PubMed Health⌕ Search

Biomedical subjects

M A Quinones

Publications and source records attributed to M A Quinones.

At least 55 records · Page 3Linked to original sources
PubMed1985

Analysis of the spontaneous variability of ventricular arrhythmias: consecutive ambulatory electrocardiographic recordings of ventricular tachycardia.

Results are reported of analysis of the variability of complex ventricular arrhythmias in a cohort of 110 patients selected for the presence of ventricular tachycardia (VT). All patients were enrolled in investigational antiarrhythmic drug trials and had an average of 4 consecutive days of placebo ambulatory electrocardiographic recording to serve as the database for this study. Using a statistical approach incorporating analysis of variance, the minimum percent reductions of ventricular premature complexes, couplets and VT were calculated to establish "drug effect" rather than variability at a significance level of 0.05. The relative variability of ventricular arrhythmias in prognostically important groups was also analyzed: (1) coronary artery disease (CAD) (n = 57) vs no CAD (n = 53); (2) patients with a left ventricular ejection fraction of 40% or less (n = 52) vs those with an ejection fraction greater than 40% (n = 58); and (3) patients with frequent runs of VT (10 or more runs/day, n = 63) vs infrequent VT (n = 47). Multiple regression analysis revealed that patients with CAD have significantly greater premature ventricular complex variability than patients without CAD (p less than 0.01). Also, patients with frequent VT runs have greater VT variability than that previously reported in smaller studies, thus requiring greater VT reductions to establish drug effect. Whether the variability of ventricular arrhythmia is itself an independent risk factor for sudden cardiac death is unknown.

Adult↗
PubMed1985

Mitral-septal angle: a new two-dimensional echocardiographic index of left ventricular performance.

The diagnostic value of a new two-dimensional echocardiographic measurement, the mitral septal angle, was evaluated as an index of left ventricular (LV) function in 122 patients. Their mean age was 56.5 years and the majority (80%) suffered from coronary artery disease, 46 with an acute myocardial infarction. Mitral septal angle was easily and reproducibly measured. An ejection fraction (EF) of greater than or equal to 50% and an angle less than or equal to 30 degrees were used as normal cut-off values. A strong negative correlation was found between the angle and radionuclide EF (-0.821) and angiographic EF (-0.82) in patients without acute myocardial infarction. For patients with acute myocardial infarction, the correlation was -0.722. For the entire group, the correlation coefficient was -0.742. In patients without acute infarction, the sensitivity, specificity, and predictive accuracy of the mitral septal angle were 92%, 86%, and 89%, respectively. In acute infarction, sensitivity dropped to 70% without change in specificity (89%). We conclude that mitral septal angle is a simple index of LV function which relates well to EF, particularly in patients with chronic heart disease.

Adult↗
PubMed1985

Determination of parameters of left ventricular diastolic filling with pulsed Doppler echocardiography: comparison with cineangiography.

To determine the relationship between Doppler-derived flow velocity through the mitral anulus and angiographic parameters of left ventricular filling, 30 patients were studied by two-dimensional echocardiography combined with pulsed Doppler echocardiography followed within 1 hr by left ventricular angiography. The average heart rate for each test was 69 beats/min. Doppler-derived parameters included: early peak diastolic velocity (E) and peak atrial velocity, peak filling rate computed as E X cross-sectional area of the mitral anulus derived from the annular diameter, normalized peak filling rate computed as peak filling rate divided by the left ventricular end-diastolic volume determined by two-dimensional echocardiography, and half filling fraction derived from the time-velocity integral of the Doppler-determined velocity curve. Frame-by-frame left ventricular volumes were obtained throughout diastole from single-plane cineangiograms. A volume-time curve with its derivative was generated by computer processing from which peak filling rate, normalized peak filling rate, and half filling fraction were measured. Morphologically, the Doppler-derived velocity profile resembled the derivative of the angiographic volume curve. In patients with reduced angiographic peak filling rates, early peak diastolic velocity was often decreased less than 45 cm/sec with a relative increase in peak atrial velocity resulting in an early peak diastolic velocity to peak atrial velocity ratio less than 1.0. There were no significant differences in mean values for peak filling rate, normalized peak filling rate, and half filling fraction by Doppler echocardiography vs angiography (296 vs 283 ml/sec, 1.9 vs 2.0 sec-1 and 0.55 vs 0.55, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Comparison of two-dimensional echocardiography with gated radionuclide ventriculography in the evaluation of global and regional left ventricular function in acute myocardial infarction.

Two-dimensional echocardiography and gated radionuclide ventriculography were performed in 93 patients (66 men, 27 women; mean age 61 years) with 95 episodes of acute myocardial infarction within 48 hours and at 10 days after infarction. Electrocardiographic sites of infarction were: 35 anterior, 49 inferoposterior and 11 nonlocalized. Abnormal motion of the anterior wall, septum or apex was seen in 97 and 100% of anterior infarctions by radionuclide ventriculography and echocardiography, respectively. Abnormal motion of an inferior or posterior wall segment was seen in 91% of inferoposterior infarctions by echocardiography versus 61% seen by radionuclide ventriculography. Ejection fractions determined by echocardiography and radionuclide ventriculography correlated well (r = 0.82) and did not change from the first 48 hours to 10 days after infarction (0.48 +/- 0.14). Similarly, wall motion score showed minimal change from the first 48 hours to 10 days. In-hospital mortality was 37 and 42% in patients with an ejection fraction of 0.35 or less by echocardiography and radionuclide ventriculography, respectively. No mortality was seen in patients with an ejection fraction above 0.40 by either test. The echocardiographic wall motion score was also predictive of mortality (40 versus 2%; score less than or equal to 0.50 versus greater than 0.50). The 1 year mortality rate in the 81 short-term survivors was 17%. Mortality was lowest in patients with an ejection fraction above 0.49 or wall motion score above (0.79 (2 to 5%) and worse in those with an ejection fraction below 0.36 or wall motion score below 0.51 (36 to 63%) by either technique. Thus in acute myocardial infarction, echocardiography and radionuclide ventriculography provide a comparable assessment of left ventricular function and wall motion in anterior infarction. Echocardiography appears more sensitive in detecting inferoposterior wall motion abnormalities. Both techniques are capable of identifying subgroups of patients with a high risk of death during the acute event and with an equally high mortality rate over a 1 year follow-up period.

Adult↗
PubMed1984

Comparative effect of disopyramide and ethmozine in suppressing complex ventricular arrhythmias by use of a double-blind, placebo-controlled, longitudinal crossover design.

This placebo-controlled, double-blind, longitudinal crossover study compares the efficacy of disopyramide and ethmozine, a new investigational drug, in suppressing frequent (40 or more per hour) ventricular premature depolarizations (VPDs) in 27 patients completing a 37 day protocol. Although both drugs significantly reduced VPDs relative to placebo, ethmozine was a superior antiarrhythmic drug in ach9eving near-total abolition of VPDs (30% of patients), which was never observed during disopyramide dosing (p less than .05). At the 80% VPD reduction level, ethmozine was effective in 56% of all patients compared with an effectiveness in only 22% of patients during disopyramide therapy (p less than .05). The mean peak plasma level of ethmozine was 0.66 +/- 0.8 micrograms/ml, which significantly fell to a trough level of 0.1 +/- 0.08 micrograms/ml (p less than .001). Mean peak and trough plasma levels of disopyramide exhibited less fluctuation (2.6 +/- 0.9 micrograms/ml vs 2.2 +/- 0.9 micrograms/ml). Ethmozine had no effect on the QT interval, whereas disopyramide prolonged it significantly. Importantly, while disopyramide produced serious side effects in 30% of patients, ethmozine was well tolerated with no statistically significant side effects compared with placebo.

Adult↗
PubMed1984

Pulsed Doppler echocardiographic determination of stroke volume and cardiac output: clinical validation of two new methods using the apical window.

Two methods of measuring stroke volume and cardiac output with pulsed Doppler two-dimensional echocardiography were developed and validated against the thermodilution technique in 39 patients, 33 of which were in an intensive care unit. With the use of the apical four-chamber view, a mitral inflow method combined the velocity of left ventricular inflow at the mitral anulus with the cross-sectional area of the anulus calculated from its diameter at middiastole (area = pi r2). From the apical five-chamber view a left ventricular outflow method combined the velocity of left ventricular outflow with the cross-sectional area of the aortic anulus calculated from its diameter during early systole (parasternal long-axis view). Measurements with the mitral inflow and left ventricular outflow methods were obtained in 35 of 39 (90%) and 39 of 39 (100%) patients, respectively. Validation of the mitral method excluded patients with mitral regurgitation (n = 11) and validation of the left ventricular outflow method excluded those with aortic regurgitation (n = 4). Good correlations were observed between thermodilution and Doppler measurements of stroke volume and cardiac output for both the mitral anulus method (R = .96 and .87, respectively) and the left ventricular outflow method (R = .95 and .91, respectively). The results of the two methods correlated well with each other in patients without regurgitant valve lesions. A greater interobserver variability was observed with the mitral anulus method, which was related solely to greater variability in measuring the annular diameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Echocardiography in acute myocardial infarction.

Echocardiography has recently gained increasing popularity as a noninvasive technique to assess left ventricular function and regional wall motion in acute myocardial infarction. Detection of regional dyssynergy is possible in over 90 per cent of patients with acute infarction, allowing assessment of site and extent of involvement. Estimates of severity of left ventricular dysfunction on admission into the coronary care unit allow stratification of patients into risk categories in terms of acute and long-term prognosis. Complications of myocardial infarction such as right ventricular infarction, ventricular septal rupture, papillary muscle rupture, papillary muscle dysfunction, formation of mural thrombi, ventricular aneurysms, and pericardial effusion can be diagnosed echocardiographically at the bedside. This article discusses these applications as well as some of the limitations of echocardiography in the setting of acute myocardial infarction.

Echocardiography↗
PubMed1984

Assessment of valvular lesions with M-mode, two-dimensional and Doppler echocardiography.

M-mode, two-dimensional and Doppler echocardiography enable evaluation of morphologic changes in valvular structures, detection of secondary changes in cardiac chambers and left ventricular function and quantification of blood flow patterns. In mitral stenosis, with M-mode echocardiography the diagnosis can be established on the basis of defined criteria, two-dimensional echocardiography enables planimetric calculation of the orifice area and Doppler echocardiography allows determination of the transvalvular pressure gradient and estimation of orifice area as well as detection of concomitant lesions. In mitral regurgitation, M-mode and two-dimensional echocardiography are less sensitive in its detection but they may be useful in delineating the etiology and whether the disease is of acute onset or chronic; the severity can only be judged indirectly on the basis of chamber dimensions. Doppler techniques render extremely sensitive and specific detection of mitral regurgitation as well as a means of quantifying severity. In this lesion, echocardiographic parameters have proven useful in the timing of valve replacement through early detection of myocardial dysfunction. In aortic regurgitation, M-mode and two-dimensional echocardiography may be useful in establishing the diagnosis, etiology, duration and, through assessment of dimensions and motion, estimating the severity as well. Doppler echocardiography is extremely sensitive and specific in the detection of aortic regurgitation and, additionally, provides a quantitative means for evaluation of severity. In aortic stenosis, both M-mode and two-dimensional echocardiography are sensitive in detection of changes in valve structure and motion but these methods are not capable of rendering reliable quantification of severity. Doppler techniques readily identify aortic stenosis and render, in addition, a close estimation of the transvalvular pressure gradient.

Aortic Valve Insufficiency↗
PubMed1983

An accurate and simplified method to calculate angiographic left ventricular ejection fraction.

An accurate and simplified method to calculate left ventricular (LV) ejection fraction (EF0 derived from the ellipsoidal formula for LV volume calculation is described. The LV Minor axis (D) is obtained from the average of three equidistant LV diameters at end-diastole (Ded) and end-systole (Des), and the shortening fraction of D2 (% delta D2) calculated as (D2ed - D2es)/D2ed. EF is calculated as EF = [delta D2 + ([1 - delta D2] X delta L)] X 100, where delta L = the shortening fraction of the long axis. The coefficient of correlation between the EF by this method and the EF derived from measurements of LV volumes with the area-length method was 0.98, SEE = 3.57% (n = 50). No significant over- or underestimation was observed according to the regression equation Y = 0.922X + 0.82. Thus, this simplified method allows accurate LVEF calculation without the need for planimetry of LV area.

Angiography↗
PubMed1983

Ethmozine suppression of single and repetitive ventricular premature depolarizations during therapy: documentation of efficacy and long-term safety.

This study reports a total of 1677 patient days' experience with the use of Ethmozine to suppress ventricular premature depolarizations. A total of 39 patients were studied on three placebo-controlled protocols. Ethmozine, given at a mean total daily dose of 830 mg +/- 318 mg on a dosing schedule of every 8 hours, resulted in a mean plasma Ethmozine level of 0.42 micrograms/ml +/- 0.28 micrograms/ml. In addition to reducing ventricular premature depolarizations from 11,049/24 hr during placebo to 2231/24 hr during Ethmozine therapy (80% reduction), the drug also resulted in a 95% reduction in paired forms and a 99% reduction in total runs of ventricular tachycardia. Ethmozine is extraordinarily well tolerated with only mild side effects of dizziness, perioral tingling, and euphoria, with no serious toxicity requiring discontinuation of therapy. Ethmozine demonstrates great potential as an effective drug in suppressing ventricular premature depolarizations with minimal side effects or toxicity.

Adult↗
PubMed1983

Evaluation of metoprolol in suppressing complex ventricular arrhythmias.

This study documents the extent of suppression of premature ventricular beats which can be achieved with metoprolol, a semiselective beta-adrenergic blocking agent, at doses of 100 to 200 mg daily, utilizing a single-blind placebo-controlled 10-day protocol with continuous ambulatory electrocardiographic recording of 20 patients with cardiac disease and complex ventricular arrhythmias. Metoprolol (200 mg/day) resulted in suppression of 60% of total premature ventricular beats, with couplets (pairs) and ventricular tachycardia decreased 84% and 94%, respectively (all p less than 0.01). Exercise-induced premature ventricular beats, especially ventricular tachycardia, were effectively suppressed. The peak plasma metoprolol level to achieve these results was 72 +/- 34 ng/ml (mean +/- 1 standard deviation). At this plasma concentration, the mean 24-hour heart rate during normal activity was reduced from 78 +/- 8 beats/min (placebo) to 62 +/- 4 (metoprolol 200 mg/day) (p less than 0.001). Beta blockade also was demonstrated by a 20% reduction in heart rate during maximal Bruce exercise testing with metoprolol 200 mg/day. Although resting left ventricular function was not affected by metoprolol, pulmonary function tests show a statistically significant decrease in forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow rates (25-75) reversible with a beta-2 agonist.

Aged↗
PubMed1983

Analysis of ambulatory electrocardiograms in 15 patients during spontaneous ventricular fibrillation with special reference to preceding arrhythmic events.

Fifteen patients sustained ventricular fibrillation during ambulatory electrocardiographic recording in a period of 3.5 years over which time 16,500 ambulatory electrocardiograms were analyzed (prevalence = 0.09% or 1/1,100). Eight patients died, and seven survived cardiopulmonary resuscitation. Quantitative analysis of hourly ventricular arrhythmias prior to ventricular fibrillation revealed an increased frequency of premature ventricular beats and ventricular tachycardia, especially in the 2 hours immediately before ventricular fibrillation. Ventricular fibrillation was initiated by ventricular tachycardia in all 15 cases. These runs of ventricular tachycardia were characterized by their unusual length (mean = 560 +/- 536 beats) and their rapid rate (241 +/- 45 beats/min). Although an R on T premature ventricular beat initiated ventricular tachycardia and ventricular fibrillation occasionally, the mean prematurity index of the initiating premature ventricular beat was not early (mean = 1.27 +/- 0.28). QT prolongation was present in only 3 of the 15 patients (mean QTc interval = 0.42 +/- 0.06). Left ventricular dysfunction (mean left ventricular ejection fraction = 34.9 +/- 9.9%) and coronary artery disease were nearly always present. The cardiac medications most frequently associated with these patients at the time of ventricular fibrillation were digitalis and quinidine.

Aged↗
PubMed1983

Cardiac echinococcal cyst: diagnosis by two-dimensional echocardiography.

A case of an intracardiac echinococcal cyst is presented. The diagnosis was made by two-dimensional echocardiography, which clearly identified a large multiseptated cystic structure in the right ventricular outflow tract. The findings were verified at surgery. It is suggested that two-dimensional echocardiography may be the procedure of choice in the diagnosis of cardiac echinococcal disease.

Adult↗
PubMed1983

Detection of coronary artery disease with exercise two-dimensional echocardiography. Description of a clinically applicable method and comparison with radionuclide ventriculography.

Two-dimensional echocardiography (2-D echo) was performed in 73 patients evaluated for coronary artery disease (CAD) and in four normal volunteers before and immediately after a maximal treadmill exercise test. Diagnostic images were obtained from the apical and parasternal windows. In 17 patients with normal coronary arteriograms, ejection fraction (EF) increased from 66 +/- 9% (+/- SD) at rest to 73 +/- 8% after exercise (p less than 0.001), while in 56 patients with proved CAD, EF fell from 56 +/- 13% at rest to 53 +/- 16% after exercise (p less than 0.01). The sensitivity of postexercise 2-D echo for detecting CAD (based on abnormal EF response and/or regional dyssynergy) was 91% (51 of 56 patients) and the specificity was 88% (15 of 17). Sensitivity for one-, two- and three-vessel disease was 64% (seven of 11), 95% (20 of 21) and 100%, respectively. Patients with multivessel disease showed a significant fall in a wall motion score index, from 0.79 +/- 0.25 to 0.63 +/- 0.26. Exercise radionuclide ventriculography (RNV) was also performed in 41 of the subjects (17 normals and 24 CAD patients) on a bicycle ergometer. The overall sensitivity of 2-D echo in this subgroup was 92%, compared with 71% for RNV. The sensitivity of 2-D echo for one-vessel disease (n = 4) was 50%, that for two-vessel disease (n = 12) was 100% and that for three-vessel disease (n = 12) was 100%. Respective values for RNV were 0%, 80% and 90%. The specificity of 2-D echo was 88% and that of RNV was 82%. A significantly higher peak heart rate response was observed on the treadmill than on the bicycle ergometer in both CAD patients and normal subjects. We conclude that postexercise 2-D echo is a clinically applicable technique for the diagnosis and evaluation of CAD patients and compares favorably with exercise RNV.

Adult↗
PubMed1982

Importance of preoperative hypertrophy, wall stress and end-systolic dimension as echocardiographic predictors of normalization of left ventricular dilatation after valve replacement in chronic aortic insufficiency.

To define and compare predictors of postoperative normalization of diastolic left ventricular dimension after aortic valve replacement, echocardiographic indexes of left ventricular size, function, degree of hypertrophy and systolic wall stress were examined in 43 patients with chronic and 14 with acute aortic insufficiency. In all of the latter 14 patients, left ventricular diastolic dimension returned to normal (mean 5.2 +/- 0.4 cm) in the postoperative follow-up period (mean 8.0 months). In contrast, of those with chronic insufficiency, 28 (group A) had postoperative normalization of diastolic dimension whereas the remaining 15 (group B) had persistent enlarged diastolic dimension. Preoperative end-systolic dimension, diastolic radius/thickness ratio, mean radius/thickness ratio, mean wall stress and end-systolic stress were 84 to 93 percent accurate in predicting normalization versus persistence of left ventricular dilatation postoperatively, and were superior to preoperative end-diastolic dimension and shortening fraction. Postoperatively, group A had complete normalization of end-systolic dimension and of mean and end-systolic wall stresses with persistence of a normal shortening fraction. Group B continued to have increases in end-systolic dimension, mean wall stress and end-systolic stress with a reduction in shortening fraction. Postoperatively there was a 43 and 29 percent incidence rate of heart failure and death by heart failure, respectively, in group B versus none in group A (p less than 0.01). These findings support the concept that inappropriate hypertrophy in chronic aortic insufficiency is associated with progressive increases in wall stress and end-systolic dimension and a reduction in shortening fraction that eventually result in irreversible cardiac dilatation and failure. Accurate and clinically relevant determination of reversible and irreversible alterations in left ventricular size and function may be obtained with these echocardiographic indexes.

Adolescent↗
PubMed1982

Pulsed doppler echocardiographic detection of mitral regurgitation in mitral valve prolapse: correlation with cardiac arrhythmias.

The incidence of mitral regurgitation in mitral valve prolapse was studied retrospectively in 88 consecutive hospital based patients with mitral valve prolapse using pulsed Doppler echocardiography. Pulsed Doppler findings of turbulence in the left atrium were predictive of angiographic findings of mitral regurgitation in 31 patients. On 24-hr Holter monitoring, patients with mitral valve prolapse and mitral insufficiency had a higher prevalence of ventricular arrhythmias than patients without mitral insufficiency (61 vs 22%; P less than 0.02). Detection of mitral insufficiency identified individuals with mitral valve prolapse who are at higher risk of ventricular arrhythmias.

Adolescent↗
PubMed1982

Effect of cardiac surgery on ventricular septal motion: assessment by intraoperative echocardiography and cross-sectional two-dimensional echocardiography.

Echocardiographic evidence of paradoxical septal motion frequently occurs after cardiac surgery. To assess possible etiologic factors 17 patients were studied preoperatively, intraoperatively, and 7 days after surgery. Preoperative septal motion was normal in 14 and paradoxical in three (two with previous cardiac surgery, one with atrial septal defect [ASD]). Intraoperative septal motion prior to surgical procedure was normal in 16 and paradoxical in one (ASD). Septal motion (excursion and thickening fraction) was normal in all patients prior to chest closure. Echocardiograms of adequate quality were obtained at 7 days post surgery in 15 patients; septal motion was paradoxical in nine (group A) and normal in six (group B). No significant differences were seen between the two groups in ischemic time or in the preoperative to postoperative change in left ventricular (LV) and right ventricular diastolic dimension, shortening fraction, or septal and posterior wall thickening fraction. A significant postoperative decrease in septal excursion was seen in group A but not in group B; significant postoperative increases in posterior wall excursion were seen in both groups. Cross-sectional two-dimensional echocardiograms performed in 20 patients (8 normal, 12 postoperative paradoxical septal motion) were analyzed. In normal controls no significant change was detected in the LV centroid position during systole. In contrast, the 12 postoperative patients showed significant anterior displacement of the LV centroid and right septum during systole. Thus, paradoxical septal motion after cardiac surgery appears to relate to excessive anterior cardiac mobility due to pericardiotomy rather than to myocardial ischemia resulting from cardiopulmonary bypass.

Adult↗