Baseline electrocardiographic changes as determinants in the prognosis of cerebrovascular accidents.

To The Editor: The effect of brain injury on the heart was demonstrated in experimental animals in the 1930s. (1) Subsequently, several studies have investigated the effect of brain injury on the heart, but few have addressed the prognostic significance of these changes. (2) This study was carried out (1) To determine if patients with stroke are more likely to have abnormal EKG at presentation (2) To determine if patients presenting with an abnormal EKG have a greater 6-month mortality.

Written informed consent was obtained and the protocol was approved by the ethics committee of our institution. Forty-six consecutive patients admitted to our service over a 26-month period with a first event of cerebrovascular accident (CVA) and no previous history of cardiovascular disease were included in the study. The control group included thirty patients matched for age, gender, ethnicity and risk factors for stroke who were admitted to the medical service for a diagnosis other than CVA. Patients admitted with a cardiac etiology were excluded from the control group. Hemorrhagic, embolic and strokes related to trauma were excluded. The diagnosis of stroke was established in all the patients by computed tomography (CT) and/or magnetic resonance imaging (MRI). A detailed history and physical examination, particularly neurologic and cardiac, were performed in all patients. EKG findings were analyzed by a cardiologist who was blinded to the clinical data. Follow-up data regarding death was collected from the patients' relatives by personal interview in the clinic or by telephone interview. Data concerning all-cause mortality at 6-month follow up was collected.

Statistical analysis was done at the end of the study using an EXCEL and SPSS program. Single-tailed Student test was used to compare continuous variables.

Differences in proportion were judged by chi-square or Fisher exact test, if necessary.

P values <0.05 were considered statistically significant. All data were reported as means [+ or -] SD or percent.

The frequency of ischemic-like EKG abnormalities was seen in 39 of 46 patients (85%) in the study group and in 9 of 30 (30%) patients in the control group (P < 0.001). In the study group, QTc prolongation was seen in 9 patients (20%) whereas in the control group the corresponding changes were observed in 5 patients (18% [NS]). At the time of presentation, none of the patients had atrial fibrillation, AV block, bundle branch blocks or significant changes in QRS complexes.

Mortality Data

1. When mortality at 6 months was compared by the parameter of normal EKG versus abnormal EKG in the cases and controls, 5 of 28 cases (17.9%) versus 19 of 48 controls (39.6%) were found to be statistically significant (P = 0.049) by test of proportion.

2. When the overall mortality at the 6-month follow-up visit was compared in the CVA patients (n = 19/46) with abnormal EKG versus both study and control patients with normal EKG (n = 5/28), the result (41% versus 18%) was found to be statistically significant.

In our study, EKG features suggestive of underlying myocardial ischemia were more common than nonischemia, consistent with the findings of other studies. (3,4) Also there was no significant difference observed in the QTc interval. Earlier studies suggest that new EKG changes, especially ST-segment changes, can be a predictor of early mortality in the acute phase of stroke. In our study, mortality at 6 months was significantly higher, although the exact cause of death could not be established.

The current study was limited by a relatively small sample. In addition, selection bias and the retrospective nature of the study may have also confounded the results. Another limitation of our study includes the higher sensitivity and low specificity of the EKG changes as manifestation of ischemia. (5) We were also unable to adjust the socioeconomic, racial and ethnic issues and our results may not be applicable to other populations.

The observations in this study suggest that (1) patients who present with an abnormal EKG have greater 6-month mortality and (2) patients with stroke are more likely to have an abnormal EKG at presentation. Electrocardiographic evaluation in patients with acute ischemic stroke may be of prognostic significance.

Sarabjeet Singh, MD

Department of Medicine

Chicago Medical School 

North Chicago, IL

Vishwajeet Bembi, MD

V. K. Goel, MD

Department of Medicine

Lala Lajpat Rai Memorial

Medical College

Sardar Vallabh Bhai Patel and associated Hospitals

Meerut, India

Updesh Singh Bedi, MD

Rohit Arora, MD, FACC 

Department of Medicine

Chicago Medical School

North Chicago, IL

References

1. Oppenheimer SM. Neurogenic cardiac effects of cerebrovascular disease. Curr Opin Neurol 1994;7:20-24.

2. Dogan A, Tunc E, Ozturk M, et al. [Comparison of electrocardiographic abnormalities in patients with ischemic and hemorrhagic stroke] Anadolu Kardiyol Derg 2004;4:135-140.

3. Korpelainen IT, Huikuri HV, Sotaniemi KA, et al. Abnormal heart rate variability reflecting autonomic dysfunction in brainstem infarction. Acta Neurol Scand 1996;94:337-342.

4. Broderick JP, Phillips SJ, O'Fallon WM, et al. Relationship of cardiac disease to stroke occurrence, recurrence, and mortality. Stroke 1992;23:1250-1256.

5. Khechinashvili G, Asplund K. Electrocardiographic changes in patients with acute stroke: a systematic review. Cerebrovasc Dis 2002;14:67-76.