the 44 patients, including 25 of 27 double-inlet univentricular hearts, all five with absent left and all 12 with absent right atrioventricular connection. One of the two blind trabecular pouches was missed on echocardiography; the other was not seen on the angiogram but was present at autopsy. In 30 of 33 patients, univentricular heart of left ventricular type was correctly identified by imaging an anterosuperior and leftward or rightward outlet chamber, and in four of five patients with univentricular heart of right ventricular type, the anomaly was correctly identified by imaging the inferior and posterior position of the rudimentary outflow chamber near the crux of the heart. Two-dimensional echocardiography provides detailed analysis of atrioventricular connections, main chamber morphology, and rudimentary chamber size and position of noninvasive diagnosis and anatomic subclassification of univentricular hearts.
Sequence and timing of ventricular wall motion in patients with bundle branch block. Assessment by radionuclide cineangiography.
Authors: Rosenbush S W , Ruggie N , Turner D A , Von Behren P L , Denes P , Fordham E W , Groch M W , Messer J V
Published: June 2011

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.
The effect of intermittent bundle branch block on the coupling interval of ventricular premature depolarizations.
Authors: Biliack S A , Denes P
Published: June 2011

The mechanism of origin of ventricular premature depolarizations (VPDs) is explained by automaticity or reentry. We studied three patients with intermittent left bundle branch block (LBBB) and unifocal VPDs of right bundle branch block (RBBB) morphology (assumed left ventricular origin). We examined the effect of different types of intraventricular conduction on the coupling intervals of the VPDs. Specifically, we proposed that the coupling intervals of VPDs would be longer during LBBB conduction of sinus beats (ipsilateral to the ventricle of origin of VPDs) compared with the coupling intervals during normal intraventricular conduction. We found that the coupling intervals during LBBB were significantly longer than those during normal conduction in all three cases (patient 1, 596 +/- 7 vs 484 +/- 5 msec; patient 2, 639 +/- 9 vs 534 +/- 11 msec; patient 3, 444 +/- 4 vs 382 +/- 9 msec) (p less than 0.005). We also examined the length of the preceding RR intervals and counted sinus beats intervening between successive VPDs (S values). One case demonstrated S values suggestive of concealed bigeminy; the other cases had S values suggesting concealed bigeminy and its variants. We have demonstrated that some VPDs are dependent on an initiating sinus beat. This dependence on a preceding beat is consistent with both a reentrant mechanism or triggered automaticity.
Evaluation of infradiaphragmatic total anomalous pulmonary venous connection with two-dimensional echocardiography.
Authors: Snider A R , Silverman N H , Turley K , Ebert P A
Published: June 2011

In three newborn infants with infradiaphragmatic total anomalous pulmonary venous connection, the common pulmonary vein was visualized with two-dimensional echocardiography and validated with saline contrast injections. The transducer was placed in the subcostal region in a sagittal body plane so as to image the descending aorta and the vertebral column. The common pulmonary vein, which connected the pulmonary veins to a systemic vein in the abdomen, was seen lying parallel and anterior to the descending aorta and to the left of the inferior vena cava. With peripheral venous contrast injections, contrast echoes first filled the inferior vena cava and then the descending aorta because of obligatory right-to-left atrial shunting. The common pulmonary vein was the only structure that remained free of contrast echoes. Thus, contrast echocardiography provided a method for identifying the site of pulmonary venous drainage and for distinguishing the common pulmonary vein from other structures such as the inferior vena cava. In cyanotic infants with respiratory distress, two-dimensional contrast echocardiography permits a rapid diagnosis of infradiaphragmatic total anomalous pulmonary venous connection.
The independent value of exercise thallium scintigraphy to physicians.
Authors: Hlatky M , Botvinick E , Brundage B
Published: June 2011

To determine the effect of exercise myocardial scintigraphy with thallium-201 on diagnostic accuracy and the need for coronary angiography, consecutive patients with a variety of clinical presentations were identified. Clinical summaries, including a detailed history, physical examination, and complete data from a standard treadmill exercise test, were presented to 91 cardiologists. The cardiologists assessed the probability of coronary disease and the need for coronary angiography. They were then presented the results of thallium scintigraphy and revised their assessments if warranted. Scintigraphy significantly increased the cardiologists' diagnostic accuracy beyond that attained with other clinical information (p less than 0.0001). The change in accuracy varied from + 4% to + 20% in different patient groups, and was greatest in patients with atypical angina and a positive exercise ECG. Ratings of the need for coronary angiography changed from -13% to +21% in different patient groups. We conclude that exercise thallium scintigraphy can provide independent diagnostic information and influence the need for coronary angiography.
The late prognostic value of acute scintigraphic measurement of myocardial infarction size.
Authors: Perez-Gonzalez J , Botvinick E H , Dunn R , Rahimtoola S , Ports T , Chatterjee K , Parmley W W
Published: June 2011

Infarct, perfusion and blood pool scintigraphy were performed in 62 patients during hospitalization for acute myocardial infarction. The largest measured infarct or perfusion image defect and left ventricular ejection fraction were related to the late prognosis determined a mean of 16 months after the event. Breakpoint values for all scintigraphic variables could separate those who were asymptomatic on follow-up from those who died. The best indicators for selection of survivors and nonsurvivors were a scintigraphic infarct size greater than or equal to 25 cm2 and a perfusion abnormality greater than or equal to 35% of the projected left ventricular area. Among patients with perfusion abnormalities above this limit, 61% died; 93% of those with small perfusion abnormalities survived. Scintigraphic measurements of relative myocardial perfusion and function best separated patients asymptomatic on follow-up from those who developed heart failure and also best identified those with an unfavorable evolution, who developed heart failure or died. Early scintigraphic parameters appeared more accurate than other clinical laboratory indicators for determining late prognosis and could be important in planning treatment after acute infarction.
The incidence and clinical significance of epicardial late potentials in patients with recurrent sustained ventricular tachycardia and coronary artery disease.
Authors: Josephson M E , Simson M B , Harken A H , Horowitz L N , Falcone R A
Published: June 2011

Seventy-eight patients with ventricular tachycardia associated with coronary artery disease underwent intraoperative mapping while in sinus rhythm to evaluate the frequency and significant of late potentials. In 30 of these patients, the surface ECG was subjected to signal averaging to correlate the incidence and duration of low-amplitude, delayed electrograms with the presence of late potentials recorded during epicardial mapping. One to four epicardial late potentials were observed in nine patients (11.5%). These nine patients did not differ hemodynamically from patients without late potentials. In four patients, the site of epicardial breakthrough during ventricular tachycardia bore no relationship (i.e., greater than 3 cm away) to the late potential or the site of origin of the tachycardia. In the five other patients with late potentials, epicardial breakthrough and site of origin of ventricular tachycardia were closely related to the free wall of an apical aneurysm. However, three of these patients had additional tachycardias from disparate sites. Twenty-seven of 30 patients in whom signal averaging was used had a low-amplitude signal in the terminal 40 msec of the amplified QRS complex. In 24 of these 27 patients (89%), the low-amplitude tail was demonstrated in the absence of epicardial late potentials. We conclude that epicardial late potentials are found infrequently in patients with ventricular tachycardia associated with coronary artery disease; epicardial late potentials cannot be used to localize ventricular tachycardia; and the specific low-amplitude tail on the signal-averaged electrogram is unrelated to epicardial events.
Antiarrhythmic drug combinations in the treatment of ventricular tachycardia.
Authors: Ross D L , Sze D Y , Keefe D L , Swerdlow C D , Echt D S , Griffin J C , Winkle R A , Mason J W
Published: June 2011

Combinations of antiarrhythmic drugs are frequently used to treat refractory ventricular tachycardia (VT), but few scientific data support this practice. We examined the efficacy and electrophysiology of 110 antiarrhythmic drug combination trials at electrophysiologic study in 74 patients with recurrent ventricular tachycardia. Lidocaine was combined with quinidine in 33 trials, procainamide in 22 and encainide in 20. Propranolol was combined with quinidine in 17 trials, procainamide in 12 and encainide in six. All individual drugs tested (except propranolol, which was usually not tested individually) had failed at electrophysiologic study or clinically in the presence of usually accepted plasma concentrations. Lidocaine in combination with quinidine was effective in 3% of the trials, with procanamide in 5% and with encainide in none of the trials. Propranolol in combination with quinidine was effective in 18% of the trials, with procainamide in 17% and with encainide in none of the trials. The electrophysiologic effects of the tested drug combinations were dominated by the individual effects of the type 1 antiarrhythmic agents. We conclude that the tested antiarrhythmic drug combinations are infrequently effective in preventing VT induction at electrophysiologic study when each agent has failed individually. The addition of lidocaine or propranolol to quinidine, procainamide or encainide does not produce significant synergistic or new effects on the electrophysiologic variables analyzed.
Arterial-venous nitroglycerin gradient during intravenous infusion in man.
Authors: Armstrong P W , Moffat J A , Marks G S
Published: June 2011

We assessed the concentration of nitroglycerin (GTN) measured in plasma at different sampling sites in the circulation during a constant i.v. infusion. Twenty patients with chronic congestive cardiac failure underwent hemodynamic monitoring during i.v. GTN infusion. Our end point was a reduction in pulmonary capillary wedge pressure by at least 25% of its control value or a 10-fold increment over the initial infusion rate. Nitroglycerin infusion produced no change in heart rate, a reduction in mean arterial pressure from 90 +/- 21 (+/- SD) to 83 +/- 17 mm Hg (p less than 0.001), a fall in total peripheral resistance from 24.3 +/- 10.8 to 20.8 +/- 7.0 units (p less than 0.02), and a substantial reduction in both pulmonary capillary wedge pressure (from 27 +/- 6 to 20 +/- 6 mm Hg, p less than 0.001) and right atrial pressure (from 12 +/- 4 to 8 +/- 4 mm Hg, p less than 0.001). The concentrations of GTN in the pulmonary artery and systemic artery were similar (29.8 ng/ml +/- 52.8 and 25.1 +/- 48.4 ng/ml, respectively) and considerably higher than the concentration in the peripheral vein (7.3 +/- 15.4 ng/ml). There was a 17.4 +/- 19.1% extraction of GTN across the pulmonary vascular bed and a 60.8 +/- 27.2% extraction across the arterial-venous bed (p less than 0.001). There was no relationship between the arterial-venous extraction and the magnitude of arterial plasma (GTN concentration, the duration of the infusion of GTN or the total dose administered. These data show that a better understanding of GTN pharmacokinetics is provided by simultaneous arterial and venous samples.
The acute hemodynamic effects of intravenous verapamil in coronary artery disease. Assessment by equilibrium-gated radionuclide ventriculography.
Authors: Klein H O , Ninio R , Oren V , Lang R , Sareli P , DiSegni E , David D , Guerrero J , Kaplinsky E
Published: June 2011

The acute hemodynamic effects of an i.v. bolus of verapamil, 0.1 mg/kg or 0.06-0.075 mg/kg, were examined by serial radionuclide studies in 46 patients with coronary artery disease. In 20 patients with ejection fractions (EFs) greater than 35% (group 1A), verapamil, 0.1 mg/kg given over 1-11/2 minutes, had a biphasic effect: first, a transient decrease in EF accompanied by increased left ventricular (LV) volumes and cardiac output equivalents; then, an overshoot of EF to values above control, accompanied by a decrease in peripheral vascular resistance and a drastic decrease in LV volumes, while cardiac output equivalent remained slightly elevated. In eight patients with EFs less than 35% (group 1B), only the first effect on EF was noted. In 10 patients with EFs greater than 35% (group 2), verapamil, 0.06-0.075 mg/kg, exerted qualitatively similar but milder effects on hemodynamic function. Finally, verapamil, 0.1 mg/kg given more slowly, over 2-21/2 minutes, produced no significant changes in EF or LV volumes in another eight patients (group 3). The acute effects of verapamil are thus both time-related and dose-dependent. They are also related to the baseline functional reserve of the left ventricle. This study documents that verapamil exerts a depressant effect on LV function. However, the transient nature of this depression and the quick recovery to normal or above-normal values indicate that verapamil, in the doses used in this study, is safe to use intravenously in patients with coronary artery disease.