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

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

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