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We performed signal-averaged electrocardiography and 24-h ambulatory electrocardiographic monitoring in 53 patients with myotonic dystrophy to determine the incidence and clinical significance of ventricular late potentials. Patients were followed up for a mean period of 31 +/- 17 months (range 11-68 months). At entry, none of the patients had bundle branch block on 12-lead electrocardiogram and none had wall motion abnormalities on routine echocardiogram. Also, no patient had history of syncope or clinical evidence of ischemic heart disease or a documented sustained ventricular tachycardia. A group of 47 healthy subjects matched for age and sex also underwent signal-averaged electrocardiography for comparison with the patient group. Late potentials were diagnosed in the presence of at least two of the following measures: duration of the filtered QRS > 114 ms, root-mean-square voltage of the terminal 40 ms of the filtered QRS < 20 microV, and duration of the low-amplitude (< 40 microV) signals of terminal filtered QRS > 38 ms. Late potentials were more frequent in patients than in controls: 18 of the 53 patients (34%) showed late potentials compared with four of the 47 controls (8.5%) (P < 0.01). In 45 patients (85%) no ventricular ectopy (40 cases) or infrequent premature ventricular complexes (five cases) were detected on Holter monitoring. Complex ventricular arrhythmias were traced in the remaining eight patients. These were six of the 18 patients with, and two of the 45 patients without late potentials (33% vs. 6%, respectively; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

We analysed the diagnostic performance of the signal-averaged QRS duration for the detection of left ventricular hypertrophy in 100 consecutive outpatients (62 men and 38 women; mean age, 49.8 +/- 11.8 years) with essential hypertension and compared the results with some of the currently employed electrocardiographic criteria. Forty-eight healthy subjects (24 men and 24 women; mean age, 46.4 +/- 12.1) with normal physical, electrocardiographic and echocardiographic findings served as a control group to derive normal reference values for signal-averaged QRS duration. Twenty-six (26%) hypertensives (22 men and 4 women) had left ventricular hypertrophy echocardiographically defined as a left ventricular mass > or = 261 g in men and > or = 172 g in women or left ventricular mass index > or = 125 g/m2 in men and > or = 112 g/m2 in women. The signal-averaged QRS duration was different in patients with than in those without left ventricular hypertrophy (102.1 +/- 10.8 vs. 95.8 +/- 8.4 ms; P < 0.01). Also, in the group with left ventricular hypertrophy QRS duration was longer, although not significantly different, in men than in women (103.5 +/- 10.7 vs. 94.2 +/- 8.8 ms; P n.s.). The correlation between the signal-averaged QRS duration and left ventricular mass was weak but statistically significant in men (r = 0.34; P < 0.05) in women (r = 0.30; P < 0.05) and in men and women together (r = 0.42; P < 0.01). Partition values of filtered QRS duration > or = 114 ms in men and > or = 107 ms in women were used to diagnose left ventricular hypertrophy as these values were above the upper limits in our control men and women when 95% confidence intervals were calculated. These criteria were insensitive (12%) but highly specific (99%) for left ventricular hypertrophy. The use of a single threshold value of filtered QRS duration > or = 111 ms in both sexes combined improved sensitivity modestly (15%) while maintaining a good specificity (95%). Also, we tested the following standard electrocardiographic criteria: the Sokolow-Lyon index, the Romhilt-Estes point score > or = 4 points and > or = 5 points, the Cornell voltage criteria, the sum of QRS voltages in all 12 leads > 175 mm, and the QRS duration > 90 ms. Sensitivities ranged from 4% to 58% and specificities from 74% to 99%.(ABSTRACT TRUNCATED AT 400 WORDS)

We performed exercise testing, 24-h ambulatory blood pressure monitoring and echocardiography in 37 selected patients with borderline hypertension (24 men and 13 women, mean age 39.8 years, range 23-50) in an attempt to detect early cardiovascular changes that could predict future established hypertension. All subjects were clinically reinvestigated after a mean period of 28 +/- 4 months. At entry 24/37 (65%) showed an exaggerated blood pressure response to exercise (systolic pressure > or = 220 mmHg and/or diastolic pressure > or = 105 mmHg) while 13 (35%) had a normal pressure response. Patients with exaggerated pressure response showed significantly higher left ventricular mass index in comparison to those with normal pressure response (98.1 +/- 10.7 vs. 84 +/- 13, respectively; P < 0.05). They also had higher, although not significantly different, average 24-h systolic and diastolic blood pressure levels. At follow up seven subjects (16%) were diagnosed as having established hypertension, while 30 (84%) remained borderline hypertensives. No subject was judged normotensive. All of the seven hypertensive subjects were a proportion (7/24 = 29%) of the group with exaggerated blood pressure response to exercise. Also, they were the eldest of the total group of borderlines (mean age 44 years) and had the highest left ventricular mass index (100.6 +/- 13 g/m2). Borderline hypertensives show a spectrum of cardiovascular changes that could be considered as a part of the hypertensive risk profile. However, there are no specific characteristics that reliably distinguish subjects prone to develop hypertension. Repeated clinical observations and correct measurements of resting blood pressure may have greater relevance in the management of patients with borderline hypertension.

We analysed the performance of the electrocardiogram in diagnosing left ventricular hypertrophy in 70 patients with isolated left anterior hemiblock and in 75 patients with right bundle branch block, either isolated (44 cases) or associated (31 cases) with left anterior hemiblock. Left ventricular hypertrophy defined as an echocardiographically determined left ventricular mass greater than 261 g in men and 172 g in women or left ventricular mass index greater than 125 g/m2 in men and 112 g/m2 in women was present in 48 subjects (57%) with isolated left anterior hemiblock and 33 subjects (44%) with right bundle branch block. In patients with isolated left anterior hemiblock the best results were obtained using the SV1 or SV2 + (RV6 + SV6) greater than 25 mm with 74% in sensitivity and 67% in specificity; the criterion SIII + (R + S) maximal in a precordial lead greater than or equal to 30 mm showed a sensitivity of 74% but a specificity of 47%. In the whole group of patients with right bundle branch block none of the criteria nor combination of criteria achieved an acceptable performance (sensitivities ranged from 17% to 41% and specificities ranged from 54% to 85%). When these patients were divided according to the presence or absence of concomitant left anterior hemiblock the electrocardiographic indexes mostly showed, in comparison to whole group, higher values in sensitivity and lower values in specificity in right bundle branch block plus left anterior hemiblock and an opposite behaviour in isolated right bundle branch block.(ABSTRACT TRUNCATED AT 250 WORDS)

We assessed the reliability of multiple electrocardiographic variables for detecting left ventricular hypertrophy in 100 patients (aged 23 to 92 years, mean age 39 +/- 14) with complete left bundle branch block and different underlying cardiac diseases. Left ventricular hypertrophy, defined as an echocardiographically evaluated left ventricular mass greater than 241 g, was present in 66 of the 100 patients. The electrocardiographic parameters with the highest sensitivity were both the Cornell voltage criteria (RaVL + SV3 greater than 28 mm in men and greater than 20 mm in women) and the combination of criteria proposed by Kafka (any of these four indexes: RaVL greater than or equal to 11 mm, QRS axis -40 degrees or less, SV1 + RV5 or RV6 greater than or equal to 40 mm, SV2 greater than or equal to 30 mm and SV3 greater than or equal to 25 mm), with a sensitivity of 77%. Both criteria had a very low specificity (32 and 35%, respectively). The high specificities (greater than or equal to 88%) of several electrocardiographic criteria were accompanied by ineffective low sensitivities (less than 35%). Moreover, the cumulative parameters of Kafka and Cornell voltage criteria achieved a sensitivity of 84 and 89%, respectively, in hypertensive patients and in those with valvar diseases. None of the electrocardiographic indexes tested showed a significant difference in sensitivity when applied in categories of patients with left ventricular hypertrophy and different left ventricular geometry (cavity dilation or concentric hypertrophy). These data indicate that both conventional and recently proposed electrocardiographic criteria for left ventricular hypertrophy in the presence of left bundle branch block poorly recognize an augmented left ventricular mass.