Effects of long-term treatment with verapamil on left ventricular function and myocardial blood flow in patients with dilated cardiomyopathy without overt heart failure

Comparative Efficacy of Different Drugs for the Treatment of Dilated Cardiomyopathy: A Systematic Review and Network Meta-analysis

BACKGROUND AND OBJECTIVE

At present, the therapies of dilated cardiomyopathy concentrated on the symptoms of heart failure and related complications. The study is to evaluate the clinical efficacy of a combination of various conventional and adjuvant drugs in treating dilated cardiomyopathy via network meta-analysis.

METHODS

The study was reported according to the PRISMA 2020 statement. From inception through 27 June 2022, the PubMed, Embase, Cochrane library, and Web of Science databases were searched for randomized controlled trials on medicines for treating dilated cardiomyopathy. The quality of the included studies was evaluated according to the Cochrane risk of bias assessment. R4.1.3 and Revman5.3 software were used for analysis.

RESULTS

There were 52 randomized controlled trials in this study, with a total of 25 medications and a sample size of 3048 cases. The network meta-analysis found that carvedilol, verapamil, and trimetazidine were the top three medicines for improving left ventricular ejection fraction (LVEF). Ivabradine, bucindolol, and verapamil were the top 3 drugs for improving left ventricular end-diastolic dimension (LVEDD). Ivabradine, L-thyroxine, and atorvastatin were the top 3 drugs for improving left ventricular end-systolic dimension (LVESD). Trimetazidine, pentoxifylline, and bucindolol were the top 3 drugs for improving the New York Heart Association classification (NYHA) cardiac function score. Ivabradine, carvedilol, and bucindolol were the top 3 drugs for reducing heart rate (HR).

CONCLUSION

A combination of different medications and conventional therapy may increase the clinical effectiveness of treating dilated cardiomyopathy. Beta-blockers, especially carvedilol, can improve ventricular remodeling, cardiac function, and clinical efficacy in patients with dilated cardiomyopathy (DCM). Hence, they can be used if patients tolerate them. If LVEF and HR do not meet the standard, ivabradine can also be used in combination with other treatments. However, since the quality and number of studies in our research were limited, large sample size, multi-center, and high-quality randomized controlled trials are required to corroborate our findings.

Effect of Oral Administration of Losartan, Prazosin, and Verapamil on Peritoneal Solute Transport in Continuous Ambulatory Peritoneal Dialysis Patients

Background

Several intraperitoneally administered drugs have been shown to modify transport of peritoneal solute and fluid. Fewer studies, however, have evaluated the effect of orally administered drugs. The present study was performed to evaluate the effects of oral losartan, prazosin, and verapamil on peritoneal membrane transport during a peritoneal equilibration test (PET), as well as the effects on creatinine clearance (CrCl), Kt/V urea, 24-hour protein in drained dialysate, and drained volume.

Methods

This was an open, controlled, crossover clinical trial performed in 20 patients on continuous ambulatory peritoneal dialysis. All subjects used four 2-L 1.5% glucose dialysis exchanges per day. After a 7-day washout period (without antihypertensives), they had a baseline standard PET and dialysis adequacy assessment performed. Subsequently, they were randomly allocated to receive the first of three study drugs (losartan, prazosin, and verapamil), which were administered orally for a 7-day period. Immediately after each drug period, patients had a new 3-day washout and subsequently started the next drug, until they had received each of the three drugs. On the last day of administration of each drug, patients were subjected to a new PET and adequacy of dialysis evaluation.

Results

None of the studied drugs significantly modified the peritoneal transport of creatinine, glucose, urea, sodium, potassium, or total protein as evaluated by PET. Verapamil significantly increased peritoneal CrCl [51.3 (44.3 – 53.3) vs baseline 45.8 (41.4 – 50.5) L/week/1.73 m2, p < 0.05], weekly Kt/V urea [1.75 (1.60 – 1.78) vs baseline 1.59 (1.54 – 1.73), p < 0.05], and drained dialysate volume [8.80 (8.30 – 8.96) vs baseline 8.44 (8.20 – 8.50) L/day, p < 0.05].

Conclusions

Oral administration of losartan, prazosin, and verapamil did not modify the peritoneal transport of solutes during a 4-hour PET. Oral verapamil significantly increased CrCl, Kt/V urea, and 24-hour drained dialysate volume. It is most likely that verapamil increases peritoneal (hydraulic) conductivity, and then net ultrafiltration volume and convective transport of urea, creatinine, and protein. Verapamil could be considered as an alternative in patients requiring increased dialysis dose and/or ultrafiltration.

Calcium channel autoantibodies predicted sudden cardiac death and all-cause mortality in patients with ischemic and nonischemic chronic heart failure

The purpose of this study was to evaluate whether CC-AAbs levels could predict prognosis in CHF patients. A total of 2096 patients with CHF (841 DCM patients and 1255 ICM patients) and 834 control subjects were recruited. CC-AAbs were detected and the relationship between CC-AAbs and patient prognosis was analyzed. During a median follow-up time of 52 months, there were 578 deaths. Of these, sudden cardiac death (SCD) occurred in 102 cases of DCM and 121 cases of ICM. The presence of CC-AAbs in patients was significantly higher than that of controls (both P < 0.001). Multivariate analysis revealed that positive CC-AAbs could predict SCD (HR 3.191, 95% CI 1.598–6.369 for DCM; HR 2.805, 95% CI 1.488–5.288 for ICM) and all-cause mortality (HR 1.733, 95% CI 1.042–2.883 for DCM; HR 2.219, 95% CI 1.461–3.371 for ICM) in CHF patients. A significant association between CC-AAbs and non-SCD (NSCD) was found in ICM patients (HR = 1.887, 95% CI 1.081–3.293). Our results demonstrated that the presence of CC-AAbs was higher in CHF patients versus controls and corresponds to a higher incidence of all-cause death and SCD. Positive CC-AAbs may serve as an independent predictor for SCD and all-cause death in these patients.

Coronary microvascular dysfunction: an update

Many patients undergoing coronary angiography because of chest pain syndromes, believed to be indicative of obstructive atherosclerosis of the epicardial coronary arteries, are found to have normal angiograms. In the past two decades, a number of studies have reported that abnormalities in the function and structure of the coronary microcirculation may occur in patients without obstructive atherosclerosis, but with risk factors or with myocardial diseases as well as in patients with obstructive atherosclerosis; furthermore, coronary microvascular dysfunction (CMD) can be iatrogenic. In some instances, CMD represents an epiphenomenon, whereas in others it is an important marker of risk or may even contribute to the pathogenesis of cardiovascular and myocardial diseases, thus becoming a therapeutic target. This review article provides an update on the clinical relevance of CMD in different clinical settings and also the implications for therapy.

Subclinical myocardial dysfunction in patients with reverse-remodeled dilated cardiomyopathy

BACKGROUND

The aim of this study was to test the hypothesis that patients with reverse-remodeled dilated cardiomyopathy (DCM), whose ejection fractions (EFs) were normalized after optimal pharmacologic therapy, had subclinical myocardial dysfunction.

METHODS

Thirty-two patients with reverse-remodeled DCM, defined as having an initial EF ≤ 35%, which then recovered to ≥50% after optimal pharmacologic therapy, and 11 normal controls with preserved EFs were retrospectively studied. Averaged peak systolic and early diastolic radial, circumferential, and longitudinal speckle-tracking strain rates were assessed from an 18-segment left ventricular model. Similarly, averaged peak systolic radial, circumferential, and longitudinal speckle-tracking strain was obtained.

RESULTS

Peak systolic and early diastolic longitudinal strain rates, peak systolic and early diastolic circumferential strain rates, and peak circumferential and longitudinal strain in patients with reverse-remodeled DCM were significantly lower than those in normal controls, but peak systolic and early diastolic radial strain rates and peak radial strain in patients with reverse-remodeled DCM were similar to those in normal controls. Isometric handgrip stress testing showed a significant decrease in EF from 56 ± 5% to 51 ± 5% (P < .001). Of note, the increase of afterload resulting from isometric handgrip stress testing was associated with a decrease in peak systolic circumferential and longitudinal strain rates and peak circumferential strain in patients with reverse-remodeled DCM.

CONCLUSIONS

The circumferential and longitudinal myocardial function of patients with reverse-remodeled DCM is lower compared with that of normal controls with preserved EFs. Furthermore, the increase in afterload was associated with the decrease in circumferential and longitudinal myocardial systolic function. These findings suggest that in treated patients with DCM with reverse remodeling, left ventricular mechanics may not be normal, even when EFs are normal.

Arrhythmogenic autoantibodies against calcium channel lead to sudden death in idiopathic dilated cardiomyopathy

AIMS

Calcium channel plays an important role in the autoimmune pathogenesis of idiopathic dilated cardiomyopathy (DCM). Autoantibodies have emerged as a new upstream target of sudden death in DCM. We sought to validate the hypothesis that autoantibodies against l-type calcium channel (CC-AAbs) are arrhythmogenic and lead to sudden death in patients with DCM.

METHODS AND RESULTS

We investigated sudden death and ventricular arrhythmias in 80 patients with DCM in a prospective, case follow-up survey. During a follow-up of 32 (SD 8) months, CC-AAbs-positive patients not only had a higher incidence of ventricular tachycardia (VT) but also a higher incidence of sudden death than CC-AAbs-negative patients (for VT: 59.0 vs. 24.4%, P = 0.002 and for sudden death: 20.5 vs. 4.9%, P = 0.045). Further univariate and multivariate analyses showed that the occurrence of CC-AAbs was the strongest independent predictor for sudden death (odds ratio: 10.20, 95% confidence interval: 2.43-36.78, P = 0.0027). Experimental studies in ex vivo systems using affinity-purified CC-AAbs from patients demonstrated that CC-AAbs were able to induce VT by prolongation of action potential duration (APD) and triggered activity by early afterdepolarization (EAD).

CONCLUSION

Our results demonstrate for the first time to our knowledge that there is a high incidence of sudden death and VT in CC-AAbs-positive patients with DCM. Furthermore, experimental data from ex vivo systems suggest that CC-AAbs might induce VT by prolongation of APD and triggered activity by EAD.

Calcium antagonists for Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is a progressive muscle condition starting in childhood, leading to severe disability and a shortened life span. It is due to severe deficiency of the protein dystrophin which performs both structural and signalling roles within skeletal and cardiac myocytes. Calcium accumulates in dystrophic muscle cells and plays a role in cell damage. It has been hypothesised that use of calcium antagonists might reduce this calcium load and its toxic effect on muscle cells.

OBJECTIVES

To evaluate the effects of calcium antagonists on muscle function and muscle strength in people with DMD.

SEARCH STRATEGY

The Cochrane Neuromuscular Disease Group Trials Register (February 2008), MEDLINE (from January 1950 to March 2008) and EMBASE (from January 1947 to March 2008) were searched. Search terms were 'calcium antagonists' or 'calcium channel blocker' or 'dantrolene' or 'verapamil' or 'nifedipine' or 'flunarizine' or 'diltiazem' or 'amlodipine' or 'nicardipine' and 'Muscular Dystrophy, Duchenne'. Bibliographies in reports of any trials were also searched.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials of any calcium antagonist in people with DMD.

DATA COLLECTION AND ANALYSIS

Both authors assessed all identified trials for inclusion in the study on the basis of whether they fulfilled the selection criteria. Both authors extracted data from the trials and assessed the methodological quality. Had there been more than one trial of the same intervention and outcome of sufficient methodological quality, we had planned to undertake a meta-analysis.

MAIN RESULTS

Five randomised or quasi-randomised double-blind trials fulfilled the selection criteria, but were not sufficiently comparable to undertake a meta-analysis. The drugs studied were verapamil (8 participants), diltiazem (56 participants), nifedipine (105 participants) and flunarizine (27 participants). There were limitations in the description of blinding and randomisation, and definition of outcome measures. One trial, using verapamil, showed a difference between groups in muscle force measured by ergometry, but also revealed cardiac side effects. The numbers of people included in the trials were low, and so the studies may not have included enough people for sufficient power to detect small differences in muscle force or function between placebo and control groups. In addition, calcium antagonists were in an early stage of development and some of the second generation drugs that have a better side effect profile, such as amlodipine, have not been studied.

AUTHORS' CONCLUSIONS

There is no evidence to show a significant beneficial effect of calcium antagonists on muscle function in DMD.

Defining the role of calcium channel antagonists in heart failure due to systolic dysfunction

Calcium channel antagonists (CCAs) may either be divided into the dihydropyridines (e.g. amlodipine, felodipine, isradipine, lacidipine, nilvadipine, nifedipine, nicardipine etc.), the phenylalkylamines (e.g. verapamil) and the benzothiazepines (e.g. diltiazem) according to their chemical structure, or into first generation agents (nifedipine, verapamil and diltiazem) and second generation agents (subsequently developed dihydropyridine-derivatives). Second generation CCAs are characterized by greater selectivity for calcium channels in vascular smooth muscle cells than the myocardium, a longer duration of action and a small trough-to-peak variation in plasma concentrations. Heart failure is characterized by decreased cardiac output resulting in inadequate oxygen delivery to peripheral tissues. Although the accompanying neurohormonal activation, leading to vasoconstriction and increased blood pressure, is initially beneficial in increasing tissue perfusion, prolonged activation is detrimental because it increases afterload and further reduces cardiac output. At the level of the myocyte, heart failure is associated with increased intracellular calcium levels which are thought to impair diastolic function. These changes indicate that the CCAs would be beneficial in patients with heart failure. There has been a strong interest and increasing experience in the use of CCAs in patients with heart failure. Despite potential beneficial effects in initial small trials, findings from larger trials suggest that CCA may have detrimental effects upon survival and cardiovascular events. However, this may not necessarily be a 'class b' effect of the CCAs as there is considerable heterogeneity in the chemical structure of individual agents. Clinical experience with different CCAs in patients with heart failure includes trials that evaluated their effects on hemodynamic parameters, exercise tolerance and on symptomatology. However, the most relevant results are those from randomized clinical trials that assessed mortality as the primary endpoint. First generation CCAs have direct negative inotropic effects and even sustained release formulations have not proved any beneficial effect upon survival. With second generation CCAs, some benefit on hemodynamic parameters has been observed but none on survival, alone or in combination with ACE inhibitors. It is noteworthy that although amlodipine had a neutral effect on morbidity and mortality in large, randomized, placebo-controlled trials in patients with heart failure, the drug was well tolerated. There is no specific indication for CCAs (first or second generation) in patients with systolic heart failure, alone or in combination with ACE inhibitors, but amlodipine may be a considered in the management of hypertension or coronary artery disease in patients with heart failure.

Detecting changes in serial myocardial perfusion SPECT: a simulation study

BACKGROUND

New algorithms were evaluated for their efficacy in detecting and quantifying serial changes in myocardial perfusion from single photon emission computed tomography (SPECT).

METHODS AND RESULTS

We generated 72 simulations with various left ventricular positions, sizes, count rates, and perfusion defect severities using the nonuniform rational B-splines (NURBs)-based CArdiac Torso (NCAT) phantom. Images were automatically aligned by use of both full linear and rigid transformations and quantified for perfusion by use of the CEqual program. Changes within a given perfusion defect were compared by use of a Student t test before and after registration. Registration approaches were compared by use of receiver operating characteristic analysis. Changes of 5% were not detected well in single patients with or without alignment. Changes of 10% and 15% could be detected with false-positive rates of 15% and 10%, respectively, in single studies if alignment was performed before perfusion analysis. Alignment also reduced the number of studies necessary to demonstrate a significant perfusion change (P < .05) in groups of patients by about half.

CONCLUSION

Comparison of mean uptake by t values in SPECT perfusion defects can be used to detect 10% and greater differences in serial perfusion studies of single patients. Image alignment is necessary to optimize automatic detection of perfusion changes in both single patients and groups of patients.

Noninvasive determination of regional myocardial perfusion with first-pass magnetic resonance (MR) imaging

RATIONALE AND OBJECTIVES

To develop a method to provide absolute values of regional myocardial perfusion by means of color maps, and to determine myocardial perfusion reserve using magnetic resonance imaging during the first pass of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA).

MATERIALS AND METHODS

The study population consisted of five patients with hypertrophic cardiomyopathy, two with dilated cardiomyopathy, four with coronary artery disease, and one with normal coronary arteries who presented with mildly abnormal electrocardiogram findings. For each heartbeat, six continuous slices were acquired during the first pass of Gd-DTPA (0.05 mmol/kg body weight) before and during adenosine triphosphate (ATP) **stress using an electrocardiogram-triggered fast low-angle shot (FLASH) sequence on a 1.5-T magnetic resonance unit. Myocardial perfusion images were created and displayed by means of a color scale. The parameters were calculated pixel by pixel, using the upslope method. Myocardial perfusion reserve was then calculated, as the quotient of myocardial perfusion during ATP stress and perfusion before ATP stress.

RESULTS

Myocardial perfusion during ATP stress in patients with normal coronary arteries (n = 1) or after successful percutaneous coronary intervention (n = 2) was increased compared with that before ATP stress. However, the patients with coronary artery disease (n = 2) failed to show increased myocardial perfusion. The patients with hypertrophic cardiomyopathy showed increased myocardial perfusion during ATP stress, although two with dilated cardiomyopathy did not.

CONCLUSION

Our new technique can provide absolute values of regional myocardial perfusion by means of color maps, and has potential for widespread use for evaluation of ischemic and other types of heart disease.

Verapamil reduces coronary endothelium damage and cardiomyocyte necrosis but not apoptosis after ischemia and reperfusion: ex-vivo study in rat hearts

We tested the hypothesis of beneficial effects of the calcium-blocker verapamil in a model of ischemia-reperfusion, and investigated its effects against coronary microcirculation and cardiomyocyte apoptosis. Isolated working rat hearts were subjected to 15 min global ischemia and 22-180 min reperfusion in the presence or absence of verapamil (0.25 &mgr;M). We evaluated creatinephosphokinase (CK) in coronary effluent, heart weight changes, microvascular permeability (extravasation of fluoresceine-labeled albumin), ultrastructural alterations, and cardiomyocyte apoptosis (by 1.5% agarose gel electrophoresis and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling technique). In this model, 0.25 &mgr;M verapamil significantly reduced myocardial damage, CK release and vascular hyperpermeability, concomitant with a reduction in endothelial and cardiomyocyte lesions; on the contrary, 0.25 &mgr;M verapamil was unable to reduce cardiomyocyte apoptosis. In conclusion, in the absence of perfusing granulocytes, the acute administration of a pharmacologically relevant verapamil concentration reduces ischemia-reperfusion injury and prevents coronary endothelial cell and cardiomyocyte necrotic cell death but it is unable to reduce apoptotic cell death in isolated working rat hearts.