Impaired holter-derived variables of parasympathetic activity in diabetic patients with daily-life silent myocardial ischemia

To evaluate Holter-derived variables of impaired parasympathetic activity in diabetic patients with silent myocardial ischemia. Cross sectional nature cohort study. Department of Medicine, Farwania Hospital, Kuwait. One hundred and sixty patients with diabetes mellitus. 24-hour Holter electrocardiography [ECG] monitoring was used for heart rate variability and silent myocardial ischemia. Predictive indices revealed that Holter derived variables of parasympathetic activity [p-NN50, rMMD, SDANN-i] are considered as indicators for prediction of likelihood of daily life silent myocardial ischemia in diabetic patients. Sensitivity was 86, 85, 82%, specificity=88, 89, 81%, accuracy = 87, 86, 87%, positive predictive value = 89, 90, 86% and negative predictive value = 84, 83, 81% respectively. Multivariate analysis revealed that duration of diabetes status and serum level of HbA1c, as independent variables were associated with likelihood of daily life silent myocardial ischemia [p < 0.05]. Receiver operating characteristic [ROC] curve data revealed that the best cut-off value of p-NN50 was 8% with sensitivity = 86% and false positive = 16%, [rMMD] = 26 msec with sensitivity = 85% and false positive =15% and [SDANN-i] = 96 msec with sensitivity = 81% and false positive = 21% for prediction of likelihood of daily life silent myocardial ischemia in diabetic patients. Silent myocardial ischemia in diabetic patients provides statistically significantly association with impaired parasympathetic activity

Diagnostic significance of tissue doppler imaging in patients with acute inferior myocardial infarction and precordial ST segment depression

To evaluate patients presenting with acute inferior myocardial infarction [IMI] and ST segment depression in the chest leads and to identify patients with anterior ischemia from those with reciprocal ECG changes using Tissue Doppler Imaging [TDI] derived variables. Cohort observational study. Department of Medicine, Sabah and Farwania Hospitals, Kuwait. One hundred and fifty patients with acute ST segment elevation IMI, stratified into: Group 1:105 patients with acute IMI and precordial ST segment depression and Group II: 45 patients with acute IMI without precordial ST segment depression. Transthoracic echocardiography with TDI and coronary angiography. Predictive indices revealed that impaired Systolic velocity [Sm] is a predictor for coronary artery stenosis in the non-infarcted region. Sensitivity was 86%, specificity 80%, accuracy 84%, positive predictive value 88% and negative predictive value 77%. Multivariate logistic analysis revealed that the site and persistence of ST-segment depression, ST-depression > 2 mm, coronary collaterals, left circumflex coronary artery dominance and 0.2 SWM score index increment are significantly associated with impaired Sm velocity of TDI corresponding to anterior non-infarct region, [p < 0.05]. Receiver operating characteristic [ROC] curve data revealed that the best cutoff value of Sm was 7.1 cm/sec with sensitivity 86%, false positive 17%, positive likelihood ratio 4.78 and negative likelihood ratio 0.160 for prediction of likelihood of multivessel coronary artery disease. TDI can be used to identify patients with likelihood of significant coronary artery disease in the non-infarcted region after acute IMI

External non-invasive cardiac pacemaker: evaluation of usefulness, function and capture failure rate

To evaluate the clinical usefulness, safety and efficacy of the non-invasive temporary pacemaker [NTP]. Cohort observational study Settings: Department of Medicine, Farwania and Sabah Hospitals, Kuwait. One hundred and forty patients who presented with asystolic cardiac arrest and symptomatic bradyarrythmias Interventions: Application of a NTP that functions as VVI demand pacemaker with separate external pacing and sensing electrodes. Evaluation of pacemaker capture done by palpating carotid artery pulse, non-invasive blood pressure recording and transthoracic echocardiography. Out of 140 patients, only 76 patients responded well to NTP. Predictive indices revealed that dilated cardiomyopathy is considered as negative predictor for the failure of NTP to capture the ventricle. Sensitivity was 73%, specificity = 90%, accuracy = 78%, positive predictive value = 95% and negative predictive value = 59% respectively. Multivariate analysis revealed that chronic obstructive pulmonary disease [COPD] status, left ventricular ejection fraction [LVEF], serum potassium, chest size and left ventricular end diastolic dimension [LVEDD] as independent variables were negative predictors for failure of NTP to capture the ventricle [p < 0.05]. Receiver operating characteristic [ROC] curve data revealed that the best cut-off value for serum potassium was 3.0 mmol/1 with a sensitivity = 77% and false positive - 24%, LVEF - 15% with sensitivity = 84% and false positive = 19% and LVEDD = 7.6 cm with sensitivity = 74% and false positive = 28% to predict the failure of NTP to capture the ventricle. Transcutaneous pacemaker appears to offer benefit and may become an important tool in the management of patients with symptomatic bradycardia and asystolic cardiac arrest

Predictive accuracy of tissue Doppler imaging for assessment of noninfarct myocardial region in patients with acute myocardial infarction

To investigate the value of pulsed tissue Doppler imaging [TDI] in order to predict significant coronary artery stenosis supplying the noninfarct region in patients after acute anterior myocardial infarction. Transthoracic echocardiography and coronary angiography were performed on 220 patients with acute anterior myocardial infarction. The TDI-derived variables of the mitral valve annulus in the noninfarct region, systolic velocity [Sm], early diastolic velocity [Em] and late diastolic velocity [Am], were estimated in centimeters per second, and the Em/Am ratio was calculated. Predictive indices revealed that the impaired TDI-derived variables, Sm, Em, Am and the Em/Am ratio, were an indicator for predicting significant coronary stenosis in the noninfarct region. Multivariate analysis revealed that the impaired Sm and Em velocities were significantly associated with age of the patients, coronary collaterals and infarct-related artery stenosis [p < 0.05]. Receiver-operating characteristic curve data of TDI-derived variables for prediction of significant coronary stenosis revealed that the cut-off values of Sm, Em, Am and Em/Am ratio were 7.2 cm/s, 6.4 cm/s, 12.1 cm/s and 0.56, respectively. The K coefficient value indicated that there was an agreement between coronary angiography and the TDI-derived variables Sm, Em, Am and Em/Am ratio in noninfarct regions [K = 0.770, 0.731, 0.693 and 0.679, respectively]. There was a significant correlation between the severity of coronary artery stenosis [independent variable] and impaired Sm and Em/Am ratio [dependent variables], y = 11.5 - 0.05x, r = -0.902, [p < 0.05], and y = - 0.14x + 1.87, r = -0.754, [p < 0.05], respectively. TDI can be used to identify patients with significant stenosis of the coronary arteries supplying the noninfarct region and consequently may be helpful in considering patients for coronary angiography in the early postinfarction period

Early changes in ventricular repolarization after thrombolytic therapy in patients with acute myocardial infarction as indicators for prediction of epicardial coronary artery reperfusion

To investigate the relationship between early T-wave inversion after thrombolytic therapy and the likelihood of successful epicardial coronary reperfusion. Thrombolytic therapy was given to 195 patients with ST segment elevation due to acute anterior myocardial infarction [AMI]. Coronary angiography was performed. Receiver operating characteristic [ROC] curve [grade of sensitivity versus false positive] was calculated using likelihood ratio method to identify the ideal cut-off values of the ventricular repolarization variables. Predictive indices showed 80% sensitivity, 83% specificity, 81% accuracy, 88% positive predictive value and 71% negative predictive value for early T-wave inversion after thrombolytic therapy. A good concordant agreement was noted between the data of coronary angiography and early T-wave inversion in the infarct-related ECG leads after thrombolysis [kappa coefficient x = 0.876]. Stepwise multivariate analysis revealed that early T-wave inversion after thrombolytic therapy of AMI was significantly associated with a history of preinfarction angina, residual infarct-related coronary artery stenosis >50%, short time to thrombolytic therapy <90 min, and evening time for occurrence of thrombolysis [p < 0.05]. The ROC curve data analysis showed that early T-wave inversion amplitude after AMI had 87% sensitivity and 84% specificity for predicting successful reperfusion, with an ideal cut-off value of 7.2 mm, while time of T-wave inversion had 80% sensitivity and 79% specificity, with an ideal cut-off value of 120 min. The data indicate that early inversion of T wave after AMI is a statistically significant independent variable in predicting successful epicardial coronary thrombolysis status

Validity and predictive value of exercise induced inverted t-wave normalization for diagnosis of ischemic heart disease

To evaluate the usefulness and validity of the exercise-induced T wave normalization for prediction and diagnosis of ischemic heart disease and to assess and quantify its correlation to autonomic dysfunction. A cohort study Department of Medicine, Farwania Hospital, Kuwait One hundred and twenty-one patients with history of exertional chest pain with inverted T wave in the resting ECG but without history of myocardial infarction and 67 patients with T wave inversion during exercise test were included in the study. All patients underwent treadmill exercise ECG test and stress thallium scintigraphy in the course of their management. Exercise induced T-wave There was no significant difference between patients from both groups as regards the resting heart rate, the time of the exercise test, peak heart rate, heart rate recovery after exercise and QT dispersion after exercise, [p = NS]. Predictive indices revealed that exercise induced T wave normalization is sensitive but not a specific indicator for prediction of ischemic heart disease, as the sensitivity was 71%, specificity = 49.2%, accuracy = 63.2%, positive predictive value = 74.4% and negative predictive value = 44.8%. A significant relation between age, smoking status, diabetes mellitus status and exercise induced T wave normalization [p < 0.05] was observed. Exercise induced T wave normalization is a sensitive but not specific marker of exercise induced myocardial ischemia and this may be due to autonomic dysfunction with impaired parasympathetic function and unopposed sympathetic action

Persistent narrow complex tachycardia: what is the diagnosis?

Supraventricular tachycardia [SVT] with long RPinterval and short PR interval is a unique form of tachycardia. The differential diagnosis includes sinus tachycardia, focal atrial tachycardia, atrial flutter with two to one ventricular response and atrioventricular reciprocating tachycardia with slow retrograde ventriculoatrial conduction. In this report, we present a case of long RP SVT and a review of the electrocardiographic features of each type of tachycardia