Ambulatory management of ventricular arrhythmias.
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Adult↗
Biomedical subjects
J Morganroth
Publications and source records attributed to J Morganroth.
Spontaneous variability in arrhythmia frequency.
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Analysis of Variance↗
Ethmozin: a new antiarrhythmic agent developed in the USSR. Efficacy and tolerance.
Ethmozin, a phenothiazine derivative, was developed in the Soviet Union as a new antiarrhythmic agent. We evaluated ethmozin using a controlled single-blinded in-hospital protocol in 14 ambulatory patients with ventricular ectopy ranging from an average of 48 to 1,801 depolarizations per hour and in eight patients with atrial ectopy ranging from 63 to 693 depolarizations per hour. Placebo was administered for the first 3 days, followed by ethmozin from 2.4 to 11.2 mg./Kg./day administered orally every 8 hours for 7 days and concluding with placebo for the final 3 days. Continuous 24-hour long-term electrocardiographic monitoring for 13 days was employed to measure drug efficacy accurately. Six of eight (75 per cent) patients with atrial ectopy and 10 of 14 (71 per cent) patients with ventricular ectopy had statistically significant reductions in ectopy during ethmozin therapy. Atrial ectopy was reduced at a lower dose and plasma level of ethmozin than was ventricular ectopy. With the exception of mild nausea in one patient, no side effects of ethmozin therapy were noted. Ethmozin appears to be a well-tolerated, effective antiarrhythmic agent with a dosage regimen that can promote patient compliance for long-term use.
Adult↗
Relationship of atrial fibrillatory wave amplitude to left atrial size and etiology of heart disease. An old generalization re-examined.
It is commonly stated that coarse f waves in atrial fibrillation suggest the presence of rheumatic heart disease and large left atrial size, whereas fine f waves indicate non-rheumatic disease and small left atrial size. Using echocardiography as a more reliable indicator of left atrial size, 37 consecutive patients with chronic atrial fibrillation were evaluated. The correlation coefficients between left atrial size and maximum f wave amplitude was -0.12 and -0.07, using average f wave amplitude. Only 53 per cent (9 of 17) of patients with rheumatic heart disease had f wave greater than 1 mm. and 56 per cent (10 of 18) of patients with f wave size less than or equal to 1 mm. had non-rheumatic disease. This study refutes the contention that the f wave amplitude in atrial fibrillation is correlated with either left atrial size or etiology of heart disease. It is possible that an intra-atrial conduction defect is responsible for coarse f wave morphology.
Atrial Fibrillation↗
Postoperative arrhythmias after coronary artery and cardiac valvular surgery detected by long-term electrocardiographic monitoring.
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Adult↗
Exercise performance after septal myotomy and myectomy in patients with obstructive hypertrophic cardiomyopathy.
The effect of left ventriculomyotomy and myectomy on exercise capacity and cardiac function in patients with obstructive hypertrophic cardiomyopathy has not previously been determined. In this study, 29 patients were evaluated during graded treadmill exercise before and after operation. Postoperatively, 27 of 29 patients reported symptomatic improvement and had greatly reduced left ventricular outflow gradient. Twenty-five of 28 patients (89 percent) attained higher exercise levels after operation, and this was accompanied by an increase in total body oxygen consumption from 16 to 21 ml/min per kg (P less than 0.005). A significant increase in cardiac index during maximal exercise also accompanied this improved exercise performance (5.0 to 5.7 liters/min per m2, P less than 0.05). The increase in maximal cardiac index was associated with greater desaturation of mixed venous blood (34 to 24 percent, P less than 0.02) in patients with preoperative angina. At a given level of mixed venous oxygen saturation (30 percent), overall mean cardiac index was higher postoperatively (4.6 to 5.2 liters/min per m2, P less than 0.05). These results suggest that, although several mechanisms probably contribute to symptomatic improvement after myotomy and myectomy, enhanced cardiac performance plays an important role in the majority of patients.
Adolescent↗
Discrete fibromembranous aortic stenosis in middle age. Natural history and case report.
Discrete fibromembranous subaortic stenosis may be severe at birth, progress in severity irrespective of the initial degree of obstruction, and morphologically change during the course of its natural history. Initial status, progression of the lesion and perhaps later development of fibromuscular (tunnel) and/or asymmetric septal hypertrophy may all contribute to a shortened life span and account for the different incidence of fibromembranous subaortic stenosis in children and adults. In the case reported here, a patient survived into the sixth decade with a discrete fibromembranous subaortic stenosis, which led to typical as well as unusual echocardiographic findings.
Age Factors↗
Retinal arteriolar changes as an indicator of coronary artery disease.
Funduscopic examination was performed in 70 non diabetic, nonhypertensive patients without valvular heart disease undergoing coronary angiography for evaluation of chest pain syndromes to determine if retinal arteriolar changes could reliably predict presence of coronary artery disease. Retinal arteriolar changes were graded with respect to light reflex, vessel caliber, arteriovenous crossing defects, and vessel tortuosity without knowledge of angiographic findings. Each coronary vessel was graded with respect to its most occlusive lesion by angiography; coronary index was derived for each patient without knowledge of eye findings. Abnormal light reflex changes were the most sensitive indicators of presence and extent of coronary artery disease. Abnormal vessel tortuosity and decreased caliber were less sensitive but more specific; their presence also suggested more extensive coronary lesions. Thus, funduscopic examination demonstrating specific retinal arteriolar lesions may indicate presence of coronary artery disease and may correlate with extent of lesions in selected patients.
Adult↗
The contributions of ambulatory ECG.
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Age Factors↗
Fascicular conduction distrubances after coronary bypass surgery.
Two hundred patients underogoing coronary bypass graft surgery were studied to determine the frequency and significance fo new fascicular conduction distrubances. The follow-up period ranged from 13 to 39 months. New disturbances developed in 39 patients (20 percent). Isolated right bundle branch block (6 percent) and left anterior hemiblock (6 percent) were the most common disturbances. Righ bundle branch block was usually transient and was not associated with further complications in the follow-up period. However, patients with either transient or persistent left bundle branch block or left anterior hemiblock, or both, had (1) increased later mortality compared with patients without new fascicular conduction disturbances (5 of 26 versus 11 of 161; P less than 0.02), and (2) increased late myocardial infarction (2 of 26 versus 2 of 161; P less than 0.05). New left fascicular conduction disturbances after coronary surgery identified a subset of patients with more extensive ischemic heart disease, suggesting that these patients require close follow-up care.
Adult↗
Apex sector echocardiography in evaluation of the right atrium in patients with mitral stenosis and atrial septal defect.
Cross-sectional echocardiography utilizing the four chamber apical view was used to evaluate right atrial dimensions as a means of detecting abnormal right heart hemodynamics in 20 patients with mitral stenosis, 5 patients with an atrial septal defect and 10 patients without heart disease. Right and left atrial dimensions on apex echocardiography were 40 mm or less in control subjects. There was a good correlation (r = 0.81) between left atrial size assessed with apex sector and M mode echocardiography. In patients with an atrial septal defect, the left atrium was of normal size on apex sector echocardiography; in patients with mitral stenosis, it was larger on apex echocardiography (59 +/- 9 mm) than on M mode echocardiography (51 +/- 8 mm). The right atrium was enlarged (54 +/- 5 mm) on apex echocardiography in all five patients with an atrial septal defect, but the right ventricle was enlarged in only four. Seventeen of 20 patients with mitral stenosis had an enlarged right atrium (53 +/- 7 mm) on apex echocardiography, whereas 15 had normal right ventricular dimensions (21 +/- 9 mm) on M mode echocardiography. Right atrial size on apex echocardiography was enlarged (54 +/- 6 mm) in 10 of 11 patients with mitral stenosis and pulmonary arterial hypertension. Thus, evaluation of the right atrial dimension with apex echocardiography may be more sensitive than M mode echocardiography in detecting early right heart involvement in specific cardiac conditions.
Adult↗
Cardiac hypertrophy in response to dynamic conditioning in female athletes.
Ten female field hockey players were studied to determine if prolonged dynamic conditioning results in an increased left ventricular internal dimension at end diastole (LVIDD) and if this increase correlates with maximal oxygen consumption (VO2max). At peak season, echocardiograms were obtained and VO2max determined during maximal treadmill exercise. VO2max, LVIDD index (LVIDD/body surface area (BSA)), and ventricular septal and posterior wall thickness were compared to agematched nonathletic women. Mean LVIDD index was significantly greater in athletes than in controls: 29.3 +/- 0.9 mm/m2 vs. 26.3 +/- 0.6, P less than 0.005. Echocardiographic wall measurements did not differ significantly in the two groups. Mean VO2max for the athletes was significantly greater than controls: 51.7 +/- 4.0 ml O2.kg-1.min-1 vs. 41.2 +/- 2.1, P less than 0.001. VO2max correlated significantly with LVIDD index; r = 0.92, P less than 0.001. Female athletes show an increased LVIDD in response to dynamic conditioning similar to that seen in male athletes. The proficiency of athletic performance as measured by VO2max may be related to the heart's ability to increase LVIDD since there is a high correlation between VO2max and LVIDD index.
Adult↗
Limitations of routine long-term electrocardiographic monitoring to assess ventricular ectopic frequency.
Variations in the frequency of ventricular premature depolarizations (VPDs) were evaluated with three consecutive 24-hour long-term electrocardiography monitor recordings from 15 clinically stable patients with various cardiac disorders. Mean hourly VPD frequencies ranged from 37--1,801 per hour. Data were subjected to 4 and 5 factor nested analyses of variance. The extent of spontaneous variation in arrhythmia frequency that occurred in individual patients from day to day was 23%, between 8-hour periods within days was 29%, and from hour to hour was 48%. In addition, the variability between repeated three-day monitoring periods over time was quantified in five patients and found to be 37%. This analysis determined that to distinguish a reduction in VPD frequency attributable to therapeutic intervention rather than biologic or spontaneous variation alone required a greater than 83% reduction in VPD frequency if only two-24-hour monitoring periods were compared, and greater than 65% reduction if two 72-hour periods were compared. The limitations of routine 24-hour electrocardiographic monitoring must be considered in diagnostic and therapeutic decision-making.
Adult↗
Fixed coupling: different mechanisms revealed by exercise-induced changes in cycle length.
Fixed coupled ventricular premature depolarizations (VPDs) are usually considered reentrant; recent experimental models have demonstrated that parasystolic rhythms may also appear in fixed coupled patterns. To analyze the mechanisms of fixed coupled VPDs, 60 exercise tests were chosen to evaluate the response of VPD coupling intervals to changes in cycle length of the dominant supraventricular rhythm. Selection criteria included the presence of frequent, unifocal VPDs that were fixed coupled (variation less than or equal to 80 msec) at any one cycle length, with the persistence of VPDs at several different cycle lengths. Three patterns of response of coupling intervals to changes in cycle length were noted: 1) 32 patients with a direct linear relation (r greater than or equal to 0.9) of coupling intervals to cycle length; 2) 16 patients with coupling intervals fixed, independent of cycle length; and 3) 12 patients with no consistent relation over a wide range of cycle lengths. Two patients in group 2 and four in group 3 fulfilled criteria for parasystole with interectopic intervals that remained constant at different cycle lengths. These results suggest that VPDs in group 1 are reentrant, while some patients with group 2 or 3 responses have evidence for parasystolic rhythms. We conclude that 1) fixed coupling of VPDs is not diagnostic of reentry, and 2) changes in cycle length induced with exercise may be useful in the analysis of mechanisms of VPDs.
Adolescent↗
Aspirin- and coumadin-related bleeding after coronary- artery bypass graft surgery.
We studied 100 consecutive patients to evaluate the potential effect of platelet active and antithrombotic agents prescribed preoperatively on bleeding complications after coronary-artery bypass graft surgery. Preoperative hemostatic values were normal in all patients. Mean mediastinal blood loss was significantly greater in 13 patients taking aspirin (892 +/- 91 ml) and six patients taking Coumadin (warfarin sodium) (858 +/- 168 ml) within 7 days of surgery than in 64 control subjects (439 +/- 28, P less than 0.001). Less marked but similar differences (P less than 0.05) were noted with other agents inhibiting platelet function. However, in nine patients given heparin, mean mediastinal blood loss (436 +/- 61 ml) was no different from that of control subjects. The degree of mediastinal blood loss did not correlate with age, sex, mean total operative time, bypass time, or number of vessels diseased or bypassed. In addition, patients taking aspirin or Coumadin required prolonged chest tube drainage compared to those in heparin or control groups (34 +/- 4 versus 20 +/- 1 h) (P less than 0.001).
Aged↗
Relation of preoperative use of aspirin to increased mediastinal blood loss after coronary artery bypass graft surgery.
To evaluate the potential effect of aspirin, a platelet inhibitory agent, on postoperative bleeding complications after coronary artery bypass graft surgery, we compared each of nine patients who had taken aspirin within 7 days prior to operation to one or two control subjects (total 16 patients) matched for age, sex, extent of coronary disease, number of grafts placed total operative time, bypass time, and preoperative use of propranolol. Preoperative prothrombin time, partial thromboplastin time, and platelet counts were normal for all patients. Mean mediastinal blood loss was significantly greater in the aspirin group (919 +/- 164 ml., S.E.) than in the control group (437 +/- 61 ml., p less than 0.001). The degree of mediastinal blood loss did not correlate with patient age, total operative time, bypass time, number of vessels diseased, or grafts placed. In addition, compared to controls the aspirin group required prolonged chest tube drainage (33 +/- 5 hours versus 19 +/- 1 hour, p less than 0.001).
Adult↗
The syndromes of familial atrioventricular block with sinus bradycardia: prognostic indices, electrophysiologic and histopathologic correlates.
A family with adult onset heart block (AOHB) and sinus bradycardia (SB) was investigated 5 yr after previous study. A 44-yr-old female previously 'normal' presented ECG evidence of 1st-degree and 2nd-degree atrioventricular block (AVB) with normal intraventricular conduction and episodic 3rd-degree AVB. His bundle electrocardiography (HBE) demonstrated A--H prolongation (245msec) with normal H--V time during sinus rhythm and 3rd-degree AV nodal block with a His bundle escape rhythm. Sinus node function served in first-order relatives. HBE and sinus node function were normal in a 38-yr-old sister with new SB. 37 families with familial 3rd-degree AVB were reviewed with attention to prognostic indices and electrophysiologic-pathologic correlates. The incidence of conduction abnormalities supported an autosomal dominant transmission with variable penetrance. Subsidiary pacemaker rate and QRS morphology showed no discriminative value with respect to prognosis. HBS identified A--H prolongation in 2 patients with AOHB and 2 with AOHB and SB, with coexistent H--V conduction delay in 2 cases of AOHB and SB with abnormal QRS morphology. Histopathology was variable, but the finding of multiple lesions in 2 of 5 patients with congenital heart block and each of 2 with AOHB and SB suggests that mixed conduction system disease is prevalent in familial heart block.
Adult↗
Electrocardiographic left atrial enlargement. Electrophysiologic, echocardiographic and hemodynamic correlates.
The mechanism of the electrocardiographic pattern termed left atrial enlargement was evaluated in 21 patients. Left atrial size and pressure as well as interatrial conduction were correlated with electrocardiographic left atrial enlargement using echocardiography, mean pulmonary capillary wedge pressure and activation time from the P wave to the coronary sinus. In the group as a whole only prolongation of interatrial conduction time was consistently related to the electrocardiographic pattern of left atrial enlargement; left atrial size or pressure was not predictably abnormal in patients with this pattern. Five patients had neither elevation of pulmonary capillary wedge pressure nor echocardiographic evidence of an enlarged left atrium. When the etiologic type of heart disease was analyzed, an enlarged left atrium correlated with electrocardiographic left atrial enlargement only in patients with rheumatic mitral valve disease (eight of nine patients). Elevated pulmonary capillary wedge pressure correlated with electrocardiographic left atrial enlargement in all four patients with cardiomyopathy. In patients with coronary artery disease the electrocardiographic pattern was unrelated to either left atrial pressure or volume overload. Thus, the electrocardiographic pattern termed left atrial enlargement appears to represent an interatrial conduction defect that can be produced by a variety of factors.
Adult↗