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

ABSTRACT

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