Relationship of ECG findings to phenotypic expression in patients with hypertrophic cardiomyopathy: a cardiac magnetic resonance study.

BACKGROUND: The 12-lead electrocardiogram (ECG) is considered an essential screening tool for hypertrophic cardiomyopathy (HCM). A vast array of ECG abnormalities has been described in HCM, although their relationship to left ventricle (LV) morphology and degree of hypertrophy appears elusive. Aim of this study was to assess the relationship of ECG patterns with the HCM phenotype assessed according to the novel opportunities offered by cardiac magnetic imaging (CMR). METHODS: CMR and 12-lead ECG were performed in 257 HCM patients. Severity of ECG abnormalities was defined by the sum of 9 criteria: abnormal cardiac rhythm, QRS duration ≥ 100 ms, Romhilt-Estes score ≥ 5, fascicular block (LAHB) and/or bundle-branch block (LBBB or RBBB), ST-T abnormalities, ST-T segment elevation ≥ 0.2 mV, prolonged QTc interval, pathological Q waves, absence of normal Q wave. Four ECG groups were identified: normal (0 criteria); mildly abnormal (1-3 criteria); moderately abnormal (4-6 criteria); markedly abnormal (7-9 criteria). RESULTS: There was a direct relationship between severity of ECG abnormalities and HCM phenotype. LV mass index was normal in most patients with normal ECG and progressively increased with each class of ECG score, from 70.9 ± 18.6g/m(2) in patients with normal ECG to 107.1 ± 55.1g/m(2) among those with markedly abnormal ECG (p=<0.0001). Likewise, the prevalence and extent of late gadolinium enhancement (LGE) increased significantly with the ECG score, from 37% in patients with normal ECG to 93% in patients with markedly abnormal ECG (overall p=0.0012). A normal ECG had a negative predictive accuracy of 96% for markedly increased LV mass (>91 g/m(2) for men and >69 g/m(2) for women), and of 100% for maximum LV thickness ≥ 30 mm. CONCLUSIONS: In a large HCM cohort, the number and severity of ECG abnormalities were directly related to phenotypic expression as revealed by CMR. Although false negative ECG findings remain a challenge in population screenings for HCM, a normal ECG proved effective in ruling out severe LV hypertrophy, suggesting potential implications for long-term follow-up of HCM patients and family members. A simple score for quantification of ECG abnormalities in HCM patients is proposed.

Efficacy of catheter ablation for atrial fibrillation in hypertrophic cardiomyopathy: impact of age, atrial remodelling, and disease progression.

AIMS: In patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF), radiofrequency catheter ablation (RFCA) represents a promising option. However, the predictors of RFCA efficacy remain largely unknown. We assessed the outcome of a multicentre HCM cohort following RFCA for symptomatic AF refractory to medical therapy. METHODS AND RESULTS: Sixty-one patients (age 54 +/- 13 years; time from AF onset 5.7 +/- 5.5 years) with paroxysmal (n = 35; 57%), recent persistent (n = 15; 25%), or long-standing persistent AF (n = 11; 18%) were enrolled. A scheme with pulmonary vein isolation plus linear lesions was employed. Of the 61 patients, 32 (52%) required redo procedures. Antiarrhythmic therapy was maintained in 22 (54%). At the end of a 29 +/- 16 months follow-up, 41 patients (67%) were in sinus rhythm, including 17 of the 19 patients aged < or = 50 years, with marked improvement in New York Heart Association (NYHA) functional class (1.2 +/- 0.5 vs. 1.9 +/- 0.7 at baseline; P < 0.001). In the remaining 20 patients (33%), with AF recurrence, there was less marked, but still significant, improvement following RFCA (NYHA class 1.8 +/- 0.7 vs. 2.3 +/- 0.7 at baseline; P = 0.002). Independent predictors of AF recurrence were increased left atrium volume [hazard ratio (HR) per unit increase 1.009, 95% confidence interval (CI) 1.001-1.018; P = 0.037] and NYHA functional class (HR 2.24, 95% CI 1.16-4.35; P = 0.016). Among 11 genotyped HCM patients (6 with MYBPC3, 2 with MYH7, 1 with MYL2 and 2 with multiple mutations), RFCA success rate was comparable with that of the overall cohort (n = 8; 73%). CONCLUSION: RFCA was successful in restoring long-term sinus rhythm and improving symptomatic status in most HCM patients with refractory AF, including the subset with proven sarcomere gene mutations, although redo procedures were often necessary. Younger HCM patients with small atrial size and mild symptoms proved to be the best RFCA candidates, likely due to lesser degrees of atrial remodelling.