[Verapamil in the cardioversion of atrial fibrillation. Clinical study]. / Il verapamile nella cardioversione della fibrillazione atriale. Studio clinico.

BACKGROUND: Prolonged periods of atrial fibrillation (AF) or high frequency atrial pacing lead to a significant shortening of atrial refractory periods. This time-dependent electric remodelling is reduced significantly by the administration of verapamil. METHODS: The present series consists of 24 patients all suffering from atrial fibrillation (33% acute AF and 66% chronic recurrent AF) admitted to our Cardiology Department (Rome University). Group G1 (13 patients) received i.v. verapamil (50 mg in 500 cc saline solution at 40 ml/hr). Group G2 (11 patients) received amiodarone i.v. (300 mg in bolus form followed by the infusion of 900 mg in 500 cc 5% glucosate solution, 33 ml/hr for 6 hours and subsequently 18 ml/hr). All patients received non-fractionated heparin i.v. at the same time. RESULTS: No statistically significant difference was observed in the percentage of pharmacological cardioversions in the two groups: G1=61% vs G2=54% p=0.94). The patients who were not cardioverted pharmacologically were done so electrically (external DC shock). CONCLUSIONS: Albeit in this small population of patients verapamil proved to possess anti-arrhythmic effects on a par with that of standard amiodarone antiarrhythmic treatment. This antiarrhythmic potential of verapamil should be demonstrated in a broader randomised study.

Electrophysiological instability in the acute phase: prognostic significance of early ventricular fibrillation in acute myocardial infarction.

BACKGROUND: In the prognostic stratification of patients affected by AMI is important to evaluate, besides the assessment of left ventricular function and residual ischemia, the presence of electrophysiological instability. METHODS: We have analysed 15 patients all affected by AMI complicated by early ventricular fibrillation. During the hospital phase we evaluated the E.F.% (ECHO) and the presence of late ventricular potentials (SAECG). After hospital discharge we followed up the patients for 6 months. RESULTS: None of the patients died during the hospital phase while the posthospital cardiac mortality was 20%. The three patients dead during the follow-up had an AMI localized in the anterolateral wall of the left ventricle, an E.F.% less than 40% and LVP positive in the hospital phase. Besides the clinical course was complicated by cardiac failure. CONCLUSIONS: We conclude that these three patients are a "high risk profile subgroup" and should be submitted to extensive evaluation with cardiac catheterization, coronary arteriography and programmed ventricular stimulation.

[The effect of cardiovascular rehabilitation on the variability of the RR cycle after a first uncomplicated acute myocardial infarct]. / Effetto della riabilitazione cardiovascolare sulla variabilità del ciclo RR dopo un primo infarto miocardico acuto non complicato.

BACKGROUND: The aim of this study was to verify the changes in the autonomic balance by means of heart rate variability assessment in patients with myocardial infarction referred for cardiac rehabilitation. METHODS: We studied 122 patients (79 males, 43 females, mean age 56 +/- 5 years), with a first uncomplicated myocardial infarction (anterior 48, thrombolysis 72), Killip class 1, preserved left ventricular function (ejection fraction 49 +/- 6%). All patients were free of inducible residual ischemia. Four weeks after myocardial infarction, patients were randomized into two groups; Group 1 (n = 58) referred for an 8 week cardiac rehabilitation program (scheduled: 24 sessions); Group 2 (n = 64): normal daily physical activity. During a 24-hour Holter ECG monitoring the following parameters were calculated in pharmacological wash-out at randomization (T0) and at the end of cardiac rehabilitation/control period (T1): mean value of RR intervals (RR), its standard deviation (SDNN), pNN50, rMSSD in the time domain; low frequency (LF) and high frequency (HF) value and the LF/HF ratio in the frequency domain. T1-T0 changes in percent values (delta %) were considered and compared between the two groups. RESULTS: Thirty-one patients were excluded from the study either for insufficient adhesion to the cardiac rehabilitation program (< 13 sessions, 22 patients) or recurrent ischemia (3 Group 1 patients and 3 Group 2 patients) and non-assessable 24-hour Holter ECG monitoring (3 patients). Thirty-one Group 1 patients and 60 Group 2 patients completed the study with a first and a second 24-hour Holter ECG monitoring performed at 30 +/- 3 days and 60 +/- 4 days respectively. At the same time an ergospirometric test was performed to evaluate cardiopulmonary function by means of exercise time, maximum oxygen consumption, anaerobic threshold, exercise time at the anaerobic threshold, and maximum oxygen consumption at the anaerobic threshold. Twenty-eight Group 1 patients and 44 Group 2 patients completed the study with a first and a second ergospirometric test. Baseline heart rate variability parameters were comparable in the two groups. During the observation period only in Group 1 patients heart rate variability parameters changed significantly: RR (Group 1 = +18.3 +/- 21.3; Group 2 = +4.2 +/- 5.2, p = 0.000), pNN50 (Group 1 = 45.0 +/- 38.9; Group 2 = +24.2 +/- 34.7, p = 0.011), HF (Group 1 = +81.6 +/- 124; Group 2 = -28.7 +/- 75.4, p = 0.014) and LF/HF ratio (Group 1 = -26.0 +/- 16.1; Group 2 = -4.9 +/- 6.1, p = 0.062). There were no significant differences in SDNN, rMSSD and LF. A linear correlation between delta LF/HF ratio and baseline LF/HF ratio values was found in Group 1 (r = 0.489, p = 0.006), whereas no correlation was found between this parameter and age, ejection fraction, creatine phosphokinase, and infarct localization. Group 1 patients had a significant improvement in exercise tolerance compared to Group 2 patients. CONCLUSIONS: A cardiac rehabilitation program positively modifies the sympatho-vagal balance in patients with uncomplicated myocardial infarction, increasing the parasympathetic tone and exercise tolerance.

[Late ventricular potentials and acute myocardial infarction]. / Potenziali tardivi ventricolari (PT) ed infarto miocardico acuto (IMA).

BACKGROUND: The presence of late ventricular potentials was evaluated in a group of patients following acute myocardial infarction hospitalised in our division. MATERIALS AND METHODS: Recordings were made between the 10th and 12th day of the pathology. The criteria for positivity were the presence of three parameters: QRSD > or = 114 msec, LAS 40 > or = 38 msec, RMS 40 < or = 20 mv. These were present in 21 patients (18 males and 3 females). Inferior acute myocardial infarction (AMI) was found to be present in 15 cases, anterior AMI in 4 cases and AMI with an unspecified localisation in 2 cases. The mean duration of qrsd was 122 msec, the mean duration of low amplitude potentials (LAS 40) were 53.5 msec, the mean amplitude of the last 40 msec (RMS 40 was 8.9 mv). CONCLUSIONS: In conclusion, the authors affirm that late potentials were present in the majority of patients with inferior AMI and the search for the latter represents an important stage in the post-AMI prognostic stratification. Delta is the positive correlation between late potentials and ventricular tachycardia in postinfarction. This non-invasive test is comparable to electrophysiological induction tests in terms of predictive capacity of arrhythmic event and/or sudden death.

[Acute myocardial infarct and residual ischemia, Study of 35 patients]. / Infarto miocardico acuto ed ischemia residua. Studio di 35 pazienti.

We studied 35 patients (4 females and 31 males) suffering from acute myocardial infarction (AMI) using ergometric tests (ET), ecostress test with Dobutamin (ESD) and coronary angiography within 20 days of the onset of symptoms 5.7% of patients did not show significant coronary lesions. ET was positive in 50% of cases in this group 31.4% of patients were diagnosed with monovessel coronary disease and ET and ESD were positive for residual ischemia in 33.3% of this group. The majority of patients (42.8%) suffered from bivessel coronary disease and ET and ESD were positive for residual ischemia in 45.4% and 53.8% respectively in this group. 20% of patients presented tri-vessel coronary disease and in this group the majority of patients were positive both for ET (83.8%) and ESD (100%). In conclusion, we affirm that the percentage of positivity to challenge tests rose in parallel to the increasing number of diseased vessels, and that ET and ESD are of reciprocal value and both are fundamental in the evaluation of post-infarction residual ischemia.