Cardiology News /Recent Literature Review / Last Quarter 2012

Abstract

HCS Working Group Seminars will take place in Thessaloniki, 14-16/2/2013

 ACC Meeting is slated for San Francisco, 9-11/3/13

 HRS Meeting will take place in Denver, 8-11/5/13

 EuroPCR to be held in Paris, 21-24/5/13

 EuroPace will be held in Athens, 23-26/6/13

 ESC Congress will be held in Amsterdam, 31/8-4/9/13

 TCT Meeting: San Francisco, 28/10-1/11/13

 AHA 2013: Dallas, 16-20/11/13  

 Metoprolol is not Effective in Long QT Syndromes Types 1 and 2 Compared to Propranolol and Nadolol

The effect of beta blockers was assessed in 382 LQT1/ LQT2 patients (56% female, 27% symptomatic, mean heart rate 76 bpm, mean QTc 472 ms) started on propranolol (n=134), metoprolol (n=147), and nadolol (n=101) at a median age of 14 years. The QTc shortening with propranolol was significantly greater than with other beta-blockers in all patients and in the subset with QTc >480 ms. None of the asymptomatic patients had arrhythmia events. Among symptomatic patients (n=101), 15 had syncope. The QTc shortening was significantly less pronounced among patients with syncope. There was a greater risk of syncope for symptomatic patients initiated on metoprolol compared to users of the other 2 beta-blockers combined, after adjustment for genotype (odds ratio: 3.95, p=0.025). Kaplan-Meier analysis showed a significantly lower event-free survival for symptomatic patients receiving metoprolol compared to propranolol/nadolol. The authors concluded that propranolol and nadolol are significantly more effective than metoprolol in preventing arrhythmic events in symptomatic patients. Also, propranolol was superior to both nadolol and metoprolol in terms of shortening the QTc, particularly in high-risk patients with markedly prolonged QTc. Patients with syncope had significantly less QTc shortening than the event-free patients (Chockalingam P et al, J Am Coll Cardiol 2012;60:2092–2099).

Still Limitations in Subcutaneous ICD

A total of 118 patients (75% males, mean age 50 years) received the entirely subcutaneous implantable cardioverter defibrillator (S-ICD) system. After 18 months of follow-up, 8 patients experienced 45 successful appropriate shocks (98% first shock conversion efficacy). No sudden deaths occurred. Inappropriate shocks occurred in 15 patients (13%), mainly due to T-wave oversensing, mostly solved by a software upgrade and changing the sensing vector of the S-ICD. Complications were noted in 16 patients (14%), more frequently in the first 15 implantations per center. The authors concluded that S-ICD is effective in terminating ventricular arrhythmias, but it has still limitations due to its subcutaneous position. Inappropriate therapy is an important issue in the S-ICD. However, both inappropriate shocks and device-related complications seemed to be related to a learning curve of both the device and the physician (Nordkamp et al, J Am Coll Cardiol 2012;60:1933–1939)... (excerpt)