ABSTRACT
Aims: There is a continuing debate as to whether cardiac resynchronization therapy-defibrillation (CRT-D) is superior to CRT-pacing (CRT-P), particularly in patients with non-ischaemic cardiomyopathy (NICM). We sought to quantify the clinical outcomes after primary prevention of CRT-D and CRT-P and identify whether these differed according to the aetiology of cardiomyopathy. Methods and results: Analyses were undertaken in the total study population of patients treated with CRT-D (n = 551) or CRT-P (n = 999) and in propensity-matched samples. Device choice was governed by the clinical guidelines in the United Kingdom. In univariable analyses of the total study population, for a maximum follow-up of 16 years (median 4.7 years, interquartile range 2.4-7.1), CRT-D was associated with a lower total mortality [hazard ratio (HR) 0.72] and the composite endpoints of total mortality or heart failure (HF) hospitalization (HR 0.72) and total mortality or hospitalization for major adverse cardiac events (MACE; HR 0.71) (all P < 0.001). After propensity matching (n = 796), CRT-D was associated with a lower total mortality (HR 0.72) and the composite endpoints (all P < 0.01). When further stratified according to aetiology, CRT-D was associated with a lower total mortality (HR 0.62), total mortality or HF hospitalization (HR 0.63), and total mortality or hospitalization for MACE (HR 0.59) (all P < 0.001) in patients with ischaemic cardiomyopathy (ICM). There were no differences in outcomes between CRT-D and CRT-P in patients with NICM. Conclusion: In this study of real-world clinical practice, CRT-D was superior to CRT-P with respect to total mortality and composite endpoints, independent of known confounders. The benefit of CRT-D was evident in ICM but not in NICM.
Subject(s)
Cardiac Pacing, Artificial , Cardiac Resynchronization Therapy , Cardiomyopathies , Electric Countershock , Aged , Cardiac Pacing, Artificial/adverse effects , Cardiac Pacing, Artificial/methods , Cardiac Resynchronization Therapy/methods , Cardiac Resynchronization Therapy/statistics & numerical data , Cardiac Resynchronization Therapy Devices , Cardiomyopathies/etiology , Cardiomyopathies/mortality , Cardiomyopathies/therapy , Cause of Death , Defibrillators, Implantable , Electric Countershock/adverse effects , Electric Countershock/instrumentation , Electric Countershock/methods , Female , Hospitalization/statistics & numerical data , Humans , Long Term Adverse Effects/diagnosis , Long Term Adverse Effects/etiology , Long Term Adverse Effects/mortality , Male , Middle Aged , Mortality , Primary Prevention/methods , Primary Prevention/statistics & numerical data , Treatment Outcome , United Kingdom/epidemiologyABSTRACT
BACKGROUND: Recent studies have cast doubt on the benefit of cardiac resynchronization therapy (CRT) with defibrillation (CRT-D) versus pacing (CRT-P) for patients with nonischemic cardiomyopathy (NICM). Left ventricular myocardial scar portends poor clinical outcomes. OBJECTIVES: The aim of this study was to determine whether CRT-D is superior to CRT-P in patients with NICM either with (+) or without (-) left ventricular midwall fibrosis (MWF), detected by cardiac magnetic resonance. METHODS: Clinical events were quantified in patients with NICM who were +MWF (n = 68) or -MWF (n = 184) who underwent cardiac magnetic resonance prior to CRT device implantation. RESULTS: In the total study population, +MWF emerged as an independent predictor of total mortality (adjusted hazard ratio [aHR]: 2.31; 95% confidence interval [CI]: 1.45 to 3.68), total mortality or heart failure hospitalization (aHR: 2.02; 95% CI: 1.32 to 3.09), total mortality or hospitalization for major adverse cardiac events (aHR: 2.02; 95% CI: 1.32 to 3.07), death from pump failure (aHR: 1.95; 95% CI: 1.11 to 3.41), and sudden cardiac death (aHR: 3.75; 95% CI: 1.26 to 11.2) over a maximum follow-up period of 14 years (median 3.8 years [interquartile range: 2.0 to 6.1 years] for +MWF and 4.6 years [interquartile range: 2.4 to 8.3 years] for -MWF). In separate analyses of +MWF and -MWF, total mortality (aHR: 0.23; 95% CI: 0.07 to 0.75), total mortality or heart failure hospitalization (aHR: 0.32; 95% CI: 0.12 to 0.82), and total mortality or hospitalization for major adverse cardiac events (aHR: 0.30; 95% CI: 0.12 to 0.78) were lower after CRT-D than after CRT-P in +MWF but not in -MWF. CONCLUSIONS: In patients with NICM, CRT-D was superior to CRT-P in +MWF but not -MWF. These findings have implications for the choice of device therapy in patients with NICM.
Subject(s)
Cardiac Resynchronization Therapy/methods , Cardiomyopathies/therapy , Electric Countershock , Aged , Cardiomyopathies/diagnosis , Cardiomyopathies/mortality , Death, Sudden, Cardiac/epidemiology , Death, Sudden, Cardiac/prevention & control , Echocardiography , Female , Hospital Mortality/trends , Humans , Incidence , Magnetic Resonance Imaging, Cine , Male , Survival Rate/trends , Treatment Outcome , United Kingdom/epidemiologyABSTRACT
Thyrotoxic periodic paralysis (TPP) is a rare metabolic disorder characterised by muscular weakness and paralysis in predisposed thyrotoxic patients. Although patients with TPP are almost uniformly men of Asian descent, cases have been reported in Caucasian and other ethnic populations. The rapid increase in ethnic diversity in Western and European nations has led to increase in TPP reports, where it was once considered exceedingly rare. Correcting the hypokalaemic and hyperthyroid state tends to reverse the paralysis. However, failure to recognise the condition may lead to delay in diagnosis and serious consequences including respiratory failure and death. We describe a young man who was diagnosed with hyperthyroidism who presented with acute paralysis. The clinical characteristics, pathophysiology and management of TTP are reviewed.
