The prevalence and the prognostic value of microvolt T-wave alternans in patients with hypertrophic cardiomyopathy.

BACKGROUND: Nonsustained ventricular tachycardia (nVT) may have ominous implications for patients with hypertrophic cardiomyopathy (HCM). The microvolt T-wave alternans (TWA) has been proposed as a noninvasive tool-identifying patients at risk of sudden cardiac death and ventricular tachycardia/fibrillation (VT/VF). The aim of the study was to determine the significance of TWA in predicting nVT episodes and compare how other electrocardiographic parameters can predict the occurrence of nVT. METHODS: The study group consisted of 88 patients with HCM. TWA was assessed during exercise test using the CH2000 system. All patients underwent Holter monitoring (HM) within 2-4 weeks before TWA test (preexercise HM1) and immediately after (postexercise HM2). During HM, we analyzed: arrhythmias, QT intervals, the presence of late ventricular potentials (LP), heart rate variability, heart rate turbulence. RESULTS: Depending on TWA results, the patients were divided into two groups: TWA+; 46 patients (52.3%) with positive/indeterminate results, and TWA-; 42 patients (47.7%) with negative results. The nVT episodes were more frequent among TWA(+) both in HM1 and HM2. The presence of TWA increases the risk of postexercise nVT over twenty times (OR = 21.03). Moreover, in HM1, QTc and LP, and in HM2, again QTc and N-terminal precursor of brain natriuretic peptide proved to be significant predictors of nVT. The addition of TWA to the models did not improve the arrhythmia risk assessment. CONCLUSIONS: Repolarization abnormality plays an important role in generating nVT in patients with HCM, but TWA does not specifically predict the risk of arrhythmic end point.

Sudden death in hypertrophic cardiomyopathy: old risk factors re-assessed in a new model of maximalized follow-up.

AIMS: in hypertrophic cardiomyopathy (HCM), the following five risk factors have a major role in the primary prevention of sudden death (SD): family history of SD (FHSD), syncope, massive wall thickness (MWTh) >30 mm, non-sustained ventricular tachycardia (nsVT) in Holter monitoring of electrocardiography, and abnormal blood pressure response to exercise (aBPRE). In HCM, as a genetic cardiac disease, the risk for SD may also exist from birth. The aim of the study was to compare the survival curves constructed for each of the five risk factors in a traditional follow-up model (started at the first presentation of a patient at the institution) and in a novel follow-up model (started at the date of birth). In an additional analysis, we compared the survival rate in three subgroups (without FHSD, with one SD, and with two or more SDs in a family). METHODS AND RESULTS: a total of 1306 consecutive HCM patients (705 males, 601 females, mean age of 47 years, and 193 patients were <18 years) evaluated at 15 referral centres in Poland were enrolled in the study. In a novel method of follow-up, all the five risk factors confirmed its prognostic power (FHSD: P = 0.0007; nsVT: P < 0.0001; aBPRE: P = 0.0081; syncope: P < 0.0001; MWTh P> 0.0001), whereas in a traditional method, only four factors predicted SD (except aBPRE). In a novel model of follow-up, FHSD in a single episode starts to influence the prognosis with a delay to the fifth decade of life (P = 0.0007). Multiple FHSD appears to be a very powerful risk factor (P < 0.0001), predicting frequent SDs in childhood and adolescence. CONCLUSION: the proposed concept of a lifelong calculated follow-up is a useful strategy in the risk stratification of SD. Multiple FHSD is a very ominous risk factor with strong impact, predicting frequent SD episodes in the early period of life.

Endothelium-dependent and -independent vasodilation is more attenuated in ischaemic than in non-ischaemic heart failure.

AIMS: Endothelial dysfunction in chronic heart failure (CHF) contributes to vasoconstriction. Underlying atherosclerosis may increase vascular abnormalities in ischaemic CHF. We aimed to compare flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD) of the brachial artery between patients with ischaemic and non-ischaemic CHF. METHODS AND RESULTS: A total of 57 patients with systolic CHF participated in the study (mean age 59 +/- 8 years, 81% male). Patients were in stable NYHA class II (40 patients, 70%) and III (17 patients, 30%). Ischaemic aetiology of CHF was confirmed by coronary angiography in 34 (60%) patients and ruled out in 23 (40%). Flow-mediated dilation and NMD of the brachial artery was assessed by high-resolution ultrasound. Endothelium-dependent vasodilation was markedly reduced in patients with ischaemic CHF compared with those with non-ischaemic aetiology of CHF-mean absolute change in artery diameter (Deltad) 0.09 +/- 0.07 mm in ischaemic group vs. 0.18 +/- 0.07 mm in non-ischaemic (P < 0.0001). Nitroglycerin-mediated vasodilation was also significantly different-Deltad = 0.14 +/- 0.06 mm in ischaemic vs. 0.31 +/- 0.10 mm in non-ischaemic CHF (P < 0.0001). CONCLUSION: Endothelium-dependent and -independent vascular response is more attenuated in ischaemic than in non-ischaemic CHF.

Selected mutations in the myosin binding protein C gene in the Polish population of patients with hypertrophic cardiomyopathy.

BACKGROUND: Mutations in the gene of myosin binding protein C (MYBPC3) are currently considered the most frequent cause of hypertrophic cardiomyopathy (HCM). AIM: To assess the frequency of selected mutations in MYBPC3 in the Polish population of HCM patients. METHODS: One hundred eighteen patients with HCM and 118 healthy, age and sex-matched controls were screened for the presence of 14 mutations of MYBPC3 using real time polymerase chain reaction. RESULTS: Five different mutations were found in six patients in the HCM group whereas no mutations were present in the control group. In three cases the mutations were missense (Arg502Gln, Cys566Arg, Asn755Lys) and in three cases terminal (Gln425ter, Gln1061ter in two unrelated probands). CONCLUSION: Mutations in MYBPC3 should be considered a frequent cause of HCM in Poland.

[Cardiotoxic properties of interferon: aggravation of atrio-ventricular block during treatment of chronic hepatitis C with peginterferon--a case report]. / Kardiotoksyczne dzialanie interferonu: Opis przypadku nasilenia zaburzen przewodzenia przedsionkowo-komorowego w czasie leczenia przewleklego zapalenia watroby typu C interferonem pegylowanym.

The authors reviewed cardiac adverse events during interferon therapy. The significance of preexisting cardiac disease (coronary artery disease, heart failure or cardiac arrhythmias) should be considered in patient selection for this treatment. A case of a 55-year old woman with chronic hepatitis C, qualified to peginterferon therapy in our hospital, is presented. No cardiac diseases were diagnosed in this patient previously. Atrio-ventricular (AV) conduction disturbances in the form of second-degree AV block were diagnosed during peginterferon therapy. The intensity of these disturbances diminished when treatment was interrupted. A pacemaker had to be implanted to enable the patient continuation of treatment without these side effects.

Doxorubicin-induced ventricular arrhythmia treated by implantation of an automatic cardioverter-defibrillator.

Anthracyclines are a group of potent antitumour agents and cardiotoxicity is an important factor limiting their therapeutic effectiveness. Although cardiomyopathy is the most widely recognized type of cardiotoxic reaction, early arrhythmia following anthracycline administration may be of clinical significance as well. We report a case of ventricular tachycardia causing cardiac arrest in a female treated with doxorubicin as adjuvant therapy of breast cancer. Due to recurrence of the arrhythmia and a desire to continue chemotherapy, an automatic cardioverter-defibrillator was implanted with excellent effect.

Elderly and patients with sick sinus syndrome have lower chances for appropriate pacemaker mode selection, according to the Polish Cardiac Society recommendations -- a single-centre retrospective analysis.

BACKGROUND: The Polish Cardiac Society recommendations for permanent heart pacing have been valid since 1999. The clinical use of these guidelines is, however, still limited. AIM: To analyse whether the chosen pacing strategy is consistent with the Polish Cardiac Society recommendations and to estimate the effects of analysed factors on selecting optimal or suboptimal pacing modes. METHOD: Retrospective analysis of medical records and procedure protocols of 1052 patients who underwent pacemaker implantation between 1 January 2000 and 31 December 2004 was performed. In each case, the applied pacing mode was compared against the optimal one defined according to the guidelines of the Polish Cardiac Society. A number of demographic and clinical factors associated with the procedure were analysed and correlated with the optimal pacing mode selection. RESULTS: During the analysed period, 59.3% of patients received optimal pacing. The percentage of patients with optimal pacing increased in the consecutive years from 40.2% in 2000 to 68.5% in 2005. In a univariate regression analysis, patients above the age of 70 years, with sick sinus syndrome as an indication for pacing, as well as cardiac heart failure and obesity, received optimal pacing significantly less frequently. In a multivariate analysis, advanced age and sick sinus syndrome were found to be independent predictors of suboptimal pacing. CONCLUSIONS: About 60% of patients had their pacemakers implanted with the optimal pacing mode selection according to the valid recommendations. Patients over the age of 70 years, as well as patients with sick sinus syndrome, had significantly lower chances of receiving optimal pacing.

Protease inhibitor leupeptin attenuates myocardial stunning in rat heart.

BACKGROUND: In order to test the hypothesis that cardiac protein degradation contributes to the pathogenesis of myocardial stunning, the effect of protease inhibitor leupeptin on the postischemic hemodynamics and metabolic functioning was measured in isolated rat hearts. MATERIAL/METHODS: Isolated rat hearts were perfused in Langendorff mode in the presence or absence of leupeptin (10 Kg/ml for 10 min.), and then subjected to 20 min. of normothermic ischemia and 30 min. of reperfusion. Aortic pressure, cardiac output, coronary flow (CF), global oxygen consumption (MVO2), carbon dioxide and [H+] release, and [Ca2+] uptake were investigated. RESULTS: Hearts pretreated with leupeptin exhibited better postischemic return of systolic, diastolic and developed aortic pressure and faster return of CF to preischemic values during reperfusion. MVO2 and CO2 release were lower in this group in the 10th and 15th min. of reperfusion and [Ca2+] uptake higher in the 5th and 15th min. of reperfusion CONCLUSIONS: Leupeptin protects the heart from myocardial stunning, which is consistent with the idea that proteases contribute to the pathogenesis of this phenomenon.

Ischemic preconditioning diminishes oxygen demand and increases coronary flow in the early phase of reperfusion in rat heart.

BACKGROUND: Ischemic preconditioning (IPC) can be defined as an adaptive mechanism induced by a brief period of reversible ischemia increasing the heart's resistance to a subsequent longer period of ischemia. The objective of our research was to describe the effects of IPC on the hemodynamic function and metabolism of the myocardium during postischemic reperfusion. MATERIAL/METHODS: 20 rat hearts were assigned to a preconditioning group (n=10) or to a control group (n=10). Preconditioning was achieved with 5 min. of global ischemia and 10 min. of reperfusion followed by 40 min. of ischemia. We investigated the postischemic recovery of aortic pressure, cardiac output, and coronary flow, as well as oxygen consumption, carbon dioxide release, and [H+] release. RESULTS: No significant intergroup differences in aortic pressure and cardiac output were observed during reperfusion. In both groups, increased coronary flow (greater in the IPC group: 11.4+/-0.6 ml/min. vs 9.1+/-0.5 ml/min. in control group) was observed in the early phase of reperfusion. This was accompanied by a rise in CO2 and [H+] release, which was also greater in the IPC group. Oxygen consumption was significantly lower in the IPC group in the later phase of reperfusion (9.39+/-0.53 vs 11.79+/-0.54 micromol/min/g dry weight), as were CO2 and [H+] release. CONCLUSIONS: IPC diminishes oxygen demand during reperfusion without changing the hemodynamic function considerably. IPC results in a transient increase of coronary flow accompanied by a rise in CO2 and [H+] release.