1 medical uses
1.1 approval
1.2 indication
1.3 therapeutic gap
1.4 recommendations
1.5 efficacy
1.5.1 meta-analyses
1.5.2 long-term survival studies
1.5.3 general
medical uses
approval
based on results of clinical trials, ccm™ devices approved , available clinical use in european union countries , in australia, turkey, india , hong kong, in other countries recognize ce marking medical devices.
at present time, ccm™ therapy not approved clinical use in united states. however, study has been initiated in order obtain fda approval, , continued access has been granted fda
indication
schematic representation of normal sinus rhythm seen on ecg. qrs complex shown in center.
based on approval of ccm™ devices, cardiac contractility modulation treatment option patients @ least 18 years old suffer heart failure symptoms due left ventricular systolic dysfunction (lvsd) despite adequate medical treatment. further clinical research under way identify patient group within scope of device approval benefits ccm™ treatment.
criteria classification of patients left ventricular systolic heart failure include severity of disease based on functional parameters (nyha classification), average percentage of blood volume ejected left ventricle each heart beat (left ventricular ejection fraction or lvef) , duration of qrs complex seen in electrocardiogram (ecg). clinical studies on ccm™ therapy have involved heart failure patients classified nyha class ii, iii or iv , had normal qrs duration (qrs duration ≤ 120 ms). efficacy of ccm™ on patients in earlier stage of heart failure has not yet been studied.
a subsequent evaluation study (subgroup analysis) has suggested particular patient group responds exceptionally ccm™ therapy. patients characterized disease severity of nyha class iii , left ventricular ejection fraction of ≥ 25%.
although studies on ccm™ therapy have focused on patients normal qrs duration (i.e. ≤ 120 ms), possible use ccm™ in patients meet treatment indication not have normal qrs duration.
a preliminary study has shown ccm™ may safe , effective in such patients have not responded cardiac resynchronization therapy (crt).
therapeutic gap
cardiac resynchronization therapy (crt; known biventricular pacing) has proven effective treatment in heart failure. however, crt recommended exclusively patients preserved sinus rhythm , prolonged qrs complex (≥ 120 ms) suffer left bundle branch block (lbbb), or patients without left bundle branch block have preserved sinus rhythm , qrs complex width of ≥ 150 ms. however, 30-40% of heart failure patients show such prolonged qrs complex, , therefore 60-70% of patients have normal qrs complex cannot treated crt. in addition, around 30% of patients eligible crt treatment not respond crt.
until recently, other available device-based treatment left ventricular assist device (lvad). lvad therapy indicated in patients severe illness , associated several hours of surgery (involving cardiopulmonary bypass). considered therapy providing “bridge transplant” heart failure patients classified nyha class iv, , intended support heart function until heart transplant received. current research results suggest therapeutic gap described above closed ccm™ therapy. additionally, long-term study on ccm™ showed therapy able stop common , prognostically unfavorable long-term prolongation of qrs duration in heart failure patients. result interpreted signaling safety of treatment , indicator patients benefit ccm™ therapy in long term. if qrs-stabilizing effect confirmed in further studies, ccm™ become first device-based treatment heart failure potential halt qrs prolongation, factor associated poor prognosis.
recommendations
the guidelines issued european society of cardiology (esc) in 2016, mention ccm™ therapy therapy option considered in selected group of patients hf. these guidelines endorsed national cardiac societies in individual countries within european union.
efficacy
cardiac contractility modulation has proven effective , safe in randomized controlled trials involving several hundred patients.
the nature , extent of effect of ccm™ have been subject of numerous investigations. although various individual publications, 1 of 2 meta-analyses, have presented ccm™‘s efficacy , significant potential in treatment of heart failure, medical evaluation of therapy efficacy not yet complete. scientists point out, however, case crt therapy when first introduced, advocating provision of ccm™ suitable patients before further studies completed.
to date (february 2015), there @ least 2 meta-analyses studying efficacy of ccm™ therapy on heart failure,
a large number of review articles (e.g.) , @ least 2 survey articles on device-based treatments of advanced heart failure address cardiac contractility modulation. furthermore, there more 70 individual publications focusing on ccm™.
further randomized controlled trials studying effect of ccm™ on progression of heart failure have been initiated , (as of feb 2015) recruiting patients.
meta-analyses
giallauria et al. evaluated 3 randomized controlled trials (rcts) available on ccm™ treatment heart failure patients. 3 trials included total of 641 patients , assessed effect of ccm™ either in comparison sham treatment or in comparison best medical treatment. in contrast earlier meta-analysis kwong et al. study did not evaluate data based on summarized results alone, on basis of individual data sets of 641 enrolled patients.
the study concluded ccm™ improved important markers of cardiac performance. these included maximal oxygen uptake (peak vo2 or pvo2 – measured ventilatory parameters during cardiopulmonary exercise test), indicative of improved survival, , 6-minute walk test. quality of life of participating patients, measured minnesota living heart failure questionnaire (mlwhfq), improved significantly. however, both meta-analyses demanded additional , larger randomized controlled trials in order evaluate effect of ccm™ more precisely.
giallauria et al. describe success of cardiac contractility modulation , further potential of therapy. particular emphasis given possibility ccm™ therapy may close therapeutic gap in heart failure treatment if previous study outcomes confirmed.
long-term survival studies
as of february 2015, effect of ccm™ therapy on long-term mortality rates of heart failure patients has not been studied in randomized controlled trial. preliminary single-center studies have been reported though. kuschyk et al. evaluated long-term efficacy , survival of patients ccm™. analysis included 81 patients disease severity of nyha class ii, iii or iv , mean follow-up of around 3 years. analysis compared observed mortality rate prediction of meta-analysis global group in chronic heart failure (maggic) model based on records of on 39,000 heart failure patients. unlike previous long-term outcome study of ccm™, study not limited heterogeneous group of patients.
following long-term observation, study concluded ccm™ improved quality of life, exercise tolerance, nyha class, left ventricular ejection fraction (lvef) , brain natriuretic peptide (bnp) levels. mortality rates lower predicted @ year 1, , lower predicted not statistically significant @ year 3.
general
heart failure chronic disease progresses gradually. rate of progression , degree of symptoms of disease varies between different patients. ccm™ therapy aims treat heart failure through medium- long-term treatment, on course of weeks , months.
according large implanting clinics, after implantation wound healed, lifestyle of patient not restricted implanted device. leisure, travel (by car, train, ship or plane), hobbies , sex life not restricted. patient may perceive improved capacity these activities , overall enhanced performance , exercise capacity in response actual therapy.
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