Anjali Om is a sophomore at Virginia Commonwealth University in the Guaranteed Admissions BS/MD program. Dr. Prabal Guha is an electrophysiologist at McLeod Regional Medical Center in Florence, SC. He completed his medical school and internal medicine training in India and a fellowship in cardiology at SUNY Syracuse. His interest is in basic electrophysiology, in the study of the role of potassium channels in cardiac arrhythmia, and he is currently an assistant professor of medicine at USC Columbia.
Nearly a million patients undergo percutaneous coronary interventions (PCI) in the United States every year.1 These patients are at high risk for arrhythmia, which can be precipitated by electrolyte imbalances, such as hypokalemia or hypomagnesemia.2 The effect of PCI or contrast used on these electrolytes post-procedure has not been well studied. \r\nWe retrospectively analyzed the charts of 426 consecutive patients who had serum magnesium levels checked within two days pre-PCI and within two days post-PCI from January 2010-July 2015. Normal serum magnesium level in our lab was 1.4-2.0 (mEq/L). Of the 426 patients, 139 (33%) had a decrease of 0.4 mEq/L or more. Ninety (21%) patients had post-PCI serum magnesium levels ≤ 1.4 mEq/L. Despite PCI, the risk of arrhythmia in these patients remains high, especially in the immediate post-procedure period. If untreated, hypomagnesaemia post-PCI could precipitate arrhythmia in such high-risk patients. If confirmed in a larger series of patients, this new observation could necessitate a post-PCI check of electrolytes in all patients to minimize the risk of arrhythmia. The pathophysiology of hypomagnesaemia post-PCI would need further elucidation. \r\n
Naresh Sen is a Consultant Cardiologist affiliated with Narayana Hrudayalaya Institute of Cardiac Science, India. He got his medical graduation from Rajasthan University, Jaipur and post-graduation in internal medicine from South America and post doctoral training in Cardiology from USA. He has also been elected for Fellowship award of European Society of Cardiology (FESC) and American College of Cardiology (FACC). He worked in Cardiology (Invasive & Non-Invasive) as Registrar or Consultant at renowned cardiac hospital ports of India like NH & Medanta last 5 years. He has special interest in coronary artery disease and heart failure prevention. He has published around 20 publications in Cardiology .For his hard work, he was awarded as best cardiology consultant in Rajasthan, 2013 by Director of AIIMS, New Delhi.
Background- CRT (Cardiac Resynchronization Therapy) has been approved beneficially in heart failure patients with refractory optimized medical therapy on based of many studies. The guidelines have shown CRT is indicated in NYHA class III-IV, QRS >150 ms, LBBB (Left bundle branch block) to improve heart functions, ventricular remodeling and clinical symptoms.rnPurpose-comparison of stress induced mechanical dyssynchrony between rate dependent LBBB and RBBB (Right bundle branch block) and beneficial role of CRT to improve LV function and reduce mortality.rnMethod-Patients presenting dyspnea on exertion NYHA class I-II to III-IV by stress test , normal QRS to rate dependent LBBB or RBBB by Stress test or Dubutamine Stress Echo were studied. CRT on cardiac function was assessed by Cath study, Echo and MRI (Magnetic Resonance Imaging).rnResult- 46 Patients, male/female ratio (1.87), 12 months observational study done on stress induced rate dependent LBBB and RBBB with worsening dyssynchrony and poor LV function were treated with CRT. Results have shown improved LV function in rate dependent LBBB patients (31+/-6 %) v/s RBBB patients (4.5+/-4%) with P value <0.04. and reduce mortality among rate dependent LBBB with CRT v/s without CRT ( 5% v/s 20 %) and another side mortality difference between rate dependent RBBB with CRT and without CRT were not found significantly.rnConclusion- Stress induced rate dependent LBBB with mechanical dyssynchrony leads to heart failure is benefited by CRT than Rate dependent RBBB.rn