Abnormalities in the electrocardiogram induced by emotional strain

Electrocardiographic indicators of excitability in horses for predicting recovery quality after general anaesthesia

OBJECTIVE

To determine whether preoperative electrocardiographic measurements linked to sympathetic nervous activity could be used to predict recovery quality after general anaesthesia in horses.

STUDY DESIGN

Prospective, clinical study.

ANIMALS

Eighteen adult client-owned horses.

METHODS

The electrocardiogram (ECG) was recorded presurgery in horses under three standard conditions: stabled unattended; with a groom whilst being led along a standard course; alone in the induction box. After surgery, each animal's recovery quality was scored by eight experienced anaesthetists or technicians using Donaldson's scoring system (2000). The digitized ECG recordings were analyzed for T-wave morphology, mean heart rate (HR), HR variability (HRV) and HRV derivatives including mean R-R interval, standard deviation of normal intervals (SDNN) and the root mean square of successive intervals (RMSSD), low (LF) and high frequency (HF) activity and the LF/HF ratio in both fast Fourier transformed and autoregressive spectra. Correlations between ECG variables and recovery score were examined using Spearman's rank correlation.

RESULTS

There was no significant correlation between preanaesthetic ECG measurements and recovery quality.

CONCLUSIONS

Predictions of recovery quality after general anaesthesia in horses cannot be based on preanaesthetic ECG variables.

CLINICAL RELEVANCE

Measures other than those based on the ECG should be investigated as predictors of recovery quality.

Rate-dependent ST segment depression--a case report

A patient with resting heart rate over 100 beats per minute (bpm) displayed 1.5-2 mm ST segment depression in her ECG during daily activities. She had unprovoked further increase in her heart rate up to 145 bpm, and during these episodes, her ECG displayed further ST segment depression up to 3 mm and of 0.12 second duration. An organic cause could not be found to explain her sinus tachycardia. Results of all laboratory investigations, including coronary angiography, were normal. It was observed that during an episode of reflex vagotonia, when her heart rate was below 95 bpm, her previously depressed ST segments became isoelectric. With the thought that this patient's ST segment depression was rate-dependent, carotid sinus massage was performed, and when the heart rate slowed to 95 bpm her depressed ST segments became isoelectric. The same response was accomplished with beta blockers. Sympathetic hyperactivity was thought to be the most likely mechanism of ST segment depression in this patient. A critical increase in heart rate caused these ECG abnormalities.

Relationship of psychologic factors to frequent symptomatic ventricular arrhythmia

Since there is very little available systematic information on the psychological profile of patients with cardiac arrhythmia, a battery of 12 standardized personality inventories was administered to 102 patients ranging in age from 19 to 69 years. Thirty-eight patients with frequent ventricular premature beats (more than 30 per hour) without myocardial infarction were significantly more psychologically symptomatic than 34 age- and sex-matched general medical/surgical patients. The variables found to be significant portray the patient with frequent ventricular premature beats without myocardial infarction: high scores for hysteria, less moral orientation, more anxiety, depression and social alienation, and an inhibited and low respectful style. This combination of psychological variables produced a discriminant function (p less than 0.001) that accounted for 53 percent of the variance between the arrhythmia/no myocardial infarction group and the medical/surgical control group and could correctly predict group membership in 83.3 percent of cases. These results may have further implications in nonpharmacologic and psychotropic adjuncts to antiarrhythmic therapy.

Transient myocardial ischemia with minimal electrocardiographic changes: an echocardiographic study in patients with Prinzmetal's angina

Kn patients with Prinzmetal's angina, episodes of transient T wave abnormalities (T abn) are often documented in addition to the typical episodes of ST segment elevation (ST). As the interpretation of these minor ECG changes is still uncertain, we investigated if transient T abn are associated with reversible ventricular asynergies, similar to episodes with ST. For this purpose an ECG lead and a two-dimensional echocardiographic projection, which showed clear-cut changes during previous episodes of ST, were simultaneously monitored in five patients with Prinzmetal's angina for a total of 13 hours and 20 minutes. In all patients, the 30 episodes of ST recorded were all accompanied by reversible ventricular asynergies. Furthermore, in four of these patients, 14 episodes of T abn (peaking, flattening, or the appearance of a diphasic T wave) were recorded. All T abn were associated with reversible asynergies, as detected by three independent observers. The mechanical impairment occurred in the same ventricular wall both during ST and during T abn. During T abn the degree of mechanical impairment appeared less severe (hypokinesia in 12 and akinesia in two episodes) than during ST (hypokinesia in one, akinesia in 25, and dyskinesia in four episodes) (p less than 0.001). The duration of asynergies was less during T abn (107 +/- 76 seconds) than during ST (169 +/- 83 seconds) (p less than 0.05). Chest pain was reported in 5 of 14 episodes of T abn (36%) and in 20 of 30 (66%) episodes of ST (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Psychological aspects of cardiac arrhythmia

A review of data from a wide spectrum of research studies suggests that psychological-emotional factors can significantly influence and alter the incidence of cardiac arrhythmia. While the existing data are, in many cases, difficult to interpret because of theoretical and methodological problems, sufficient evidence does exist to warrant a concerted investigation into the total involvement of psychological factors in cardiac arrhythmia.

The quiz electrocardiogram: a new diagnostic and research technique for evaluating the relation between emotional stress and ischemic heart disease

To evaluate possible cardiovascular effects of emotional stress, a specially designed 12 minute tape-recorded stress quiz was administered to 43 subjects while blood pressure and the electrocardiogram were monitored. For the entire group, the heart rate and blood pressure rose from respective control levels of 76 beats/min and 136/87 mm Hg to a mean during the quiz of 87 beats/min and 158/94 mm Hg. This difference was highly significant. Of the 43 subjects, 33 were classified as executives and 10 as nonexecutives. There were three groups of executives: control and angina with and without a history of hypertension. Both groups of executives with angina responded with a significantly higher heart rate than that of the executive control group. Blood pressure response was significantly greater in executives with angina and hypertension than in the other groups. Heart rate and systolic blood pressure responses to the quiz were lower in nonexecutives with angina than in executives with angina. During the quiz, 10 of 14 executives with angina had S-T segment depression greater than 0.5 mm; of these, 7 evidenced greater than 1.0 mm depression, andin 3 of these the depression was greater than 1.5 mm and in 2 greater than or equal to 2.0 mm. None of the executive control subjects had S-T depression greater than 0.5 mm Among nonexecutives, 2 had S-T depression greater than 0.5 mm but none greater than 1.0 mm S-T depression. Seventeen of the patients also were given a bicycle exercise tolerance test. There was a significant correlation between S-T depression in response to exercise and to the quiz (r = 0.63; P less than 0.01). The quiz electrocardiogram is presented as a new research technique and diagnostic test for evaluating the relation of emotional stress to ischemic heart disease.