M. Abdulla

Long-term medical management of hypertrophic obstructive cardiomyopathy.

Abstract Twenty-two patients, aged 15 to 61 years, with hypertrophic obstructive cardiomyopathy documented at catheterization were followed up prospectively for 2 to 8 years (mean 5) while receiving “complete” beta receptor blocking doses of propranolol (average dose 462 mg/day). Hypertension, fluid retention, pulmonary disease and arrhythmias were treated as required. Dyspnea, angina, syncope, presyncope and palpitations were graded from 0 to 3 based on severity, and the scores were added to obtain a total score. This group was compared with 14 nonrandomized control patients, aged 17 to 78 years, who were not receiving propranolol and were evaluated retrospectively for a mean follow-up period of 5 years (range 2 to 13). The average total score for the protocol group was initially 7.9 and is now 1.9. No patient died; the condition of all patients is improved, with an average improvement in dyspnea of 58 percent. Eighteen patients are currently asymptomatic during usual daily activities. In contrast, symptoms increased in severity in 13 of the 14 control patients. Their mean score increased from 2.9 to 5.4, and dyspnea increased by 133 percent. Of the 10 control patients treated only medically, 4 died suddenly. Improvement in protocol patients was independent of the severity of subvalve obstruction. Potentially life-threatening arrhythmias were found in 11 of the 22 protocol patients, including the 3 patients without obstruction at rest. Rhythm disturbance responded to propranolol alone in four patients, but antiarrhythmic drugs or pacemaker insertion, or both, was required in the remaining seven patients. Thus, “complete” beta blockade supplemented by control of arrhythmia is optimal management for hypertrophic obstructive cardiomyopathy. Most patients do not require surgery.

Serial noninvasive evaluation of cardiovascular hemodynamics during pregnancy

M-mode echocardiography, in combination with electrocardiography and phonocardiography, has been used to measure pulmonary capillary pressure as well as other cardiac functions. Serial hemodynamic evaluations by use of this technique were performed in seven healthy pregnant women in the recumbent position. Each patient had five studies: four antenatal studies and one postpartum study that served as a control. Mean pulmonary capillary pressure was within normal limits throughout pregnancy and the puerperium. Cardiac output did not increase significantly by the end of the first or second trimester but became elevated by 31% in the early third trimester. This elevation in cardiac output persisted until delivery and resulted from a comparable increase in heart rate. Stroke volume and ejection fraction did not change significantly, while peripheral vascular resistance fell, although not significantly, reaching a nadir at approximately 28 weeks of gestation. Our findings indicate that maternal cardiac output increases due to an increased heart rate and reduced afterload.

Rhythm disturbances in hypertrophic cardiomyopathy: Prevalence, relation to symptoms and management

Abstract The prevalence of arrhythmias, associated symptoms and the effect of antiarrhythmic therapy were studied in 33 patients with hypertrophic obstructive cardiomyopathy (mean follow-up period 4.7 years). Arrhythmias were found in 29 patients (88 percent) and were potentially life-threatening in 13 (39 percent). Most patients had more than one type of arrhythmia. All patients were symptomatic at Initial evaluation: A history of syncope was noted in 12 patients, of presyncope in 27 and of palpitations in 23. All patients received large doses of propranolol (more than 240 mg/day or more than 3.5 mg/kg per day; average 460 mg/day or 6.7 mg/kg per day) for treatment of hypertrophic obstructive cardiomyopathy. In addition, pacemaker insertion or additional antiarrhythmic therapy was required in 10 patients; these patients underwent repeated Holter monitoring until arrhythmia control was documented, and at least at yearly intervals thereafter. Although some patients had arrhythmias, including short runs of ventricular tachycardia, in the absence of symptoms during ambulatory monitoring and others had symptoms in the absence of rhythm disturbances, the relation between suppression of potentially life-threatening arrhythmias and symptomatic improvement was striking: potentially life-threatening arrhythmias were suppressed in all but one patient, palpitations and episodes of presyncope have decreased in most, syncope has been eliminated in all and there have been no deaths. In addition, atrial fibrillation appears to have been prevented. Symptomatic improvement was independent of the severity of left ventricular outflow tract obstruction. It is concluded that Holter monitoring and stress testing should be a routine part of the evaluation of all patients with hypertrophic cardiomyopathy and that aggressive therapy of potentially life-threatening arrhythmias results in a lessening of palpitations and episodes of presyncope and syncope and appears to prevent sudden death in these patients when combined with large doses of propranolol.

Potentially lethal arrhythmias and their management in hypertrophic cardiomyopathy

The prevalence of potentially lethal arrhythmias (PLA) in groups of patients with hypertrophic cardiomyopathy has been assessed, but the rate at which they develop (their incidence) during long-term follow-up has not been reported. Therefore, conduction system disease (CSD) (sick sinus syndrome and His-ventricular disease), ventricular couplets and ventricular tachycardia (VT) detected by routine electrocardiograms, periodic 24-hour Holter monitoring and periodic exercise stress testing were studied in 50 patients treated with large doses of beta-adrenergic blocking drugs who were followed for 2 to 14 years (mean 5.9). Sixteen PLAs detected at the beginning of observation were excluded from actuarial analysis for new PLAs . Twenty-one patients had 24 new PLAs (7 with CSD, 1 patient with sustained supraventricular tachycardia, 6 with ventricular couplets and 10 with VT); only 43% of these PLAs were heralded by new symptoms. In 6 patients, the arrhythmia caused symptoms and was identified by a routine electrocardiogram. The 3 patients with His-ventricular disease presented with syncope and required electrophysiologic confirmation of this diagnosis. In only 1 patient was a PLA (ventricular couplets) detected only by exercise testing. All other ventricular arrhythmias were detected by Holter monitoring. The incidence of CSD in 47 patients free of this condition at entry was 5% at 5 years and 33% at 10 years. The incidence of ventricular couplets or VT in 39 patients free of these at entry was 26% at 5 years and 75% at 10 years, and the incidence of VT only was 18% at 5 years and 40% at 10 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Classroom use of personal computers in medical education: a practical approach

Classroom lectures in medical schools have traditionally employed a blackboard and slides. We have developed a compact, durable, and relatively lowpriced system for computer‐assisted instruction which introduces audiovisual material in a random‐access manner. When this system was used in the classroom to provide flexible, clinical simulations, it promoted a high level of audience‐instructor interaction and facilitated problem‐based learning. The system has been used successfully in lectures in our medical school, at other medical schools, at community hospitals and at national scientific meetings.

Hypercalcemia and idiopathic hypertrophic subaortic stenosis.

Excerpt Although the primary cause of idiopathic hypertrophic subaortic stenosis is not known, it has been suggested that this cardiomyopathy may be induced by continuous excessive positive inotrop...

Usefulness of computer-assisted instruction for medical education

Although computer-assisted instruction (CAD has been used in many disciplines for more than 3 decades, 1 it has not been widely used in medical education. Several factors may account for this. Main-frame computers and minicomputers, the early types of equipment, were expensive and, in many cases, were available only intermittently for educational purposes. In addition, the medical educator with an interest in CAI had to acquire complex programming skills. The use of several brands of computers and different programming languages prevented lessons from being shared widely among institutions. CAI lessons were often not sufficiently attractive to encourage enthusiastic use by students, because many of these lessons were similar to programmed textbooks, and interaction was often restricted to responding to multiple-choice questions. Few lessons incorporated relevant pictorial or auditory information. Because of these limitations, most students and teachers came to regard CAI as a novelty rather than as a method of instruction suitable for integration into the medical curriculum. The advent of inexpensive microcomputers and reliable random-access audiovisual electronic devices has altered the situation radically. At the Medical College of Georgia, we have developed an authoring system that allows teachers with no knowledge of computer programming to write microcomputer-assisted lessons and use random-access audiovisual devices to present pictorial and auditory information. We have used it to create clinical simulations for teaching problem-solving skills and to develop a competency-based curriculum in electrocardiographic interpretation. In this report, we describe the use of these simulations for promoting problem-based learning and comment on the opportunities offered by computer technology in medical education. The CAI system employs an Apple II series microcomputer or an IBM personal computer. These are interfaced to audiovisual devices. Previously, we have

Computer-aided learning: Experiences, perspectives and promises

Despite the recent strong interest in computer-aided learning, very few high quality programs are available. This article describes an authoring system that was designed to help faculty at medical schools develop a library of effective computer-based lessons. Features of the system include ease of authoring and the ability to incorporate natural language input by the learner, model complex situations, keep track of 100 performance variables and employ interactive laser video disk technology. The authors describe the experience that has been gained in the development and implementation of computer-aided learning at a medical school, and reflect on its future applications and value.

Internally recorded systolic time intervals in hypertrophic subaortic stenosis

Abstract The cardiac catheterization records of 20 patients with documented hypertrophic subaortic stenosis were analyzed to evaluate the utility of systolic time intervals in quantitating left ventricular outflow tract obstruction in this disease. The preejection period, ejection time and instantaneous peak outflow pressure gradient were measured from simultaneous recordings of the electrocardiogram and left ventricular and central aortic pressure signals, and the preejection period/ejection time (PEP/ET) ratio was computed. Most patients had a significant spontaneous or induced (with isoproterenol or postextrasystolic potentiation) variation in peak outflow gradient (range 0 to 186, average 85 mm Hg) with a high linear correlation between the peak outflow gradient and the systolic time intervals. For the group, peak outflow gradient correlated best with PEP/ET ratio ( r = −0.82, no. = 183) and less well with preejection period ( r = −0.62), ejection time ( r = 0.56) or their rate-corrected values ( r = −0.71 and r = 0.60, respectively). The PEP/ET ratio for beats recorded at the time of cardiac output measurement correlated with instantaneous mean outflow pressure gradient ( r = −0.88, no. = 28, P r = 0.72, no. = 28, P

Mexiletine Versus Quinidine as First-Line Antiarrhythmia Therapy: Results From Consecutive Trials

The efficacy of mexiletine and quinidine in controlling ventricular couplets (VC) and ventricular tachycardia (VT) was compared in 156 trials (78 for each drug) in 114 consecutive patients. Forty‐two patients received both drugs, whereas 36 patients were given mexiletine, and 36 patients received quinidine only. During acute drug testing, mexiletine was more effective than quinidine in controlling VC and VT (54 vs. 32 patients, respectively, P < .001) and resulted in fewer proarrhythmic events (4 vs. 13, respectively, P < .05). Mean duration of follow‐up for mexiletine (27 ± 14 mo) and quinidine (21 ± 14 mo) did not differ. Long‐term success was more frequent with mexiletine administration than quinidine administration (33/47 vs. 10/30 patients, respectively, P < .01). The incidence of sudden death during follow‐up with the two drugs did not differ overall, but more patients with ejection fraction ≥ 40% died suddenly while taking quinidine than while receiving mexiletine (4/17 vs. 0/24, P < .02). Mexiletine is as effective as quinidine for treating VC and VT and appears to be less proarrhythmic. It should be considered as an initial choice in the management of VC and VT.