Precipitation of ventricular fibrillation by intravenous diltiazem and metoprolol in a young patient with occult Wolff-Parkinson-White syndrome

We report the case of a young man who presented with a rapid, narrow-complex atrial fibrillation. A few hours after being administered intravenous metoprolol and diltiazem for rate control, he developed intermittent ventricular preexcitation on the electrocardiogram (ECG) and experienced ventricular fibrillation, from which he was successfully defibrillated. A subsequent electrocardiogram in sinus rhythm demonstrated previously unknown Wolff-Parkinson-White pattern. A left lateral accessory pathway was successfully ablated. Wolff-Parkinson-White syndrome should be included in the differential diagnosis when a young patient presents with atrial fibrillation, even if the ventricular complexes on the ECG are not preexcited.     

I/D-polymorphism of ACE gene, morphofunctional heart condition and blood pressure 24-h profile in young men with arterial hypertension

AIM: To study the effects of ACE gene polymorphism on morphofunctional condition of the heart and 24-h blood pressure profile (BPP) in young men with hypertension. MATERIAL AND METHODS: A total of 174 young and middle-aged hypertensive men (mean age 32 +/- 4.6 years and 48 +/- 3.1 years, respectively) were examined (echocardiography, 24-h BP monitoring, tests for I/D-polymorphism of ACE gene). RESULTS: Genotype ID appeared most prevalent both in the young and middle-aged examinees (56 and 49%, respectively). Interventricular septal thickness and left ventricular myocardial mass were the largest in young hypertensive patients carrying genotype DD. Mean 24-h and nocturnal diastolic BP was significantly higher in young hypertensive patients with genotype II vs middle-aged patients with the same genotype. Carriers of genotype II had maximal variability of systolic and pulse blood pressure. CONCLUSION: Genotype DD appeared most unfavourable in relation to left ventricular myocardial hypertrophy. Its carriers had the thickest right ventricular myocardium, the largest mass of the left ventricle. Homozygotes by allele-I had most pronounced changes in a 24-h BP profile.     

Magnesium deficiency during lactation as a precipitant of ventricular tachyarrhythmias

A young ICD recipient with a history of syncope and idiopathic polymorphic ventricular tachycardia/ventricular fibrillation presented after an ICD discharge. She had delivered her first child 8 days prior to the event and she had been lactating. Numerous short runs of polymorphic ventricular tachycardia/ventricular fibrillation resolved with aggressive replacement of magnesium and elimination of breast-feeding.     

Single versus dual chamber pacing in the young: noninvasive comparative evaluation of cardiac function

The advantages of atrial synchrony over asynchronous ventricular pacing remain unclear in the young, chronically right ventricular (RV) - paced patient. This is in contrast to the older patient with inherent diastolic dysfunction who has been shown to benefit from atrial synchrony with dual chamber (DDD,R/VDD), over single chamber rate response (VVI,R) ventricular pacing. The goal of this study was to noninvasively assess cardiac function in a group of young, RV-paced patients before and after establishment of atrial synchrony. Echocardiographic data were retrospectively analyzed from 10 patients with congenital or acquired complete AV block, who were VVI,R paced for 10.2 +/- 2 years (mean age at study 19.2 +/- 8.9 years), and were subsequently converted to DDD,R/VDD pacing (mean age at study 20.7 +/- 9.5 years). Paired t-test analysis of left ventricular (LV) systolic and diastolic function during VVI,R versus DDD,R/VDD pacing did not result in any short-term difference in LV short axis fractional area of change or FAC (53% +/- 7.5% vs 56.8% +/- 8.7%) or mitral maximal velocity (E) normalized to mitral flow velocity time integral (VTI) (5.2/s +/- 1.5 vs 4.4/s +/- 1.5). A decrease in mitral flow E/A ratio was observed after short-term DDD,R/VDD pacing (2.2 +/- 0.5 vs 1.9 +/- 0.3). Atrial synchronous dual chamber pacing in young patients with complete AV block does not lead to any appreciable early change in global LV function over single-site RV pacing. Therefore, early establishment of atrial synchrony in the young asymptomatic VVI,R-paced patient with normal intrinsic ventricular function may not be warranted.     

Ischemic postconditioning's benefit on reperfusion ventricular arrhythmias is maintained in the senescent heart

The purpose of this study is to determine if postconditioning's beneficial effect on ventricular arrhythmias is maintained in elderly hearts. In elderly populations, the cardioprotective effects of ischemic preconditioning are lost. Previously, the authors observed that ischemic postconditioning markedly reduced reperfusion-induced ventricular arrhythmias in adult rats. Whether this benefit is maintained in senescent hearts is unknown. Here, the authors study young adult rats compared with senescent animals. They chose 24-month-old Fischer female rats as these rats are approaching the end of their normal life span. Unlike some studies that suggest that the benefits of preconditioning and postconditioning are lost in the elderly, their data show that antiarrhythmic protection conferred by postconditioning is present in both the young and old rats.     

Isolated Ventricular Noncompaction: Implications for Mechanisms of Sudden Cardiac Death

We present a case of a young patient, whose first manifestation of isolated ventricular noncompaction (IVNC) was sudden cardiac arrest precipitated by ventricular fibrillation. Furthermore we had the rare opportunity to record the onset of subsequent episodes of ventricular fibrillation—with discussion on the mechanisms of ventricular arrhythmias in IVNC. (PACE 2013; 36:e153–e155)     

Polymorphous Ventricular Tachyarrhythmias in the Absence of Structural Heart Disease

Polymorphous ventricular tachyarrhythmias (PVTA) in the absence of structural heart disease form a particularly important target for comprehensive research. They occur in young, healthy children and young adults and most probably cover several underlying electrophysiological abnormalities. We individualized two syndromes, namely catecholaminergic ventricular tachyarrhythmias, and torsade de pointes (TDP) with a short coupling interval, but these two entities certainly represent only a part of the problem of id-iopathic ventricular fibrillation. Having the implanted defibrillator as a therapeutic umbrella for those patients who were fortunate enough to escape from sudden death is not sufficient. Too often in modern cardiology the therapeutic achievements tend to precede the process of diagnosis and comprehension. At least, the former should not preclude the latter, a situation that can be observed, for instance, when the favorable effect of a drug is evidenced before its mode of action was understood. At best, both progress together, provided we pay attention to adequately exploit the resources of modern technology.     

Prospective ECG-triggered sequential versus retrospective ECG-gated spiral CT: Pros and cons

Advancement of multidetector CT makes it possible to visualize the coronary arteries, as well as ventricular and valvular motion. However, the necessary radiation dose is higher than that associated with x-ray coronary angiography. Recently introduced prospective electrocardiograph (ECG)-triggered CT angiography (CTA), using conventional axial scan, can markedly reduce the radiation dose, while maintaining diagnostic performance, when appropriately applied in selected patients. The prospective ECG-triggered CTA is technically feasible in patients with low and stable heart rate. The indication for the CT examination should be exclusion of obstructive coronary disease, rather than analysis of ventricular and valvular function. The technique is most beneficial for young patients, especially young women, who are at low risk for significant coronary artery disease and for whom radiation dose is of great concern.     

Successful Treatment of Ventricular Tachycardia by Physiological Pacing

The case is presented of a young patient with atrioventricular (AV) block but no evidence of other disease; in this patient exercise or stress-related syncope continued after implantation of a ventricular inhibited (VVI) pacemaker. Investigation revealed exercise-induced limited rapid multiform ventricular tachycardia (VT) which was associated with faintness or syncope. Temporary atrial triggered ventricular inhibited ventricular (VDD) pacing resulted in enhanced exercise tolerance with no significant arrhythmia. A permanent full function dual chamber [DDD] pacemaker was implanted and prevented the VT. There have been no further exercise-related symptoms during two years 0f follow up.     

Carbamazepine-Associated Severe Left Ventricular Dysfunction

Introduction: The cardiovascular effects of carbamazepine are well-known but left ventricular dysfunction is rarely reported. Case Report: We describe 2 cases of severe carbamazepine-associated left ventricular dysfunction during massive self intoxications in young patients without preexistent cardiac disease. We compare our cases to the available literature and discuss the mechanisms implied in the development of left ventricular dysfunction following carbamazepine overdose. Bedside echocardiography was useful in both diagnosis and treatment.     

多普勒超声心动图对胎儿新生儿婴儿及幼儿心室舒张功能的评价

运用多普勒超声心动图分别检测胎儿、新生儿、婴儿及幼儿心室舒张功能。结果显示：胎儿左右房室瓣口血流ＰＦＶ、ＶＴＩ及ＰＰＧ均为Ｅ＜Ａ，左右心室舒张功能处于生理性非健全期；新生儿右房室瓣口血流转变为Ｅ＞Ａ，示右室松弛性的转变先于左室，心室舒张功能处于生理性过渡期；婴儿左右房室瓣口血流均为Ｅ＞Ａ，但ＭＶＯ比值较小，心室舒张功能处于正常过渡期；幼儿左右房室瓣口血流各项参数均为Ｅ＞Ａ，比值为ＭＶＯ＞ＴＶＯ，ＩＶＲＴ明显延长，表明人体心室舒张功能从此进入正常期。     

Efficacy of ivabradine to control ventricular arrhythmias in catecholaminergic polymorphic ventricular tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a potentially lethal hereditary disease characterized by complex ventricular arrhythmias provoked by exercise or emotional stress and by a high mortality rate in young individuals. Nadolol alone or in combination with flecainide is the most effective therapy. However, compliance to treatment is often low due to side effects. We report two patients with CPVT in whom side effects of treatment prompted discontinuation of flecainide or nadolol and in whom ivabradine was successfully added to therapy. In these two patients, ivabradine in combination with nadolol or flecainide was well tolerated and successfully suppressed nonsustained polymorphic ventricular tachycardia and couplets. Thus, ivabradine could limit the use of implantable cardioverter‐defibrillators or left cardiac sympathetic denervation in CPVT patients with uncontrollable ventricular arrhythmias.     

Cardiac responses to burn injury in young and adult guinea pigs.

The present study examined functional and biochemical differences in young compared to adult hearts, and determined if developmental differences altered the ability of the young heart to respond to burn injury. Compared to the adult heart, hearts from young sham burns had diminished responsiveness to isoproterenol, extracellular calcium, and increases in either ventricular filling or coronary flow rate. In contrast, there were no age-related differences in maximal calcium uptake (360+/-11 vs. 367+/-14 nmol/mg) or calcium uptake velocity (59+/-2 vs. 60+/-4 nmol/mg/min) in sarcoplasmic reticulum (SR) vesicles isolated from adult and compared to young control hearts. Burn injury (43% TBSA for adults, 35% TBSA for young) impaired myocardial function in all hearts, regardless of age. Age-related differences in adult and young hearts persisted after burn trauma with significantly lower left ventricular developed pressure (49+/-2 vs. 63 +/-3 mmHg, P < 0.01), +dP/dt max (860+/-89 vs. 1151+/-62 mmHg/sec, P < 0.01), and -dP/dt max (790+/-39 vs. 901+/-50 mmHg/sec, P < 0.02) in young vs. adult burn hearts. Burn injury reduced cardiac SR maximal calcium uptake in adults (sham, 360+/-11; burn, 298+/-12 nmol/mg, P < 0.05), but not in young hearts (sham, 367+/-14; burn, 380+/-12 nmol/mg); however, burn trauma increased the SR calcium velocity/capacity ratio in both young and adult burn groups. Our data confirm age-related differences in ventricular performance in young and adult guinea pigs; these differences persisted after burn trauma. The burn-mediated changes in SR Ca2+ transport suggest that disturbances in intracellular calcium handling may contribute, in part, to post-burn cardiac contractile deficits regardless of age.     

APATHETIC THYROTOXICOSIS

A previously fit 37-year-old woman was admitted with acute left ventricular failure, atrial fibrillation and a left-sided thromboembolic stroke. Her ventricular rate progressively increased despite full digitalisation. She had a cardiac arrest and was successfully resuscitated. Investigations revealed evidence of hyperthyroidism and she was treated for thyrotoxic crisis. She has made a complete recovery from the hemiparesis and is now in sinus rhythm. She denied any symptoms of hyperthyroidism. This patient had apathetic thyroid crisis, which is exceedingly rare in the young.     

Risk stratification for sudden death in arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC) is an uncommon but increasingly recognized inherited cardiomyopathy that is associated with malignant ventricular arrhythmias and sudden cardiac death, particularly in young individuals. The implantable cardioverter-defibrillator (ICD) is widely regarded as the only treatment modality with evidence to support improved survival in patients with ARVC and secondary prevention indications. In contrast, there is no universally accepted risk stratification scheme to guide ICD therapy for primary prevention against sudden cardiac death. Potential benefits must be weighed against the considerable risks of complications and inappropriate shocks in this young patient population. This article tackles the challenges of risk stratification for sudden cardiac death in ARVC and critically appraises available evidence for various proposed risk factors. The authors’ over-arching objective is to provide the clinician with evidence-based guidance to inform decisions regarding the selection of appropriate candidates with ARVC for ICD therapy.     

Arrhythmogenic right ventricular dysplasia in the elderly

Arrhythmogenic right ventricular dysplasia (ARVD) is a syndrome characterized by recurrent ventricular tachycardia. However, cases of ARVD have also presented as dilated cardiomyopathy later associated with ventricular arrhythmias. Histologically, this syndrome manifests as a fibrofatty replacement of the RV myocardium, predisposing the heart to ventricular arrhythmias. ARVD was once considered a disease of the young, but may be underrecognized in the older population. This report presents two cases of elderly men with newly symptomatic ARVD, believed to represent the oldest patients with ARVD described in the literature to date. The diagnosis of ARVD should be considered in individuals of all ages who present with a clinical syndrome consistent with ARVD and supportive evidence on ECG.     

Paradoxic Embolism Due to Altered Hemodynamic Sequencing Following Transvenous Pacing

A young patient, who experienced a cerebral embolic event 30 days after transvenous pacemaker iead placement, is reported. This patient had previously been paced with an epicardial lead without evidence of right to left intracardiac shunt. However, hemodynamic evaluation post-embolism demonstrated a marked temporal disparity of the pulmonary and systemic ventricles. This phasic divergence resulted in a brief reversal of right and left ventricular pressure ratios, and a paradoxic intracardiac shunt at a small ventricular septal defect. The potential for similar events in the presence of any defect of the atrial or ventricular septum mandates caution in the use of transvenous pacemaker leads in such patients.     

Dual Epicardial Ventricular Tachycardia: A Tale of Two VTs

A young female with isolated ventricular noncompaction and acute myocarditis presented with incessant dual epicardial ventricular tachycardia consisting of a manifest reentrant circuit and a shorter cycle length concealed circuit. A single radiofrequency terminated both tachycardias. (PACE 2012; 35:e1–e5)     

Recurrent Ventricular Tachycardia Responsive to Verapamil

We describe five young patients with recurrent ventricular tachycardia in the absence of organic heart disease. In all patients tachycardia could be terminated or prevented with verapamil. Tachycardia in four patients was very similar, with a QRS pattern of right bundle branch block and left axis deviation. Electrophysiology studies in two patients showed that VT was inducible in one patient (rapid atrial or ventricular pacing, ventricular extrastimuli) but not in the other. The clinical and electrocardiographic similarities in these patients suggest that their ventricular tachycardias may share a common pathophysiology and may be dependent on slow channel activity.     

Potential role of a disintegrin and metalloproteinase-17 (ADAM17) in age-associated ventricular remodeling of rats

Excessive tumor necrosis factor-α (TNF-α) could enhance cell death and aggravate left ventricular remodeling and myocardial dysfunction. A disintegrin and metalloproteinase-17 (ADAM17), an important maturation regulator of TNF-α, might be involved in the aging-associated ventricular remodeling. The present study observed myocardial ADAM17 expression in young and aged rats and explored the association between cardiac structure/function and expression of ADAM17 in 6 month-old (n = 10, young group) and 24 month-old SD rats (n = 10, old group). The body, heart weight and heart weight/body weight ratio of rats in the old group were all significantly increased compared to that in the young group (P < 0.05). The left ventricular systolic end-diameter and end-diastolic diameters were significantly enlarged in the old group compared to the young group (P < 0.05), while the systolic function index including the left ventricular ejection fraction and left ventricular fractional shortening were similar between the two groups. The peak mitral flow velocity (E)/peak mitral annulus velocity (E′) ratio was significantly higher in the old group than in the young group (P < 0.05). Histological examination showed more damage of cardiomyocytes, interstitial collagen deposition and inflammatory cell infiltration in the old group. Immunohistochemistry examination showed that myocardial TNF-α expression was mainly located in cardiomyocytes and was significantly higher in the old group than in the young group (P < 0.05). The protein expression of myocardial ADAM17 detected by western blot was significantly higher in the old group than in the young group (P < 0.05), while TIMP-3 expression was similar between the two groups. The present study suggested that ADAM17 and inflammation might play an important role in aging-related myocardial remodeling through regulating TNF-α.

Excessive tumor necrosis factor-α (TNF-α) could enhance cell death and aggravate left ventricular remodeling and myocardial dysfunction.