Minor ECG Abnormalities Research Articles

Long-term Clinical Outcomes Following Vaccinia Associated Myopericarditis

RATIONALE: Approximately 115 cases of MP have been identified during the ongoing DoD smallpox vaccination program. There is little known regarding the long-term clinical outcome of Vaccinia associated myopericarditis (VAMP) and the risk of late onset sequelae arising from the acute inflammation. METHODS: A registry of all DoD VAMP patients maintained by the Walter Reed National Vaccine Healthcare Center Network was analyzed for clinical outcomes. Study entry criteria included adequate follow-up data at 6-18 and/or 18-24 months. Outcome measures included any vaccine related symptoms, ECG, graded exercise test (GXT), cardiac imaging (Echo, MRI) and cardiac enzymes. RESULTS: There were 2 deaths during acute VAMP presentation. 53 of the remaining 113 patients met entry criteria. 45/53 (85%) had no VAMP related symptoms beyond 6 months. 8/53 (15%) reported symptoms of mild intermittent chest pain/tightness, palpitations and/or dyspnea. Objective findings did not correlate with symptoms and included 5 (9.4%) minor ECG abnormalities, 2 transient densities on cardiac imaging (1 Echo, 1 MRI), 1 abnormal GXT with normal perfusion study and no abnormal cardiac enzyme tests. The ejection fraction was normal in all examined. CONCLUSIONS: The vast majority of VAMP patients are asymptomatic by 6 months and have preserved systolic function. In addition to the risk of rare early death, some VAMP patients have symptoms that persist beyond 6-18 months that affect quality of life. Minor ECG and cardiac imaging abnormalities may also be present beyond 6 months but rarely correlate with symptoms. Further study is needed to assess longer term outcomes.

Serial Reevaluation for ARVD/C Is Indicated in Patients Presenting with Left Bundle Branch Block Ventricular Tachycardia and Minor ECG Abnormalities

Diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is based on a set of criteria proposed by the International Task Force (TF) for Cardiomyopathies in 1994. To fulfill these criteria, presence of both electrocardiographic and anatomical abnormalities must be assessed with ECG and imaging techniques, respectively. This may be difficult in patients with early/mild forms of the disease as detectable structural abnormalities may still be absent. We evaluated in which patients presenting with right ventricular tachycardia (VT) serial reevaluation for ARVD/C is indicated. Sixty consecutive patients (41 men, mean age 40+/-15 years) were evaluated by the TF criteria for possible ARVD/C because of presentation with a left bundle branch block (LBBB) VT, representing 1 minor criterion. The presence on the ECG of a T-wave inversion beyond lead V2 (1 minor), right precordial QRS prolongation (1 major), or an epsilon wave (1 major) was assessed together with the visualization of severe regional/global right ventricle dysfunction (1 major) or mild segmental dilatation/regional hypokinesia (1 minor) by standard imaging techniques. Initially, 22 (37%) patients were diagnosed as having ARVD/C. After 47+/-39 (range 6-146) months, 23 initially TF-negative patients were reevaluated because of recurrent symptoms, with 12 (52%) additional patients now meeting the TF criteria. Eleven of these 12 (92%) patients presented initially with ECG abnormalities only, but developed structural abnormalities on imaging at follow-up. ECG abnormalities may precede structural abnormalities warranting serial reevaluation for ARVD/C in initially TF-negative patients presenting with LBBB VT with only ECG abnormalities.

Hyperkalemia-induced ECG abnormalities in patients with reduced renal function

Hyperkalemia is a potentially lethal condition to be aware of in the presence of ECG abnormalities especially in patients with reduced renal function. However, ECG abnormalities are not always dependent on the degree ofhyperkalemia but may be aggravated by the rapidity of the development of hyperkalemia and by associated electrolyte disorders. We describe 3 patients with renal failure and different ECG changes induced by hyperkalemia. More severe changes were observed when hyperkalemia developed rapidly, but not in presence of electrolyte disorders. Even minor ECG abnormalities must alarm physicians in patients with renal failure since severe hyperkalemia is not always associated with critical ECG changes.

Diagnostic value of electrocardiography and echocardiography for familial hypertrophic cardiomyopathy in a genotyped adult population.

The diagnostic value of ECG and echocardiography for familial hypertrophic cardiomyopathy (FHC) has not been reassessed since the development of molecular genetics. The aim of the study was to evaluate it in adults, with the genetic status used as the criterion of reference. Ten families with previously identified mutations were studied (9 mutations in 3 genes). ECG and echocardiography were analyzed in 155 adults, of whom 77 were genetically affected and 78 unaffected. The major diagnostic criteria were, for echocardiography, a left ventricular wall thickness > 13 mm and, for ECG, abnormal Q waves, left ventricular hypertrophy, and marked ST-T changes. Minor ECG and echographic abnormalities were also analyzed. (1) Sensitivity and specificity of major criteria were 61% and 97% for ECG and 62% and 100% for echocardiography. (2) Sensitivity but not specificity was age related (from 50% at < 30 years to 94% at > 50 years old, P < .01) and sex related (83% in men versus 57% in women, P = .01). (3) Sensitivity was improved by the addition of minor criteria and by the association of ECG and echocardiography. The negative predictive value was therefore very good (95%) at > 30 years of age. (4) Healthy carriers without any ECG or echocardiographic abnormality represented 17% of genetically affected adults. ECG and echocardiography have similar diagnostic values for FHC in adults, with an excellent specificity and a lower sensitivity. The association of the two techniques allows a better evaluation of the risk of being genetically affected in families with hypertrophic cardiomyopathy.

Cardiovascular Effects of Carbamazepine Toxicity

Study objective: To evaluate the cardiovascular effects of carbamazepine in patients presenting to the emergency department. Design: A retrospective case series from February 1, 1985, to July 30, 1993. Setting: Six urban EDs. Participants: Seventy-two adult and pediatric patients with serum carbamazepine concentrations greater than 12 μg/ml and concurrent 12-lead ECGs. Results: The mean carbamazepine level was 24 μg/ml (range, 12.6 to 55 μg/ml). Minor ECG abnormalities were noted but no clinically significant arrhythmias were found. No correlation was found between carbamazepine concentration and heart rate or PR, QRS, or corrected QT intervals. Four adult patients had transient hypotension. Conclusion: Clinically significant cardiovascular toxicity occurs rarely in patients with toxic carbamazepine concentrations. ECG findings do not correlate with serum carbamazepine concentration. [Apfelbaum JD, Caravati EM, Kerns WP II, Bossart PJ, Larsen G: Cardiovascular effects of carbamazepine toxicity. Ann Emerg Med May 1995;25:631-635.]

Diuretics and Coronary Heart Disease-Reply

In Reply.— We could not agree more with Drs Moser and Gifford. The reported adverse effect of diuretics for the treatment of mild hypertension in patients with certain minorECG abnormalities needs to be viewed with caution. We also agree that all adequately designed hypertension studies using diuretics have shown a reduction in morbidity and mortality from pressure complications such as stroke, but not from CHD, and that is just the point. The Hypertension Detection and Follow-up Program study 1 that is mentioned cannot help to solve this question because of its lack of an untreated control group. In the Australian study 2 which we believe is the best designed randomized trial in mild hypertension, no beneficial effect of thiazides on the incidence of acute myocardial infarction could be demonstrated: 33 cases of acute myocardial infection were observed in each group. Vague indications of a possible adverse effect on CHD

Acute Maprotiline Intoxication-Report on Six Cases

Tetracyclic antidepressants are claimed to be less car-diotoxic than tricyclic antidepressants. The tetracyclic antidepressant maprotiline has been on the market in Sweden since 1977, but only isolated cases of acute side effects have been reported. We have seen six patients with maprotiline intoxication. All had minor ECG-abnormalities, and one patient also developed hypotension.Neurologic symptoms, however, seemed to be more predominant than cardiotoxic ones. Four of the six patients had convulsions, and all but one had a reduced level of consciousness. One patient had dysarthria and developed ataxia with unsteady gait.We suggest that maprotiline intoxication causes more serious central nervous system disturbances than cardiotoxic ones. It also seems reasonable to believe that these effects can be induced by comparatively low dosages of the drug.

Tricyclic antidepressive poisoning with special reference to cardiac complications.

Sixty-eight cases of tricyclic antidepressive (TCA) poisoning are discussed. Cardiac arrest occurred in 8 patients, preceded by minor ECG-abnormalities. Five patients died. All cardiac arrests arose within the first 24 h after TCA ingestion. Fifty-seven patients developed ECG-abnormalities, of which 84% began within the first 6 h after TCA ingestion. ECG-abnormalities and other symptoms (respiratory arrest, coma, convulsion and hypotension) often occurred in the same patients. Treatment is described, and cardiac monitoring for at least the first 24 h is recommended. In cases of severe cardiac (ECG) abnormalities, monitoring is recommended until no ECG abnormalities are observed for at least 12 h. In conclusion, the unrestricted use of TCA is cautioned against, since TCA must be regarded as potentially cardiotoxic.