Biomedical subjects
Publications and source records attributed to M E Silverman.
Hemodynamically stable atrial flutter should be treated with direct-current cardioversion using 200 J as an initial setting. This can be accomplished in an outpatient setting, saving the cost of hospitalization and avoiding the hazards of drug therapy.
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We describe herein a case of dilated cardiomyopathy. The diagnosis of myocardial sarcoid was suggested by abnormal findings on an MRI of the chest. This was subsequently confirmed by a histology of a subcutaneous nodule. MRI is well suited in imaging myocardial scarring associated with sarcoidosis. Its use should be considered where sarcoidosis is suspected. Early detection and intervention with steroids may improve function.
Studies of electrocardiographic predictors of mortality in patients with chronic heart failure have reached varying conclusions. Differences in the characteristics of the patients studied may explain the conflicting results regarding both a prolonged QRS and an abnormal signal-averaged electrocardiogram (SAE). We therefore investigated the impact of the etiology of heart failure on the prognostic importance of a prolonged QRS and an abnormal SAE in 200 patients with heart failure. Patients were categorized according to etiology of heart failure and electrocardiographic parameters. The mortality of patients with a prolonged QRS was compared with mortality in those with both abnormal and normal SAEs. This was done for the entire group, and separately for those with ischemic and those with nonischemic cardiomyopathy. The mean follow-up was 18.8 months. Nonischemic patients with a prolonged QRS had significantly worse survival than other patients. However, nonischemic patients with an abnormal SAE did not have a worse prognosis than patients with a normal SAE. One-year survival of patients with a prolonged QRS was 71%, compared with 98% in patients with a normal and 87% in patients with an abnormal SAE (p < 0.05). In contrast, a prolonged QRS was not a predictor of poor prognosis in patients with ischemic cardiomyopathy (81% one year mortality). Patients with ischemic cardiomyopathy and an abnormal SAE tended to have a poorer survival than patients with a normal SAE (73% and 81% one year mortality, respectively). Thus, the etiology of heart failure affects the prognostic importance of both a prolonged QRS and an abnormal SAE.
In patients with congestive heart failure the frequency of ventricular arrhythmias poorly predicts mortality. It is unknown whether the length of ventricular tachycardia is a better predictor of mortality in these patients. We therefore investigated the prognostic importance of the length of the longest run of ventricular tachycardia, the frequency of ventricular tachycardia, and the frequency of ventricular premature depolarizations with 24-hour ambulatory electrocardiographic recordings in 122 patients with heart failure. We also determined whether the cause of heart failure affects the prognostic importance of these parameters. Each ambulatory electrocardiographic recording was evaluated for the frequency of ventricular premature depolarizations and ventricular tachycardia and for the length of the longest run of ventricular tachycardia. For each electrocardiographic parameter patients were divided into groups based on the median value of that parameter. Mortality among groups was compared in all patients and then separately for nonischemic and ischemic patients. Neither the frequency of ventricular premature depolarizations nor the frequency of ventricular tachycardia predicted mortality whether or not cause was considered. When all patients were examined, the length of ventricular tachycardia did predict an increased risk of death. However, when cause was considered, length of ventricular tachycardia predicted mortality only in the nonischemic patients and not in the ischemic patients. We conclude that the length of ventricular tachycardia may be the best electrocardiographic predictor of mortality in patients with nonischemic heart failure.
An irregular pulse, referred to as rebellious palpitations, delirium cordis and pulsus irregularis perpetuus, was a cause of speculation by physicians since early times. It was James Mackenzie, a Scottish general practitioner in Burnley, England, utilizing an ink-writing polygraph to record and label jugular venous pulses, who would pioneer in deciphering normal and abnormal cardiac rhythms. His key observation that the jugular "A wave" was lost in a patient who went from a normal to an irregular rhythm provided the first insight into the mechanism of auricular fibrillation. Similar jugular venous and arterial pulse findings were discovered by Cushny, Edmunds and Lewis in directly observed experimental auricular fibrillation. In 1909 Lewis in England and Rothberger and Winterberg in Vienna, taking advantage of Einthoven's newly developed string galvanometer, were the first to establish electrocardiographically that auricular fibrillation was the cause of pulsus irregularis perpetuus.
Platypnea is the rare symptom of dyspnea in the upright position, which is relieved by assumption of the recumbent position. This symptom has been previously described in association with several conditions, but never with constrictive pericarditis. The authors report the case of a patient with constrictive pericarditis and severe platypnea, which resolved after pericardiectomy.
Pulmonary sequestration is an uncommon anomaly for which the arterial supply is usually derived from the aorta or its major branches. A 66-year-old man is described with a pulmonary sequestration that received its arterial supply from a coronary artery.
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Ventricular tachycardia is the diagnosis in approximately 80% of cases of WCT and in approximately 95% of cases with structural heart disease. The presence of atrioventricular dissociation, fusion beats, capture beats, and concordance are important findings strongly suggesting VT; whereas, QRS frontal axis and ventricular rate provide less definitive diagnostic information. A QRS width greater than 160 msec. for LBBB configuration WCT or greater than 140 msec. for RBBB configuration argues strongly for VT. The QRS morphology may be very helpful in selected cases. The duration of the arrhythmia does not discriminate between the etiologies of WCT, as all rhythms may be hemodynamically stable for prolonged periods. Finally, response to treatment may give diagnostic information in addition to therapeutic benefit.
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Spontaneous coronary artery dissection is rare. In comparison with the usual myocardial infarction population, it occurs in relatively young people with a striking predilection for women. Of 83 cases that have been described, 62 were diagnosed at autopsy and 21 were found antemortem. A series of 11 patients with the antemortem diagnosis of spontaneous coronary artery dissection is reported and follow-up is provided for 16 of the 21 previously reported cases. Of the 62 autopsy cases, 10 (16%) were men (mean age 47) and 52 (84%) were women (mean age 40). Dissection of the left anterior descending coronary artery predominated in this group of patients, occurring in 80% of men and 65% of women. Of the 32 cases diagnosed antemortem, 15 (47%) were men (mean age 46) and 17 (53%) were women (mean age 38). Men were found to have dissection predominantly of the right coronary artery (73%). Women were found to have dissection predominantly of the left coronary artery system (88%). The etiology of spontaneous coronary artery dissection remains unclear. The 3 groups that can be identified are those associated with atherosclerotic coronary artery disease, those in the postpartum period and those found to be idiopathic. Of the 94 known cases, 69 (73%) occurred in women; 21 (31%) of these were associated with the postpartum state. The prognosis of patients surviving the initial event is good, with an 82% survival rate (follow-up: range 1.5 to 144 months, mean 38). The indications for medical or surgical treatment are presented. Spontaneous coronary artery dissection should be considered in the differential diagnosis of any young person sustaining an acute myocardial infarction, especially women in the postpartum state.